> -----Original Message-----
> From: David Vrabel [mailto:david.vra...@csr.com]
> Sent: Wednesday, February 10, 2010 5:52 AM
> To: linux-...@vger.kernel.org
> Cc: David Vrabel; linux-omap@vger.kernel.org; madhu...@ti.com
> Subject: [PATCH 1/3] mmc: omap_hsmmc: use packet sync'd DMA
>
> Use packet sync'd DMA in the omap_hsmmc driver to avoid the
> restriction that transfers must be a multiple of the block size. This
> is required for byte-mode transfers to SDIO cards.
>
What is the typical scenario here? Is it IO_RW_EXTENDED with block_mode
turned off?
> Signed-off-by: David Vrabel <david.vra...@csr.com>
> ---
> drivers/mmc/host/omap_hsmmc.c | 17 +++++------------
> 1 files changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 4b23225..e7142a2 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -114,6 +114,7 @@
>
> #define MMC_TIMEOUT_MS 20
> #define OMAP_MMC_MASTER_CLOCK 96000000
> +#define OMAP_HSMMC_FIFO_WORDS (512/4)
> #define DRIVER_NAME "mmci-omap-hs"
>
> /* Timeouts for entering power saving states on inactivity, msec */
> @@ -887,12 +888,12 @@ static void omap_hsmmc_config_dma_params(struct
> omap_hsmmc_host *host,
> dma_ch = host->dma_ch;
> if (data->flags & MMC_DATA_WRITE) {
> omap_set_dma_dest_params(dma_ch, 0, OMAP_DMA_AMODE_CONSTANT,
> - (host->mapbase + OMAP_HSMMC_DATA), 0, 0);
> + (host->mapbase + OMAP_HSMMC_DATA), 0,
> OMAP_HSMMC_FIFO_WORDS);
> omap_set_dma_src_params(dma_ch, 0, OMAP_DMA_AMODE_POST_INC,
> sg_dma_address(sgl), 0, 0);
> } else {
> omap_set_dma_src_params(dma_ch, 0, OMAP_DMA_AMODE_CONSTANT,
> - (host->mapbase + OMAP_HSMMC_DATA), 0, 0);
> + (host->mapbase + OMAP_HSMMC_DATA), 0,
> OMAP_HSMMC_FIFO_WORDS);
> omap_set_dma_dest_params(dma_ch, 0, OMAP_DMA_AMODE_POST_INC,
> sg_dma_address(sgl), 0, 0);
> }
> @@ -901,7 +902,7 @@ static void omap_hsmmc_config_dma_params(struct
> omap_hsmmc_host *host,
> nblk = sg_dma_len(sgl) / blksz;
>
> omap_set_dma_transfer_params(dma_ch, OMAP_DMA_DATA_TYPE_S32,
> - blksz / 4, nblk, OMAP_DMA_SYNC_FRAME,
> + blksz / 4, nblk, OMAP_DMA_SYNC_PACKET,
> omap_hsmmc_get_dma_sync_dev(host, data),
> !(data->flags & MMC_DATA_WRITE));
>
How does this configuration help? Isn't the PACKET again a multiple of
blksz?
> @@ -944,17 +945,9 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status,
> void *data)
> static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
> struct mmc_request *req)
> {
> - int dma_ch = 0, ret = 0, err = 1, i;
> + int dma_ch = 0, ret = 0, err = 1;
> struct mmc_data *data = req->data;
>
> - /* Sanity check: all the SG entries must be aligned by block size.
> */
> - for (i = 0; i < data->sg_len; i++) {
> - struct scatterlist *sgl;
> -
> - sgl = data->sg + i;
> - if (sgl->length % data->blksz)
> - return -EINVAL;
> - }
> if ((data->blksz % 4) != 0)
> /* REVISIT: The MMC buffer increments only when MSB is
> written.
> * Return error for blksz which is non multiple of four.
> --
> 1.6.3.3
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