Re: [PATCH] b43: Allow PIO mode to be selected at module load

[John Daiker <daikerjohn@gmail.com>]

On 12/10/2009 03:35 PM, Larry Finger wrote:
> 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>
> ---
>
> John,
>
> This version implements the changes suggested by Michael Buesch.
>
> I don't know where this change should go. It is likely too large
> and invasive to be applied to 2.6.33; however, it should be
> applied to 2.6.32. Hmm? I guess that is why you get the "big money".
> :)
>
> Larry
> ---
>
>
> Index: wireless-testing/drivers/net/wireless/b43/Kconfig
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/Kconfig
> +++ wireless-testing/drivers/net/wireless/b43/Kconfig
> @@ -3,6 +3,7 @@ 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.
>
> @@ -78,14 +79,6 @@ config B43_SDIO
>
>   	  If unsure, say N.
>
> -# Data transfers to the device via PIO
> -# This is only needed on PCMCIA and SDIO devices. All others can do DMA properly.
> -config B43_PIO
> -	bool
> -	depends on B43&&  (B43_SDIO || B43_PCMCIA || B43_FORCE_PIO)
> -	select SSB_BLOCKIO
> -	default y
> -
>   config B43_NPHY
>   	bool "Pre IEEE 802.11n support (BROKEN)"
>   	depends on B43&&  EXPERIMENTAL&&  BROKEN
> @@ -137,12 +130,4 @@ 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.
> +
> Index: wireless-testing/drivers/net/wireless/b43/Makefile
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/Makefile
> +++ wireless-testing/drivers/net/wireless/b43/Makefile
> @@ -12,7 +12,7 @@ b43-y				+= xmit.o
>   b43-y				+= lo.o
>   b43-y				+= wa.o
>   b43-y				+= dma.o
> -b43-$(CONFIG_B43_PIO)		+= pio.o
> +b43-y				+= pio.o
>   b43-y				+= rfkill.o
>   b43-$(CONFIG_B43_LEDS)		+= leds.o
>   b43-$(CONFIG_B43_PCMCIA)	+= pcmcia.o
> Index: wireless-testing/drivers/net/wireless/b43/b43.h
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/b43.h
> +++ wireless-testing/drivers/net/wireless/b43/b43.h
> @@ -821,11 +821,9 @@ struct b43_wl {
>   	/* The device LEDs. */
>   	struct b43_leds leds;
>
> -#ifdef CONFIG_B43_PIO
>   	/* Kmalloc'ed scratch space for PIO TX/RX. Protected by wl->mutex. */
>   	u8 pio_scratchspace[110] __attribute__((__aligned__(8)));
>   	u8 pio_tailspace[4] __attribute__((__aligned__(8)));
> -#endif /* CONFIG_B43_PIO */
>   };
>
>   static inline struct b43_wl *hw_to_b43_wl(struct ieee80211_hw *hw)
> @@ -876,20 +874,9 @@ static inline void b43_write32(struct b4
>
>   static inline bool b43_using_pio_transfers(struct b43_wldev *dev)
>   {
> -#ifdef CONFIG_B43_PIO
>   	return dev->__using_pio_transfers;
> -#else
> -	return 0;
> -#endif
>   }
>
> -#ifdef CONFIG_B43_FORCE_PIO
> -# define B43_FORCE_PIO	1
> -#else
> -# define B43_FORCE_PIO	0
> -#endif
> -
> -
>   /* Message printing */
>   void b43info(struct b43_wl *wl, const char *fmt, ...)
>       __attribute__ ((format(printf, 2, 3)));
> Index: wireless-testing/drivers/net/wireless/b43/main.c
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/main.c
> +++ wireless-testing/drivers/net/wireless/b43/main.c
> @@ -102,6 +102,9 @@ int b43_modparam_verbose = B43_VERBOSITY
>   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(stru
>   			       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
>
>   	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 {
> Index: wireless-testing/drivers/net/wireless/b43/dma.c
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/dma.c
> +++ wireless-testing/drivers/net/wireless/b43/dma.c
> @@ -1760,7 +1760,6 @@ void b43_dma_tx_resume(struct b43_wldev
>   	b43_power_saving_ctl_bits(dev, 0);
>   }
>
> -#ifdef CONFIG_B43_PIO
>   static void direct_fifo_rx(struct b43_wldev *dev, enum b43_dmatype type,
>   			   u16 mmio_base, bool enable)
>   {
> @@ -1794,4 +1793,3 @@ void b43_dma_direct_fifo_rx(struct b43_w
>   	mmio_base = b43_dmacontroller_base(type, engine_index);
>   	direct_fifo_rx(dev, type, mmio_base, enable);
>   }
> -#endif /* CONFIG_B43_PIO */
> Index: wireless-testing/drivers/net/wireless/b43/pio.h
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/pio.h
> +++ wireless-testing/drivers/net/wireless/b43/pio.h
> @@ -55,8 +55,6 @@
>   #define B43_PIO_MAX_NR_TXPACKETS	32
>
>
> -#ifdef CONFIG_B43_PIO
> -
>   struct b43_pio_txpacket {
>   	/* Pointer to the TX queue we belong to. */
>   	struct b43_pio_txqueue *queue;
> @@ -169,42 +167,4 @@ void b43_pio_rx(struct b43_pio_rxqueue *
>   void b43_pio_tx_suspend(struct b43_wldev *dev);
>   void b43_pio_tx_resume(struct b43_wldev *dev);
>
> -
> -#else /* CONFIG_B43_PIO */
> -
> -
> -static inline int b43_pio_init(struct b43_wldev *dev)
> -{
> -	return 0;
> -}
> -static inline void b43_pio_free(struct b43_wldev *dev)
> -{
> -}
> -static inline void b43_pio_stop(struct b43_wldev *dev)
> -{
> -}
> -static inline int b43_pio_tx(struct b43_wldev *dev,
> -			     struct sk_buff *skb)
> -{
> -	return 0;
> -}
> -static inline void b43_pio_handle_txstatus(struct b43_wldev *dev,
> -					   const struct b43_txstatus *status)
> -{
> -}
> -static inline void b43_pio_get_tx_stats(struct b43_wldev *dev,
> -					struct ieee80211_tx_queue_stats *stats)
> -{
> -}
> -static inline void b43_pio_rx(struct b43_pio_rxqueue *q)
> -{
> -}
> -static inline void b43_pio_tx_suspend(struct b43_wldev *dev)
> -{
> -}
> -static inline void b43_pio_tx_resume(struct b43_wldev *dev)
> -{
> -}
> -
> -#endif /* CONFIG_B43_PIO */
>   #endif /* B43_PIO_H_ */
> --
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Tested-by: John Daiker <daikerjohn@gmail.com>