Messages in this thread | | | From | Alim Akhtar <> | Date | Fri, 17 Oct 2014 17:58:22 +0530 | Subject | Re: [PATCH v2] mmc: dw_mmc: Reset DMA before enabling IDMAC |
| |
Hi Sonny,
On Thu, Oct 16, 2014 at 10:28 PM, Sonny Rao <sonnyrao@chromium.org> wrote: > We've already got a reset of DMA after it's done. Add one before we > start DMA too. This fixes a data corruption on Rockchip SoCs which > will get bad data when doing a DMA transfer after doing a PIO transfer. > > We tested this on an Exynos 5800 with HS200 and didn't notice any > difference in sequential read throughput. > > Signed-off-by: Sonny Rao <sonnyrao@chromium.org> > Signed-off-by: Doug Anderson <dianders@chromium.org> > Tested-by: Doug Anderson <dianders@chromium.org>
This looks fine.
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com> > --- > drivers/mmc/host/dw_mmc.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 69f0cc6..ca67f69 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -83,6 +83,7 @@ struct idmac_desc { > #endif /* CONFIG_MMC_DW_IDMAC */ > > static bool dw_mci_reset(struct dw_mci *host); > +static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset); > > #if defined(CONFIG_DEBUG_FS) > static int dw_mci_req_show(struct seq_file *s, void *v) > @@ -448,6 +449,10 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len) > > dw_mci_translate_sglist(host, host->data, sg_len); > > + /* Make sure to reset DMA in case we did PIO before this */ > + dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET); > + dw_mci_idmac_reset(host); > + > /* Select IDMAC interface */ > temp = mci_readl(host, CTRL); > temp |= SDMMC_CTRL_USE_IDMAC; > -- > 2.1.2 >
-- Regards, Alim
| |