mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: barebox@lists.infradead.org
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: [PATCH 03/13] nvmem: add support for new read-only memory (rmem) binding
Date: Sat, 19 Jun 2021 05:45:06 +0200	[thread overview]
Message-ID: <20210619034516.6737-4-a.fatoum@pengutronix.de> (raw)
In-Reply-To: <20210619034516.6737-1-a.fatoum@pengutronix.de>

Only upstream user of this binding is the raspberry pi 4 DT, where it's
used to pass along bootloader-provided info to Linux. We have instances
in barebox, where a previous stage bootloader passes along a memory
region with info for barebox to interpret. This could in future be
modelled as nvmem-rmem nodes. The binding is also quite handy for
debugging.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/nvmem/Kconfig  |  6 ++++
 drivers/nvmem/Makefile |  2 ++
 drivers/nvmem/rmem.c   | 67 ++++++++++++++++++++++++++++++++++++++++++
 drivers/of/base.c      | 21 ++++++++++---
 fs/devfs-core.c        |  2 +-
 include/driver.h       |  3 ++
 6 files changed, 96 insertions(+), 5 deletions(-)
 create mode 100644 drivers/nvmem/rmem.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index e4a72b1431a9..0d7c0b7b9e3d 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -9,6 +9,12 @@ menuconfig NVMEM
 
 if NVMEM
 
+config NVMEM_RMEM
+	bool "Reserved Memory Based Driver Support"
+	help
+	  This driver maps reserved memory into an nvmem device. It might be
+	  useful to expose information left by firmware in memory.
+
 config NVMEM_SNVS_LPGPR
 	tristate "Freescale SNVS LPGPR support"
 	select MFD_SYSCON
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 617e3725a726..6330f3d6e681 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -5,6 +5,8 @@
 obj-$(CONFIG_NVMEM)		+= nvmem_core.o
 nvmem_core-y			:= core.o regmap.o
 
+obj-$(CONFIG_NVMEM_RMEM)	+= rmem.o
+
 # Devices
 obj-$(CONFIG_NVMEM_SNVS_LPGPR)	+= nvmem_snvs_lpgpr.o
 nvmem_snvs_lpgpr-y		:= snvs_lpgpr.o
diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c
new file mode 100644
index 000000000000..e103cec4482a
--- /dev/null
+++ b/drivers/nvmem/rmem.c
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+ */
+
+#include <io.h>
+#include <driver.h>
+#include <linux/nvmem-provider.h>
+#include <init.h>
+
+struct rmem {
+	struct device_d *dev;
+	const struct resource *mem;
+};
+
+static int rmem_read(void *context, unsigned int offset,
+		     void *val, size_t bytes)
+{
+	struct rmem *rmem = context;
+	return mem_copy(rmem->dev, val, (void *)rmem->mem->start + offset,
+			bytes, offset, 0);
+}
+
+static struct nvmem_bus rmem_nvmem_bus = {
+	.read = rmem_read,
+};
+
+static int rmem_probe(struct device_d *dev)
+{
+	struct nvmem_config config = { };
+	struct resource *mem;
+	struct rmem *priv;
+
+	mem = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(mem))
+		return PTR_ERR(mem);
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->mem = mem;
+
+	config.dev = priv->dev = dev;
+	config.priv = priv;
+	config.name = "rmem";
+	config.size = resource_size(mem);
+	config.bus = &rmem_nvmem_bus;
+
+	return PTR_ERR_OR_ZERO(nvmem_register(&config));
+}
+
+static const struct of_device_id rmem_match[] = {
+	{ .compatible = "nvmem-rmem", },
+	{ /* sentinel */ },
+};
+
+static struct driver_d rmem_driver = {
+	.name = "rmem",
+	.of_compatible = rmem_match,
+	.probe = rmem_probe,
+};
+device_platform_driver(rmem_driver);
+
+MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
+MODULE_DESCRIPTION("Reserved Memory Based nvmem Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 193bae7fa017..015629e1e967 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2331,9 +2331,14 @@ static void of_platform_device_create_root(struct device_node *np)
 		free(dev);
 }
 
+static const struct of_device_id reserved_mem_matches[] = {
+	{ .compatible = "nvmem-rmem" },
+	{}
+};
+
 int of_probe(void)
 {
-	struct device_node *firmware;
+	struct device_node *node;
 	int ret;
 
 	if(!root_node)
@@ -2347,9 +2352,17 @@ int of_probe(void)
 
 	ret = of_probe_memory();
 
-	firmware = of_find_node_by_path("/firmware");
-	if (firmware)
-		of_platform_populate(firmware, NULL, NULL);
+	/*
+	 * Handle certain compatibles explicitly, since we don't want to create
+	 * platform_devices for every node in /reserved-memory with a
+	 * "compatible",
+	 */
+	for_each_matching_node(node, reserved_mem_matches)
+		of_platform_device_create(node, NULL);
+
+	node = of_find_node_by_path("/firmware");
+	if (node)
+		of_platform_populate(node, NULL, NULL);
 
 	of_platform_device_create_root(root_node);
 
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index f804f969745c..30ad0e050835 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -529,7 +529,7 @@ void cdev_remove_loop(struct cdev *cdev)
 	free(cdev);
 }
 
-static ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
+ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
 			resource_size_t count, resource_size_t offset,
 			unsigned long flags)
 {
diff --git a/include/driver.h b/include/driver.h
index d84fe35d5063..c7f5903fcea0 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -347,6 +347,9 @@ struct cdev;
 /* These are used by drivers which work with direct memory accesses */
 ssize_t mem_read(struct cdev *cdev, void *buf, size_t count, loff_t offset, ulong flags);
 ssize_t mem_write(struct cdev *cdev, const void *buf, size_t count, loff_t offset, ulong flags);
+ssize_t mem_copy(struct device_d *dev, void *dst, const void *src,
+		 resource_size_t count, resource_size_t offset,
+		 unsigned long flags);
 
 int generic_memmap_ro(struct cdev *dev, void **map, int flags);
 int generic_memmap_rw(struct cdev *dev, void **map, int flags);
-- 
2.29.2


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


  parent reply	other threads:[~2021-06-19  3:47 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-19  3:45 [PATCH 00/13] nvmem: misc enhancements Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 01/13] nvmem: bsec: remove unused, left-over, struct member Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 02/13] nvmem: treat devices without nvmem_bus::write as read only Ahmad Fatoum
2021-06-19  3:45 ` Ahmad Fatoum [this message]
2021-06-19  3:45 ` [PATCH 04/13] nvmem: add support for nvmem-cells binding Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 05/13] sandbox: use nvmem on top of stickypage for reset reason Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 06/13] power: reset: port Linux generic NVMEM reboot mode driver Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 07/13] sandbox: use nvmem-reboot-mode instead of syscon-reboot-mode Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 08/13] sandbox: dts: fix unit-address for state partition Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 09/13] nvmem: add command to list nvmem devices Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 10/13] sandbox: hostfile: move initcall to earlier postcore level Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 11/13] of: of_net: sync of_get_mac_address with Linux for NVMEM support Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 12/13] net: consult device tree for ethernet address in NVMEM as fall-back Ahmad Fatoum
2021-06-19  3:45 ` [PATCH 13/13] sandbox: ship sample environment Ahmad Fatoum
2021-06-21  6:05 ` [PATCH 00/13] nvmem: misc enhancements Sascha Hauer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210619034516.6737-4-a.fatoum@pengutronix.de \
    --to=a.fatoum@pengutronix.de \
    --cc=barebox@lists.infradead.org \
    --subject='Re: [PATCH 03/13] nvmem: add support for new read-only memory (rmem) binding' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox