[PATCH 1/9] virtio: align virtio_config_ops::generation return type with Linux

[PATCH 1/9] virtio: align virtio_config_ops::generation return type with Linux

[Ahmad Fatoum]

The U-Boot return type for the function differs from Linux. We use
the Linux API elsewhere, so use it here as well.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/virtio/virtio_mmio.c  | 8 +++-----
 include/linux/virtio_config.h | 9 ++++-----
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 821b43871a04..4a689495b8df 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -141,16 +141,14 @@ static int virtio_mmio_set_config(struct virtio_device *vdev, unsigned int offse
 	return 0;
 }
 
-static int virtio_mmio_generation(struct virtio_device *vdev, u32 *counter)
+static u32 virtio_mmio_generation(struct virtio_device *vdev)
 {
 	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
 
 	if (priv->version == 1)
-		*counter = 0;
-	else
-		*counter = readl(priv->base + VIRTIO_MMIO_CONFIG_GENERATION);
+		return 0;
 
-	return 0;
+	return readl(priv->base + VIRTIO_MMIO_CONFIG_GENERATION);
 }
 
 static int virtio_mmio_get_status(struct virtio_device *vdev)
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 5ee0807fb098..3ed7001f4800 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -49,10 +49,9 @@ struct virtio_config_ops {
 	 * generation() - config generation counter
 	 *
 	 * @vdev:	the real virtio device
-	 * @counter:	the returned config generation counter
-	 * @return 0 if OK, -ve on error
+	 * @return the config generation counter
 	 */
-	int (*generation)(struct virtio_device *vdev, u32 *counter);
+	u32 (*generation)(struct virtio_device *vdev);
 	/**
 	 * get_status() - read the status byte
 	 *
@@ -311,7 +310,7 @@ static inline void __virtio_cread_many(struct virtio_device *vdev,
 	int i;
 
 	/* no need to check return value as generation can be optional */
-	vdev->config->generation(vdev, &gen);
+	gen = vdev->config->generation(vdev);
 	do {
 		old = gen;
 
@@ -319,7 +318,7 @@ static inline void __virtio_cread_many(struct virtio_device *vdev,
 			virtio_get_config(vdev, offset + bytes * i,
 					  buf + i * bytes, bytes);
 
-		vdev->config->generation(vdev, &gen);
+		gen = vdev->config->generation(vdev);
 	} while (gen != old);
 }
 
-- 
2.30.0


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[PATCH 2/9] virtio: remove unused, left-over, virtio_config_ops::set_features

[Ahmad Fatoum]

Linux finalize_features was renamed to set_features in the U-Boot port.
We adhere to the Linux naming and set_features is unused anywhere.
Drop it.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 include/linux/virtio_config.h | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 3ed7001f4800..e6fc31f627fc 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -82,13 +82,6 @@ struct virtio_config_ops {
 	 * @return features
 	 */
 	u64 (*get_features)(struct virtio_device *vdev);
-	/**
-	 * set_features() - confirm what device features we'll be using
-	 *
-	 * @vdev:	the real virtio device
-	 * @return 0 if OK, -ve on error
-	 */
-	int (*set_features)(struct virtio_device *vdev);
 	/**
 	 * find_vqs() - find virtqueues and instantiate them
 	 *
-- 
2.30.0


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[PATCH 3/9] hw_random: virtio: simplify code

[Ahmad Fatoum]

The Linux code did a bit more than we do, but after deleting the
unneeded parts virtrng_probe and virtrng_remove do nothing but
call probe_common/remove_common. Drop the intermediate functions.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/hw_random/virtio-rng.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/hw_random/virtio-rng.c b/drivers/hw_random/virtio-rng.c
index fbf1a5715a33..7bdacc976e72 100644
--- a/drivers/hw_random/virtio-rng.c
+++ b/drivers/hw_random/virtio-rng.c
@@ -61,7 +61,7 @@ static int virtio_rng_read(struct hwrng *hwrng, void *data, size_t len, bool wai
 	return len;
 }
 
-static int probe_common(struct virtio_device *vdev)
+static int virtrng_probe(struct virtio_device *vdev)
 {
 	struct virtrng_info *vi;
 
@@ -76,22 +76,12 @@ static int probe_common(struct virtio_device *vdev)
 	return virtio_find_vqs(vdev, 1, &vi->rng_vq);
 }
 
-static void remove_common(struct virtio_device *vdev)
+static void virtrng_remove(struct virtio_device *vdev)
 {
 	vdev->config->reset(vdev);
 	vdev->config->del_vqs(vdev);
 }
 
-static int virtrng_probe(struct virtio_device *vdev)
-{
-	return probe_common(vdev);
-}
-
-static void virtrng_remove(struct virtio_device *vdev)
-{
-	remove_common(vdev);
-}
-
 static void virtrng_scan(struct virtio_device *vdev)
 {
 	struct virtrng_info *vi = vdev->priv;
-- 
2.30.0


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[PATCH 4/9] dma: move dma_map/unmap_single from ARM to common code

[Ahmad Fatoum]

There's nothing ARM specific about these functions. Move them to a
common location, so other arches can use them as well.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 arch/arm/cpu/mmu-common.c | 41 +-------------------------------------
 drivers/dma/Makefile      |  1 +
 drivers/dma/map.c         | 42 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 40 deletions(-)
 create mode 100644 drivers/dma/map.c

diff --git a/arch/arm/cpu/mmu-common.c b/arch/arm/cpu/mmu-common.c
index 287622b20399..5cc5138cfa3d 100644
--- a/arch/arm/cpu/mmu-common.c
+++ b/arch/arm/cpu/mmu-common.c
@@ -10,27 +10,6 @@
 #include <memory.h>
 #include "mmu.h"
 
-
-static inline dma_addr_t cpu_to_dma(struct device_d *dev, unsigned long cpu_addr)
-{
-	dma_addr_t dma_addr = cpu_addr;
-
-	if (dev)
-		dma_addr -= dev->dma_offset;
-
-	return dma_addr;
-}
-
-static inline unsigned long dma_to_cpu(struct device_d *dev, dma_addr_t addr)
-{
-	unsigned long cpu_addr = addr;
-
-	if (dev)
-		cpu_addr += dev->dma_offset;
-
-	return cpu_addr;
-}
-
 void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 			     enum dma_data_direction dir)
 {
@@ -41,24 +20,6 @@ void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 		dma_inv_range((void *)address, size);
 }
 
-dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
-			  enum dma_data_direction dir)
-{
-	unsigned long addr = (unsigned long)ptr;
-
-	dma_sync_single_for_device(addr, size, dir);
-
-	return cpu_to_dma(dev, addr);
-}
-
-void dma_unmap_single(struct device_d *dev, dma_addr_t dma_addr, size_t size,
-		      enum dma_data_direction dir)
-{
-	unsigned long addr = dma_to_cpu(dev, dma_addr);
-
-	dma_sync_single_for_cpu(addr, size, dir);
-}
-
 void *dma_alloc_map(size_t size, dma_addr_t *dma_handle, unsigned flags)
 {
 	void *ret;
@@ -108,4 +69,4 @@ static int mmu_init(void)
 
 	return 0;
 }
-mmu_initcall(mmu_init);
\ No newline at end of file
+mmu_initcall(mmu_init);
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 7a3a3b2bd85d..49d6d6573f4f 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_MXS_APBH_DMA)	+= apbh_dma.o
+obj-$(CONFIG_HAS_DMA)		+= map.o
diff --git a/drivers/dma/map.c b/drivers/dma/map.c
new file mode 100644
index 000000000000..a3e1b3b5b527
--- /dev/null
+++ b/drivers/dma/map.c
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* SPDX-FileCopyrightText: 2012 Marc Kleine-Budde <mkl@pengutronix.de> */
+
+#include <dma.h>
+
+static inline dma_addr_t cpu_to_dma(struct device_d *dev, unsigned long cpu_addr)
+{
+	dma_addr_t dma_addr = cpu_addr;
+
+	if (dev)
+		dma_addr -= dev->dma_offset;
+
+	return dma_addr;
+}
+
+static inline unsigned long dma_to_cpu(struct device_d *dev, dma_addr_t addr)
+{
+	unsigned long cpu_addr = addr;
+
+	if (dev)
+		cpu_addr += dev->dma_offset;
+
+	return cpu_addr;
+}
+
+dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
+			  enum dma_data_direction dir)
+{
+	unsigned long addr = (unsigned long)ptr;
+
+	dma_sync_single_for_device(addr, size, dir);
+
+	return cpu_to_dma(dev, addr);
+}
+
+void dma_unmap_single(struct device_d *dev, dma_addr_t dma_addr, size_t size,
+		      enum dma_data_direction dir)
+{
+	unsigned long addr = dma_to_cpu(dev, dma_addr);
+
+	dma_sync_single_for_cpu(addr, size, dir);
+}
-- 
2.30.0


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[PATCH 5/9] virtio: ring: fix erroneous behavior around caches and MMU

[Ahmad Fatoum]

The U-Boot code assumes 1:1 phys2virt mapping and either disabled
caches or a lot of luck. Use the DMA API to get appropriate addresses
for DMA and use coherent/streaming DMA mappings where appropriate.

This is required for proper operation on MIPS.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/virtio/virtio_ring.c | 98 +++++++++++++++++++++++++++++++-----
 include/linux/virtio_ring.h  |  2 +
 2 files changed, 87 insertions(+), 13 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cac3362e7251..68180fe37da0 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -22,12 +22,45 @@
 #define vq_info(vq, fmt, ...) \
 	dev_info(&vq->vdev->dev, fmt, ##__VA_ARGS__)
 
+static inline struct device_d *vring_dma_dev(const struct virtqueue *vq)
+{
+	return vq->vdev->dev.parent;
+}
+
+/* Map one sg entry. */
+static dma_addr_t vring_map_one_sg(struct virtqueue *vq,
+				   struct virtio_sg *sg,
+				   enum dma_data_direction direction)
+{
+	return dma_map_single(vring_dma_dev(vq), sg->addr, sg->length, direction);
+}
+
+static int vring_mapping_error(struct virtqueue *vq,
+			       dma_addr_t addr)
+{
+	return dma_mapping_error(vring_dma_dev(vq), addr);
+}
+
+static void vring_unmap_one(struct virtqueue *vq,
+			    struct vring_desc *desc)
+{
+	u16 flags;
+
+	flags = virtio16_to_cpu(vq->vdev, desc->flags);
+
+	dma_unmap_single(vring_dma_dev(vq),
+		       virtio64_to_cpu(vq->vdev, desc->addr),
+		       virtio32_to_cpu(vq->vdev, desc->len),
+		       (flags & VRING_DESC_F_WRITE) ?
+		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
+}
+
 int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
 		  unsigned int out_sgs, unsigned int in_sgs)
 {
 	struct vring_desc *desc;
 	unsigned int total_sg = out_sgs + in_sgs;
-	unsigned int i, n, avail, descs_used, uninitialized_var(prev);
+	unsigned int i, err_idx, n, avail, descs_used, uninitialized_var(prev);
 	int head;
 
 	WARN_ON(total_sg == 0);
@@ -53,9 +86,13 @@ int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
 
 	for (n = 0; n < out_sgs; n++) {
 		struct virtio_sg *sg = sgs[n];
+		dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
+		if (vring_mapping_error(vq, addr))
+			goto unmap_release;
+
 
 		desc[i].flags = cpu_to_virtio16(vq->vdev, VRING_DESC_F_NEXT);
-		desc[i].addr = cpu_to_virtio64(vq->vdev, (u64)(size_t)sg->addr);
+		desc[i].addr = cpu_to_virtio64(vq->vdev, addr);
 		desc[i].len = cpu_to_virtio32(vq->vdev, sg->length);
 
 		prev = i;
@@ -63,11 +100,13 @@ int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
 	}
 	for (; n < (out_sgs + in_sgs); n++) {
 		struct virtio_sg *sg = sgs[n];
+		dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE);
+		if (vring_mapping_error(vq, addr))
+			goto unmap_release;
 
 		desc[i].flags = cpu_to_virtio16(vq->vdev, VRING_DESC_F_NEXT |
 						VRING_DESC_F_WRITE);
-		desc[i].addr = cpu_to_virtio64(vq->vdev,
-					       (u64)(uintptr_t)sg->addr);
+		desc[i].addr = cpu_to_virtio64(vq->vdev, addr);
 		desc[i].len = cpu_to_virtio32(vq->vdev, sg->length);
 
 		prev = i;
@@ -106,6 +145,19 @@ int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
 		virtqueue_kick(vq);
 
 	return 0;
+
+unmap_release:
+	err_idx = i;
+
+	for (n = 0; n < total_sg; n++) {
+		if (i == err_idx)
+			break;
+		vring_unmap_one(vq, &desc[i]);
+		i = virtio16_to_cpu(vq->vdev, desc[i].next);
+	}
+
+	return -ENOMEM;
+
 }
 
 static bool virtqueue_kick_prepare(struct virtqueue *vq)
@@ -149,10 +201,12 @@ static void detach_buf(struct virtqueue *vq, unsigned int head)
 	i = head;
 
 	while (vq->vring.desc[i].flags & nextflag) {
+		vring_unmap_one(vq, &vq->vring.desc[i]);
 		i = virtio16_to_cpu(vq->vdev, vq->vring.desc[i].next);
 		vq->num_free++;
 	}
 
+	vring_unmap_one(vq, &vq->vring.desc[i]);
 	vq->vring.desc[i].next = cpu_to_virtio16(vq->vdev, vq->free_head);
 	vq->free_head = head;
 
@@ -225,6 +279,8 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	vq->avail_flags_shadow = 0;
 	vq->avail_idx_shadow = 0;
 	vq->num_added = 0;
+	vq->queue_dma_addr = 0;
+	vq->queue_size_in_bytes = 0;
 	list_add_tail(&vq->list, &vdev->vqs);
 
 	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
@@ -243,12 +299,24 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	return vq;
 }
 
+static void *vring_alloc_queue(size_t size, dma_addr_t *dma_handle)
+{
+	return dma_alloc_coherent(size, dma_handle);
+}
+
+static void vring_free_queue(size_t size, void *queue, dma_addr_t dma_handle)
+{
+	dma_free_coherent(queue, dma_handle, size);
+}
+
 struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
 					 unsigned int vring_align,
 					 struct virtio_device *vdev)
 {
 	struct virtqueue *vq;
 	void *queue = NULL;
+	dma_addr_t dma_addr;
+	size_t queue_size_in_bytes;
 	struct vring vring;
 
 	/* We assume num is a power of 2 */
@@ -259,7 +327,7 @@ struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
 
 	/* TODO: allocate each queue chunk individually */
 	for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
-		queue = memalign(PAGE_SIZE, vring_size(num, vring_align));
+		queue = vring_alloc_queue(vring_size(num, vring_align), &dma_addr);
 		if (queue)
 			break;
 	}
@@ -269,27 +337,31 @@ struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
 
 	if (!queue) {
 		/* Try to get a single page. You are my only hope! */
-		queue = memalign(PAGE_SIZE, vring_size(num, vring_align));
+		queue = vring_alloc_queue(vring_size(num, vring_align), &dma_addr);
 	}
 	if (!queue)
 		return NULL;
 
-	memset(queue, 0, vring_size(num, vring_align));
+	queue_size_in_bytes = vring_size(num, vring_align);
 	vring_init(&vring, num, queue, vring_align);
 
 	vq = __vring_new_virtqueue(index, vring, vdev);
 	if (!vq) {
-		free(queue);
+		vring_free_queue(queue_size_in_bytes, queue, dma_addr);
 		return NULL;
 	}
-	vq_debug(vq, "created vring @ %p for vq with num %u\n", queue, num);
+	vq_debug(vq, "created vring @ (virt=%p, phys=%pad) for vq with num %u\n",
+		 queue, &dma_addr, num);
+
+	vq->queue_dma_addr = dma_addr;
+	vq->queue_size_in_bytes = queue_size_in_bytes;
 
 	return vq;
 }
 
 void vring_del_virtqueue(struct virtqueue *vq)
 {
-	free(vq->vring.desc);
+	vring_free_queue(vq->queue_size_in_bytes, vq->vring.desc, vq->queue_dma_addr);
 	list_del(&vq->list);
 	free(vq);
 }
@@ -301,18 +373,18 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq)
 
 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq)
 {
-	return (dma_addr_t)vq->vring.desc;
+	return vq->queue_dma_addr;
 }
 
 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq)
 {
-	return (dma_addr_t)vq->vring.desc +
+	return vq->queue_dma_addr +
 	       ((char *)vq->vring.avail - (char *)vq->vring.desc);
 }
 
 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq)
 {
-	return (dma_addr_t)vq->vring.desc +
+	return vq->queue_dma_addr +
 	       ((char *)vq->vring.used - (char *)vq->vring.desc);
 }
 
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 3c11592b09e4..c349af90ce50 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -108,6 +108,8 @@ struct virtqueue {
 	u16 last_used_idx;
 	u16 avail_flags_shadow;
 	u16 avail_idx_shadow;
+	dma_addr_t queue_dma_addr;
+	size_t queue_size_in_bytes;
 };
 
 /*
-- 
2.30.0


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[PATCH 6/9] virtio: fix support for big-endian clients

[Ahmad Fatoum]

With virtio 1.0 everything is little endian. Add back the Version 1.0
check that got lost during porting virtio to barebox.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 include/linux/virtio_config.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index e6fc31f627fc..f33cfdacaa2c 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -203,7 +203,8 @@ static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
 
 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
 {
-	return virtio_legacy_is_little_endian();
+	return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
+		virtio_legacy_is_little_endian();
 }
 
 
-- 
2.30.0


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[PATCH 7/9] PCI: port Linux pci_find_capability

[Ahmad Fatoum]

Incomding Linux virtio_pci code uses these functions, so port them over.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/pci/pci.c   | 90 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pci.h |  5 +++
 2 files changed, 95 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7d1024d8d1d2..945a983387ed 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -506,6 +506,96 @@ int pci_enable_device(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_enable_device);
 
+static u8 __pci_find_next_cap_ttl(struct pci_bus *bus, unsigned int devfn,
+				  u8 pos, int cap, int *ttl)
+{
+	u8 id;
+	u16 ent;
+
+	pci_bus_read_config_byte(bus, devfn, pos, &pos);
+
+	while ((*ttl)--) {
+		if (pos < 0x40)
+			break;
+		pos &= ~3;
+		pci_bus_read_config_word(bus, devfn, pos, &ent);
+
+		id = ent & 0xff;
+		if (id == 0xff)
+			break;
+		if (id == cap)
+			return pos;
+		pos = (ent >> 8);
+	}
+	return 0;
+}
+
+static u8 __pci_find_next_cap(struct pci_bus *bus, unsigned int devfn,
+			      u8 pos, int cap)
+{
+	int ttl = PCI_FIND_CAP_TTL;
+
+	return __pci_find_next_cap_ttl(bus, devfn, pos, cap, &ttl);
+}
+
+u8 pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap)
+{
+	return __pci_find_next_cap(dev->bus, dev->devfn,
+				   pos + PCI_CAP_LIST_NEXT, cap);
+}
+EXPORT_SYMBOL_GPL(pci_find_next_capability);
+
+static u8 __pci_bus_find_cap_start(struct pci_bus *bus,
+				    unsigned int devfn, u8 hdr_type)
+{
+	u16 status;
+
+	pci_bus_read_config_word(bus, devfn, PCI_STATUS, &status);
+	if (!(status & PCI_STATUS_CAP_LIST))
+		return 0;
+
+	switch (hdr_type) {
+	case PCI_HEADER_TYPE_NORMAL:
+	case PCI_HEADER_TYPE_BRIDGE:
+		return PCI_CAPABILITY_LIST;
+	case PCI_HEADER_TYPE_CARDBUS:
+		return PCI_CB_CAPABILITY_LIST;
+	}
+
+	return 0;
+}
+
+/**
+ * pci_find_capability - query for devices' capabilities
+ * @dev: PCI device to query
+ * @cap: capability code
+ *
+ * Tell if a device supports a given PCI capability.
+ * Returns the address of the requested capability structure within the
+ * device's PCI configuration space or 0 in case the device does not
+ * support it.  Possible values for @cap include:
+ *
+ *  %PCI_CAP_ID_PM           Power Management
+ *  %PCI_CAP_ID_AGP          Accelerated Graphics Port
+ *  %PCI_CAP_ID_VPD          Vital Product Data
+ *  %PCI_CAP_ID_SLOTID       Slot Identification
+ *  %PCI_CAP_ID_MSI          Message Signalled Interrupts
+ *  %PCI_CAP_ID_CHSWP        CompactPCI HotSwap
+ *  %PCI_CAP_ID_PCIX         PCI-X
+ *  %PCI_CAP_ID_EXP          PCI Express
+ */
+u8 pci_find_capability(struct pci_dev *dev, int cap)
+{
+	u8 pos;
+
+	pos = __pci_bus_find_cap_start(dev->bus, dev->devfn, dev->hdr_type);
+	if (pos)
+		pos = __pci_find_next_cap(dev->bus, dev->devfn, pos, cap);
+
+	return pos;
+}
+EXPORT_SYMBOL(pci_find_capability);
+
 static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
 			  struct pci_fixup *end)
 {
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c742570e3684..0c8fed7c8e0d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -31,6 +31,8 @@
 
 #define PCI_ANY_ID (~0)
 
+#define PCI_FIND_CAP_TTL	48
+
 /*
  * The PCI interface treats multi-function devices as independent
  * devices.  The slot/function address of each device is encoded
@@ -320,6 +322,9 @@ void pci_set_master(struct pci_dev *dev);
 void pci_clear_master(struct pci_dev *dev);
 int pci_enable_device(struct pci_dev *dev);
 
+u8 pci_find_next_capability(struct pci_dev *dev, u8 pos, int cap);
+u8 pci_find_capability(struct pci_dev *dev, int cap);
+
 extern void __iomem *pci_iomap(struct pci_dev *dev, int bar);
 
 /*
-- 
2.30.0


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

[PATCH 8/9] virtio: support virtio-based device drivers over PCI

[Ahmad Fatoum]

This driver provides support for virtio based paravirtual device
drivers over PCI. This is useful with Qemu for boards that barebox
has PCI support for, e.g. MIPS Malta.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 Documentation/user/virtio.rst      |  30 ++-
 drivers/virtio/Kconfig             |  12 +-
 drivers/virtio/Makefile            |   2 +
 drivers/virtio/virtio_pci_common.c |  88 ++++++
 drivers/virtio/virtio_pci_common.h |  64 +++++
 drivers/virtio/virtio_pci_modern.c | 417 +++++++++++++++++++++++++++++
 include/uapi/linux/virtio_pci.h    | 208 ++++++++++++++
 7 files changed, 807 insertions(+), 14 deletions(-)
 create mode 100644 drivers/virtio/virtio_pci_common.c
 create mode 100644 drivers/virtio/virtio_pci_common.h
 create mode 100644 drivers/virtio/virtio_pci_modern.c
 create mode 100644 include/uapi/linux/virtio_pci.h

diff --git a/Documentation/user/virtio.rst b/Documentation/user/virtio.rst
index 5d2a8c8208d8..7e125c0ca839 100644
--- a/Documentation/user/virtio.rst
+++ b/Documentation/user/virtio.rst
@@ -20,7 +20,7 @@ just the guest's device driver "knows" it is running in a virtual environment,
 and cooperates with the hypervisor. This enables guests to get high performance
 network and disk operations, and gives most of the performance benefits of
 paravirtualization. In the barebox case, the guest is barebox itself, while the
-virtual environment will normally be QEMU_ targets like ARM, RISC-V and x86.
+virtual environment will normally be QEMU_ targets like ARM, MIPS, RISC-V or x86.
 
 Status
 ------
@@ -31,8 +31,8 @@ embedded devices models like ARM/RISC-V, which does not normally come with
 PCI support might use simple memory mapped device (MMIO) instead of the PCI
 device. The memory mapped virtio device behaviour is based on the PCI device
 specification. Therefore most operations including device initialization,
-queues configuration and buffer transfers are nearly identical. Only MMIO
-is currently supported in barebox.
+queues configuration and buffer transfers are nearly identical. Both MMIO
+and non-legacy PCI are supported in barebox.
 
 The VirtIO spec defines a lots of VirtIO device types, however at present only
 block, console and RNG devices are supported.
@@ -67,16 +67,20 @@ to pass barebox a fixed-up device tree describing the ``virtio-mmio``
 rings.
 
 Except for the console, multiple instances of a VirtIO device can be created
-by appending more '-device' parameters. For example to create one HWRNG
-and 2 block devices::
-
-  $ qemu-system-arm -m 256M -M virt -nographic                  \
-    	-kernel ./images/barebox-dt-2nd.img                     \
-  	-device virtio-rng-device                               \
-  	-drive if=none,file=/tmp/first.hdimg,format=raw,id=hd0  \
-  	-device virtio-blk-device,drive=hd0		        \
-  	-drive if=none,file=/tmp/second.hdimg,format=raw,id=hd1 \
-  	-device virtio-blk-device,drive=hd1
+by appending more '-device' parameters. For example to extend a MIPS
+malta VM with one HWRNG and 2 block VirtIO PCI devices::
+
+  $ qemu-system-mips -m 256M -M malta -serial stdio         \
+    	-bios ./images/barebox-qemu-malta.img -monitor null \
+  	-device virtio-rng-pci,disable-legacy=on            \
+  	-drive if=none,file=image1.hdimg,format=raw,id=hd0  \
+  	-device virtio-blk-pci,drive=hd0,disable-legacy=on  \
+  	-drive if=none,file=image2.hdimg,format=raw,id=hd1  \
+  	-device virtio-blk-pci,drive=hd1,disable-legacy=on
+
+Note the use of ``disable-legacy=on``. barebox doesn't support legacy
+or transitional VirtIO devices. Some versions of QEMU may need to
+have ``,disable-modern=off`` specfied as well.
 
 .. _VirtIO: http://docs.oasis-open.org/virtio/virtio/v1.0/virtio-v1.0.pdf
 .. _qemu: https://www.qemu.org
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 59e3d3c3f54b..ecf66987b3ed 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -3,7 +3,7 @@ config VIRTIO
 	bool
 	help
 	  This option is selected by any driver which implements the virtio
-	  bus, such as CONFIG_VIRTIO_MMIO.
+	  bus, such as CONFIG_VIRTIO_MMIO, CONFIG_VIRTIO_PCI.
 
 config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
 	bool
@@ -25,4 +25,14 @@ config VIRTIO_MMIO
 	 This drivers provides support for memory mapped virtio
 	 platform device driver. This is usually used with Qemu.
 
+config VIRTIO_PCI
+	tristate "PCI driver for virtio devices"
+	depends on PCI && HAS_DMA
+	select VIRTIO
+	help
+	  This driver provides support for virtio based paravirtual device
+	  drivers over PCI. This requires that your VMM has appropriate PCI
+	  virtio backends.  Most QEMU based VMMs should support these devices
+	  (like KVM or Xen).
+
 endif # VIRTIO_MENU
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 94ff1398fb3c..44d35a13340d 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -1,3 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
+obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
+virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
new file mode 100644
index 000000000000..b0ac8befd49b
--- /dev/null
+++ b/drivers/virtio/virtio_pci_common.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Virtio PCI driver - common functionality for all device versions
+ *
+ * This module allows virtio devices to be used over a virtual PCI device.
+ * This can be used with QEMU based VMMs like KVM or Xen.
+ *
+ * Copyright IBM Corp. 2007
+ * Copyright Red Hat, Inc. 2014
+ *
+ * Authors:
+ *  Anthony Liguori  <aliguori@us.ibm.com>
+ *  Rusty Russell <rusty@rustcorp.com.au>
+ *  Michael S. Tsirkin <mst@redhat.com>
+ */
+
+#include <common.h>
+#include <init.h>
+#include "virtio_pci_common.h"
+
+/* Qumranet donated their vendor ID for devices 0x1000 thru 0x10FF. */
+static const struct pci_device_id virtio_pci_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
+	{ 0 }
+};
+
+static int virtio_pci_probe(struct pci_dev *pci_dev,
+			    const struct pci_device_id *id)
+{
+	struct virtio_pci_device *vp_dev;
+	int rc;
+
+	/* allocate our structure and fill it out */
+	vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
+	if (!vp_dev)
+		return -ENOMEM;
+
+	pci_dev->dev.priv = vp_dev;
+	vp_dev->vdev.dev.parent = &pci_dev->dev;
+	vp_dev->pci_dev = pci_dev;
+
+	/* enable the device */
+	rc = pci_enable_device(pci_dev);
+	if (rc)
+		goto err_enable_device;
+
+	rc = virtio_pci_modern_probe(vp_dev);
+	if (rc == -ENODEV)
+		dev_err(&pci_dev->dev, "Legacy and transitional devices unsupported\n");
+	if (rc)
+		goto err_enable_device;
+
+	pci_set_master(pci_dev);
+
+	rc = register_virtio_device(&vp_dev->vdev);
+	if (rc)
+		goto err_probe;
+
+	return 0;
+
+err_probe:
+	pci_clear_master(pci_dev);
+err_enable_device:
+	kfree(vp_dev);
+	return rc;
+}
+
+static void virtio_pci_remove(struct pci_dev *pci_dev)
+{
+	struct virtio_pci_device *vp_dev = pci_dev->dev.priv;
+
+	unregister_virtio_device(&vp_dev->vdev);
+
+	pci_clear_master(pci_dev);
+}
+
+static struct pci_driver virtio_pci_driver = {
+	.name		= "virtio-pci",
+	.id_table	= virtio_pci_id_table,
+	.probe		= virtio_pci_probe,
+	.remove		= virtio_pci_remove,
+};
+
+device_pci_driver(virtio_pci_driver);
+
+MODULE_AUTHOR("Anthony Liguori <aliguori@us.ibm.com>");
+MODULE_DESCRIPTION("virtio-pci");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
new file mode 100644
index 000000000000..32f0f451ab49
--- /dev/null
+++ b/drivers/virtio/virtio_pci_common.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _DRIVERS_VIRTIO_VIRTIO_PCI_COMMON_H
+#define _DRIVERS_VIRTIO_VIRTIO_PCI_COMMON_H
+/*
+ * Virtio PCI driver - APIs for common functionality for all device versions
+ *
+ * This module allows virtio devices to be used over a virtual PCI device.
+ * This can be used with QEMU based VMMs like KVM or Xen.
+ *
+ * Copyright IBM Corp. 2007
+ * Copyright Red Hat, Inc. 2014
+ *
+ * Authors:
+ *  Anthony Liguori  <aliguori@us.ibm.com>
+ *  Rusty Russell <rusty@rustcorp.com.au>
+ *  Michael S. Tsirkin <mst@redhat.com>
+ */
+
+#include <linux/list.h>
+#include <linux/list.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_pci.h>
+
+struct virtio_pci_vq_info {
+	/* the actual virtqueue */
+	struct virtqueue *vq;
+
+	/* the list node for the virtqueues list */
+	struct list_head node;
+};
+
+/* Our device structure */
+struct virtio_pci_device {
+	struct virtio_device vdev;
+	struct pci_dev *pci_dev;
+
+	/* Modern only fields */
+	/* The IO mapping for the PCI config space (non-legacy mode) */
+	struct virtio_pci_common_cfg __iomem *common;
+	/* Device-specific data (non-legacy mode)  */
+	void __iomem *device;
+	/* Base of vq notifications (non-legacy mode). */
+	void __iomem *notify_base;
+
+	/* So we can sanity-check accesses. */
+	size_t device_len;
+
+	/* Multiply queue_notify_off by this value. (non-legacy mode). */
+	u32 notify_offset_multiplier;
+};
+
+/* Convert a generic virtio device to our structure */
+static inline struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
+{
+	return container_of(vdev, struct virtio_pci_device, vdev);
+}
+
+int virtio_pci_modern_probe(struct virtio_pci_device *);
+
+#endif
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
new file mode 100644
index 000000000000..180c14771aad
--- /dev/null
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -0,0 +1,417 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * VirtIO PCI bus transport driver
+ * Ported from Linux drivers/virtio/virtio_pci*.c
+ */
+
+#include <common.h>
+#include <linux/virtio_types.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/pci.h>
+#include <io.h>
+#include "virtio_pci_common.h"
+
+#define VIRTIO_PCI_DRV_NAME	"virtio-pci.m"
+
+static int virtio_pci_get_config(struct virtio_device *vdev, unsigned int offset,
+				 void *buf, unsigned int len)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u8 b;
+	__le16 w;
+	__le32 l;
+
+	BUG_ON(offset + len > vp_dev->device_len);
+
+	switch (len) {
+	case 1:
+		b = ioread8(vp_dev->device + offset);
+		memcpy(buf, &b, sizeof(b));
+		break;
+	case 2:
+		w = cpu_to_le16(ioread16(vp_dev->device + offset));
+		memcpy(buf, &w, sizeof(w));
+		break;
+	case 4:
+		l = cpu_to_le32(ioread32(vp_dev->device + offset));
+		memcpy(buf, &l, sizeof(l));
+		break;
+	case 8:
+		l = cpu_to_le32(ioread32(vp_dev->device + offset));
+		memcpy(buf, &l, sizeof(l));
+		l = cpu_to_le32(ioread32(vp_dev->device + offset + sizeof(l)));
+		memcpy(buf + sizeof(l), &l, sizeof(l));
+		break;
+	default:
+		WARN_ON(true);
+	}
+
+	return 0;
+}
+
+static int virtio_pci_set_config(struct virtio_device *vdev, unsigned int offset,
+				 const void *buf, unsigned int len)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u8 b;
+	__le16 w;
+	__le32 l;
+
+	WARN_ON(offset + len > vp_dev->device_len);
+
+	switch (len) {
+	case 1:
+		memcpy(&b, buf, sizeof(b));
+		iowrite8(b, vp_dev->device + offset);
+		break;
+	case 2:
+		memcpy(&w, buf, sizeof(w));
+		iowrite16(le16_to_cpu(w), vp_dev->device + offset);
+		break;
+	case 4:
+		memcpy(&l, buf, sizeof(l));
+		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
+		break;
+	case 8:
+		memcpy(&l, buf, sizeof(l));
+		iowrite32(le32_to_cpu(l), vp_dev->device + offset);
+		memcpy(&l, buf + sizeof(l), sizeof(l));
+		iowrite32(le32_to_cpu(l), vp_dev->device + offset + sizeof(l));
+		break;
+	default:
+		WARN_ON(true);
+	}
+
+	return 0;
+}
+
+static u32 virtio_pci_generation(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	return ioread8(&vp_dev->common->config_generation);
+}
+
+static int virtio_pci_get_status(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	return ioread8(&vp_dev->common->device_status);
+}
+
+static int virtio_pci_set_status(struct virtio_device *vdev, u8 status)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	/* We should never be setting status to 0 */
+	WARN_ON(status == 0);
+
+	iowrite8(status, &vp_dev->common->device_status);
+
+	return 0;
+}
+
+static int virtio_pci_reset(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	/* 0 status means a reset */
+	iowrite8(0, &vp_dev->common->device_status);
+
+	/*
+	 * After writing 0 to device_status, the driver MUST wait for a read
+	 * of device_status to return 0 before reinitializing the device.
+	 * This will flush out the status write, and flush in device writes,
+	 * including MSI-X interrupts, if any.
+	 */
+	while (ioread8(&vp_dev->common->device_status))
+		udelay(1000);
+
+	return 0;
+}
+
+static u64 virtio_pci_get_features(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u64 features;
+
+	iowrite32(0, &vp_dev->common->device_feature_select);
+	features = ioread32(&vp_dev->common->device_feature);
+	iowrite32(1, &vp_dev->common->device_feature_select);
+	features |= ((u64)ioread32(&vp_dev->common->device_feature) << 32);
+
+	return features;
+}
+
+static int virtio_pci_set_features(struct virtio_device *vdev)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+
+	if (!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
+		dev_dbg(&vdev->dev, "device uses modern interface but does not have VIRTIO_F_VERSION_1\n");
+		return -EINVAL;
+	}
+
+	iowrite32(0, &vp_dev->common->guest_feature_select);
+	iowrite32((u32)vdev->features, &vp_dev->common->guest_feature);
+	iowrite32(1, &vp_dev->common->guest_feature_select);
+	iowrite32(vdev->features >> 32, &vp_dev->common->guest_feature);
+
+	return 0;
+}
+
+static struct virtqueue *virtio_pci_setup_vq(struct virtio_device *vdev,
+					     unsigned int index)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	struct virtio_pci_common_cfg __iomem *cfg = vp_dev->common;
+	struct virtqueue *vq;
+	u16 num;
+	u64 addr;
+	int err;
+
+	if (index >= ioread16(&cfg->num_queues))
+		return ERR_PTR(-ENOENT);
+
+	/* Select the queue we're interested in */
+	iowrite16(index, &cfg->queue_select);
+
+	/* Check if queue is either not available or already active */
+	num = ioread16(&cfg->queue_size);
+	if (!num || ioread16(&cfg->queue_enable))
+		return ERR_PTR(-ENOENT);
+
+	if (num & (num - 1)) {
+		dev_warn(&vdev->dev, "bad queue size %u", num);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* Create the vring */
+	vq = vring_create_virtqueue(index, num, VIRTIO_PCI_VRING_ALIGN, vdev);
+	if (!vq) {
+		err = -ENOMEM;
+		goto error_available;
+	}
+
+	/* Activate the queue */
+	iowrite16(virtqueue_get_vring_size(vq), &cfg->queue_size);
+
+	addr = virtqueue_get_desc_addr(vq);
+	iowrite32((u32)addr, &cfg->queue_desc_lo);
+	iowrite32(addr >> 32, &cfg->queue_desc_hi);
+
+	addr = virtqueue_get_avail_addr(vq);
+	iowrite32((u32)addr, &cfg->queue_avail_lo);
+	iowrite32(addr >> 32, &cfg->queue_avail_hi);
+
+	addr = virtqueue_get_used_addr(vq);
+	iowrite32((u32)addr, &cfg->queue_used_lo);
+	iowrite32(addr >> 32, &cfg->queue_used_hi);
+
+	iowrite16(1, &cfg->queue_enable);
+
+	return vq;
+
+error_available:
+	return ERR_PTR(err);
+}
+
+static void virtio_pci_del_vq(struct virtqueue *vq)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
+	unsigned int index = vq->index;
+
+	iowrite16(index, &vp_dev->common->queue_select);
+
+	/* Select and deactivate the queue */
+	iowrite16(0, &vp_dev->common->queue_enable);
+
+	vring_del_virtqueue(vq);
+}
+
+static int virtio_pci_del_vqs(struct virtio_device *vdev)
+{
+	struct virtqueue *vq, *n;
+
+	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+		virtio_pci_del_vq(vq);
+
+	return 0;
+}
+
+static int virtio_pci_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
+			       struct virtqueue *vqs[])
+{
+	int i;
+
+	for (i = 0; i < nvqs; ++i) {
+		vqs[i] = virtio_pci_setup_vq(vdev, i);
+		if (IS_ERR(vqs[i])) {
+			virtio_pci_del_vqs(vdev);
+			return PTR_ERR(vqs[i]);
+		}
+	}
+
+	return 0;
+}
+
+static int virtio_pci_notify(struct virtio_device *vdev, struct virtqueue *vq)
+{
+	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
+	u16 off;
+
+	/* Select the queue we're interested in */
+	iowrite16(vq->index, &vp_dev->common->queue_select);
+
+	/* get offset of notification word for this vq */
+	off = ioread16(&vp_dev->common->queue_notify_off);
+
+	/*
+	 * We write the queue's selector into the notification register
+	 * to signal the other end
+	 */
+	iowrite16(vq->index,
+		  vp_dev->notify_base + off * vp_dev->notify_offset_multiplier);
+
+	return 0;
+}
+
+/**
+ * virtio_pci_find_capability - walk capabilities to find device info
+ *
+ * @dev:	the PCI device
+ * @cfg_type:	the VIRTIO_PCI_CAP_* value we seek
+ *
+ * @return offset of the configuration structure
+ */
+static int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type)
+{
+	int pos;
+	int offset;
+	u8 type, bar;
+
+	for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
+	     pos > 0;
+	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
+		offset = pos + offsetof(struct virtio_pci_cap, cfg_type);
+		pci_read_config_byte(dev, offset, &type);
+		offset = pos + offsetof(struct virtio_pci_cap, bar);
+		pci_read_config_byte(dev, offset, &bar);
+
+		/* Ignore structures with reserved BAR values */
+		if (bar > 0x5)
+			continue;
+
+		if (type == cfg_type)
+			return pos;
+	}
+
+	return 0;
+}
+
+/**
+ * virtio_pci_map_capability - map base address of the capability
+ *
+ * @dev:	the PCI device
+ * @off:	offset of the configuration structure
+ *
+ * @return base address of the capability
+ */
+static void __iomem *virtio_pci_map_capability(struct pci_dev *dev, int off)
+{
+	u32 offset;
+	u8 bar;
+
+	if (!off)
+		return NULL;
+
+	offset = off + offsetof(struct virtio_pci_cap, bar);
+	pci_read_config_byte(dev, offset, &bar);
+	offset = off + offsetof(struct virtio_pci_cap, offset);
+	pci_read_config_dword(dev, offset, &offset);
+
+	/*
+	 * TODO: adding 64-bit BAR support
+	 *
+	 * Per spec, the BAR is permitted to be either 32-bit or 64-bit.
+	 * For simplicity, only read the BAR address as 32-bit.
+	 */
+
+        return pci_iomap(dev, bar) + offset;
+}
+
+static const struct virtio_config_ops virtio_pci_config_ops = {
+	.get_config	= virtio_pci_get_config,
+	.set_config	= virtio_pci_set_config,
+	.generation	= virtio_pci_generation,
+	.get_status	= virtio_pci_get_status,
+	.set_status	= virtio_pci_set_status,
+	.reset		= virtio_pci_reset,
+	.get_features	= virtio_pci_get_features,
+	.finalize_features	= virtio_pci_set_features,
+	.find_vqs	= virtio_pci_find_vqs,
+	.del_vqs	= virtio_pci_del_vqs,
+	.notify		= virtio_pci_notify,
+};
+
+int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
+{
+	struct pci_dev *pci_dev = vp_dev->pci_dev;
+	struct device_d *dev = &pci_dev->dev;
+	int common, notify, device;
+	int offset;
+
+	/*
+	 * We only own devices >= 0x1000 and <= 0x107f. We don't support
+	 * transitional devices, so start at 0x1040 and leave the rest.
+	 */
+	if (pci_dev->device < 0x1040 || pci_dev->device > 0x107f)
+		return -ENODEV;
+
+	/* Modern devices: simply use PCI device id, but start from 0x1040. */
+	vp_dev->vdev.id.device = pci_dev->device - 0x1040;
+	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
+
+	/* Check for a common config: if not, driver could fall back to legacy mode (bar 0) */
+	common = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG);
+	if (!common)
+		return -ENODEV;
+
+	/* If common is there, notify should be too */
+	notify = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_NOTIFY_CFG);
+	if (!notify) {
+		dev_warn(dev, "missing capabilities %i/%i\n", common, notify);
+		return -EINVAL;
+	}
+
+	/*
+	 * Device capability is only mandatory for devices that have
+	 * device-specific configuration.
+	 */
+	device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG);
+	if (device) {
+		offset = notify + offsetof(struct virtio_pci_cap, length);
+		pci_read_config_dword(pci_dev, offset, &vp_dev->device_len);
+	}
+
+	/* Map configuration structures */
+	vp_dev->common = virtio_pci_map_capability(pci_dev, common);
+	vp_dev->notify_base = virtio_pci_map_capability(pci_dev, notify);
+	vp_dev->device = virtio_pci_map_capability(pci_dev, device);
+	dev_dbg(dev, "common @ %p, notify base @ %p, device @ %p\n",
+		vp_dev->common, vp_dev->notify_base, vp_dev->device);
+
+	/* Read notify_off_multiplier from config space */
+	offset = notify + offsetof(struct virtio_pci_notify_cap,
+				   notify_off_multiplier);
+	pci_read_config_dword(pci_dev, offset, &vp_dev->notify_offset_multiplier);
+
+	vp_dev->vdev.config = &virtio_pci_config_ops;
+
+	return 0;
+}
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
new file mode 100644
index 000000000000..3a86f36d7e3d
--- /dev/null
+++ b/include/uapi/linux/virtio_pci.h
@@ -0,0 +1,208 @@
+/*
+ * Virtio PCI driver
+ *
+ * This module allows virtio devices to be used over a virtual PCI device.
+ * This can be used with QEMU based VMMs like KVM or Xen.
+ *
+ * Copyright IBM Corp. 2007
+ *
+ * Authors:
+ *  Anthony Liguori  <aliguori@us.ibm.com>
+ *
+ * This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_VIRTIO_PCI_H
+#define _LINUX_VIRTIO_PCI_H
+
+#include <linux/types.h>
+
+#ifndef VIRTIO_PCI_NO_LEGACY
+
+/* A 32-bit r/o bitmask of the features supported by the host */
+#define VIRTIO_PCI_HOST_FEATURES	0
+
+/* A 32-bit r/w bitmask of features activated by the guest */
+#define VIRTIO_PCI_GUEST_FEATURES	4
+
+/* A 32-bit r/w PFN for the currently selected queue */
+#define VIRTIO_PCI_QUEUE_PFN		8
+
+/* A 16-bit r/o queue size for the currently selected queue */
+#define VIRTIO_PCI_QUEUE_NUM		12
+
+/* A 16-bit r/w queue selector */
+#define VIRTIO_PCI_QUEUE_SEL		14
+
+/* A 16-bit r/w queue notifier */
+#define VIRTIO_PCI_QUEUE_NOTIFY		16
+
+/* An 8-bit device status register.  */
+#define VIRTIO_PCI_STATUS		18
+
+/* An 8-bit r/o interrupt status register.  Reading the value will return the
+ * current contents of the ISR and will also clear it.  This is effectively
+ * a read-and-acknowledge. */
+#define VIRTIO_PCI_ISR			19
+
+/* MSI-X registers: only enabled if MSI-X is enabled. */
+/* A 16-bit vector for configuration changes. */
+#define VIRTIO_MSI_CONFIG_VECTOR        20
+/* A 16-bit vector for selected queue notifications. */
+#define VIRTIO_MSI_QUEUE_VECTOR         22
+
+/* The remaining space is defined by each driver as the per-driver
+ * configuration space */
+#define VIRTIO_PCI_CONFIG_OFF(msix_enabled)	((msix_enabled) ? 24 : 20)
+/* Deprecated: please use VIRTIO_PCI_CONFIG_OFF instead */
+#define VIRTIO_PCI_CONFIG(dev)	VIRTIO_PCI_CONFIG_OFF((dev)->msix_enabled)
+
+/* Virtio ABI version, this must match exactly */
+#define VIRTIO_PCI_ABI_VERSION		0
+
+/* How many bits to shift physical queue address written to QUEUE_PFN.
+ * 12 is historical, and due to x86 page size. */
+#define VIRTIO_PCI_QUEUE_ADDR_SHIFT	12
+
+/* The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize again. */
+#define VIRTIO_PCI_VRING_ALIGN		4096
+
+#endif /* VIRTIO_PCI_NO_LEGACY */
+
+/* The bit of the ISR which indicates a device configuration change. */
+#define VIRTIO_PCI_ISR_CONFIG		0x2
+/* Vector value used to disable MSI for queue */
+#define VIRTIO_MSI_NO_VECTOR            0xffff
+
+#ifndef VIRTIO_PCI_NO_MODERN
+
+/* IDs for different capabilities.  Must all exist. */
+
+/* Common configuration */
+#define VIRTIO_PCI_CAP_COMMON_CFG	1
+/* Notifications */
+#define VIRTIO_PCI_CAP_NOTIFY_CFG	2
+/* ISR access */
+#define VIRTIO_PCI_CAP_ISR_CFG		3
+/* Device specific configuration */
+#define VIRTIO_PCI_CAP_DEVICE_CFG	4
+/* PCI configuration access */
+#define VIRTIO_PCI_CAP_PCI_CFG		5
+/* Additional shared memory capability */
+#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
+
+/* This is the PCI capability header: */
+struct virtio_pci_cap {
+	__u8 cap_vndr;		/* Generic PCI field: PCI_CAP_ID_VNDR */
+	__u8 cap_next;		/* Generic PCI field: next ptr. */
+	__u8 cap_len;		/* Generic PCI field: capability length */
+	__u8 cfg_type;		/* Identifies the structure. */
+	__u8 bar;		/* Where to find it. */
+	__u8 id;		/* Multiple capabilities of the same type */
+	__u8 padding[2];	/* Pad to full dword. */
+	__le32 offset;		/* Offset within bar. */
+	__le32 length;		/* Length of the structure, in bytes. */
+};
+
+struct virtio_pci_cap64 {
+	struct virtio_pci_cap cap;
+	__le32 offset_hi;             /* Most sig 32 bits of offset */
+	__le32 length_hi;             /* Most sig 32 bits of length */
+};
+
+struct virtio_pci_notify_cap {
+	struct virtio_pci_cap cap;
+	__le32 notify_off_multiplier;	/* Multiplier for queue_notify_off. */
+};
+
+/* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */
+struct virtio_pci_common_cfg {
+	/* About the whole device. */
+	__le32 device_feature_select;	/* read-write */
+	__le32 device_feature;		/* read-only */
+	__le32 guest_feature_select;	/* read-write */
+	__le32 guest_feature;		/* read-write */
+	__le16 msix_config;		/* read-write */
+	__le16 num_queues;		/* read-only */
+	__u8 device_status;		/* read-write */
+	__u8 config_generation;		/* read-only */
+
+	/* About a specific virtqueue. */
+	__le16 queue_select;		/* read-write */
+	__le16 queue_size;		/* read-write, power of 2. */
+	__le16 queue_msix_vector;	/* read-write */
+	__le16 queue_enable;		/* read-write */
+	__le16 queue_notify_off;	/* read-only */
+	__le32 queue_desc_lo;		/* read-write */
+	__le32 queue_desc_hi;		/* read-write */
+	__le32 queue_avail_lo;		/* read-write */
+	__le32 queue_avail_hi;		/* read-write */
+	__le32 queue_used_lo;		/* read-write */
+	__le32 queue_used_hi;		/* read-write */
+};
+
+/* Fields in VIRTIO_PCI_CAP_PCI_CFG: */
+struct virtio_pci_cfg_cap {
+	struct virtio_pci_cap cap;
+	__u8 pci_cfg_data[4]; /* Data for BAR access. */
+};
+
+/* Macro versions of offsets for the Old Timers! */
+#define VIRTIO_PCI_CAP_VNDR		0
+#define VIRTIO_PCI_CAP_NEXT		1
+#define VIRTIO_PCI_CAP_LEN		2
+#define VIRTIO_PCI_CAP_CFG_TYPE		3
+#define VIRTIO_PCI_CAP_BAR		4
+#define VIRTIO_PCI_CAP_OFFSET		8
+#define VIRTIO_PCI_CAP_LENGTH		12
+
+#define VIRTIO_PCI_NOTIFY_CAP_MULT	16
+
+#define VIRTIO_PCI_COMMON_DFSELECT	0
+#define VIRTIO_PCI_COMMON_DF		4
+#define VIRTIO_PCI_COMMON_GFSELECT	8
+#define VIRTIO_PCI_COMMON_GF		12
+#define VIRTIO_PCI_COMMON_MSIX		16
+#define VIRTIO_PCI_COMMON_NUMQ		18
+#define VIRTIO_PCI_COMMON_STATUS	20
+#define VIRTIO_PCI_COMMON_CFGGENERATION	21
+#define VIRTIO_PCI_COMMON_Q_SELECT	22
+#define VIRTIO_PCI_COMMON_Q_SIZE	24
+#define VIRTIO_PCI_COMMON_Q_MSIX	26
+#define VIRTIO_PCI_COMMON_Q_ENABLE	28
+#define VIRTIO_PCI_COMMON_Q_NOFF	30
+#define VIRTIO_PCI_COMMON_Q_DESCLO	32
+#define VIRTIO_PCI_COMMON_Q_DESCHI	36
+#define VIRTIO_PCI_COMMON_Q_AVAILLO	40
+#define VIRTIO_PCI_COMMON_Q_AVAILHI	44
+#define VIRTIO_PCI_COMMON_Q_USEDLO	48
+#define VIRTIO_PCI_COMMON_Q_USEDHI	52
+
+#endif /* VIRTIO_PCI_NO_MODERN */
+
+#endif
-- 
2.30.0


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[PATCH 9/9] virtio: virtio-pci: restrict MIPS support to MMU configuration

[Ahmad Fatoum]

MMU-less MIPS doesn't play along nicely with VIRTIO_PCI.
e.g. Reading from a virtio-rng, will return clearly bogus data.
Document this in the Kconfig, so no one else trips over this.

Eventually, this should be fixed..

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
 drivers/virtio/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index ecf66987b3ed..91a89d3e1b89 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -28,6 +28,7 @@ config VIRTIO_MMIO
 config VIRTIO_PCI
 	tristate "PCI driver for virtio devices"
 	depends on PCI && HAS_DMA
+	depends on MMU && MIPS || !MIPS
 	select VIRTIO
 	help
 	  This driver provides support for virtio based paravirtual device
-- 
2.30.0


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Re: [PATCH 1/9] virtio: align virtio_config_ops::generation return type with Linux

[Sascha Hauer]

On Sun, Feb 28, 2021 at 08:08:28PM +0100, Ahmad Fatoum wrote:
> The U-Boot return type for the function differs from Linux. We use
> the Linux API elsewhere, so use it here as well.
> 
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
>  drivers/virtio/virtio_mmio.c  | 8 +++-----
>  include/linux/virtio_config.h | 9 ++++-----
>  2 files changed, 7 insertions(+), 10 deletions(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 821b43871a04..4a689495b8df 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -141,16 +141,14 @@ static int virtio_mmio_set_config(struct virtio_device *vdev, unsigned int offse
>  	return 0;
>  }
>  
> -static int virtio_mmio_generation(struct virtio_device *vdev, u32 *counter)
> +static u32 virtio_mmio_generation(struct virtio_device *vdev)
>  {
>  	struct virtio_mmio_device *priv = to_virtio_mmio_device(vdev);
>  
>  	if (priv->version == 1)
> -		*counter = 0;
> -	else
> -		*counter = readl(priv->base + VIRTIO_MMIO_CONFIG_GENERATION);
> +		return 0;
>  
> -	return 0;
> +	return readl(priv->base + VIRTIO_MMIO_CONFIG_GENERATION);
>  }
>  
>  static int virtio_mmio_get_status(struct virtio_device *vdev)
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 5ee0807fb098..3ed7001f4800 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -49,10 +49,9 @@ struct virtio_config_ops {
>  	 * generation() - config generation counter
>  	 *
>  	 * @vdev:	the real virtio device
> -	 * @counter:	the returned config generation counter
> -	 * @return 0 if OK, -ve on error
> +	 * @return the config generation counter
>  	 */
> -	int (*generation)(struct virtio_device *vdev, u32 *counter);
> +	u32 (*generation)(struct virtio_device *vdev);
>  	/**
>  	 * get_status() - read the status byte
>  	 *
> @@ -311,7 +310,7 @@ static inline void __virtio_cread_many(struct virtio_device *vdev,
>  	int i;
>  
>  	/* no need to check return value as generation can be optional */
> -	vdev->config->generation(vdev, &gen);
> +	gen = vdev->config->generation(vdev);
>  	do {
>  		old = gen;
>  
> @@ -319,7 +318,7 @@ static inline void __virtio_cread_many(struct virtio_device *vdev,
>  			virtio_get_config(vdev, offset + bytes * i,
>  					  buf + i * bytes, bytes);
>  
> -		vdev->config->generation(vdev, &gen);
> +		gen = vdev->config->generation(vdev);
>  	} while (gen != old);
>  }
>  
> -- 
> 2.30.0
> 
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

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Re: [PATCH 9/9] virtio: virtio-pci: restrict MIPS support to MMU configuration

[Antony Pavlov]

On Sun, 28 Feb 2021 20:08:36 +0100
Ahmad Fatoum <ahmad@a3f.at> wrote:

Hi!

> MMU-less MIPS doesn't play along nicely with VIRTIO_PCI.
> e.g. Reading from a virtio-rng, will return clearly bogus data.
> Document this in the Kconfig, so no one else trips over this.
> 
> Eventually, this should be fixed..


Please describe, how can I reproduce the problem.


> 
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
>  drivers/virtio/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> index ecf66987b3ed..91a89d3e1b89 100644
> --- a/drivers/virtio/Kconfig
> +++ b/drivers/virtio/Kconfig
> @@ -28,6 +28,7 @@ config VIRTIO_MMIO
>  config VIRTIO_PCI
>  	tristate "PCI driver for virtio devices"
>  	depends on PCI && HAS_DMA
> +	depends on MMU && MIPS || !MIPS
>  	select VIRTIO
>  	help
>  	  This driver provides support for virtio based paravirtual device
> -- 
> 2.30.0
> 
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox


-- 
Best regards,
  Antony Pavlov

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Re: [PATCH 4/9] dma: move dma_map/unmap_single from ARM to common code

[Sascha Hauer]

Hi Ahmad,

On Sun, Feb 28, 2021 at 08:08:31PM +0100, Ahmad Fatoum wrote:
> There's nothing ARM specific about these functions. Move them to a
> common location, so other arches can use them as well.
> 
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
>  arch/arm/cpu/mmu-common.c | 41 +-------------------------------------
>  drivers/dma/Makefile      |  1 +
>  drivers/dma/map.c         | 42 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 44 insertions(+), 40 deletions(-)
>  create mode 100644 drivers/dma/map.c

This breaks several arm configs:

drivers/dma/map.c:26:12: error: redefinition of 'dma_map_single'
   26 | dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
      |            ^~~~~~~~~~~~~~
In file included from include/dma.h:13,
                 from drivers/dma/map.c:4:
/ptx/work/WORK_EIHEI/sha/backup/barebox/barebox-maintainer-utils/barebox/arch/arm/include/asm/dma.h:35:26: note: previous definition of 'dma_map_single' was here
   35 | static inline dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
      |                          ^~~~~~~~~~~~~~
drivers/dma/map.c:36:6: error: redefinition of 'dma_unmap_single'
   36 | void dma_unmap_single(struct device_d *dev, dma_addr_t dma_addr, size_t size,
      |      ^~~~~~~~~~~~~~~~
In file included from include/dma.h:13,
                 from drivers/dma/map.c:4:
/ptx/work/WORK_EIHEI/sha/backup/barebox/barebox-maintainer-utils/barebox/arch/arm/include/asm/dma.h:41:20: note: previous definition of 'dma_unmap_single' was here
   41 | static inline void dma_unmap_single(struct device_d *dev, dma_addr_t addr, size_t size,
      |                    ^~~~~~~~~~~~~~~~

This happens for example in dss11_defconfig, but several others as well.

Sascha

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31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
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[PATCH] dma: move dma_map/unmap_single from ARM to common code

[Ahmad Fatoum]

There's nothing ARM specific about these functions. Move them to a
common location, so other arches can use them as well.

This also fixes a bug on ARM MMU=n configurations:
Previously these two functions these functions only respected
dma-ranges translation when compiled with MMU support. DMA address
translation is applicable regardless of CPU use of MMU though.
Now, dma-ranges should be respected unconditionally.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
---
Sascha, please replace the original patch with this one.
---
 arch/arm/cpu/mmu-common.c      | 41 +--------------------------------
 arch/arm/include/asm/dma.h     | 11 ---------
 arch/sandbox/include/asm/dma.h | 11 ---------
 drivers/dma/Makefile           |  1 +
 drivers/dma/map.c              | 42 ++++++++++++++++++++++++++++++++++
 5 files changed, 44 insertions(+), 62 deletions(-)
 create mode 100644 drivers/dma/map.c

diff --git a/arch/arm/cpu/mmu-common.c b/arch/arm/cpu/mmu-common.c
index 287622b20399..5cc5138cfa3d 100644
--- a/arch/arm/cpu/mmu-common.c
+++ b/arch/arm/cpu/mmu-common.c
@@ -10,27 +10,6 @@
 #include <memory.h>
 #include "mmu.h"
 
-
-static inline dma_addr_t cpu_to_dma(struct device_d *dev, unsigned long cpu_addr)
-{
-	dma_addr_t dma_addr = cpu_addr;
-
-	if (dev)
-		dma_addr -= dev->dma_offset;
-
-	return dma_addr;
-}
-
-static inline unsigned long dma_to_cpu(struct device_d *dev, dma_addr_t addr)
-{
-	unsigned long cpu_addr = addr;
-
-	if (dev)
-		cpu_addr += dev->dma_offset;
-
-	return cpu_addr;
-}
-
 void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 			     enum dma_data_direction dir)
 {
@@ -41,24 +20,6 @@ void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 		dma_inv_range((void *)address, size);
 }
 
-dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
-			  enum dma_data_direction dir)
-{
-	unsigned long addr = (unsigned long)ptr;
-
-	dma_sync_single_for_device(addr, size, dir);
-
-	return cpu_to_dma(dev, addr);
-}
-
-void dma_unmap_single(struct device_d *dev, dma_addr_t dma_addr, size_t size,
-		      enum dma_data_direction dir)
-{
-	unsigned long addr = dma_to_cpu(dev, dma_addr);
-
-	dma_sync_single_for_cpu(addr, size, dir);
-}
-
 void *dma_alloc_map(size_t size, dma_addr_t *dma_handle, unsigned flags)
 {
 	void *ret;
@@ -108,4 +69,4 @@ static int mmu_init(void)
 
 	return 0;
 }
-mmu_initcall(mmu_init);
\ No newline at end of file
+mmu_initcall(mmu_init);
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h
index 08a9fc43b7fc..226b1c146479 100644
--- a/arch/arm/include/asm/dma.h
+++ b/arch/arm/include/asm/dma.h
@@ -32,17 +32,6 @@ static inline void dma_free_coherent(void *mem, dma_addr_t dma_handle,
 	free(mem);
 }
 
-static inline dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
-					enum dma_data_direction dir)
-{
-	return (dma_addr_t)ptr;
-}
-
-static inline void dma_unmap_single(struct device_d *dev, dma_addr_t addr, size_t size,
-				    enum dma_data_direction dir)
-{
-}
-
 static inline void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 					   enum dma_data_direction dir)
 {
diff --git a/arch/sandbox/include/asm/dma.h b/arch/sandbox/include/asm/dma.h
index 5e72d8e7df2d..34c0fc5190f8 100644
--- a/arch/sandbox/include/asm/dma.h
+++ b/arch/sandbox/include/asm/dma.h
@@ -40,17 +40,6 @@ static inline void dma_free_coherent(void *mem, dma_addr_t dma_handle,
 	free(mem);
 }
 
-static inline dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
-					enum dma_data_direction dir)
-{
-	return (dma_addr_t)ptr;
-}
-
-static inline void dma_unmap_single(struct device_d *dev, dma_addr_t addr, size_t size,
-				    enum dma_data_direction dir)
-{
-}
-
 static inline void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
 					   enum dma_data_direction dir)
 {
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 7a3a3b2bd85d..49d6d6573f4f 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_MXS_APBH_DMA)	+= apbh_dma.o
+obj-$(CONFIG_HAS_DMA)		+= map.o
diff --git a/drivers/dma/map.c b/drivers/dma/map.c
new file mode 100644
index 000000000000..a3e1b3b5b527
--- /dev/null
+++ b/drivers/dma/map.c
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* SPDX-FileCopyrightText: 2012 Marc Kleine-Budde <mkl@pengutronix.de> */
+
+#include <dma.h>
+
+static inline dma_addr_t cpu_to_dma(struct device_d *dev, unsigned long cpu_addr)
+{
+	dma_addr_t dma_addr = cpu_addr;
+
+	if (dev)
+		dma_addr -= dev->dma_offset;
+
+	return dma_addr;
+}
+
+static inline unsigned long dma_to_cpu(struct device_d *dev, dma_addr_t addr)
+{
+	unsigned long cpu_addr = addr;
+
+	if (dev)
+		cpu_addr += dev->dma_offset;
+
+	return cpu_addr;
+}
+
+dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
+			  enum dma_data_direction dir)
+{
+	unsigned long addr = (unsigned long)ptr;
+
+	dma_sync_single_for_device(addr, size, dir);
+
+	return cpu_to_dma(dev, addr);
+}
+
+void dma_unmap_single(struct device_d *dev, dma_addr_t dma_addr, size_t size,
+		      enum dma_data_direction dir)
+{
+	unsigned long addr = dma_to_cpu(dev, dma_addr);
+
+	dma_sync_single_for_cpu(addr, size, dir);
+}
-- 
2.30.0


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Re: [PATCH 9/9] virtio: virtio-pci: restrict MIPS support to MMU configuration

[Ahmad Fatoum]

Hello Antony,

On 02.03.21 15:28, Antony Pavlov wrote:
> On Sun, 28 Feb 2021 20:08:36 +0100
> Ahmad Fatoum <ahmad@a3f.at> wrote:
> 
> Hi!
> 
>> MMU-less MIPS doesn't play along nicely with VIRTIO_PCI.
>> e.g. Reading from a virtio-rng, will return clearly bogus data.
>> Document this in the Kconfig, so no one else trips over this.
>>
>> Eventually, this should be fixed..
> 
> 
> Please describe, how can I reproduce the problem.

- Apply this series on top of next, but revert this patch
- Use qemu-malta-defconfig
- Built with CONFIG_HW_RANDOM_VIRTIO=y and CONFIG_VIRTIO_PCI=y
- Run:
  qemu-system-mips -m 256M -device VGA -M malta -serial stdio -monitor null \
  -bios ./images/barebox-qemu-malta.img -device virtio-rng-pci,disable-legacy=on
- Execute md -s /dev/hwrng0 three times:

barebox@qemu malta:/ md -s /dev/hwrng0 
00000000: 0000e632 0000000d 81ff8410 00000000                ...2............
00000010: 0000e632 0000000d 81ff8410 00000000                ...2............
00000020: 0000e632 0000000d 81ff8410 00000000                ...2............
00000030: 0000e632 0000000d 81ff8410 00000000                ...2............
00000040: 0000e632 0000000d 81ff8410 00000000                ...2............
00000050: 0000e632 0000000d 81ff8410 00000000                ...2............
00000060: 0000e632 0000000d 81ff8410 00000000                ...2............
00000070: 0000e632 0000000d 81ff8410 00000000                ...2............
00000080: 0000e632 0000000d 81ff8410 00000000                ...2............
00000090: 0000e632 0000000d 81ff8410 00000000                ...2............
000000a0: 0000e632 0000000d 81ff8410 00000000                ...2............
000000b0: 0000e632 0000000d 81ff8410 00000000                ...2............
000000c0: 0000e632 0000000d 81ff8410 00000000                ...2............
000000d0: 0000e632 0000000d 81ff8410 00000000                ...2............
000000e0: 0000e632 0000000d 81ff8410 00000000                ...2............
000000f0: 0000e632 0000000d 81ff8410 00000000                ...2............
barebox@qemu malta:/ md -s /dev/hwrng0 
00000000: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000010: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000020: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000030: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000040: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000050: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000060: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000070: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000080: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
00000090: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000a0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000b0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000c0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000d0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000e0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
000000f0: 30303030 30306630 3a203030 30306536                000000f0: 0000e6
barebox@qemu malta:/ md -s /dev/hwrng0 
00000000: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000010: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000020: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000030: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000040: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000050: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000060: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000070: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000080: 30303030 30306630 3a203330 33303330                000000f0: 303030
00000090: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000a0: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000b0: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000c0: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000d0: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000e0: 30303030 30306630 3a203330 33303330                000000f0: 303030
000000f0: 30303030 30306630 3a203330 33303330                000000f0: 303030


Something is clearly wrong here, but I didn't look further.
If you repeat the same steps but with CONFIG_MMU=y, you will see random
data as expected (You can cp /dev/hwrng0 /dev/fb0 to see for yourself
that there is no obvious pattern, unlike with MMU=n).

Cheers,
Ahmad

> 
> 
>>
>> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
>> ---
>>  drivers/virtio/Kconfig | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
>> index ecf66987b3ed..91a89d3e1b89 100644
>> --- a/drivers/virtio/Kconfig
>> +++ b/drivers/virtio/Kconfig
>> @@ -28,6 +28,7 @@ config VIRTIO_MMIO
>>  config VIRTIO_PCI
>>  	tristate "PCI driver for virtio devices"
>>  	depends on PCI && HAS_DMA
>> +	depends on MMU && MIPS || !MIPS
>>  	select VIRTIO
>>  	help
>>  	  This driver provides support for virtio based paravirtual device
>> -- 
>> 2.30.0
>>
>>
>> _______________________________________________
>> barebox mailing list
>> barebox@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/barebox
> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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