Hi, Shawn. On 10/22/2015 03:19 PM, Shawn Lin wrote: > This patch implement hw_reset function for DesignWare > MMC controller. By adding this feature, mmc blk can > do some basic recovery if emmc device cannot work any > more for unknown reasons. Are there any other issue before applied this patch? > > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> > > --- > > drivers/mmc/host/dw_mmc.c | 29 +++++++++++++++++++++++++++++ > drivers/mmc/host/dw_mmc.h | 4 ++++ > 2 files changed, 33 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 6e600e8..8a0f2995 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1478,6 +1478,34 @@ static int dw_mci_get_cd(struct mmc_host *mmc) > return present; > } > > +static void dw_mci_hw_reset(struct mmc_host *mmc) > +{ > + struct dw_mci_slot *slot = mmc_priv(mmc); > + struct dw_mci *host = slot->host; > + > + if (host->use_dma == TRANS_MODE_IDMAC) > + dw_mci_idmac_reset(host); > + > + if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET) || > + (!dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET))) Why does it reset twice? Can't reset together with DMA and FIFO? dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET | SDMMC_CTRL_FIFO_RESET)? > + return; > + > + /* CARD_RESET > + * According to eMMC spec > + * tRstW >= 1us: RST_n pulse width > + * tRSCA >= 200us: RST_n to Command time > + * tRSTH >= 1us: RST_n high period > + * Note: add some margin to make rst timing not too > + * "spec" for some bad qulity eMMC devices. some bad quality? Which devices are bad quality devices? > + */ > + mci_writel(slot->host, RST_N, SDMMC_RST_HWRESET); > + wmb(); /* drain writebuffer */ > + usleep_range(5, 10); > + mci_writel(slot->host, RST_N, SDMMC_RST_HWACTIVE); > + wmb(); /* drain writebuffer */ > + usleep_range(500, 1000); Need to drain writebuffer at here? I don't know why you choose those values..Just some margin? And if you want to apply this, i recommend to use the shift with card number. Best Regards, Jaehoon Chung > +} > + > static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card) > { > struct dw_mci_slot *slot = mmc_priv(mmc); > @@ -1564,6 +1592,7 @@ static const struct mmc_host_ops dw_mci_ops = { > .set_ios = dw_mci_set_ios, > .get_ro = dw_mci_get_ro, > .get_cd = dw_mci_get_cd, > + .hw_reset = dw_mci_hw_reset, > .enable_sdio_irq = dw_mci_enable_sdio_irq, > .execute_tuning = dw_mci_execute_tuning, > .card_busy = dw_mci_card_busy, > diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h > index f2a88d4..9df18c1 100644 > --- a/drivers/mmc/host/dw_mmc.h > +++ b/drivers/mmc/host/dw_mmc.h > @@ -46,6 +46,7 @@ > #define SDMMC_VERID 0x06c > #define SDMMC_HCON 0x070 > #define SDMMC_UHS_REG 0x074 > +#define SDMMC_RST_N 0x078 > #define SDMMC_BMOD 0x080 > #define SDMMC_PLDMND 0x084 > #define SDMMC_DBADDR 0x088 > @@ -169,6 +170,9 @@ > #define SDMMC_IDMAC_ENABLE BIT(7) > #define SDMMC_IDMAC_FB BIT(1) > #define SDMMC_IDMAC_SWRESET BIT(0) > +/* H/W reset*/ > +#define SDMMC_RST_HWACTIVE 0x1 > +#define SDMMC_RST_HWRESET 0x0 > /* Version ID register define */ > #define SDMMC_GET_VERID(x) ((x) & 0xFFFF) > /* Card read threshold */ > -- 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