mmc: tegra: add Tegra186 WAR for CQE

Tegra186 CQHCI host has a known bug where CQHCI controller selects
DATA_PRESENT_SELECT bit to 1 for DCMDs with R1B response type and
since DCMD does not trigger any data transfer, DCMD task complete
happens leaving the DATA FSM of host controller in wait state for
the data.

This effects the data transfer tasks issued after the DCMDs with
R1b response type resulting in timeout.

SW WAR is to set CMD_TIMING to 1 in DCMD task descriptor. This bug
and SW WAR is applicable only for Tegra186 and not for Tegra194.

This patch implements this WAR thru NVQUIRK_CQHCI_DCMD_R1B_CMD_TIMING
for Tegra186 and also implements update_dcmd_desc of cqhci_host_ops
interface to set CMD_TIMING bit depending on the NVQUIRK.

Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-tegra.c

@@ -106,6 +106,7 @@
 #define NVQUIRK_HAS_PADCALIB				BIT(6)
 #define NVQUIRK_NEEDS_PAD_CONTROL			BIT(7)
 #define NVQUIRK_DIS_CARD_CLK_CONFIG_TAP			BIT(8)
+#define NVQUIRK_CQHCI_DCMD_R1B_CMD_TIMING		BIT(9)
 
 /* SDMMC CQE Base Address for Tegra Host Ver 4.1 and Higher */
 #define SDHCI_TEGRA_CQE_BASE_ADDR			0xF000
@@ -1123,6 +1124,18 @@ static void tegra_sdhci_voltage_switch(struct sdhci_host *host)
 		tegra_host->pad_calib_required = true;
 }
 
+static void sdhci_tegra_update_dcmd_desc(struct mmc_host *mmc,
+					 struct mmc_request *mrq, u64 *data)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(mmc_priv(mmc));
+	struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
+	const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;
+
+	if (soc_data->nvquirks & NVQUIRK_CQHCI_DCMD_R1B_CMD_TIMING &&
+	    mrq->cmd->flags & MMC_RSP_R1B)
+		*data |= CQHCI_CMD_TIMING(1);
+}
+
 static void sdhci_tegra_cqe_enable(struct mmc_host *mmc)
 {
 	struct cqhci_host *cq_host = mmc->cqe_private;
@@ -1164,6 +1177,7 @@ static const struct cqhci_host_ops sdhci_tegra_cqhci_ops = {
 	.enable	= sdhci_tegra_cqe_enable,
 	.disable = sdhci_cqe_disable,
 	.dumpregs = sdhci_tegra_dumpregs,
+	.update_dcmd_desc = sdhci_tegra_update_dcmd_desc,
 };
 
 static const struct sdhci_ops tegra_sdhci_ops = {
@@ -1345,7 +1359,8 @@ static const struct sdhci_tegra_soc_data soc_data_tegra186 = {
 		    NVQUIRK_HAS_PADCALIB |
 		    NVQUIRK_DIS_CARD_CLK_CONFIG_TAP |
 		    NVQUIRK_ENABLE_SDR50 |
-		    NVQUIRK_ENABLE_SDR104,
+		    NVQUIRK_ENABLE_SDR104 |
+		    NVQUIRK_CQHCI_DCMD_R1B_CMD_TIMING,
 	.min_tap_delay = 84,
 	.max_tap_delay = 136,
 };