Message-Id: <1578527663-10243-2-git-send-email-jolly.shah@xilinx.com>
Date:   Wed,  8 Jan 2020 15:54:20 -0800
From:   Jolly Shah <jolly.shah@...inx.com>
To:     ard.biesheuvel@...aro.org, mingo@...nel.org,
        gregkh@...uxfoundation.org, matt@...eblueprint.co.uk,
        sudeep.holla@....com, hkallweit1@...il.com, keescook@...omium.org,
        dmitry.torokhov@...il.com, michal.simek@...inx.com
Cc:     rajanv@...inx.com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Rajan Vaja <rajan.vaja@...inx.com>,
        Jolly Shah <jollys@...inx.com>
Subject: [PATCH v2 1/4] firmware: xilinx: Add sysfs interface

From: Rajan Vaja <rajan.vaja@...inx.com>

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

Signed-off-by: Rajan Vaja <rajan.vaja@...inx.com>
Signed-off-by: Michal Simek <michal.simek@...inx.com>
Signed-off-by: Jolly Shah <jollys@...inx.com>
---
Changes in v2:
 - Updated Linux kernel version in documentation.
 - Used DEVICE_ATTR_* and ATTRIBUTE_GROUPS macros.
 - Free Kobject structure in case of error.
 - Resolved smatch errors.
 - Updated Signed-off-by sequence.
---
 Documentation/ABI/stable/sysfs-firmware-zynqmp |  50 +++++
 drivers/firmware/xilinx/Makefile               |   2 +-
 drivers/firmware/xilinx/zynqmp-ggs.c           | 284 +++++++++++++++++++++++++
 drivers/firmware/xilinx/zynqmp.c               |  32 +++
 include/linux/firmware/xlnx-zynqmp.h           |  10 +
 5 files changed, 377 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/stable/sysfs-firmware-zynqmp
 create mode 100644 drivers/firmware/xilinx/zynqmp-ggs.c

diff --git a/Documentation/ABI/stable/sysfs-firmware-zynqmp b/Documentation/ABI/stable/sysfs-firmware-zynqmp
new file mode 100644
index 0000000..cffa2fc
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-firmware-zynqmp
@@ -0,0 +1,50 @@
+What:		/sys/firmware/zynqmp/ggs*
+Date:		January 2018
+KernelVersion:	5.5
+Contact:	"Jolly Shah" <jollys@...inx.com>
+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/firmware/zynqmp/ggs0
+		# echo <mask> <value> > /sys/firmware/zynqmp/ggs0
+
+		Example:
+		# cat /sys/firmware/zynqmp/ggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/firmware/zynqmp/ggs0
+
+Users:		Xilinx
+
+What:		/sys/firmware/zynqmp/pggs*
+Date:		January 2018
+KernelVersion:	5.5
+Contact:	"Jolly Shah" <jollys@...inx.com>
+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/firmware/zynqmp/pggs0
+		# echo <mask> <value> > /sys/firmware/zynqmp/pggs0
+
+		Example:
+		# cat /sys/firmware/zynqmp/pggs0
+		# echo 0xFFFFFFFF 0x1234ABCD > /sys/firmware/zynqmp/pggs0
+
+Users:		Xilinx
diff --git a/drivers/firmware/xilinx/Makefile b/drivers/firmware/xilinx/Makefile
index 875a537..1e8643c 100644
--- a/drivers/firmware/xilinx/Makefile
+++ b/drivers/firmware/xilinx/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 # Makefile for Xilinx firmwares
 
-obj-$(CONFIG_ZYNQMP_FIRMWARE) += zynqmp.o
+obj-$(CONFIG_ZYNQMP_FIRMWARE) += zynqmp.o zynqmp-ggs.o
 obj-$(CONFIG_ZYNQMP_FIRMWARE_DEBUG) += zynqmp-debug.o
diff --git a/drivers/firmware/xilinx/zynqmp-ggs.c b/drivers/firmware/xilinx/zynqmp-ggs.c
new file mode 100644
index 0000000..e2a6700
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp-ggs.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Xilinx Zynq MPSoC Firmware layer
+ *
+ *  Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ *  Jolly Shah <jollys@...inx.com>
+ *  Rajan Vaja <rajanv@...inx.com>
+ */
+
+#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/firmware/xlnx-zynqmp.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 = zynqmp_pm_get_eemi_ops();
+
+	if (IS_ERR(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 = zynqmp_pm_get_eemi_ops();
+
+	if (IS_ERR(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
+ * @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/firmware/zynqmp/ggs0
+ */
+static ssize_t ggs_show(struct device *device,
+			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
+ * @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/firmware/zynqmp/ggs0
+ */
+static ssize_t ggs_store(struct device *device,
+			 struct device_attribute *attr,
+			 const char *buf, size_t count,
+			 u32 reg)
+{
+	if (!device || !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 *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)
+{
+	return read_register(buf, IOCTL_READ_PGGS, reg);
+}
+
+/**
+ * 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)
+{
+	return write_register(buf, count, IOCTL_READ_PGGS,
+			      IOCTL_WRITE_PGGS, reg);
+}
+
+#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,
+};
+
+ATTRIBUTE_GROUPS(zynqmp_ggs);
+
+int zynqmp_pm_ggs_init(struct kobject *parent_kobj)
+{
+	return sysfs_create_group(parent_kobj, zynqmp_ggs_groups[0]);
+}
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 75bdfaa..4c1117d 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -473,6 +473,10 @@ static inline int zynqmp_is_valid_ioctl(u32 ioctl_id)
 	case IOCTL_GET_PLL_FRAC_MODE:
 	case IOCTL_SET_PLL_FRAC_DATA:
 	case IOCTL_GET_PLL_FRAC_DATA:
+	case IOCTL_WRITE_GGS:
+	case IOCTL_READ_GGS:
+	case IOCTL_WRITE_PGGS:
+	case IOCTL_READ_PGGS:
 		return 1;
 	default:
 		return 0;
@@ -704,6 +708,28 @@ const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_get_eemi_ops);
 
+static int zynqmp_pm_sysfs_init(void)
+{
+	struct kobject *zynqmp_kobj;
+	int ret;
+
+	zynqmp_kobj = kobject_create_and_add("zynqmp", firmware_kobj);
+	if (!zynqmp_kobj) {
+		pr_err("zynqmp: Firmware kobj add failed.\n");
+		return -ENOMEM;
+	}
+
+	ret = zynqmp_pm_ggs_init(zynqmp_kobj);
+	if (ret) {
+		kobject_put(zynqmp_kobj);
+		pr_err("%s() GGS init fail with error %d\n",
+		       __func__, ret);
+		goto err;
+	}
+err:
+	return ret;
+}
+
 static int zynqmp_firmware_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -751,6 +777,12 @@ static int zynqmp_firmware_probe(struct platform_device *pdev)
 	/* Assign eemi_ops_table */
 	eemi_ops_tbl = &eemi_ops;
 
+	ret = zynqmp_pm_sysfs_init();
+	if (ret) {
+		pr_err("%s() sysfs init fail with error %d\n", __func__, ret);
+		return ret;
+	}
+
 	zynqmp_pm_api_debugfs_init();
 
 	ret = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, firmware_devs,
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index e41ad9e..534814e 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
@@ -97,6 +101,10 @@ enum pm_ioctl_id {
 	IOCTL_GET_PLL_FRAC_MODE,
 	IOCTL_SET_PLL_FRAC_DATA,
 	IOCTL_GET_PLL_FRAC_DATA,
+	IOCTL_WRITE_GGS,
+	IOCTL_READ_GGS,
+	IOCTL_WRITE_PGGS,
+	IOCTL_READ_PGGS,
 };
 
 enum pm_query_id {
@@ -311,6 +319,8 @@ struct zynqmp_eemi_ops {
 int zynqmp_pm_invoke_fn(u32 pm_api_id, u32 arg0, u32 arg1,
 			u32 arg2, u32 arg3, u32 *ret_payload);
 
+int zynqmp_pm_ggs_init(struct kobject *parent_kobj);
+
 #if IS_REACHABLE(CONFIG_ARCH_ZYNQMP)
 const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void);
 #else
-- 
2.7.4

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