[PATCH v3 3/4] drivers: firmware: xilinx: Add sysfs interface

[Jolly Shah]

Add Firmware-ggs sysfs interface which provides read/write
interface to global storage registers.

Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx>
---
 .../ABI/stable/sysfs-driver-zynqmp-firmware        |  50 ++++
 drivers/firmware/xilinx/zynqmp/Makefile            |   2 +-
 drivers/firmware/xilinx/zynqmp/firmware-ggs.c      | 297 +++++++++++++++++++++
 drivers/firmware/xilinx/zynqmp/firmware.c          |  31 +++
 include/linux/firmware/xilinx/zynqmp/firmware.h    |   2 +
 5 files changed, 381 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
 create mode 100644 drivers/firmware/xilinx/zynqmp/firmware-ggs.c

diff --git a/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware b/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
new file mode 100644
index 0000000..b04727a
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-driver-zynqmp-firmware
@@ -0,0 +1,50 @@
+What:		/sys/devices/platform/zynqmp-firmware/ggs*
+Date:		January 2018
+KernelVersion:	4.15.0
+Contact:	"Jolly Shah" <jollys@xxxxxxxxxx>
+Description:
+		Read/Write PMU global general storage register value,
+		GLOBAL_GEN_STORAGE{0:3}.
+		Global general storage register that can be used
+		by system to pass information between masters.
+
+		The register is reset during system or power-on
+		resets. Three registers are used by the FSBL and
+		other Xilinx software products: GLOBAL_GEN_STORAGE{4:6}.
+
+		Usage:
+		# cat /sys/.../zynqmp-firmware/ggs0
+		# echo <mask> <value> > /sys/.../zynqmp-firmware/ggs0
+
+		Example:
+		# cat /sys/.../zynqmp-firmware/ggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/.../zynqmp-firmware/ggs0
+
+Users:		Xilinx
+
+What:		/sys/devices/platform/zynqmp-firmware/pggs*
+Date:		January 2018
+KernelVersion:	4.15.0
+Contact:	"Jolly Shah" <jollys@xxxxxxxxxx>
+Description:
+		Read/Write PMU persistent global general storage register
+		value, PERS_GLOB_GEN_STORAGE{0:3}.
+		Persistent global general storage register that
+		can be used by system to pass information between
+		masters.
+
+		This register is only reset by the power-on reset
+		and maintains its value through a system reset.
+		Four registers are used by the FSBL and other Xilinx
+		software products: PERS_GLOB_GEN_STORAGE{4:7}.
+		Register is reset only by a POR reset.
+
+		Usage:
+		# cat /sys/.../zynqmp-firmware/pggs0
+		# echo <mask> <value> > /sys/.../zynqmp-firmware/pggs0
+
+		Example:
+		# cat /sys/.../zynqmp-firmware/pggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/.../zynqmp-firmware/pggs0
+
+Users:		Xilinx
diff --git a/drivers/firmware/xilinx/zynqmp/Makefile b/drivers/firmware/xilinx/zynqmp/Makefile
index c3ec669..6629781 100644
--- a/drivers/firmware/xilinx/zynqmp/Makefile
+++ b/drivers/firmware/xilinx/zynqmp/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0+
 # Makefile for Xilinx firmwares
 
-obj-$(CONFIG_ZYNQMP_FIRMWARE) += firmware.o
+obj-$(CONFIG_ZYNQMP_FIRMWARE) += firmware.o firmware-ggs.o
diff --git a/drivers/firmware/xilinx/zynqmp/firmware-ggs.c b/drivers/firmware/xilinx/zynqmp/firmware-ggs.c
new file mode 100644
index 0000000..79661f5
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp/firmware-ggs.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Xilinx Zynq MPSoC Firmware layer
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ *  Jolly Shah <jollys@xxxxxxxxxx>
+ *  Rajan Vaja <rajanv@xxxxxxxxxx>
+ */
+
+#include <linux/compiler.h>
+#include <linux/of.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+#include <linux/firmware/xilinx/zynqmp/firmware.h>
+
+static ssize_t read_register(char *buf, u32 ioctl_id, u32 reg)
+{
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+	const struct zynqmp_eemi_ops *eemi_ops = get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->ioctl)
+		return -EFAULT;
+
+	ret = eemi_ops->ioctl(0, ioctl_id, reg, 0, ret_payload);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "0x%x\n", ret_payload[1]);
+}
+
+static ssize_t write_register(const char *buf, size_t count, u32 read_ioctl,
+			      u32 write_ioctl, u32 reg)
+{
+	char *kern_buff, *inbuf, *tok;
+	long mask, value;
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+	const struct zynqmp_eemi_ops *eemi_ops = get_eemi_ops();
+
+	if (!eemi_ops || !eemi_ops->ioctl)
+		return -EFAULT;
+
+	kern_buff = kzalloc(count, GFP_KERNEL);
+	if (!kern_buff)
+		return -ENOMEM;
+
+	ret = strlcpy(kern_buff, buf, count);
+	if (ret < 0) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	inbuf = kern_buff;
+
+	/* Read the write mask */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &mask);
+	if (ret) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	/* Read the write value */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &value);
+	if (ret) {
+		ret = -EFAULT;
+		goto err;
+	}
+
+	ret = eemi_ops->ioctl(0, read_ioctl, reg, 0, ret_payload);
+	if (ret) {
+		ret = -EFAULT;
+		goto err;
+	}
+	ret_payload[1] &= ~mask;
+	value &= mask;
+	value |= ret_payload[1];
+
+	ret = eemi_ops->ioctl(0, write_ioctl, reg, value, NULL);
+	if (ret)
+		ret = -EFAULT;
+
+err:
+	kfree(kern_buff);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+/**
+ * ggs_show - Show global general storage (ggs) sysfs attribute
+ * @dev: Device structure
+ * @attr: Device attribute structure
+ * @buf: Requested available shutdown_scope attributes string
+ * @reg: Register number
+ *
+ * Return:Number of bytes printed into the buffer.
+ *
+ * Helper function for viewing a ggs register value.
+ *
+ * User-space interface for viewing the content of the ggs0 register.
+ * cat /sys/devices/platform/firmware/ggs0
+ */
+static ssize_t ggs_show(struct device *dev,
+			struct device_attribute *attr,
+			char *buf,
+			u32 reg)
+{
+	return read_register(buf, IOCTL_READ_GGS, reg);
+}
+
+/**
+ * ggs_store - Store global general storage (ggs) sysfs attribute
+ * @dev: Device structure
+ * @attr: Device attribute structure
+ * @buf: User entered shutdown_scope attribute string
+ * @count: Size of buf
+ * @reg: Register number
+ *
+ * Return: count argument if request succeeds, the corresponding
+ * error code otherwise
+ *
+ * Helper function for storing a ggs register value.
+ *
+ * For example, the user-space interface for storing a value to the
+ * ggs0 register:
+ * echo 0xFFFFFFFF 0x1234ABCD > /sys/devices/platform/firmware/ggs0
+ */
+static ssize_t ggs_store(struct device *dev,
+			 struct device_attribute *attr,
+			 const char *buf,
+			 size_t count,
+			 u32 reg)
+{
+	if (!dev || !attr || !buf || !count || reg >= GSS_NUM_REGS)
+		return -EINVAL;
+
+	return write_register(buf, count, IOCTL_READ_GGS, IOCTL_WRITE_GGS, reg);
+}
+
+/* GGS register show functions */
+#define GGS0_SHOW(N) \
+	ssize_t ggs##N##_show(struct device *dev, \
+			 struct device_attribute *attr, \
+			 char *buf) \
+	{ \
+		return ggs_show(dev, attr, buf, N); \
+	}
+
+static GGS0_SHOW(0);
+static GGS0_SHOW(1);
+static GGS0_SHOW(2);
+static GGS0_SHOW(3);
+
+/* GGS register store function */
+#define GGS0_STORE(N) \
+	ssize_t ggs##N##_store(struct device *dev, \
+				   struct device_attribute *attr, \
+				   const char *buf, \
+				   size_t count) \
+	{ \
+		return ggs_store(dev, attr, buf, count, N); \
+	}
+
+#define CREATE_GGS_DEVICE(dev, N) \
+do { \
+	if (device_create_file(dev, &dev_attr_ggs##N)) \
+		dev_err(dev, "unable to create ggs%d attribute\n", N); \
+} while (0)
+
+static GGS0_STORE(0);
+static GGS0_STORE(1);
+static GGS0_STORE(2);
+static GGS0_STORE(3);
+
+/**
+ * pggs_show - Show persistent global general storage (pggs) sysfs attribute
+ * @dev: Device structure
+ * @attr: Device attribute structure
+ * @buf: Requested available shutdown_scope attributes string
+ * @reg: Register number
+ *
+ * Return:Number of bytes printed into the buffer.
+ *
+ * Helper function for viewing a pggs register value.
+ */
+static ssize_t pggs_show(struct device *dev,
+			 struct device_attribute *attr,
+			 char *buf,
+			 u32 reg)
+{
+	return read_register(buf, IOCTL_READ_PGGS, reg);
+}
+
+/**
+ * pggs_store - Store persistent global general storage (pggs) sysfs attribute
+ * @dev: Device structure
+ * @attr: Device attribute structure
+ * @buf: User entered shutdown_scope attribute string
+ * @count: Size of buf
+ * @reg: Register number
+ *
+ * Return: count argument if request succeeds, the corresponding
+ * error code otherwise
+ *
+ * Helper function for storing a pggs register value.
+ */
+static ssize_t pggs_store(struct device *dev,
+			  struct device_attribute *attr,
+			  const char *buf,
+			  size_t count,
+			  u32 reg)
+{
+	return write_register(buf, count, IOCTL_READ_PGGS,
+			      IOCTL_WRITE_PGGS, reg);
+}
+
+#define PGGS0_SHOW(N) \
+	ssize_t pggs##N##_show(struct device *dev, \
+			 struct device_attribute *attr, \
+			 char *buf) \
+	{ \
+		return pggs_show(dev, attr, buf, N); \
+	}
+
+#define PGGS0_STORE(N) \
+	ssize_t pggs##N##_store(struct device *dev, \
+				   struct device_attribute *attr, \
+				   const char *buf, \
+				   size_t count) \
+	{ \
+		return pggs_store(dev, attr, buf, count, N); \
+	}
+
+/* PGGS register show functions */
+static PGGS0_SHOW(0);
+static PGGS0_SHOW(1);
+static PGGS0_SHOW(2);
+static PGGS0_SHOW(3);
+
+/* PGGS register store functions */
+static PGGS0_STORE(0);
+static PGGS0_STORE(1);
+static PGGS0_STORE(2);
+static PGGS0_STORE(3);
+
+/* GGS register device attributes */
+static DEVICE_ATTR_RW(ggs0);
+static DEVICE_ATTR_RW(ggs1);
+static DEVICE_ATTR_RW(ggs2);
+static DEVICE_ATTR_RW(ggs3);
+
+/* PGGS register device attributes */
+static DEVICE_ATTR_RW(pggs0);
+static DEVICE_ATTR_RW(pggs1);
+static DEVICE_ATTR_RW(pggs2);
+static DEVICE_ATTR_RW(pggs3);
+
+static struct attribute *attrs[] = {
+	&dev_attr_ggs0.attr,
+	&dev_attr_ggs1.attr,
+	&dev_attr_ggs2.attr,
+	&dev_attr_ggs3.attr,
+	&dev_attr_pggs0.attr,
+	&dev_attr_pggs1.attr,
+	&dev_attr_pggs2.attr,
+	&dev_attr_pggs3.attr,
+	NULL,
+};
+
+static const struct attribute_group attr_group = {
+	.attrs = attrs,
+	NULL,
+};
+
+int zynqmp_pm_ggs_init(struct device *dev)
+{
+	return sysfs_create_group(&dev->kobj, &attr_group);
+}
diff --git a/drivers/firmware/xilinx/zynqmp/firmware.c b/drivers/firmware/xilinx/zynqmp/firmware.c
index 2313ae7..fe7b044 100644
--- a/drivers/firmware/xilinx/zynqmp/firmware.c
+++ b/drivers/firmware/xilinx/zynqmp/firmware.c
@@ -15,11 +15,14 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 
 #include <linux/firmware/xilinx/zynqmp/firmware.h>
 
+#define DRIVER_NAME	"zynqmp_firmware"
+
 /**
  * zynqmp_pm_ret_code - Convert PMU-FW error codes to Linux error codes
  * @ret_status:		PMUFW return code
@@ -996,4 +999,32 @@ static int __init zynqmp_plat_init(void)
 	return ret;
 }
 
+static const struct of_device_id firmware_of_match[] = {
+	{ .compatible = "xlnx,zynqmp-firmware", },
+	{ /* end of table */ },
+};
+
+MODULE_DEVICE_TABLE(of, firmware_of_match);
+
+static int zynqmp_firmware_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = zynqmp_pm_ggs_init(&pdev->dev);
+	if (ret)
+		dev_err(&pdev->dev, "%s() GGS init fail with error %d\n",
+			__func__, ret);
+
+	return ret;
+}
+
+static struct platform_driver zynqmp_firmware_platform_driver = {
+	.probe   = zynqmp_firmware_probe,
+	.driver  = {
+			.name             = DRIVER_NAME,
+			.of_match_table   = firmware_of_match,
+		   },
+};
+builtin_platform_driver(zynqmp_firmware_platform_driver);
+
 early_initcall(zynqmp_plat_init);
diff --git a/include/linux/firmware/xilinx/zynqmp/firmware.h b/include/linux/firmware/xilinx/zynqmp/firmware.h
index 3c323b6..35bb8c5 100644
--- a/include/linux/firmware/xilinx/zynqmp/firmware.h
+++ b/include/linux/firmware/xilinx/zynqmp/firmware.h
@@ -567,6 +567,8 @@ int invoke_pm_fn(u32 pm_api_id, u32 arg0, u32 arg1, u32 arg2, u32 arg3,
 		 u32 *ret_payload);
 int zynqmp_pm_ret_code(u32 ret_status);
 
+int zynqmp_pm_ggs_init(struct device *dev);
+
 #if IS_REACHABLE(CONFIG_ARCH_ZYNQMP)
 const struct zynqmp_eemi_ops *get_eemi_ops(void);
 #else
-- 
2.7.4