Re: [PATCH v3] mmc: dw_mmc: add hw_reset support

[Shawn Lin]

On 2016/1/20 12:24, Jaehoon Chung wrote:
> Hi, Shawn.
>
> On 01/14/2016 10:08 AM, Shawn Lin wrote:
> > This patch implement hw_reset function for DesignWare
> > MMC controller. By adding this feature, mmc blk can
> > do some basic recovery.
> >
> > Set the following resets:
> > software reset â BMOD[0] for IDMAC only
> > DMA resetâ CTRL[2]
> > FIFO reset â CTRL[1] bits
> >
> > Program the CARD_RESET register with a value of 0 for the bit
> > corresponding to the card number; This programming asserts the
> > RST_n signal and resets the card. After a minimum of 1 Îs, de-asserts the
> > RST_n signal and takes the card out of reset. The application can program
> > a new CMD only after a minimum of 200 us
> >
> > This implementation can be easily tested by cutting off->On vmmc
> > while doing data accessing in background to simulate that case.
> >
> > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> >
> > ---
> >
> > Changes in v3:
> > - reset for each slot
> > - simply the commit msg
> >
> > Changes in v2:
> > - remove unecessary mb
> > - reduce time cost for hw_reset
> > - combine SDMMC_CTRL_DMA_RESET and SDMMC_CTRL_FIFO_RESET
> >
> >   drivers/mmc/host/dw_mmc.c | 29 +++++++++++++++++++++++++++++
> >   drivers/mmc/host/dw_mmc.h |  3 +++
> >   2 files changed, 32 insertions(+)
> >
> > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> > index 7128351..fddbcb6 100644
> > --- a/drivers/mmc/host/dw_mmc.c
> > +++ b/drivers/mmc/host/dw_mmc.c
> > @@ -1477,6 +1477,34 @@ 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;
> > +	int reset;
> > +
> > +	if (host->use_dma == TRANS_MODE_IDMAC)
> > +		dw_mci_idmac_reset(host);
> > +
> > +	if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET |
> > +				     SDMMC_CTRL_FIFO_RESET))
> > +		return;
> > +
> > +	/*
> > +	 * According to eMMC spec, card reset procedure:
> > +	 * tRstW >= 1us:   RST_n pulse width
> > +	 * tRSCA >= 200us: RST_n to Command time
> > +	 * tRSTH >= 1us:   RST_n high period
> > +	 */
> > +	reset = mci_readl(host, RST_N);
> > +	reset &= ~(SDMMC_RST_HWACTIVE << slot->id);
> > +	mci_writel(slot->host, RST_N, reset);
>
> I will pick this patch, after change "host" instead of "slot->host".
> (I will change it when i apply this.)
>
> Thanks!

Thanks, Jaehoon. :)

> Best Regards,
> Jaehoon Chung
>
> > +	usleep_range(1, 2);
> > +	reset |= SDMMC_RST_HWACTIVE << slot->id;
> > +	mci_writel(slot->host, RST_N, reset);
> > +	usleep_range(200, 300);
> > +}
> > +
> >   static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card)
> >   {
> >   	struct dw_mci_slot *slot = mmc_priv(mmc);
> > @@ -1563,6 +1591,7 @@ 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 f695b58..a14b7fc 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 +170,8 @@
> >   #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
> >   /* Version ID register define */
> >   #define SDMMC_GET_VERID(x)		((x) & 0xFFFF)
> >   /* Card read threshold */


--
Best Regards
Shawn Lin