ath6kl: Add debugfs entry to modify roaming parameters.

Firmware initiates roaming only after it reaches a rssi of 20.
This lower rssi threshold can be modified through a wmi command
to modify the roaming behavior.

kvalo: rename debugfs functions and move comment about rssi units next to
ath6kl_wmi_set_roam_lrssi_cmd()

Signed-off-by: Vivek Natarajan <nataraja@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath6kl/debug.c b/drivers/net/wireless/ath/ath6kl/debug.c
index cb89776..8bc4753 100644
--- a/drivers/net/wireless/ath/ath6kl/debug.c
+++ b/drivers/net/wireless/ath/ath6kl/debug.c
@@ -714,6 +714,51 @@
 	.llseek = default_llseek,
 };
 
+static ssize_t ath6kl_lrssi_roam_write(struct file *file,
+				       const char __user *user_buf,
+				       size_t count, loff_t *ppos)
+{
+	struct ath6kl *ar = file->private_data;
+	unsigned long lrssi_roam_threshold;
+	char buf[32];
+	ssize_t len;
+
+	len = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, len))
+		return -EFAULT;
+
+	buf[len] = '\0';
+	if (strict_strtoul(buf, 0, &lrssi_roam_threshold))
+		return -EINVAL;
+
+	ar->lrssi_roam_threshold = lrssi_roam_threshold;
+
+	ath6kl_wmi_set_roam_lrssi_cmd(ar->wmi, ar->lrssi_roam_threshold);
+
+	return count;
+}
+
+static ssize_t ath6kl_lrssi_roam_read(struct file *file,
+				      char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	struct ath6kl *ar = file->private_data;
+	char buf[32];
+	unsigned int len;
+
+	len = snprintf(buf, sizeof(buf), "%u\n", ar->lrssi_roam_threshold);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static const struct file_operations fops_lrssi_roam_threshold = {
+	.read = ath6kl_lrssi_roam_read,
+	.write = ath6kl_lrssi_roam_write,
+	.open = ath6kl_debugfs_open,
+	.owner = THIS_MODULE,
+	.llseek = default_llseek,
+};
+
 int ath6kl_debug_init(struct ath6kl *ar)
 {
 	ar->debug.fwlog_buf.buf = vmalloc(ATH6KL_FWLOG_SIZE);
@@ -760,6 +805,8 @@
 	debugfs_create_file("reg_dump", S_IRUSR, ar->debugfs_phy, ar,
 			    &fops_reg_dump);
 
+	debugfs_create_file("lrssi_roam_threshold", S_IRUSR | S_IWUSR,
+			    ar->debugfs_phy, ar, &fops_lrssi_roam_threshold);
 	return 0;
 }