From: Haibo Chen <haibo.chen@xxxxxxx>
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: Haibo Chen <haibo.chen@xxxxxxx>
---
drivers/mmc/host/sdhci-esdhc-imx.c | 41 ++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index bf8d6f60a9ee..8f5ee5964396 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -337,6 +337,16 @@ 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 */
@@ -431,6 +441,8 @@ 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;
@@ -448,6 +460,20 @@ 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);
@@ -1055,6 +1081,15 @@ 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);
@@ -1673,6 +1708,12 @@ 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);
--
2.34.1
