b43: Allow PIO mode to be selected at module load

If userencounter the "Fatal DMA Problem" with a BCM43XX device, and
still wish to use b43 as the driver, their only option is to rebuild
the kernel with CONFIG_B43_FORCE_PIO. This patch removes this option and
allows PIO mode to be selected with a load-time parameter for the module.
Note that the configuration variable CONFIG_B43_PIO is also removed.

Once the DMA problem with the BCM4312 devices is solved, this patch will
likely be reverted.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: John Daiker <daikerjohn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 19b4eae47b59..b0b5ce950008 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -102,6 +102,9 @@ 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");
 
 static const struct ssb_device_id b43_ssb_tbl[] = {
         SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_80211, 5),
@@ -1786,8 +1789,8 @@ 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, "CONFIG_B43_FORCE_PIO must be set in "
-                               "your kernel configuration.\n");
+                        b43err(dev->wl, "Unload the b43 module and reload "
+                               "with 'pio=1'\n");
                         return;
                 }
                 if (merged_dma_reason & B43_DMAIRQ_NONFATALMASK) {
@@ -4353,7 +4356,7 @@ 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) ||
-            B43_FORCE_PIO) {
+            modparam_pio) {
                 dev->__using_pio_transfers = 1;
                 err = b43_pio_init(dev);
         } else {