mmc: mediatek: fix SDIO irq issue

SDIO irq is not triggered by low level, but by falling edge in our
previous IC. This mechanism only have one chance to catch the SDIO irq
if a SDIO irq comes within the multiple block transmission. This SDIO
irq may be easily lost, because falling edge appears only once within 2
clock after data transmission is completed.

SDIO irq recheck mechanism will make sure all irqs can be
processed correctly.
Signed-off-by: Yong Mao <yong.mao@mediatek.com>
Link: https://lore.kernel.org/r/1585299097-6897-2-git-send-email-yong.mao@mediatek.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mtk-sd.c

@@ -128,6 +128,7 @@
 #define MSDC_PS_CDSTS           (0x1 << 1)	/* R  */
 #define MSDC_PS_CDDEBOUNCE      (0xf << 12)	/* RW */
 #define MSDC_PS_DAT             (0xff << 16)	/* R  */
+#define MSDC_PS_DATA1           (0x1 << 17)	/* R  */
 #define MSDC_PS_CMD             (0x1 << 24)	/* R  */
 #define MSDC_PS_WP              (0x1 << 31)	/* R  */
 
@@ -361,6 +362,7 @@ struct msdc_save_para {
 
 struct mtk_mmc_compatible {
 	u8 clk_div_bits;
+	bool recheck_sdio_irq;
 	bool hs400_tune; /* only used for MT8173 */
 	u32 pad_tune_reg;
 	bool async_fifo;
@@ -436,6 +438,7 @@ struct msdc_host {
 
 static const struct mtk_mmc_compatible mt8135_compat = {
 	.clk_div_bits = 8,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE,
 	.async_fifo = false,
@@ -448,6 +451,7 @@ static const struct mtk_mmc_compatible mt8135_compat = {
 
 static const struct mtk_mmc_compatible mt8173_compat = {
 	.clk_div_bits = 8,
+	.recheck_sdio_irq = true,
 	.hs400_tune = true,
 	.pad_tune_reg = MSDC_PAD_TUNE,
 	.async_fifo = false,
@@ -460,6 +464,7 @@ static const struct mtk_mmc_compatible mt8173_compat = {
 
 static const struct mtk_mmc_compatible mt8183_compat = {
 	.clk_div_bits = 12,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE0,
 	.async_fifo = true,
@@ -472,6 +477,7 @@ static const struct mtk_mmc_compatible mt8183_compat = {
 
 static const struct mtk_mmc_compatible mt2701_compat = {
 	.clk_div_bits = 12,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE0,
 	.async_fifo = true,
@@ -484,6 +490,7 @@ static const struct mtk_mmc_compatible mt2701_compat = {
 
 static const struct mtk_mmc_compatible mt2712_compat = {
 	.clk_div_bits = 12,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE0,
 	.async_fifo = true,
@@ -496,6 +503,7 @@ static const struct mtk_mmc_compatible mt2712_compat = {
 
 static const struct mtk_mmc_compatible mt7622_compat = {
 	.clk_div_bits = 12,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE0,
 	.async_fifo = true,
@@ -508,6 +516,7 @@ static const struct mtk_mmc_compatible mt7622_compat = {
 
 static const struct mtk_mmc_compatible mt8516_compat = {
 	.clk_div_bits = 12,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE0,
 	.async_fifo = true,
@@ -518,6 +527,7 @@ static const struct mtk_mmc_compatible mt8516_compat = {
 
 static const struct mtk_mmc_compatible mt7620_compat = {
 	.clk_div_bits = 8,
+	.recheck_sdio_irq = false,
 	.hs400_tune = false,
 	.pad_tune_reg = MSDC_PAD_TUNE,
 	.async_fifo = false,
@@ -591,6 +601,7 @@ static void msdc_reset_hw(struct msdc_host *host)
 
 static void msdc_cmd_next(struct msdc_host *host,
 		struct mmc_request *mrq, struct mmc_command *cmd);
+static void __msdc_enable_sdio_irq(struct msdc_host *host, int enb);
 
 static const u32 cmd_ints_mask = MSDC_INTEN_CMDRDY | MSDC_INTEN_RSPCRCERR |
 			MSDC_INTEN_CMDTMO | MSDC_INTEN_ACMDRDY |
@@ -1007,6 +1018,32 @@ static int msdc_auto_cmd_done(struct msdc_host *host, int events,
 	return cmd->error;
 }
 
+/**
+ * msdc_recheck_sdio_irq - recheck whether the SDIO irq is lost
+ *
+ * Host controller may lost interrupt in some special case.
+ * Add SDIO irq recheck mechanism to make sure all interrupts
+ * can be processed immediately
+ *
+ */
+static void msdc_recheck_sdio_irq(struct msdc_host *host)
+{
+	u32 reg_int, reg_inten, reg_ps;
+
+	if (host->mmc->caps & MMC_CAP_SDIO_IRQ) {
+		reg_inten = readl(host->base + MSDC_INTEN);
+		if (reg_inten & MSDC_INTEN_SDIOIRQ) {
+			reg_int = readl(host->base + MSDC_INT);
+			reg_ps = readl(host->base + MSDC_PS);
+			if (!(reg_int & MSDC_INT_SDIOIRQ ||
+			      reg_ps & MSDC_PS_DATA1)) {
+				__msdc_enable_sdio_irq(host, 0);
+				sdio_signal_irq(host->mmc);
+			}
+		}
+	}
+}
+
 static void msdc_track_cmd_data(struct msdc_host *host,
 				struct mmc_command *cmd, struct mmc_data *data)
 {
@@ -1035,6 +1072,8 @@ static void msdc_request_done(struct msdc_host *host, struct mmc_request *mrq)
 	if (host->error)
 		msdc_reset_hw(host);
 	mmc_request_done(host->mmc, mrq);
+	if (host->dev_comp->recheck_sdio_irq)
+		msdc_recheck_sdio_irq(host);
 }
 
 /* returns true if command is fully handled; returns false otherwise */
@@ -1393,6 +1432,8 @@ static void __msdc_enable_sdio_irq(struct msdc_host *host, int enb)
 	if (enb) {
 		sdr_set_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
 		sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
+		if (host->dev_comp->recheck_sdio_irq)
+			msdc_recheck_sdio_irq(host);
 	} else {
 		sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
 		sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);