rtw88: add a debugfs entry to enable/disable coex mechanism

Sometimes we need to stop the coex mechanism to debug, so that we
can manually control the device through various outer commands.
Hence, add a new debugfs coex_enable to allow us to enable/disable
the coex mechanism when driver is running.

To disable coex
echo 0 > /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable

To enable coex
echo 1 > /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable

To check coex dm is enabled or not
cat /sys/kernel/debug/ieee80211/phyX/rtw88/coex_enable
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200313033008.20070-3-yhchuang@realtek.com

drivers/net/wireless/realtek/rtw88/debug.c

@@ -706,6 +706,45 @@ static int rtw_debugfs_get_coex_info(struct seq_file *m, void *v)
 	return 0;
 }
 
+static ssize_t rtw_debugfs_set_coex_enable(struct file *filp,
+					   const char __user *buffer,
+					   size_t count, loff_t *loff)
+{
+	struct seq_file *seqpriv = (struct seq_file *)filp->private_data;
+	struct rtw_debugfs_priv *debugfs_priv = seqpriv->private;
+	struct rtw_dev *rtwdev = debugfs_priv->rtwdev;
+	struct rtw_coex *coex = &rtwdev->coex;
+	char tmp[32 + 1];
+	bool enable;
+	int ret;
+
+	rtw_debugfs_copy_from_user(tmp, sizeof(tmp), buffer, count, 1);
+
+	ret = kstrtobool(tmp, &enable);
+	if (ret) {
+		rtw_warn(rtwdev, "invalid arguments\n");
+		return ret;
+	}
+
+	mutex_lock(&rtwdev->mutex);
+	coex->stop_dm = enable == 0;
+	mutex_unlock(&rtwdev->mutex);
+
+	return count;
+}
+
+static int rtw_debugfs_get_coex_enable(struct seq_file *m, void *v)
+{
+	struct rtw_debugfs_priv *debugfs_priv = m->private;
+	struct rtw_dev *rtwdev = debugfs_priv->rtwdev;
+	struct rtw_coex *coex = &rtwdev->coex;
+
+	seq_printf(m, "coex mechanism %s\n",
+		   coex->stop_dm ? "disabled" : "enabled");
+
+	return 0;
+}
+
 #define rtw_debug_impl_mac(page, addr)				\
 static struct rtw_debugfs_priv rtw_debug_priv_mac_ ##page = {	\
 	.cb_read = rtw_debug_get_mac_page,			\
@@ -796,6 +835,11 @@ static struct rtw_debugfs_priv rtw_debug_priv_phy_info = {
 	.cb_read = rtw_debugfs_get_phy_info,
 };
 
+static struct rtw_debugfs_priv rtw_debug_priv_coex_enable = {
+	.cb_write = rtw_debugfs_set_coex_enable,
+	.cb_read = rtw_debugfs_get_coex_enable,
+};
+
 static struct rtw_debugfs_priv rtw_debug_priv_coex_info = {
 	.cb_read = rtw_debugfs_get_coex_info,
 };
@@ -831,6 +875,7 @@ void rtw_debugfs_init(struct rtw_dev *rtwdev)
 	rtw_debugfs_add_rw(rsvd_page);
 	rtw_debugfs_add_r(phy_info);
 	rtw_debugfs_add_r(coex_info);
+	rtw_debugfs_add_rw(coex_enable);
 	rtw_debugfs_add_r(mac_0);
 	rtw_debugfs_add_r(mac_1);
 	rtw_debugfs_add_r(mac_2);