[PATCH v3 21/24] firmware: xilinx: Add sysfs interface

[Jolly Shah]

From: Rajan Vaja <rajan.vaja@xxxxxxxxxx>

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

Signed-off-by: Rajan Vaja <rajan.vaja@xxxxxxxxxx>
Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
Signed-off-by: Tejas Patel <tejas.patel@xxxxxxxxxx>
Signed-off-by: Jolly Shah <jolly.shah@xxxxxxxxxx>
---
 .../ABI/stable/sysfs-driver-firmware-zynqmp        |  50 ++++
 drivers/firmware/xilinx/zynqmp.c                   | 319 ++++++++++++++++++++-
 include/linux/firmware/xlnx-zynqmp.h               |   4 +
 3 files changed, 372 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/stable/sysfs-driver-firmware-zynqmp

diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
new file mode 100644
index 0000000..7fd6e70
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
@@ -0,0 +1,50 @@
+What:		/sys/devices/platform/firmware\:zynqmp-firmware/ggs*
+Date:		March 2020
+KernelVersion:	5.6
+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/devices/platform/firmware\:zynqmp-firmware/ggs0
+		# echo <mask> <value> > /sys/devices/platform/firmware\:zynqmp-firmware/ggs0
+
+		Example:
+		# cat /sys/devices/platform/firmware\:zynqmp-firmware/ggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/devices/platform/firmware\:zynqmp-firmware/ggs0
+
+Users:		Xilinx
+
+What:		/sys/devices/platform/firmware\:zynqmp-firmware/pggs*
+Date:		March 2020
+KernelVersion:	5.6
+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/devices/platform/firmware\:zynqmp-firmware/pggs0
+		# echo <mask> <value> > /sys/devices/platform/firmware\:zynqmp-firmware/pggs0
+
+		Example:
+		# cat /sys/devices/platform/firmware\:zynqmp-firmware/pggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/devices/platform/firmware\:zynqmp-firmware/pggs0
+
+Users:		Xilinx
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index de99613..f671b6b 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -2,7 +2,7 @@
 /*
  * Xilinx Zynq MPSoC Firmware layer
  *
- *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *  Copyright (C) 2014-2020 Xilinx, Inc.
  *
  *  Michal Simek <michal.simek@xxxxxxxxxx>
  *  Davorin Mista <davorin.mista@xxxxxxxxxx>
@@ -833,6 +833,322 @@ int zynqmp_pm_set_requirement(const u32 node, const u32 capabilities,
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_set_requirement);
 
+/**
+ * ggs_show - Show global general storage (ggs) sysfs attribute
+ * @device: 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\:zynqmp-firmware/ggs0
+ */
+static ssize_t ggs_show(struct device *device,
+			struct device_attribute *attr,
+			char *buf,
+			u32 reg)
+{
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+
+	ret = zynqmp_pm_read_ggs(reg, ret_payload);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "0x%x\n", ret_payload[1]);
+}
+
+/**
+ * ggs_store - Store global general storage (ggs) sysfs attribute
+ * @device: 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\:zynqmp-firmware/ggs0
+ */
+static ssize_t ggs_store(struct device *device,
+			 struct device_attribute *attr,
+			 const char *buf, size_t count,
+			 u32 reg)
+{
+	char *kern_buff, *inbuf, *tok;
+	long mask, value;
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+
+	if (!device || !attr || !buf || !count || reg >= GSS_NUM_REGS)
+		return -EINVAL;
+
+	kern_buff = kzalloc(count, GFP_KERNEL);
+	if (!kern_buff)
+		return -ENOMEM;
+
+	ret = strlcpy(kern_buff, buf, count);
+	if (ret < 0) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	inbuf = kern_buff;
+
+	/* Read the write mask */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &mask);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	/* Read the write value */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &value);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = zynqmp_pm_read_ggs(reg, ret_payload);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+	ret_payload[1] &= ~mask;
+	value &= mask;
+	value |= ret_payload[1];
+
+	ret = zynqmp_pm_write_ggs(reg, value);
+	if (ret)
+		count = -EFAULT;
+
+err:
+	kfree(kern_buff);
+
+	return count;
+}
+
+/* GGS register show functions */
+#define GGS0_SHOW(N)						\
+	ssize_t ggs##N##_show(struct device *device,		\
+			      struct device_attribute *attr,	\
+			      char *buf)			\
+	{							\
+		return ggs_show(device, 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 *device,		\
+			       struct device_attribute *attr,	\
+			       const char *buf,			\
+			       size_t count)			\
+	{							\
+		return ggs_store(device, attr, buf, count, N);	\
+	}
+
+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
+ * @device: 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 *device,
+			 struct device_attribute *attr,
+			 char *buf,
+			 u32 reg)
+{
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+
+	ret = zynqmp_pm_read_pggs(reg, ret_payload);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "0x%x\n", ret_payload[1]);
+}
+
+/**
+ * pggs_store - Store persistent global general storage (pggs) sysfs attribute
+ * @device: 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 *device,
+			  struct device_attribute *attr,
+			  const char *buf, size_t count,
+			  u32 reg)
+{
+	char *kern_buff, *inbuf, *tok;
+	long mask, value;
+	int ret;
+	u32 ret_payload[PAYLOAD_ARG_CNT];
+
+	if (!device || !attr || !buf || !count || reg >= GSS_NUM_REGS)
+		return -EINVAL;
+
+	kern_buff = kzalloc(count, GFP_KERNEL);
+	if (!kern_buff)
+		return -ENOMEM;
+
+	ret = strlcpy(kern_buff, buf, count);
+	if (ret < 0) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	inbuf = kern_buff;
+
+	/* Read the write mask */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &mask);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	/* Read the write value */
+	tok = strsep(&inbuf, " ");
+	if (!tok) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = kstrtol(tok, 16, &value);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+
+	ret = zynqmp_pm_read_pggs(reg, ret_payload);
+	if (ret) {
+		count = -EFAULT;
+		goto err;
+	}
+	ret_payload[1] &= ~mask;
+	value &= mask;
+	value |= ret_payload[1];
+
+	ret = zynqmp_pm_write_pggs(reg, value);
+	if (ret)
+		count = -EFAULT;
+
+err:
+	kfree(kern_buff);
+
+	return count;
+}
+
+#define PGGS0_SHOW(N)						\
+	ssize_t pggs##N##_show(struct device *device,		\
+			       struct device_attribute *attr,	\
+			       char *buf)			\
+	{							\
+		return pggs_show(device, attr, buf, N);		\
+	}
+
+#define PGGS0_STORE(N)						\
+	ssize_t pggs##N##_store(struct device *device,		\
+				struct device_attribute *attr,	\
+				const char *buf,		\
+				size_t count)			\
+	{							\
+		return pggs_store(device, 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 attributes */
+static DEVICE_ATTR_RW(ggs0);
+static DEVICE_ATTR_RW(ggs1);
+static DEVICE_ATTR_RW(ggs2);
+static DEVICE_ATTR_RW(ggs3);
+
+/* PGGS register attributes */
+static DEVICE_ATTR_RW(pggs0);
+static DEVICE_ATTR_RW(pggs1);
+static DEVICE_ATTR_RW(pggs2);
+static DEVICE_ATTR_RW(pggs3);
+
+static struct attribute *zynqmp_ggs_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 ggs_attribute_group = {
+	.attrs = zynqmp_ggs_attrs,
+};
+
+const struct attribute_group *firmware_attribute_groups[] = {
+	&ggs_attribute_group,
+	NULL,
+};
+
 static int zynqmp_firmware_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -910,6 +1226,7 @@ static struct platform_driver zynqmp_firmware_driver = {
 	.driver = {
 		.name = "zynqmp_firmware",
 		.of_match_table = zynqmp_firmware_of_match,
+		.dev_groups = firmware_attribute_groups,
 	},
 	.probe = zynqmp_firmware_probe,
 	.remove = zynqmp_firmware_remove,
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index 725dccf..8ccaa39 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -13,6 +13,8 @@
 #ifndef __FIRMWARE_ZYNQMP_H__
 #define __FIRMWARE_ZYNQMP_H__
 
+#include <linux/device.h>
+
 #define ZYNQMP_PM_VERSION_MAJOR	1
 #define ZYNQMP_PM_VERSION_MINOR	0
 
@@ -42,6 +44,8 @@
 
 #define ZYNQMP_PM_MAX_QOS		100U
 
+#define GSS_NUM_REGS	(4)
+
 /* Node capabilities */
 #define	ZYNQMP_PM_CAPABILITY_ACCESS	0x1U
 #define	ZYNQMP_PM_CAPABILITY_CONTEXT	0x2U
-- 
2.7.4