On Fri, 14 May 2010 14:04:17 +0300 Grazvydas Ignotas <notasas@xxxxxxxxx> wrote: > Hi Kalle, > > On Wed, Apr 28, 2010 at 12:18 AM, Grazvydas Ignotas <notasas@xxxxxxxxx> wrote: > > SDIO specification allows RAW (Read after Write) operation using > > IO_RW_DIRECT command (CMD52) by setting the RAW bit. This operation is > > similar to ordinary read/write commands, except that both write and read > > are performed using single command/response pair. The Linux SDIO layer > > already supports this internaly, only external function is missing for > > drivers to make use, which is added by this patch. > > > > This type of command is required to implement proper power save mode > > support in wl1251 wifi driver. > > As wl1251 maintainer, can you confirm this is needed for wl1251 driver > to function in SDIO mode? Perhaps this could help convince Andrew to > merge this patch. I kinda ducked the patch because there are no callers of the function. > Without this the chip is having problems leaving ELP > mode. Android has similar patch for G1 in it's tree for the same > reason: > > http://android.git.kernel.org/?p=kernel/common.git;a=commitdiff;h=74a47786f6ecbe6c1cf9fb15efe6a968451deb52 Well let's cc Dmitry then. Dmitry's patch is somewhat different from yours and that needs to be looked at. Some comments: : From: Grazvydas Ignotas <notasas@xxxxxxxxx> : : SDIO specification allows RAW (Read after Write) operation using : IO_RW_DIRECT command (CMD52) by setting the RAW bit. This operation is : similar to ordinary read/write commands, except that both write and read : are performed using single command/response pair. The Linux SDIO layer : already supports this internaly, only external function is missing for : drivers to make use, which is added by this patch. : : This type of command is required to implement proper power save mode : support in wl1251 wifi driver. : : Signed-off-by: Grazvydas Ignotas <notasas@xxxxxxxxx> : Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> : --- : : drivers/mmc/core/sdio_io.c | 31 +++++++++++++++++++++++++++++++ : include/linux/mmc/sdio_func.h | 3 +++ : 2 files changed, 34 insertions(+) : : diff -puN drivers/mmc/core/sdio_io.c~sdio-add-new-function-for-raw-read-after-write-operation drivers/mmc/core/sdio_io.c : --- a/drivers/mmc/core/sdio_io.c~sdio-add-new-function-for-raw-read-after-write-operation : +++ a/drivers/mmc/core/sdio_io.c : @@ -406,6 +406,37 @@ void sdio_writeb(struct sdio_func *func, : EXPORT_SYMBOL_GPL(sdio_writeb); : : /** : + * sdio_writeb_readb - write and read a byte from SDIO function : + * @func: SDIO function to access : + * @b: byte to write : + * @addr: address to write to : + * @err_ret: optional status value from transfer : + * : + * Performs a RAW (Read after Write) operation as defined by SDIO spec - : + * single byte is written to address space of a given SDIO function and : + * response is read back from the same address, both using single request. : + * If there is a problem with the operation, 0xff is returned and : + * @err_ret will contain the error code. : + */ : +u8 sdio_writeb_readb(struct sdio_func *func, u8 b, "b" is a poor name. Please choose something meaningful. : + unsigned int addr, int *err_ret) : +{ : + int ret; : + u8 val; : + : + BUG_ON(!func); This test doesn't gain us much. If `func' is NULL, we'll reliably oops when dereferencing it, which gives the same info as the BUG_ON(). : + ret = mmc_io_rw_direct(func->card, 1, func->num, addr, b, &val); : + if (err_ret) : + *err_ret = ret; : + if (ret) : + val = 0xff; : + : + return val; : +} : +EXPORT_SYMBOL_GPL(sdio_writeb_readb); : + : +/** : * sdio_memcpy_fromio - read a chunk of memory from a SDIO function : * @func: SDIO function to access : * @dst: buffer to store the data : diff -puN include/linux/mmc/sdio_func.h~sdio-add-new-function-for-raw-read-after-write-operation include/linux/mmc/sdio_func.h : --- a/include/linux/mmc/sdio_func.h~sdio-add-new-function-for-raw-read-after-write-operation : +++ a/include/linux/mmc/sdio_func.h : @@ -145,6 +145,9 @@ extern void sdio_writew(struct sdio_func : extern void sdio_writel(struct sdio_func *func, u32 b, : unsigned int addr, int *err_ret); : : +extern u8 sdio_writeb_readb(struct sdio_func *func, u8 b, : + unsigned int addr, int *err_ret); : + : extern int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr, : void *src, int count); : extern int sdio_writesb(struct sdio_func *func, unsigned int addr, -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
