On 3 August 2015 at 17:04, Heiko Stübner <heiko@xxxxxxxxx> wrote:
> The dw_mci_init_dma() may decide to not use dma, but pio instead, caused
> by things like wrong dma settings in the system.
>
> Till now the code dw_mci_init_slot() always assumed that dma is available
> when CONFIG_MMC_DW_IDMAC was defined, ignoring the host->use_dma var
> set during dma init.
>
> So when now the dma init failed for whatever reason, the transfer sizes
> would still be set for dma transfers, especially including the maximum
> block-count calculated from host->ring_size and resulting in a
>
> [ 4.991109] ------------[ cut here ]------------
> [ 4.991111] kernel BUG at drivers/mmc/core/core.c:256!
> [ 4.991113] Internal error: Oops - BUG: 0 [#1] SMP ARM
>
> because host->ring_size is 0 in this case and the slot init code uses
> the wrong code to calculate the values.
>
> Fix this by selecting the correct calculations using the host->use_dma
> variable instead of the CONFIG_MMC_DW_IDMAC config option.
>
> Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
> ---
> drivers/mmc/host/dw_mmc.c | 27 ++++++++++++++-------------
> 1 file changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 40e9d8e..9ec3521 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2391,19 +2391,20 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
> mmc->max_seg_size = host->pdata->blk_settings->max_seg_size;
> } else {
> /* Useful defaults if platform data is unset. */
> -#ifdef CONFIG_MMC_DW_IDMAC
> - mmc->max_segs = host->ring_size;
> - mmc->max_blk_size = 65536;
> - mmc->max_seg_size = 0x1000;
> - mmc->max_req_size = mmc->max_seg_size * host->ring_size;
> - mmc->max_blk_count = mmc->max_req_size / 512;
> -#else
> - mmc->max_segs = 64;
> - mmc->max_blk_size = 65536; /* BLKSIZ is 16 bits */
> - mmc->max_blk_count = 512;
> - mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
> - mmc->max_seg_size = mmc->max_req_size;
> -#endif /* CONFIG_MMC_DW_IDMAC */
> + if (host->use_dma) {
> + mmc->max_segs = host->ring_size;
I expect this may cause a compiler error since host->ring_size is only
available in the struct dw_mci *host when CONFIG_MMC_DW_IDMAC is set.
I have already pulled in this patch from Jaehoon's pull request.
Perhaps I should only amend the patch and change the host->ring_size
to be always available no matter if CONFIG_MMC_DW_IDMAC is set or not?
> + mmc->max_blk_size = 65536;
> + mmc->max_seg_size = 0x1000;
> + mmc->max_req_size = mmc->max_seg_size * host->ring_size;
> + mmc->max_blk_count = mmc->max_req_size / 512;
> + } else {
> + mmc->max_segs = 64;
> + mmc->max_blk_size = 65536; /* BLKSIZ is 16 bits */
> + mmc->max_blk_count = 512;
> + mmc->max_req_size = mmc->max_blk_size *
> + mmc->max_blk_count;
> + mmc->max_seg_size = mmc->max_req_size;
> + }
> }
>
> if (dw_mci_get_cd(mmc))
> --
> 2.1.4
>
>
Kind regards
Uffe
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