Commit 935a665e authored by Shawn Lin's avatar Shawn Lin Committed by Ulf Hansson
Browse files

mmc: dw_mmc: add hw_reset support 



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 – BMOD[0] for IDMAC only
DMA reset - CTRL[2]
FIFO reset - 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 ?s, 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: default avatarShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent aaaaeb7a

drivers/mmc/host/dw_mmc.c

+29 −0
Original line number Diff line number Diff line
@@ -1474,6 +1474,34 @@ 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(host, RST_N, reset);

	usleep_range(1, 2);

	reset |= SDMMC_RST_HWACTIVE << slot->id;

	mci_writel(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);
@@ -1560,6 +1588,7 @@ 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,

drivers/mmc/host/dw_mmc.h

+3 −0
Original line number Diff line number Diff line
@@ -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 */

CRA Git | Maintained and supported by SUSTech CRA and CCSE