[PATCH v11 06/11] firmware: xilinx: Add debugfs interface

Jolly Shah
2018-08-03T18:09:19Z

From: Rajan Vaja <rajanv@xilinx.com>

Firmware-debug provides debugfs interface to all APIs.
Debugfs can be used to call firmware APIs with required
parameters.

Usage:
* Calling firmware API through debugfs:
# echo "<api-name> <arg1> .. <argn>" > /sys/.../zynqmp-firmware/pm

* Read output of last called firmware API:
# cat /sys/.../zynqmp-firmware/pm

Refer ug1200 for more information on these APIs:
* https://www.xilinx.com/support/documentation/user_guides/ug1200-eemi-api.pdf

Add basic debugfs file to get API version.

Signed-off-by: Rajan Vaja <rajanv@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
---
drivers/firmware/xilinx/Kconfig | 7 ++
drivers/firmware/xilinx/Makefile | 1 +
drivers/firmware/xilinx/zynqmp-debug.c | 212 +++++++++++++++++++++++++++++++++
drivers/firmware/xilinx/zynqmp-debug.h | 22 ++++
drivers/firmware/xilinx/zynqmp.c | 9 ++
5 files changed, 251 insertions(+)
create mode 100644 drivers/firmware/xilinx/zynqmp-debug.c
create mode 100644 drivers/firmware/xilinx/zynqmp-debug.h

diff --git a/drivers/firmware/xilinx/Kconfig b/drivers/firmware/xilinx/Kconfig
index 64d976e..8f44b9c 100644
--- a/drivers/firmware/xilinx/Kconfig
+++ b/drivers/firmware/xilinx/Kconfig
@@ -13,4 +13,11 @@ config ZYNQMP_FIRMWARE
Say yes to enable ZynqMP firmware interface driver.
If in doubt, say N.

+config ZYNQMP_FIRMWARE_DEBUG
+ bool "Enable Xilinx Zynq MPSoC firmware debug APIs"
+ depends on ZYNQMP_FIRMWARE && DEBUG_FS
+ help
+ Say yes to enable ZynqMP firmware interface debug APIs.
+ If in doubt, say N.
+
endmenu
diff --git a/drivers/firmware/xilinx/Makefile b/drivers/firmware/xilinx/Makefile
index 29f7bf2..875a537 100644
--- a/drivers/firmware/xilinx/Makefile
+++ b/drivers/firmware/xilinx/Makefile
@@ -2,3 +2,4 @@
# Makefile for Xilinx firmwares

obj-$(CONFIG_ZYNQMP_FIRMWARE) += zynqmp.o
+obj-$(CONFIG_ZYNQMP_FIRMWARE_DEBUG) += zynqmp-debug.o
diff --git a/drivers/firmware/xilinx/zynqmp-debug.c b/drivers/firmware/xilinx/zynqmp-debug.c
new file mode 100644
index 0000000..fcbdd6e
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp-debug.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
+ *
+ * Copyright (C) 2014-2018 Xilinx, Inc.
+ *
+ * Michal Simek <michal.simek@xilinx.com>
+ * Davorin Mista <davorin.mista@aggios.com>
+ * Jolly Shah <jollys@xilinx.com>
+ * Rajan Vaja <rajanv@xilinx.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include <linux/firmware/xlnx-zynqmp.h>
+#include "zynqmp-debug.h"
+
+#define PM_API_NAME_LEN 50
+
+struct pm_api_info {
+ u32 api_id;
+ char api_name[PM_API_NAME_LEN];
+ char api_name_len;
+};
+
+static char debugfs_buf[PAGE_SIZE];
+
+#define PM_API(id) {id, #id, strlen(#id)}
+static struct pm_api_info pm_api_list[] = {
+ PM_API(PM_GET_API_VERSION),
+};
+
+/**
+ * zynqmp_pm_argument_value() - Extract argument value from a PM-API request
+ * @arg: Entered PM-API argument in string format
+ *
+ * Return: Argument value in unsigned integer format on success
+ * 0 otherwise
+ */
+static u64 zynqmp_pm_argument_value(char *arg)
+{
+ u64 value;
+
+ if (!arg)
+ return 0;
+
+ if (!kstrtou64(arg, 0, &value))
+ return value;
+
+ return 0;
+}
+
+/**
+ * get_pm_api_id() - Extract API-ID from a PM-API request
+ * @pm_api_req: Entered PM-API argument in string format
+ * @pm_id: API-ID
+ *
+ * Return: 0 on success else error code
+ */
+static int get_pm_api_id(char *pm_api_req, u32 *pm_id)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pm_api_list) ; i++) {
+ if (!strncasecmp(pm_api_req, pm_api_list[i].api_name,
+ pm_api_list[i].api_name_len)) {
+ *pm_id = pm_api_list[i].api_id;
+ break;
+ }
+ }
+
+ /* If no name was entered look for PM-API ID instead */
+ if (i == ARRAY_SIZE(pm_api_list) && kstrtouint(pm_api_req, 10, pm_id))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
+{
+ const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+ u32 pm_api_version;
+ int ret;
+
+ if (!eemi_ops)
+ return -ENXIO;
+
+ switch (pm_id) {
+ case PM_GET_API_VERSION:
+ ret = eemi_ops->get_api_version(&pm_api_version);
+ sprintf(debugfs_buf, "PM-API Version = %d.%d\n",
+ pm_api_version >> 16, pm_api_version & 0xffff);
+ break;
+ default:
+ sprintf(debugfs_buf, "Unsupported PM-API request\n");
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_write() - debugfs write function
+ * @file: User file
+ * @ptr: User entered PM-API string
+ * @len: Length of the userspace buffer
+ * @off: Offset within the file
+ *
+ * Used for triggering pm api functions by writing
+ * echo <pm_api_id> > /sys/kernel/debug/zynqmp_pm/power or
+ * echo <pm_api_name> > /sys/kernel/debug/zynqmp_pm/power
+ *
+ * Return: Number of bytes copied if PM-API request succeeds,
+ * the corresponding error code otherwise
+ */
+static ssize_t zynqmp_pm_debugfs_api_write(struct file *file,
+ const char __user *ptr, size_t len,
+ loff_t *off)
+{
+ char *kern_buff, *tmp_buff;
+ char *pm_api_req;
+ u32 pm_id = 0;
+ u64 pm_api_arg[4] = {0, 0, 0, 0};
+ /* Return values from PM APIs calls */
+ u32 pm_api_ret[4] = {0, 0, 0, 0};
+
+ int ret;
+ int i = 0;
+
+ strcpy(debugfs_buf, "");
+
+ if (*off != 0 || len == 0)
+ return -EINVAL;
+
+ kern_buff = kzalloc(len, GFP_KERNEL);
+ if (!kern_buff)
+ return -ENOMEM;
+
+ tmp_buff = kern_buff;
+
+ ret = strncpy_from_user(kern_buff, ptr, len);
+ if (ret < 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ /* Read the API name from a user request */
+ pm_api_req = strsep(&kern_buff, " ");
+
+ ret = get_pm_api_id(pm_api_req, &pm_id);
+ if (ret < 0)
+ goto err;
+
+ /* Read node_id and arguments from the PM-API request */
+ pm_api_req = strsep(&kern_buff, " ");
+ while ((i < ARRAY_SIZE(pm_api_arg)) && pm_api_req) {
+ pm_api_arg[i++] = zynqmp_pm_argument_value(pm_api_req);
+ pm_api_req = strsep(&kern_buff, " ");
+ }
+
+ ret = process_api_request(pm_id, pm_api_arg, pm_api_ret);
+
+err:
+ kfree(tmp_buff);
+ if (ret)
+ return ret;
+
+ return len;
+}
+
+/**
+ * zynqmp_pm_debugfs_api_read() - debugfs read function
+ * @file: User file
+ * @ptr: Requested pm_api_version string
+ * @len: Length of the userspace buffer
+ * @off: Offset within the file
+ *
+ * Return: Length of the version string on success
+ * else error code
+ */
+static ssize_t zynqmp_pm_debugfs_api_read(struct file *file, char __user *ptr,
+ size_t len, loff_t *off)
+{
+ return simple_read_from_buffer(ptr, len, off, debugfs_buf,
+ strlen(debugfs_buf));
+}
+
+/* Setup debugfs fops */
+static const struct file_operations fops_zynqmp_pm_dbgfs = {
+ .owner = THIS_MODULE,
+ .write = zynqmp_pm_debugfs_api_write,
+ .read = zynqmp_pm_debugfs_api_read,
+};
+
+/**
+ * zynqmp_pm_api_debugfs_init - Initialize debugfs interface
+ *
+ * Return: None
+ */
+void zynqmp_pm_api_debugfs_init(void)
+{
+ struct dentry *root_dir;
+
+ /* Initialize debugfs interface */
+ root_dir = debugfs_create_dir("zynqmp-firmware", NULL);
+ debugfs_create_file("pm", 0660, root_dir, NULL,
+ &fops_zynqmp_pm_dbgfs);
+}
diff --git a/drivers/firmware/xilinx/zynqmp-debug.h b/drivers/firmware/xilinx/zynqmp-debug.h
new file mode 100644
index 0000000..3303b37
--- /dev/null
+++ b/drivers/firmware/xilinx/zynqmp-debug.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Xilinx Zynq MPSoC Firmware layer
+ *
+ * Copyright (C) 2014-2018 Xilinx
+ *
+ * Michal Simek <michal.simek@xilinx.com>
+ * Davorin Mista <davorin.mista@aggios.com>
+ * Jolly Shah <jollys@xilinx.com>
+ * Rajan Vaja <rajanv@xilinx.com>
+ */
+
+#ifndef __FIRMWARE_ZYNQMP_DEBUG_H__
+#define __FIRMWARE_ZYNQMP_DEBUG_H__
+
+#if IS_REACHABLE(CONFIG_ZYNQMP_FIRMWARE_DEBUG)
+void zynqmp_pm_api_debugfs_init(void);
+#else
+static inline void zynqmp_pm_api_debugfs_init(void) { }
+#endif
+
+#endif /* __FIRMWARE_ZYNQMP_DEBUG_H__ */
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 41ed800..7ccedf0 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -21,6 +21,7 @@
#include <linux/uaccess.h>

#include <linux/firmware/xlnx-zynqmp.h>
+#include "zynqmp-debug.h"

/**
* zynqmp_pm_ret_code() - Convert PMU-FW error codes to Linux error codes
@@ -551,3 +552,11 @@ static int __init zynqmp_plat_init(void)
return ret;
}
early_initcall(zynqmp_plat_init);
+
+static int zynqmp_firmware_init(void)
+{
+ zynqmp_pm_api_debugfs_init();
+
+ return 0;
+}
+device_initcall(zynqmp_firmware_init);
--
2.7.4