Commit 52e4c32b authored by Haibo Chen's avatar Haibo Chen Committed by Ulf Hansson
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mmc: sdhci-esdhc-imx: only enable DAT[0] and CMD line auto tuning for SDIO device 



USDHC IP has one limitation: the tuning circuit can't handle the async
sdio device interrupt correctly. When sdio device use 4 data lines,
async sdio interrupt will use the shared DAT[1], if enable auto tuning
circuit to check these 4 data lines, include the DAT[1], this circuit
will detect this interrupt, take this as data on DAT[1], and adjust the
delay cell wrongly, finally will cause the DATA/CMD CRC error.
So for SDIO device, only enable DAT[0] and CMD line for auto tuning.
To distinguish the card type during card init, involve init_card().

Signed-off-by: default avatarHaibo Chen <haibo.chen@nxp.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20221223025022.1893102-3-haibo.chen@nxp.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent c8c49a5a

drivers/mmc/host/sdhci-esdhc-imx.c

+41 −0
Original line number Diff line number Diff line
@@ -338,6 +338,16 @@ struct pltfm_imx_data { 
	struct clk *clk_ahb;

	struct clk *clk_per;

	unsigned int actual_clock;



	/*

	 * USDHC has one limition, require the SDIO device a different

	 * register setting. Driver has to recognize card type during

	 * the card init, but at this stage, mmc_host->card is not

	 * available. So involve this field to save the card type

	 * during card init through usdhc_init_card().

	 */

	unsigned int init_card_type;



	enum {

		NO_CMD_PENDING,      /* no multiblock command pending */

		MULTIBLK_IN_PROCESS, /* exact multiblock cmd in process */
@@ -432,6 +442,8 @@ static inline void esdhc_wait_for_card_clock_gate_off(struct sdhci_host *host) 
/* Enable the auto tuning circuit to check the CMD line and BUS line */

static inline void usdhc_auto_tuning_mode_sel_and_en(struct sdhci_host *host)

{

	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);

	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);

	u32 buswidth, auto_tune_buswidth;

	u32 reg;
@@ -449,6 +461,20 @@ static inline void usdhc_auto_tuning_mode_sel_and_en(struct sdhci_host *host) 
		break;

	}



	/*

	 * For USDHC, auto tuning circuit can not handle the async sdio

	 * device interrupt correctly. When sdio device use 4 data lines,

	 * async sdio interrupt will use the shared DAT[1], if enable auto

	 * tuning circuit check these 4 data lines, include the DAT[1],

	 * this circuit will detect this interrupt, take this as a data on

	 * DAT[1], and adjust the delay cell wrongly.

	 * This is the hardware design limitation, to avoid this, for sdio

	 * device, config the auto tuning circuit only check DAT[0] and CMD

	 * line.

	 */

	if (imx_data->init_card_type == MMC_TYPE_SDIO)

		auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_1BIT_EN;



	esdhc_clrset_le(host, ESDHC_VEND_SPEC2_AUTO_TUNE_MODE_MASK,

			auto_tune_buswidth | ESDHC_VEND_SPEC2_AUTO_TUNE_CMD_EN,

			ESDHC_VEND_SPEC2);
@@ -1056,6 +1082,15 @@ static void esdhc_reset_tuning(struct sdhci_host *host) 
	}

}



static void usdhc_init_card(struct mmc_host *mmc, struct mmc_card *card)

{

	struct sdhci_host *host = mmc_priv(mmc);

	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);

	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);



	imx_data->init_card_type = card->type;

}



static int usdhc_execute_tuning(struct mmc_host *mmc, u32 opcode)

{

	struct sdhci_host *host = mmc_priv(mmc);
@@ -1681,6 +1716,12 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev) 
		 * to replace the standard one in sdhci_ops.

		 */

		host->mmc_host_ops.execute_tuning = usdhc_execute_tuning;



		/*

		 * Link usdhc specific mmc_host_ops init card function,

		 * to distinguish the card type.

		 */

		host->mmc_host_ops.init_card = usdhc_init_card;

	}



	err = sdhci_esdhc_imx_probe_dt(pdev, host, imx_data);