3 files changed, 31 insertions, 7 deletions

diff --git a/drivers/net/wireless/b43/Kconfig b/drivers/net/wireless/b43/Kconfig
index 073be566d05e..0a00d42642cd 100644
--- a/drivers/net/wireless/b43/Kconfig
+++ b/drivers/net/wireless/b43/Kconfig
@@ -3,7 +3,6 @@ config B43
         depends on SSB_POSSIBLE && MAC80211 && HAS_DMA
         select SSB
         select FW_LOADER
-        select SSB_BLOCKIO
         ---help---
           b43 is a driver for the Broadcom 43xx series wireless devices.
 
@@ -79,6 +78,14 @@ config B43_SDIO
 
           If unsure, say N.
 
+#Data transfers to the device via PIO. We want it as a fallback even
+# if we can do DMA.
+config B43_PIO
+        bool
+        depends on B43
+        select SSB_BLOCKIO
+        default y
+
 config B43_NPHY
         bool "Pre IEEE 802.11n support (BROKEN)"
         depends on B43 && EXPERIMENTAL && BROKEN
@@ -130,4 +137,12 @@ config B43_DEBUG
           for production use.
           Only say Y, if you are debugging a problem in the b43 driver sourcecode.
 
+config B43_FORCE_PIO
+        bool "Force usage of PIO instead of DMA"
+        depends on B43 && B43_DEBUG
+        ---help---
+          This will disable DMA and always enable PIO instead.
 
+          Say N!
+          This is only for debugging the PIO engine code. You do
+          _NOT_ want to enable this.
diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index 6a6ab0f630e5..b8807fb12c92 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -702,6 +702,7 @@ struct b43_wldev {
         bool radio_hw_enable;   /* saved state of radio hardware enabled state */
         bool qos_enabled;               /* TRUE, if QoS is used. */
         bool hwcrypto_enabled;          /* TRUE, if HW crypto acceleration is enabled. */
+        bool use_pio;                   /* TRUE if next init should use PIO */
 
         /* PHY/Radio device. */
         struct b43_phy phy;
@@ -886,6 +887,12 @@ static inline bool b43_using_pio_transfers(struct b43_wldev *dev)
         return dev->__using_pio_transfers;
 }
 
+#ifdef CONFIG_B43_FORCE_PIO
+# define B43_PIO_DEFAULT 1
+#else
+# define B43_PIO_DEFAULT 0
+#endif
+
 /* Message printing */
 void b43info(struct b43_wl *wl, const char *fmt, ...)
     __attribute__ ((format(printf, 2, 3)));
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 8f7a8c0ec27d..16580d0d3a02 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -107,9 +107,9 @@ int b43_modparam_verbose = B43_VERBOSITY_DEFAULT;
 module_param_named(verbose, b43_modparam_verbose, int, 0644);
 MODULE_PARM_DESC(verbose, "Log message verbosity: 0=error, 1=warn, 2=info(default), 3=debug");
 
-static int modparam_pio;
-module_param_named(pio, modparam_pio, int, 0444);
-MODULE_PARM_DESC(pio, "enable(1) / disable(0) PIO mode");
+int b43_modparam_pio = B43_PIO_DEFAULT;
+module_param_named(pio, b43_modparam_pio, int, 0644);
+MODULE_PARM_DESC(pio, "Use PIO accesses by default: 0=DMA, 1=PIO");
 
 static const struct ssb_device_id b43_ssb_tbl[] = {
         SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_80211, 5),
@@ -1804,8 +1804,9 @@ static void b43_do_interrupt_thread(struct b43_wldev *dev)
                                dma_reason[4], dma_reason[5]);
                         b43err(dev->wl, "This device does not support DMA "
                                "on your system. Please use PIO instead.\n");
-                        b43err(dev->wl, "Unload the b43 module and reload "
-                               "with 'pio=1'\n");
+                        /* Fall back to PIO transfers if we get fatal DMA errors! */
+                        dev->use_pio = 1;
+                        b43_controller_restart(dev, "DMA error");
                         return;
                 }
                 if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
@@ -4357,7 +4358,7 @@ static int b43_wireless_core_init(struct b43_wldev *dev)
 
         if ((dev->dev->bus->bustype == SSB_BUSTYPE_PCMCIA) ||
             (dev->dev->bus->bustype == SSB_BUSTYPE_SDIO) ||
-            modparam_pio) {
+            dev->use_pio) {
                 dev->__using_pio_transfers = 1;
                 err = b43_pio_init(dev);
         } else {
@@ -4824,6 +4825,7 @@ static int b43_one_core_attach(struct ssb_device *dev, struct b43_wl *wl)
         if (!wldev)
                 goto out;
 
+        wldev->use_pio = b43_modparam_pio;
         wldev->dev = dev;
         wldev->wl = wl;
         b43_set_status(wldev, B43_STAT_UNINIT);