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

Signed-off-by: Jolly Shah <jol...@xilinx.com>
Signed-off-by: Rajan Vaja <raj...@xilinx.com>
---
 .../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          |  13 +
 include/linux/firmware/xilinx/zynqmp/firmware.h    |   2 +
 5 files changed, 363 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" <jol...@xilinx.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/.../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" <jol...@xilinx.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/.../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..e08f6a6
--- /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 <jol...@xilinx.com>
+ *  Rajan Vaja <raj...@xilinx.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/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 = zynqmp_pm_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 = zynqmp_pm_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
+ * @kobj: Kobject structure
+ * @attr: Kobject 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 kobject *kobj,
+                       struct kobj_attribute *attr,
+                       char *buf,
+                       u32 reg)
+{
+       return read_register(buf, IOCTL_READ_GGS, reg);
+}
+
+/**
+ * ggs_store - Store global general storage (ggs) sysfs attribute
+ * @kobj: Kobject structure
+ * @attr: Kobject 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 kobject *kobj,
+                        struct kobj_attribute *attr,
+                        const char *buf,
+                        size_t count,
+                        u32 reg)
+{
+       if (!kobj || !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 kobject *kobj,             \
+                               struct kobj_attribute *attr,    \
+                               char *buf)                      \
+       {                                                       \
+               return ggs_show(kobj, 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 kobject *kobj,            \
+                               struct kobj_attribute *attr,    \
+                               const char *buf,                \
+                               size_t count)                   \
+       {                                                       \
+               return ggs_store(kobj, 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
+ * @kobj: Kobject structure
+ * @attr: Kobject 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 kobject *kobj,
+                        struct kobj_attribute *attr,
+                        char *buf,
+                        u32 reg)
+{
+       return read_register(buf, IOCTL_READ_PGGS, reg);
+}
+
+/**
+ * pggs_store - Store persistent global general storage (pggs) sysfs attribute
+ * @kobj: Kobject structure
+ * @attr: Kobject 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 kobject *kobj,
+                         struct kobj_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 kobject *kobj,            \
+                               struct kobj_attribute *attr,    \
+                               char *buf)                      \
+       {                                                       \
+               return pggs_show(kobj, attr, buf, N);           \
+       }
+
+#define PGGS0_STORE(N)                                         \
+       ssize_t pggs##N##_store(struct kobject *kobj,           \
+                                  struct kobj_attribute *attr, \
+                                  const char *buf,             \
+                                  size_t count)                \
+       {                                                       \
+               return pggs_store(kobj, 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 struct kobj_attribute zynqmp_attr_ggs0 = __ATTR_RW(ggs0);
+static struct kobj_attribute zynqmp_attr_ggs1 = __ATTR_RW(ggs1);
+static struct kobj_attribute zynqmp_attr_ggs2 = __ATTR_RW(ggs2);
+static struct kobj_attribute zynqmp_attr_ggs3 = __ATTR_RW(ggs3);
+
+/* PGGS register attributes */
+static struct kobj_attribute zynqmp_attr_pggs0 = __ATTR_RW(pggs0);
+static struct kobj_attribute zynqmp_attr_pggs1 = __ATTR_RW(pggs1);
+static struct kobj_attribute zynqmp_attr_pggs2 = __ATTR_RW(pggs2);
+static struct kobj_attribute zynqmp_attr_pggs3 = __ATTR_RW(pggs3);
+
+static struct attribute *attrs[] = {
+       &zynqmp_attr_ggs0.attr,
+       &zynqmp_attr_ggs1.attr,
+       &zynqmp_attr_ggs2.attr,
+       &zynqmp_attr_ggs3.attr,
+       &zynqmp_attr_pggs0.attr,
+       &zynqmp_attr_pggs1.attr,
+       &zynqmp_attr_pggs2.attr,
+       &zynqmp_attr_pggs3.attr,
+       NULL,
+};
+
+static const struct attribute_group attr_group = {
+       .attrs = attrs,
+       NULL,
+};
+
+int zynqmp_pm_ggs_init(void)
+{
+       struct kobject *zynqmp_kobj;
+
+       zynqmp_kobj = kobject_create_and_add("zynqmp", firmware_kobj);
+       if (!zynqmp_kobj) {
+               pr_err("zynqmp: Firmware kobj add failed.\n");
+               return -ENOMEM;
+       }
+
+       return sysfs_create_group(zynqmp_kobj, &attr_group);
+}
diff --git a/drivers/firmware/xilinx/zynqmp/firmware.c 
b/drivers/firmware/xilinx/zynqmp/firmware.c
index 6979f4b..02266d9 100644
--- a/drivers/firmware/xilinx/zynqmp/firmware.c
+++ b/drivers/firmware/xilinx/zynqmp/firmware.c
@@ -1049,3 +1049,16 @@ static int __init zynqmp_plat_init(void)
        return ret;
 }
 early_initcall(zynqmp_plat_init);
+
+static int zynqmp_firmware_init(void)
+{
+       int ret;
+
+       ret = zynqmp_pm_ggs_init();
+       if (ret)
+               pr_err("%s() GGS init fail with error %d\n",
+                      __func__, ret);
+
+       return ret;
+}
+device_initcall(zynqmp_firmware_init);
diff --git a/include/linux/firmware/xilinx/zynqmp/firmware.h 
b/include/linux/firmware/xilinx/zynqmp/firmware.h
index 859d809..94b5a43 100644
--- a/include/linux/firmware/xilinx/zynqmp/firmware.h
+++ b/include/linux/firmware/xilinx/zynqmp/firmware.h
@@ -578,6 +578,8 @@ 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(void);
+
 #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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