mwifiex: add support for FW memory read/write operations

This patch adds support for FW memory read/write operations via debugfs.
This is useful during debugging FW issues.

Examples:

For reading FW memory location:
echo r 0x01ac > /sys/kernel/debug/mwifiex/mlan0/memrw
cat /sys/kernel/debug/mwifiex/mlan0/memrw

For writing FW memory location:
echo w 0x01ac 0x55aa > /sys/kernel/debug/mwifiex/mlan0/memrw

Signed-off-by: Chin-ran Lo <crlo@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/drivers/net/wireless/mwifiex/debugfs.c b/drivers/net/wireless/mwifiex/debugfs.c
index 1fb329dc6744..414ee2da9bfc 100644
--- a/drivers/net/wireless/mwifiex/debugfs.c
+++ b/drivers/net/wireless/mwifiex/debugfs.c
@@ -535,6 +535,83 @@ done:
 	return ret;
 }
 
+/* Proc memrw file write handler.
+ * This function is called when the 'memrw' file is opened for writing
+ * This function can be used to write to a memory location.
+ */
+static ssize_t
+mwifiex_memrw_write(struct file *file, const char __user *ubuf, size_t count,
+		    loff_t *ppos)
+{
+	int ret;
+	char cmd;
+	struct mwifiex_ds_mem_rw mem_rw;
+	u16 cmd_action;
+	struct mwifiex_private *priv = (void *)file->private_data;
+	unsigned long addr = get_zeroed_page(GFP_KERNEL);
+	char *buf = (void *)addr;
+	size_t buf_size = min(count, (size_t)(PAGE_SIZE - 1));
+
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, ubuf, buf_size)) {
+		ret = -EFAULT;
+		goto done;
+	}
+
+	ret = sscanf(buf, "%c %x %x", &cmd, &mem_rw.addr, &mem_rw.value);
+	if (ret != 3) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	if ((cmd == 'r') || (cmd == 'R')) {
+		cmd_action = HostCmd_ACT_GEN_GET;
+		mem_rw.value = 0;
+	} else if ((cmd == 'w') || (cmd == 'W')) {
+		cmd_action = HostCmd_ACT_GEN_SET;
+	} else {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	memcpy(&priv->mem_rw, &mem_rw, sizeof(mem_rw));
+	if (mwifiex_send_cmd(priv, HostCmd_CMD_MEM_ACCESS, cmd_action, 0,
+			     &mem_rw, true))
+		ret = -1;
+	else
+		ret = count;
+
+done:
+	free_page(addr);
+	return ret;
+}
+
+/* Proc memrw file read handler.
+ * This function is called when the 'memrw' file is opened for reading
+ * This function can be used to read from a memory location.
+ */
+static ssize_t
+mwifiex_memrw_read(struct file *file, char __user *ubuf,
+		   size_t count, loff_t *ppos)
+{
+	struct mwifiex_private *priv = (void *)file->private_data;
+	unsigned long addr = get_zeroed_page(GFP_KERNEL);
+	char *buf = (char *)addr;
+	int ret, pos = 0;
+
+	if (!buf)
+		return -ENOMEM;
+
+	pos += snprintf(buf, PAGE_SIZE, "0x%x 0x%x\n", priv->mem_rw.addr,
+			priv->mem_rw.value);
+	ret = simple_read_from_buffer(ubuf, count, ppos, buf, pos);
+
+	free_page(addr);
+	return ret;
+}
+
 static u32 saved_offset = -1, saved_bytes = -1;
 
 /*
@@ -749,6 +826,7 @@ MWIFIEX_DFS_FILE_READ_OPS(getlog);
 MWIFIEX_DFS_FILE_READ_OPS(fw_dump);
 MWIFIEX_DFS_FILE_OPS(regrdwr);
 MWIFIEX_DFS_FILE_OPS(rdeeprom);
+MWIFIEX_DFS_FILE_OPS(memrw);
 MWIFIEX_DFS_FILE_OPS(hscfg);
 MWIFIEX_DFS_FILE_OPS(histogram);
 
@@ -773,6 +851,7 @@ mwifiex_dev_debugfs_init(struct mwifiex_private *priv)
 	MWIFIEX_DFS_ADD_FILE(regrdwr);
 	MWIFIEX_DFS_ADD_FILE(rdeeprom);
 	MWIFIEX_DFS_ADD_FILE(fw_dump);
+	MWIFIEX_DFS_ADD_FILE(memrw);
 	MWIFIEX_DFS_ADD_FILE(hscfg);
 	MWIFIEX_DFS_ADD_FILE(histogram);
 }