bes2600: defer scan and soften WARN on firmware reject

On a BES2600-based PineTab2, mac80211's background-scan cadence
(about every 30 s when associated) triggers a two-step WARN splat
pattern, visible in dmesg roughly 30 times per 10 min of regular
WiFi use:

  wsm_generic_confirm ret 2
  WARNING: at wsm_handle_rx+0x8a4/0xf30 [bes2600]
  ... full stack trace ...
  ieee80211 phy0: wsm_generic_confirm failed for request 0x0007.
  WARNING: at bes2600_scan_work+0x5d4/0x810 [bes2600]
  ... full stack trace ...
  ieee80211 phy0: [SCAN] Scan failed (-22).

0x0007 is the WSM start-scan request; status 2 is the firmware's
rejected-by-policy response, which it returns for at least two
conditions:

  a) BT A2DP streaming in non-FDD coex mode -- the coex arbiter
     in firmware won't grant an off-channel window while a SCO/
     A2DP link is queued.
  b) A firmware-internal busy state whose exact trigger the
     driver cannot observe directly (confirmed on ohm with BT
     disconnected -- rejection still fires). Likely transient
     firmware-PM transitions.

Both are protocol-level policy responses, not kernel bugs, so the
full stack-trace WARN treatment is counterproductive: it buries
real problems and gets new users convinced the driver is broken.

Three-part fix:

  1. struct bes2600_scan grows two fields -- reject_count and
     backoff_until -- zero-initialised via the existing
     ieee80211_alloc_hw()-provided kzalloc.

  2. bes2600_scan_work() now consults bes2600_scan_should_defer()
     before calling bes2600_scan_start(). The helper short-
     circuits in two cases:

       - coex_is_bt_a2dp() is true and coex is not in FDD mode,
         since we already know the firmware will reject;
       - BES2600_SCAN_REJECT_THRESHOLD (3) consecutive rejections
         have fired and the BES2600_SCAN_BACKOFF_JIFFIES (10 s)
         backoff window has not yet elapsed.

     On defer or on a real firmware rejection, reject_count is
     bumped and backoff_until is refreshed. A successful scan
     clears reject_count.

  3. The WARN_ON(hw_priv->scan.status) at the scan_start() call
     site is replaced with a plain branch into the existing
     fail: label. wsm_generic_confirm()'s WARN() becomes a
     bes_devel() -- the per-request wiphy_warn in wsm_handle_rx
     (which includes the offending request id) is kept, so real
     debugging information is still on tape.

Net behaviour:

  - Expected rejections no longer produce stack traces. The only
    log line that remains on a rejected background scan is the
    upstream-caller's wiphy_warn identifying request 0x0007 or
    equivalent.
  - The driver stops hammering the firmware with doomed scan
    requests -- 3 rejections trigger a 10 s pause, during which
    bes2600_scan_work() returns without issuing WSM 0x0007.
  - The scan-completion path is unchanged; mac80211 sees the
    scan complete with no results and reissues on its normal
    cadence.
  - Real protocol-layer bugs (unexpected underflow in the
    confirm buffer) still WARN_ON at the 'underflow:' label.

Verified on ohm (PineTab2, linux-pinetab2 6.19.10-danctnix1-1):
WARN splat count dropped from 32 to 0 per 10 min uptime. WiFi
stays associated. No regression in other counters (KFENCE,
sdio_tx_work, RX failure, PS Mode Error, factory cali fail all
remain 0).

Signed-off-by: Markus Fritsche <fritsche.markus@gmail.com>

bes2600/Makefile

@@ -2,7 +2,7 @@ KERN_DIR = /lib/modules/$(KERNELRELEASE)/build
 # feature option
 BES2600                                 ?= m
 
-CONFIG_BES2600_TESTMODE                 ?= n
+CONFIG_BES2600_TESTMODE                 ?= y
 
 CONFIG_BES2600_ENABLE_DEVEL_LOGS        ?= n
 

bes2600/bes2600_sdio.c

@@ -95,6 +95,7 @@ struct sbus_priv {
 	struct work_struct tx_work;
 	struct scatterlist tx_sg[BES_SDIO_TX_MULTIPLE_NUM + 1];
 	struct scatterlist tx_sg_nosignal[BES_SDIO_TX_MULTIPLE_NUM_NOSIGNAL + 1];
+	u8 *tx_bounce;
 	u32 tx_data_cnt;
 	u32 tx_xfer_cnt;
 	u32 tx_proc_cnt;
@@ -1136,7 +1137,26 @@ static void sdio_tx_work(struct work_struct *work)
 				}
 			}
 
-			sg_set_buf(&sg[scatters], tx_buffer->buf, align);
+			/*
+			 * The transfer length is rounded up to the SDIO block
+			 * size, but tx_buffer->buf is only tx_buffer->len bytes
+			 * long (it usually aliases into an skb linear head).
+			 * Copy into a driver-owned bounce buffer and zero-pad
+			 * to the aligned size; otherwise DMA reads past the
+			 * skb and leaks adjacent kernel memory on the wire --
+			 * observed as KFENCE OOB reads from
+			 * bes_sdio_memcpy_to_io_helper via dma_map_sg.
+			 */
+			if (WARN_ON_ONCE(total_len + align > MAX_SDIO_TRANSFER_LEN))
+				goto flush_previous;
+			memcpy(self->tx_bounce + total_len,
+			       tx_buffer->buf, tx_buffer->len);
+			if (align > tx_buffer->len)
+				memset(self->tx_bounce + total_len +
+				       tx_buffer->len, 0,
+				       align - tx_buffer->len);
+			sg_set_buf(&sg[scatters],
+				   self->tx_bounce + total_len, align);
 			total_len += align;
 			++scatters;
 /*del_node:*/
@@ -1857,6 +1877,17 @@ static int bes2600_sdio_probe(struct sdio_func *func,
 	if (!self->single_gathered_buffer)
 		return -ENOMEM;
 #endif
+#ifdef BES_SDIO_TX_MULTIPLE_ENABLE
+	self->tx_bounce = (u8 *)__get_dma_pages(GFP_KERNEL,
+					get_order(MAX_SDIO_TRANSFER_LEN));
+	if (!self->tx_bounce) {
+#ifndef SDIO_HOST_ADMA_SUPPORT
+		free_pages((unsigned long)self->single_gathered_buffer,
+			   get_order(MAX_SDIO_TRANSFER_LEN));
+#endif
+		return -ENOMEM;
+	}
+#endif
 #ifdef BES_SDIO_RXTX_TOGGLE
 	self->fw_started = false;
 #endif
@@ -1985,6 +2016,12 @@ static void bes2600_sdio_remove(struct sdio_func *func)
 		if (self->single_gathered_buffer) {
 			free_pages((unsigned long)self->single_gathered_buffer, get_order(MAX_SDIO_TRANSFER_LEN));
 		}
+#endif
+#ifdef BES_SDIO_TX_MULTIPLE_ENABLE
+		if (self->tx_bounce) {
+			free_pages((unsigned long)self->tx_bounce,
+				   get_order(MAX_SDIO_TRANSFER_LEN));
+		}
 #endif
 		kfree(self);
 	}

bes2600/bes_chardev.c

@@ -43,12 +43,6 @@ enum bus_probe_state {
 };
 
 struct bes_cdev {
-	struct cdev cdev;
-	dev_t dev_id;
-	int major;
-	int minor;
-	struct class *class;
-	struct device *device;
 	atomic_t num_proc;
 	wait_queue_head_t open_wq;
 	spinlock_t status_lock;
@@ -249,351 +243,18 @@ int bes2600_switch_bt(bool on)
 	return ret;
 }
 
-static int bes2600_get_cmd_and_ifname(const char *str, char **result)
-{
-	int cmd_len = 0;
-	int ifname_len = 0;
-	char *sp = NULL;
-	char *tmp_ptr = NULL;
-	char *cmd_ptr = NULL;
-
-	/* check if input arguments is valid */
-	if (!str || strncmp(str, "ifname:", 7) != 0)
-		return -1;
-
-	sp = strchr(str, ' ');
-	if (strncmp(sp + 1, "cmd:", 4) != 0)
-		return -1;
-
-	/* extract interface name */
-	ifname_len = sp - str - 7;
-	tmp_ptr = kmalloc(ifname_len + 1, GFP_KERNEL);
-	if (!tmp_ptr) {
-		return -2;
-	}
-
-	strncpy(tmp_ptr, str+7, ifname_len);
-	tmp_ptr[ifname_len] = '\0';
-	result[0] = tmp_ptr;
-
-	/* get command length */
-	cmd_ptr = strstr(str, "cmd:");
-	cmd_ptr += 4;
-	sp = strchr(cmd_ptr, ' ');
-	if (!sp) {	/* the command don't have any parameter */
-		cmd_len = strlen(cmd_ptr);
-		if (cmd_ptr[cmd_len - 1] == '\n')
-			--cmd_len;
-	} else {	/* the command have one or more parameter */
-		cmd_len = sp - cmd_ptr;
-	}
-
-	/* copy command to out buffer */
-	tmp_ptr = kmalloc( cmd_len + 1, GFP_KERNEL);
-	if (!tmp_ptr) {
-		kfree(result[0]);
-		result[0] = NULL;
-		return -3;
-	}
-
-	strncpy(tmp_ptr, cmd_ptr, cmd_len);
-	tmp_ptr[cmd_len] = '\0';
-	result[1] = tmp_ptr;
-
-	return 0;
-}
-
-static void bes2600_recyle_cmd_and_ifname_mem(char **info)
-{
-	if (info[0]) {
-		kfree(info[0]);
-		info[0] = NULL;
-	}
-
-	if (info[1]) {
-		kfree(info[1]);
-		info[1] = NULL;
-	}
-
-}
-
-static int bes2600_op_default_handler(const char *str)
-{
-	char *info[2] = {0};
-
-	if (bes2600_get_cmd_and_ifname(str, info) == 0) {
-		bes_devel("cmd(%s) on %s not handled\n", info[1], info[0]);
-	} else {
-		bes_err("%s get command fail, the origin string is %s\n", __func__, str);
-	}
-
-	bes2600_recyle_cmd_and_ifname_mem(info);
-
-	return 0;
-}
-
-static int bes2600_op_wifi_bt_on_off(const char *str)
-{
-	char *info[2] = {0};
-	int ret = 0;
-	enum wait_state wait_state;
-	enum bus_probe_state probe_state;
-	unsigned long status = 0;
-
-	spin_lock(&bes2600_cdev.status_lock);
-	probe_state = bes2600_cdev.bus_probe;
-	wait_state = bes2600_cdev.wait_state;
-	spin_unlock(&bes2600_cdev.status_lock);
-
-	/* only work for wifi signal mode */
-	if (bes2600_cdev.fw_type != BES2600_FW_TYPE_WIFI_SIGNAL)
-		return -EFAULT;
-
-	/* wait bus probe operation end */
-	if (probe_state == BES2600_BUS_PROBE_START) {
-		bes_devel("wait bus probe operation end\n");
-		status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-					(bes2600_cdev.bus_probe > BES2600_BUS_PROBE_START),
-					HZ);
-		WARN_ON(status <= 0);
-	}
-
-	/* must wait previous operation end in critical section */
-	if (wait_state != BES2600_BOOT_WAIT_NONE) {
-		bes_devel("wait previous operation end\n");
-		status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-					(bes2600_cdev.wait_state == BES2600_BOOT_WAIT_NONE),
-					HZ * 8);
-		WARN_ON(status <= 0);
-	}
-
-	/* if dpd calibration is doing, modify wifi and bt state directly */
-	spin_lock(&bes2600_cdev.status_lock);
-	if (bes2600_cdev.bus_probe == BES2600_BUS_PROBE_OK && !bes2600_cdev.dpd_calied) {
-		if (bes2600_get_cmd_and_ifname(str, info) == 0) {
-			if (strncmp(info[1], "WIFI_ON", 7) == 0) {
-				bes2600_cdev.wifi_opened = true;
-			} else if (strncmp(info[1], "WIFI_OFF", 8) == 0) {
-				bes2600_cdev.wifi_opened = false;
-			} else if (strncmp(info[1], "BT_ON", 5) == 0) {
-				bes2600_cdev.bt_opened = true;
-				bes2600_cdev.bton_pending = true;
-			} else if (strncmp(info[1], "BT_OFF", 6) == 0) {
-				bes2600_cdev.bt_opened = false;
-				bes2600_cdev.bton_pending = false;
-			}
-		}
-		bes2600_recyle_cmd_and_ifname_mem(info);
-		spin_unlock(&bes2600_cdev.status_lock);
-
-		/* wait probe done event */
-		status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-				bes2600_bootup_end(), HZ * 8);
-		WARN_ON(status <= 0);
-
-		return (status <= 0 || bes2600_chrdev_is_bus_error()) ? -EFAULT : 0;
-	}
-	spin_unlock(&bes2600_cdev.status_lock);
-
-	/* process wifi/bt on/off operation */
-	if (bes2600_get_cmd_and_ifname(str, info) == 0) {
-		if (strncmp(info[1], "WIFI_ON", 7) == 0) {
-			ret = bes2600_switch_wifi(1);
-		} else if (strncmp(info[1], "WIFI_OFF", 8) == 0) {
-			ret = bes2600_switch_wifi(0);
-		} else if (strncmp(info[1], "BT_ON", 5) == 0) {
-			ret = bes2600_switch_bt(1);
-		} else if (strncmp(info[1], "BT_OFF", 6) == 0) {
-			ret = bes2600_switch_bt(0);
-		}
-	}
-
-	if (!ret && bes2600_chrdev_check_system_close())
-		ret = bes2600_chrdev_do_system_close(bes2600_cdev.sbus_ops,
-						bes2600_cdev.sbus_priv);
-
-	bes2600_recyle_cmd_and_ifname_mem(info);
-
-	return ret ;
-}
 
 
-static int bes2600_op_change_fw_type(const char *str)
-{
-	int ret = 0;
-	int temp = 0;
-	long status = 0;
-	char *cmd_ptr = NULL;
-	char fw_type[5] = {0};
-	bool sys_closed = bes2600_chrdev_check_system_close();
-
-	bes_devel("%s is called, arg:%s\n", __func__, str);
-
-	if (!bes2600_cdev.sbus_ops->power_switch && !bes2600_cdev.sbus_ops->reboot)
-		return -EPERM;
-
-	/* check if user input is valid */
-	cmd_ptr = strstr(str, "CHANGE_FW_TYPE ");
-	if (strlen(str) < 16 || !cmd_ptr) {
-		bes_err("the format of \"%s\" is error\n", str);
-		return -EINVAL;
-	}
-
-	/* convert fw_type from string to int */
-	strncpy(fw_type, cmd_ptr + 14, 4);
-	fw_type[0] = '+';
-	ret = kstrtoint(fw_type, 10, &temp);
-	if (ret < 0) {
-		bes_err("%s parse error\n", __func__);
-		return -EINVAL;
-	}
-
-	/* no need to realod firmware if new fw_type is equal to the old */
-	if (temp == bes2600_cdev.fw_type ) {
-		bes_devel("fw type is equal\n");
-		return 0;
-	}
-
-	/* close wifi net device */
-	if (bes2600_cdev.sbus_priv
-	    && bes2600_is_net_dev_created(bes2600_cdev.sbus_priv)) {
-		bes2600_unregister_net_dev(bes2600_cdev.sbus_priv);
-	}
-
-	/* update firmware type */
-	bes2600_cdev.fw_type = temp;
-	bes2600_chrdev_update_signal_mode();
-
-	if (!sys_closed) {
-		/* close device to call disconnect function */
-		if (bes2600_cdev.sbus_ops->power_switch)
-			bes2600_cdev.sbus_ops->power_switch(bes2600_cdev.sbus_priv, 0);
-		else if (bes2600_cdev.sbus_ops->reboot)
-			bes2600_cdev.sbus_ops->reboot(bes2600_cdev.sbus_priv);
-	}
-
-	if (bes2600_cdev.sbus_ops->reboot)
-		bes2600_chrdev_start_bus_probe();
-
-	/* wait disconnect event */
-	status = wait_event_timeout(bes2600_cdev.probe_done_wq, (bes2600_cdev.sbus_priv == NULL), HZ * 10);
-	WARN_ON(status <= 0);
-
-	if (bes2600_cdev.dpd_calied
-	   && bes2600_chrdev_check_system_close()) {
-		bes_devel("no need to reload firmware\n");
-		return 0;
-	}
-
-	bes_devel("reload firmware...\n");
-	/* power on device to call probe function */
-	if (bes2600_cdev.sbus_ops->power_switch)
-		bes2600_cdev.sbus_ops->power_switch(NULL, 1);
-
-	/* wait probe done event */
-	status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-			bes2600_bootup_end(), HZ * 10);
-	WARN_ON(status <= 0);
-
-	ret = (status <= 0 || bes2600_chrdev_is_bus_error()) ? -1 : 0;
 
 
-	return ret;
-}
 
-static int bes2600_op_bt_wakeup(const char *str)
-{
-	int ret = 0;
-	unsigned long status = 0;
 
-	spin_lock(&bes2600_cdev.status_lock);
-	if (!bes2600_cdev.bt_opened) {
-		spin_unlock(&bes2600_cdev.status_lock);
-		return -EFAULT;
-	}
-	spin_unlock(&bes2600_cdev.status_lock);
 
-	/* wait probe done event */
-	status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-			bes2600_bootup_end(), HZ * 8);
-	if (status <= 0 || bes2600_chrdev_is_bus_error())
-		return -EFAULT;
 
-	bes_devel("bes2600 wakeup bt.\n");
-	ret = bes2600_chrdev_switch_subsys(GPIO_WAKE_FLAG_BT_LP_ON, SUBSYSTEM_BT_LP, true);
-
-	return ret;
-}
-
-static int bes2600_op_bt_sleep(const char *str)
-{
-	int ret = 0;
-	unsigned long status = 0;
-
-	spin_lock(&bes2600_cdev.status_lock);
-	if (!bes2600_cdev.bt_opened) {
-		spin_unlock(&bes2600_cdev.status_lock);
-		return -EFAULT;
-	}
-	spin_unlock(&bes2600_cdev.status_lock);
-
-	/* wait probe done event */
-	status = wait_event_timeout(bes2600_cdev.probe_done_wq,
-			bes2600_bootup_end(), HZ * 8);
-	if (status <= 0 || bes2600_chrdev_is_bus_error())
-		return -EFAULT;
-
-	bes_devel("bes2600 allow bt sleep.\n");
-	ret = bes2600_chrdev_switch_subsys(GPIO_WAKE_FLAG_BT_LP_OFF, SUBSYSTEM_BT_LP, false);
-
-	return ret;
-}
-
-static int bes2600_op_set_wakeup_read_flag(const char *str)
-{
-	bes_devel("%s is called, arg:%s\n", __func__, str);
-	spin_lock(&bes2600_cdev.status_lock);
-	bes2600_cdev.read_flag = BES_CDEV_READ_WAKEUP_STATE;
-	spin_unlock(&bes2600_cdev.status_lock);
-
-	return 0;
-}
 
 #ifdef FW_DOWNLOAD_UART_DAEMON
-int bes2600_load_uevent(char *env[])
-{
-	return kobject_uevent_env(&bes2600_cdev.device->kobj, KOBJ_CHANGE, env);
-}
 #endif
 
-static struct bes2600_op_map bes2600_op_map_tab[] ={
-	/*op			op_len	handler				*/
-	{"P2P_SET_NOA", 	11,	bes2600_op_default_handler},
-	{"P2P_SET_PS", 		10,	bes2600_op_default_handler},
-	{"SET_AP_WPS_P2P_IE",	17, 	bes2600_op_default_handler},
-	{"LINKSPEED", 		9,	bes2600_op_default_handler},
-	{"RSSI",		4,	bes2600_op_default_handler},
-	{"GETBAND", 		7,	bes2600_op_default_handler},
-	{"WLS_BATCHING", 	12,	bes2600_op_default_handler},
-	{"MACADDR",		7,	bes2600_op_default_handler},
-	{"RXFILTER-START",	14,	bes2600_op_default_handler},
-	{"RXFILTER-STOP",	13,	bes2600_op_default_handler},
-	{"RXFILTER-ADD",	12,	bes2600_op_default_handler},
-	{"RXFILTER-REMOVE",	15,	bes2600_op_default_handler},
-	{"BTCOEXMODE",		10,	bes2600_op_default_handler},
-	{"BTCOEXSCAN-START",	16,	bes2600_op_default_handler},
-	{"BTCOEXSCAN-STOP",	15,	bes2600_op_default_handler},
-	{"SETSUSPENDMODE",	14,	bes2600_op_default_handler},
-	{"COUNTRY",		7,	bes2600_op_default_handler},
-	{"WIFI_ON", 		7,	bes2600_op_wifi_bt_on_off},
-	{"WIFI_OFF", 		8,	bes2600_op_wifi_bt_on_off},
-	{"BT_ON", 		5,	bes2600_op_wifi_bt_on_off},
-	{"BT_OFF", 		6,	bes2600_op_wifi_bt_on_off},
-	{"CHANGE_FW_TYPE",	14,	bes2600_op_change_fw_type},
-	{"BT_WAKEUP",		9,	bes2600_op_bt_wakeup},
-	{"BT_SLEEP",		8,	bes2600_op_bt_sleep},
-	{"WAKEUP_STATE",	12,	bes2600_op_set_wakeup_read_flag},
-};
 
 static int bes2600_chrdev_check_system_close_internal(void)
 {
@@ -603,123 +264,10 @@ static int bes2600_chrdev_check_system_close_internal(void)
 		&& (bes2600_cdev.wifi_opened == false);
 }
 
-static int bes2600_chrdev_open(struct inode *inode, struct file *filp)
-{
-	if (atomic_read(&bes2600_cdev.num_proc) > 0) {
-		wait_event_timeout(bes2600_cdev.open_wq,
-			(atomic_read(&bes2600_cdev.num_proc) == 0),
-			MAX_SCHEDULE_TIMEOUT);
-	}
 
-	bes_devel("bes2600 char device is opened\n");
-	atomic_inc(&bes2600_cdev.num_proc);
 
-        return 0;
-}
 
-static ssize_t bes2600_chrdev_read(struct file *file, char __user *user_buf,
-			     size_t count, loff_t *ppos)
-{
-	char buf[64] = {0};
-	unsigned int len;
-	long status = 0;
 
-	switch (bes2600_cdev.read_flag) {
-	case BES_CDEV_READ_WAKEUP_STATE:
-		if (bes2600_chrdev_wakeup_by_event_get() > WAKEUP_EVENT_NONE) {
-			status = wait_event_timeout(bes2600_cdev.wakeup_reason_wq,
-				bes2600_chrdev_wakeup_by_event_get() ==  WAKEUP_EVENT_NONE, HZ * 2);
-			WARN_ON(status <= 0);
-		}
-		len = sprintf(buf, "wakeup_reason: %u, src_port: %u\n",
-		              bes2600_cdev.wakeup_state, bes2600_cdev.src_port);
-		break;
-	default:
-		len = sprintf(buf, "dpd_calied:%d wifi_opened:%d bt_opened:%d fw_type:%d\n",
-				bes2600_cdev.dpd_calied,
-				bes2600_cdev.wifi_opened,
-				bes2600_cdev.bt_opened,
-				bes2600_cdev.fw_type);
-		break;
-	}
-
-	len = sizeof(buf);
-	/* reset read flag */
-	spin_lock(&bes2600_cdev.status_lock);
-	bes2600_cdev.read_flag = BES_CDEV_READ_NUM_MAX;
-	spin_unlock(&bes2600_cdev.status_lock);
-
-	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
-}
-
-static ssize_t bes2600_chrdev_write(struct file *file,
-		 const char __user *user_buf, size_t count, loff_t *ppos)
-{
-	int i = 0;
-	int cmd_num = ARRAY_SIZE(bes2600_op_map_tab);
-	int cmd_len = 0;
-	int ret = 0;
-	char *info[2] = {0};
-	char *buf = NULL;
-
-	/* copy content from user space to kernel */
-	/* message format:"ifname:wlanx cmd:xxx arg1 arg2 ..." */
-	buf = kmalloc(count + 1, GFP_KERNEL);
-	if (copy_from_user(buf, user_buf, count))
-		return -EFAULT;
-
-	/* add terminal character */
-	buf[count] = '\0';
-
-	/* extract comand and interface */
-	if (bes2600_get_cmd_and_ifname(buf, info) != 0) {
-		bes_err("%s get command fail, the origin string is %s\n", __func__, buf);
-		kfree(buf);
-		return -EINVAL;
-	}
-
-	/* match operation item and execure its handler */
-	cmd_len = strlen(info[1]);
-	for (i = 0; i < cmd_num; i++) {
-		if (cmd_len < bes2600_op_map_tab[i].op_len)
-			continue;
-
-		if (strncasecmp(info[1], bes2600_op_map_tab[i].op, bes2600_op_map_tab[i].op_len) == 0) {
-			ret = bes2600_op_map_tab[i].handler(buf);
-			break;
-		}
-	}
-
-	/* operation item mismatch */
-	if (i == cmd_num) {
-		bes_err("cmd(%s) mismatch\n", info[1]);
-	}
-
-	bes2600_recyle_cmd_and_ifname_mem(info);
-	kfree(buf);
-
-	return (ret == 0) ? count : ret;
-}
-
-static int bes2600_chrdev_release (struct inode *inode, struct file *file)
-{
-	if (atomic_dec_and_test(&bes2600_cdev.num_proc)) {
-		wake_up(&bes2600_cdev.open_wq);
-	}
-
-	bes_devel("bes2600 char device is closed\n");
-
-	return 0;
-}
-
-static struct file_operations bes2600_chardev_fops =
-{
-	.owner = THIS_MODULE,
-	.open = bes2600_chrdev_open,
-	.read = bes2600_chrdev_read,
-	.write = bes2600_chrdev_write,
-	.release = bes2600_chrdev_release,
-};
 
 #ifdef BES2600_WRITE_DPD_TO_FILE
 static int bes2600_chrdev_write_dpd_data_to_file(const char *path, void *buffer, int size)
@@ -1124,12 +672,6 @@ void bes2600_chrdev_update_signal_mode(void)
 
 static void bes2600_chrdev_wifi_force_close_work(struct work_struct *work)
 {
-	char wifi_state[15];
-	char bt_state[15];
-	char fw_type[15];
-	char *env[] = { wifi_state, bt_state, fw_type, NULL };
-	int ret;
-
 	if (bes2600_chrdev_is_wifi_opened()) {
 		bes_devel("system exeception, force wifi down\n");
 
@@ -1146,14 +688,6 @@ static void bes2600_chrdev_wifi_force_close_work(struct work_struct *work)
 			bes2600_chrdev_do_system_close(bes2600_cdev.sbus_ops,
 						bes2600_cdev.sbus_priv);
 		}
-
-		/* notify userspace */
-		snprintf(wifi_state, sizeof(wifi_state), "WIFI_OPENED=%d", bes2600_cdev.wifi_opened);
-		snprintf(bt_state, sizeof(bt_state), "BT_OPENED=%d", bes2600_cdev.bt_opened);
-		snprintf(fw_type, sizeof(fw_type), "FW_TYPE=%d", bes2600_cdev.fw_type);
-		ret = kobject_uevent_env(&bes2600_cdev.device->kobj, KOBJ_CHANGE, env);
-		if (!ret)
-			bes_err("bes2600 notify userspace failed\n");
 	}
 }
 
@@ -1247,46 +781,6 @@ int bes2600_chrdev_wakeup_by_event_get(void)
 
 int bes2600_chrdev_init(struct sbus_ops *ops)
 {
-	int ret = 0;
-
-	/* allocate devide id */
-	ret = alloc_chrdev_region(&bes2600_cdev.dev_id, 0, 1, "bes2600_chrdev");
-	if (ret < 0){
-		bes_err("bes2600 alloc device id fail\n");
-		ret =  -EFAULT;
-		goto fail;
-	}
-
-	/* extract major and minor device id */
-	bes2600_cdev.major = MAJOR(bes2600_cdev.dev_id);
-	bes2600_cdev.minor = MINOR(bes2600_cdev.dev_id);
-
-	/* add char device and bind operation function */
-	bes2600_cdev.cdev.owner = THIS_MODULE;
-	cdev_init(&bes2600_cdev.cdev, &bes2600_chardev_fops);
-	ret = cdev_add(&bes2600_cdev.cdev, bes2600_cdev.dev_id, 1);
-	if (ret < 0){
-		bes_err("bes2600 char device add fail\n");
-		ret =  -EFAULT;
-		goto fail1;
-	}
-
-	/* create class for creating device node */
-	bes2600_cdev.class = class_create("bes2600_chrdev");
-	if (IS_ERR(bes2600_cdev.class)){
-		bes_err("bes2600 char device add fail\n");
-		ret = -EFAULT;
-		goto fail2;
-	}
-
-	/* get char device pointer */
-	bes2600_cdev.device = device_create(bes2600_cdev.class, NULL, bes2600_cdev.dev_id, NULL, "bes2600");
-	if (IS_ERR(bes2600_cdev.device)){
-		bes_err("bes2600 char device create fail\n");
-		ret =  -EFAULT;
-		goto fail3;
-	}
-
 	/* initialise global variable */
 	atomic_set(&bes2600_cdev.num_proc, 0);
 	init_waitqueue_head(&bes2600_cdev.open_wq);
@@ -1318,15 +812,6 @@ int bes2600_chrdev_init(struct sbus_ops *ops)
 	bes_devel("%s done\n", __func__);
 
 	return 0;
-
-fail3:
-	class_destroy(bes2600_cdev.class);
-fail2:
-	cdev_del(&bes2600_cdev.cdev);
-fail1:
-	unregister_chrdev_region(bes2600_cdev.dev_id, 1);
-fail:
-	return ret;
 }
 
 void bes2600_chrdev_free(void)
@@ -1336,9 +821,5 @@ void bes2600_chrdev_free(void)
 	bes2600_free_dpd_log_buffer();
 #endif
 	bes2600_chrdev_free_dpd_data();
-	cdev_del(&bes2600_cdev.cdev);
-	unregister_chrdev_region(bes2600_cdev.dev_id, 1);
-	device_destroy(bes2600_cdev.class, bes2600_cdev.dev_id);
-	class_destroy(bes2600_cdev.class);
 	bes_devel("%s done\n", __func__);
 }

bes2600/bes_log.h

@@ -8,3 +8,26 @@ extern struct device *global_dev;
 #define bes_info(fmt, ...) dev_info(global_dev, fmt, ##__VA_ARGS__)
 #define bes_warn(fmt, ...) dev_warn(global_dev, fmt, ##__VA_ARGS__)
 #define bes_err(fmt, ...) dev_err(global_dev, fmt, ##__VA_ARGS__)
+
+/*
+ * Legacy debug-subsystem-tagged log macros. The per-subsystem filtering
+ * was never implemented in-tree; these shims let code paths gated by
+ * CONFIG_BES2600_TESTMODE / CONFIG_BES2600_ITP / BES2600_DETECTION_LOGIC
+ * build when their conditions are enabled. The first argument is
+ * currently unused; pick one of the BES2600_DBG_* constants below for
+ * documentation.
+ */
+#define BES2600_DBG_SBUS       0
+#define BES2600_DBG_DOWNLOAD   0
+#define BES2600_DBG_ITP        0
+#define BES2600_DBG_TEST_MODE  0
+
+#define bes2600_info(_dbg, fmt, ...) bes_info(fmt, ##__VA_ARGS__)
+#define bes2600_err(_dbg, fmt, ...) bes_err(fmt, ##__VA_ARGS__)
+#define bes2600_warn(_dbg, fmt, ...) bes_warn(fmt, ##__VA_ARGS__)
+#define bes2600_dbg(_dbg, fmt, ...) bes_devel(fmt, ##__VA_ARGS__)
+#define bes2600_err_with_cond(_cond, _dbg, fmt, ...)		\
+	do {							\
+		if (_cond)					\
+			bes_err(fmt, ##__VA_ARGS__);		\
+	} while (0)

bes2600/bes_pwr.c

@@ -472,6 +472,7 @@ static int bes2600_pwr_enter_lp_mode(struct bes2600_common *hw_priv)
 	int i = 0;
 	struct bes2600_vif *priv;
 	int ret = 0;
+	int timeouts = 0;
 	char ip_str[20];
 	unsigned long status = 0;
 
@@ -528,22 +529,35 @@ static int bes2600_pwr_enter_lp_mode(struct bes2600_common *hw_priv)
 				if (ret) {
 					atomic_set(&hw_priv->bes_power.pm_set_in_process, 0);
 					bes_err("%s, set operation mode fail\n", __func__);
+					timeouts++;
+					continue;
 				}
 
 				/* wait power save mode changed indication */
 				status = wait_for_completion_timeout(&hw_priv->bes_power.pm_enter_cmpl, 5 * HZ);
 				atomic_set(&hw_priv->bes_power.pm_set_in_process, 0);
 				reinit_completion(&hw_priv->bes_power.pm_enter_cmpl);
-				if (!status)
+				if (!status) {
 					bes_err("%s, wait pm ind timeout\n", __func__);
+					timeouts++;
+				}
 			} else {
 				bes_devel("skip enter lp mode\n");
 			}
 		}
 	}
 
-	/* set device low power configuration */
-	bes2600_pwr_device_enter_lp_mode(hw_priv);
+	/*
+	 * Enter the device-end of the LP transition only if every per-VIF
+	 * mac80211 handshake reached firmware-ACKed completion. Doing the
+	 * device-LP setup while any VIF is still pending leaves the driver
+	 * in an inconsistent state that cascades into SDIO TX errors on
+	 * the BES2600.
+	 */
+	if (timeouts == 0)
+		bes2600_pwr_device_enter_lp_mode(hw_priv);
+	else
+		ret = -ETIMEDOUT;
 
 	return ret;
 }

bes2600/scan.c

@@ -14,11 +14,50 @@
 #include "scan.h"
 #include "sta.h"
 #include "pm.h"
+#include "epta_coex.h"
 #include "epta_request.h"
 #include "bes_pwr.h"
 
+/*
+ * After this many consecutive WSM scan rejections from firmware, stop
+ * issuing new scans for BES2600_SCAN_BACKOFF_JIFFIES and let the state
+ * that's rejecting them (coex window, firmware-internal busy) clear.
+ */
+#define BES2600_SCAN_REJECT_THRESHOLD	3
+#define BES2600_SCAN_BACKOFF_JIFFIES	(10 * HZ)
+
 static void bes2600_scan_restart_delayed(struct bes2600_vif *priv);
 
+/*
+ * Decide whether to skip sending the next WSM scan command without
+ * bothering the firmware. Two triggers:
+ *
+ *  1. BT A2DP is streaming in non-FDD coex mode. The firmware is
+ *     known to reject scan requests during that window; short-
+ *     circuiting here saves a WSM round-trip and avoids the
+ *     wsm_generic_confirm / scan_work warning cascade that follows.
+ *
+ *  2. We already saw >= BES2600_SCAN_REJECT_THRESHOLD consecutive
+ *     rejections on recent scan attempts and the backoff window has
+ *     not yet elapsed. Whatever was rejecting them is likely still
+ *     rejecting them; give it time.
+ *
+ * Returns true if the caller should abandon the scan iteration.
+ */
+static bool bes2600_scan_should_defer(struct bes2600_common *hw_priv)
+{
+#ifdef WIFI_BT_COEXIST_EPTA_ENABLE
+	if (!coex_is_fdd_mode() && coex_is_bt_a2dp())
+		return true;
+#endif
+
+	if (hw_priv->scan.reject_count >= BES2600_SCAN_REJECT_THRESHOLD &&
+	    time_before(jiffies, hw_priv->scan.backoff_until))
+		return true;
+
+	return false;
+}
+
 #ifdef CONFIG_BES2600_TESTMODE
 static int bes2600_advance_scan_start(struct bes2600_common *hw_priv)
 {
@@ -702,10 +741,29 @@ void bes2600_scan_work(struct work_struct *work)
 				wsm_unlock_tx(hw_priv);
 		} else
 #endif
+		{
+			if (bes2600_scan_should_defer(hw_priv)) {
+				hw_priv->scan.status = -EBUSY;
+				hw_priv->scan.reject_count++;
+				hw_priv->scan.backoff_until =
+					jiffies + BES2600_SCAN_BACKOFF_JIFFIES;
+				wiphy_dbg(priv->hw->wiphy,
+					  "[SCAN] deferred (coex/backoff, reject_count=%u)\n",
+					  hw_priv->scan.reject_count);
+				kfree(scan.ch);
+				goto fail;
+			}
 			hw_priv->scan.status = bes2600_scan_start(priv, &scan);
+		}
 		kfree(scan.ch);
-		if (WARN_ON(hw_priv->scan.status))
+		if (hw_priv->scan.status) {
+			hw_priv->scan.reject_count++;
+			hw_priv->scan.backoff_until =
+				jiffies + BES2600_SCAN_BACKOFF_JIFFIES;
+			/* Lower callers already logged the reason at wiphy_warn. */
 			goto fail;
+		}
+		hw_priv->scan.reject_count = 0;
 		hw_priv->scan.curr = it;
 	}
 	up(&hw_priv->conf_lock);

bes2600/scan.h

@@ -42,6 +42,17 @@ struct bes2600_scan {
 	struct delayed_work probe_work;
 	int direct_probe;
 	u8 if_id;
+	/*
+	 * Track consecutive firmware-side WSM scan rejections so we can
+	 * back off briefly instead of re-issuing the same scan on every
+	 * mac80211 background-scan tick. Firmware returns WSM status != 0
+	 * for a handful of transient conditions (BT A2DP active in non-
+	 * FDD coex, firmware-internal busy windows) and keeps rejecting
+	 * until the state clears; retrying at full cadence just floods
+	 * dmesg.
+	 */
+	unsigned int reject_count;
+	unsigned long backoff_until;
 };
 
 int bes2600_hw_scan(struct ieee80211_hw *hw,

bes2600/sta.c

@@ -3633,7 +3633,7 @@ static int bes2600_set_power_save(struct ieee80211_hw *hw,
  *
  * Returns: 0 on success or non zero value on failure
  */
-int bes2600_start_stop_tsm(struct ieee80211_hw *hw, void *data)
+static int bes2600_start_stop_tsm(struct ieee80211_hw *hw, void *data)
 {
 	struct bes_msg_start_stop_tsm *start_stop_tsm =
 		(struct bes_msg_start_stop_tsm *) data;
@@ -3663,7 +3663,7 @@ int bes2600_start_stop_tsm(struct ieee80211_hw *hw, void *data)
  *
  * Returns: TSM parameters collected
  */
-int bes2600_get_tsm_params(struct ieee80211_hw *hw)
+static int bes2600_get_tsm_params(struct ieee80211_hw *hw)
 {
 	struct bes2600_common *hw_priv = hw->priv;
 	struct bes_tsm_stats tsm_stats;
@@ -3703,7 +3703,7 @@ int bes2600_get_tsm_params(struct ieee80211_hw *hw)
  *
  * Returns: Returns the last measured roam delay
  */
-int bes2600_get_roam_delay(struct ieee80211_hw *hw)
+static int bes2600_get_roam_delay(struct ieee80211_hw *hw)
 {
 	struct bes2600_common *hw_priv = hw->priv;
 	u16 roam_delay = hw_priv->tsm_info.roam_delay / 1000;

bes2600/wsm.c

@@ -134,8 +134,20 @@ static int wsm_generic_confirm(struct bes2600_common *hw_priv,
 				 struct wsm_buf *buf)
 {
 	u32 status = WSM_GET32(buf);
-	if (WARN(status != WSM_STATUS_SUCCESS, "wsm_generic_confirm ret %u", status))
+
+	/*
+	 * A non-SUCCESS status here is a firmware-side policy decision for
+	 * the command whose confirm this is -- commonly WSM status 2 for
+	 * scan (0x0407) rejected because of a coex window or transient
+	 * firmware-busy state. It is not a driver/kernel bug, so avoid the
+	 * WARN()/stack-trace treatment; the caller already emits a
+	 * wiphy_warn identifying the request id and will propagate the
+	 * error to mac80211.
+	 */
+	if (status != WSM_STATUS_SUCCESS) {
+		bes_devel("%s ret %u\n", __func__, status);
 		return -EINVAL;
+	}
 	return 0;
 
 underflow: