[PATCH v3 03/10] drivers: fpga: add socfpga bridges

[Steffen Trumtrar <s.trumtrar@pengutronix.de>]

Import the SoCFPGA bridges drivers from linux v4.10-rc2.

Description from the original commit:
e5f8efa5c8bf86c1fa698551d54db8f6aee221fd

    ARM: socfpga: fpga bridge driver support

    Supports Altera SOCFPGA bridges:
     * fpga2sdram
     * fpga2hps
     * hps2fpga
     * lwhps2fpga

    Allows enabling/disabling the bridges through the FPGA
    Bridge Framework API functions.

    The fpga2sdram driver only supports enabling and disabling
    of the ports that been configured early on.  This is due to
    a hardware limitation where the read, write, and command
    ports on the fpga2sdram bridge can only be reconfigured
    while there are no transactions to the sdram, i.e. when
    running out of OCRAM before the kernel boots.

    Device tree property 'init-val' configures the driver to
    enable or disable the bridge during probe.  If the property
    does not exist, the driver will leave the bridge in its
    current state.

    Signed-off-by: Alan Tull <atull@opensource.altera.com>
    Signed-off-by: Matthew Gerlach <mgerlach@altera.com>
    Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
 drivers/fpga/Kconfig                     |   8 +
 drivers/fpga/Makefile                    |   1 +
 drivers/fpga/fpga-bridge.c               |   2 +-
 drivers/fpga/socfpga-fpga2sdram-bridge.c | 139 ++++++++++++++++++
 drivers/fpga/socfpga-hps2fpga-bridge.c   | 179 +++++++++++++++++++++++
 5 files changed, 328 insertions(+), 1 deletion(-)
 create mode 100644 drivers/fpga/socfpga-fpga2sdram-bridge.c
 create mode 100644 drivers/fpga/socfpga-hps2fpga-bridge.c

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index fccdbff6eb3f..64ce9f91b6a8 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -17,6 +17,14 @@ config FPGA_BRIDGE
 	  Say Y here if you want to support bridges connected between host
 	  processors and FPGAs or between FPGAs.
 
+config SOCFPGA_FPGA_BRIDGE
+	tristate "Altera SoCFPGA FPGA Bridges"
+	depends on ARCH_SOCFPGA && FPGA_BRIDGE
+	select RESET_CONTROLLER
+	help
+	  Say Y to enable drivers for FPGA bridges for Altera SOCFPGA
+	  devices.
+
 endif # FPGA
 
 endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index fc71a29d3b33..86178fe7c078 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -4,3 +4,4 @@
 
 # FPGA Bridge Drivers
 obj-$(CONFIG_FPGA_BRIDGE)		+= fpga-bridge.o
+obj-$(CONFIG_SOCFPGA_FPGA_BRIDGE)	+= socfpga-hps2fpga-bridge.o socfpga-fpga2sdram-bridge.o
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index 6e8dcbfc0d16..6f9e943de904 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -68,7 +68,7 @@ struct fpga_bridge *of_fpga_bridge_get(struct device_node *np)
 {
 	struct device_d *dev;
 	struct fpga_bridge *bridge;
-	int ret = -ENODEV;
+	int ret = -EPROBE_DEFER;
 
 	dev = of_find_device_by_node(np);
 	if (!dev || !dev->priv)
diff --git a/drivers/fpga/socfpga-fpga2sdram-bridge.c b/drivers/fpga/socfpga-fpga2sdram-bridge.c
new file mode 100644
index 000000000000..a9760597ddb5
--- /dev/null
+++ b/drivers/fpga/socfpga-fpga2sdram-bridge.c
@@ -0,0 +1,139 @@
+/*
+ * FPGA to SDRAM Bridge Driver for Altera SoCFPGA Devices
+ *
+ *  Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This driver manages a bridge between an FPGA and the SDRAM used by the ARM
+ * host processor system (HPS).
+ *
+ * The bridge contains 4 read ports, 4 write ports, and 6 command ports.
+ * Reconfiguring these ports requires that no SDRAM transactions occur during
+ * reconfiguration.  The code reconfiguring the ports cannot run out of SDRAM
+ * nor can the FPGA access the SDRAM during reconfiguration.  This driver does
+ * not support reconfiguring the ports.  The ports are configured by code
+ * running out of on chip ram before Linux is started and the configuration
+ * is passed in a handoff register in the system manager.
+ *
+ * This driver supports enabling and disabling of the configured ports, which
+ * allows for safe reprogramming of the FPGA, assuming that the new FPGA image
+ * uses the same port configuration.  Bridges must be disabled before
+ * reprogramming the FPGA and re-enabled after the FPGA has been programmed.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <fpga-bridge.h>
+#include <mfd/syscon.h>
+#include <of_device.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+
+#define SOCFPGA_SDRCTL_ADDR			0xffc25000
+#define ALT_SDR_CTL_FPGAPORTRST_OFST		0x80
+#define ALT_SDR_CTL_FPGAPORTRST_PORTRSTN_MSK	0x00003fff
+#define ALT_SDR_CTL_FPGAPORTRST_RD_SHIFT	0
+#define ALT_SDR_CTL_FPGAPORTRST_WR_SHIFT	4
+#define ALT_SDR_CTL_FPGAPORTRST_CTRL_SHIFT	8
+
+#define SOCFPGA_SYSMGR_ADDR			0xffd08000
+/*
+ * From the Cyclone V HPS Memory Map document:
+ *   These registers are used to store handoff information between the
+ *   preloader and the OS. These 8 registers can be used to store any
+ *   information. The contents of these registers have no impact on
+ *   the state of the HPS hardware.
+ */
+#define SYSMGR_ISWGRP_HANDOFF3          (0x8C)
+
+#define F2S_BRIDGE_NAME "fpga2sdram"
+
+struct alt_fpga2sdram_data {
+	struct device_d *dev;
+	int mask;
+};
+
+static inline int _alt_fpga2sdram_enable_set(struct alt_fpga2sdram_data *priv,
+					     bool enable)
+{
+	int val;
+
+	val = readl(SOCFPGA_SDRCTL_ADDR + ALT_SDR_CTL_FPGAPORTRST_OFST);
+
+	if (enable)
+		val |= priv->mask;
+	else
+		val = 0;
+
+	/* The kernel driver expects this value in this register :-( */
+	writel(priv->mask, SOCFPGA_SYSMGR_ADDR + SYSMGR_ISWGRP_HANDOFF3);
+
+	dev_dbg(priv->dev, "setting fpgaportrst to 0x%08x\n", val);
+
+	return writel(val, SOCFPGA_SDRCTL_ADDR + ALT_SDR_CTL_FPGAPORTRST_OFST);
+}
+
+static int alt_fpga2sdram_enable_set(struct fpga_bridge *bridge, bool enable)
+{
+	return _alt_fpga2sdram_enable_set(bridge->priv, enable);
+}
+
+struct prop_map {
+	char *prop_name;
+	u32 *prop_value;
+	u32 prop_max;
+};
+
+static const struct fpga_bridge_ops altera_fpga2sdram_br_ops = {
+	.enable_set = alt_fpga2sdram_enable_set,
+};
+
+static struct of_device_id altera_fpga_of_match[] = {
+	{ .compatible = "altr,socfpga-fpga2sdram-bridge" },
+	{},
+};
+
+static int alt_fpga_bridge_probe(struct device_d *dev)
+{
+	struct alt_fpga2sdram_data *priv;
+	int ret = 0;
+
+	priv = xzalloc(sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	/* enable all ports for now */
+	priv->mask = ALT_SDR_CTL_FPGAPORTRST_PORTRSTN_MSK;
+
+	priv->dev = dev;
+
+	ret = fpga_bridge_register(dev, F2S_BRIDGE_NAME,
+				   &altera_fpga2sdram_br_ops, priv);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "driver initialized with handoff %08x\n", priv->mask);
+
+	return ret;
+}
+
+static struct driver_d altera_fpga_driver = {
+	.probe = alt_fpga_bridge_probe,
+	.name = "altera-fpga2sdram-bridge",
+	.of_compatible = DRV_OF_COMPAT(altera_fpga_of_match),
+};
+device_platform_driver(altera_fpga_driver);
diff --git a/drivers/fpga/socfpga-hps2fpga-bridge.c b/drivers/fpga/socfpga-hps2fpga-bridge.c
new file mode 100644
index 000000000000..ecb33ea0b3a5
--- /dev/null
+++ b/drivers/fpga/socfpga-hps2fpga-bridge.c
@@ -0,0 +1,179 @@
+/*
+ * FPGA to/from HPS Bridge Driver for Altera SoCFPGA Devices
+ *
+ *  Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
+ *
+ * Includes this patch from the mailing list:
+ *   fpga: altera-hps2fpga: fix HPS2FPGA bridge visibility to L3 masters
+ *   Signed-off-by: Anatolij Gustschin <agust@denx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This driver manages bridges on a Altera SOCFPGA between the ARM host
+ * processor system (HPS) and the embedded FPGA.
+ *
+ * This driver supports enabling and disabling of the configured ports, which
+ * allows for safe reprogramming of the FPGA, assuming that the new FPGA image
+ * uses the same port configuration.  Bridges must be disabled before
+ * reprogramming the FPGA and re-enabled after the FPGA has been programmed.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <io.h>
+#include <fpga-bridge.h>
+#include <mfd/syscon.h>
+#include <of_device.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+
+#define SOCFPGA_L3_ADDR				0xff800000
+#define ALT_L3_REMAP_OFST			0x0
+#define ALT_L3_REMAP_MPUZERO_MSK		0x00000001
+#define ALT_L3_REMAP_H2F_MSK			0x00000008
+#define ALT_L3_REMAP_LWH2F_MSK			0x00000010
+
+#define HPS2FPGA_BRIDGE_NAME			"hps2fpga"
+#define LWHPS2FPGA_BRIDGE_NAME			"lwhps2fpga"
+#define FPGA2HPS_BRIDGE_NAME			"fpga2hps"
+
+struct altera_hps2fpga_data {
+	struct device_d *dev;
+	const char *name;
+	struct reset_control *bridge_reset;
+	unsigned int remap_mask;
+	struct clk *clk;
+};
+
+/* The L3 REMAP register is write only, so keep a cached value. */
+static unsigned int l3_remap_shadow;
+
+static int _alt_hps2fpga_enable_set(struct altera_hps2fpga_data *priv,
+				    bool enable)
+{
+	int ret;
+
+	/* bring bridge out of reset */
+	if (enable)
+		ret = reset_control_deassert(priv->bridge_reset);
+	else
+		ret = reset_control_assert(priv->bridge_reset);
+	if (ret)
+		return ret;
+
+	/* Allow bridge to be visible to L3 masters or not */
+	if (priv->remap_mask) {
+		l3_remap_shadow |= ALT_L3_REMAP_MPUZERO_MSK;
+
+		if (enable)
+			l3_remap_shadow |= priv->remap_mask;
+		else
+			l3_remap_shadow &= ~priv->remap_mask;
+
+		dev_dbg(priv->dev, "setting L3 visibility to 0x%08x\n",
+			l3_remap_shadow);
+
+		writel(l3_remap_shadow, SOCFPGA_L3_ADDR + ALT_L3_REMAP_OFST);
+	}
+
+	return ret;
+}
+
+static int alt_hps2fpga_enable_set(struct fpga_bridge *bridge, bool enable)
+{
+	return _alt_hps2fpga_enable_set(bridge->priv, enable);
+}
+
+static const struct fpga_bridge_ops altera_hps2fpga_br_ops = {
+	.enable_set = alt_hps2fpga_enable_set,
+};
+
+static struct altera_hps2fpga_data hps2fpga_data  = {
+	.name = HPS2FPGA_BRIDGE_NAME,
+	.remap_mask = ALT_L3_REMAP_H2F_MSK,
+};
+
+static struct altera_hps2fpga_data lwhps2fpga_data  = {
+	.name = LWHPS2FPGA_BRIDGE_NAME,
+	.remap_mask = ALT_L3_REMAP_LWH2F_MSK,
+};
+
+static struct altera_hps2fpga_data fpga2hps_data  = {
+	.name = FPGA2HPS_BRIDGE_NAME,
+};
+
+static struct of_device_id altera_fpga_of_match[] = {
+	{ .compatible = "altr,socfpga-hps2fpga-bridge",
+	  .data = &hps2fpga_data },
+	{ .compatible = "altr,socfpga-lwhps2fpga-bridge",
+	  .data = &lwhps2fpga_data },
+	{ .compatible = "altr,socfpga-fpga2hps-bridge",
+	  .data = &fpga2hps_data },
+	{ /* sentinel */ },
+};
+
+static int alt_fpga_bridge_probe(struct device_d *dev)
+{
+	struct altera_hps2fpga_data *priv;
+	const struct of_device_id *of_id;
+	u32 enable;
+	int ret;
+
+	of_id = of_match_device(altera_fpga_of_match, dev);
+	priv = (struct altera_hps2fpga_data *)of_id->data;
+
+	priv->bridge_reset = of_reset_control_get(dev->device_node, NULL);
+	if (IS_ERR(priv->bridge_reset)) {
+		dev_err(dev, "Could not get %s reset control\n", priv->name);
+		return PTR_ERR(priv->bridge_reset);
+	}
+
+	priv->clk = clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "no clock specified\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	ret = clk_enable(priv->clk);
+	if (ret) {
+		dev_err(dev, "could not enable clock\n");
+		return -EBUSY;
+	}
+
+	priv->dev = dev;
+
+	if (!of_property_read_u32(dev->device_node, "bridge-enable", &enable)) {
+		if (enable > 1) {
+			dev_warn(dev, "invalid bridge-enable %u > 1\n", enable);
+		} else {
+			dev_info(dev, "%s bridge\n",
+				 (enable ? "enabling" : "disabling"));
+
+			ret = _alt_hps2fpga_enable_set(priv, enable);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
+				    priv);
+}
+
+static struct driver_d alt_fpga_bridge_driver = {
+	.probe = alt_fpga_bridge_probe,
+	.name = "altera-hps2fpga-bridge",
+	.of_compatible = DRV_OF_COMPAT(altera_fpga_of_match),
+};
+device_platform_driver(alt_fpga_bridge_driver);
-- 
2.29.2


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