wlcore: don't allow SDIO read/writes after failure

Set a flag and after the first read/write failure is encountered.
This flag will disallow further SDIO read/writes until op_stop() is
executed, which will clear all flags.

This prevents further errors from occurring, since one error usually
indicates that IO operations won't work anymore until the chip is
rebooted.  By blocking more calls, we avoid extra timeouts and having
to wait for them to occur.

[Added second paragraph explaining why the change is needed. -- Luca]
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/ti/wlcore/io.h

@@ -57,14 +57,32 @@ static inline int __must_check wlcore_raw_write(struct wl1271 *wl, int addr,
 						void *buf, size_t len,
 						bool fixed)
 {
-	return wl->if_ops->write(wl->dev, addr, buf, len, fixed);
+	int ret;
+
+	if (test_bit(WL1271_FLAG_SDIO_FAILED, &wl->flags))
+		return -EIO;
+
+	ret = wl->if_ops->write(wl->dev, addr, buf, len, fixed);
+	if (ret)
+		set_bit(WL1271_FLAG_SDIO_FAILED, &wl->flags);
+
+	return ret;
 }
 
 static inline int __must_check wlcore_raw_read(struct wl1271 *wl, int addr,
 					       void *buf, size_t len,
 					       bool fixed)
 {
-	return wl->if_ops->read(wl->dev, addr, buf, len, fixed);
+	int ret;
+
+	if (test_bit(WL1271_FLAG_SDIO_FAILED, &wl->flags))
+		return -EIO;
+
+	ret = wl->if_ops->read(wl->dev, addr, buf, len, fixed);
+	if (ret)
+		set_bit(WL1271_FLAG_SDIO_FAILED, &wl->flags);
+
+	return ret;
 }
 
 static inline int __must_check wlcore_raw_read_data(struct wl1271 *wl, int reg,

drivers/net/wireless/ti/wlcore/wlcore_i.h

@@ -247,6 +247,7 @@ enum wl12xx_flags {
 	WL1271_FLAG_RECOVERY_IN_PROGRESS,
 	WL1271_FLAG_VIF_CHANGE_IN_PROGRESS,
 	WL1271_FLAG_INTENDED_FW_RECOVERY,
+	WL1271_FLAG_SDIO_FAILED,
 };
 
 enum wl12xx_vif_flags {