mmc: mmci: stm32: add SDIO in-band interrupt mode

Add the support of SDIO in-band interrupt mode for STM32 and Ux500
variants.
It allows the SD I/O card to interrupt the host on SDMMC_D1 data line.
It is not enabled by default on Ux500 variant as this is unstable and
Ux500 users should use out-of-band IRQs.

Signed-off-by: Christophe Kerello <[email protected]>
Signed-off-by: Yann Gautier <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: Christophe Kerello

drivers/mmc/host/mmci.c

@@ -273,6 +273,7 @@ static struct variant_data variant_stm32_sdmmc = {
 	.datactrl_mask_sdio	= MCI_DPSM_ST_SDIOEN,
 	.stm32_idmabsize_mask	= GENMASK(12, 5),
 	.stm32_idmabsize_align	= BIT(5),
+	.supports_sdio_irq	= true,
 	.busy_timeout		= true,
 	.busy_detect		= true,
 	.busy_detect_flag	= MCI_STM32_BUSYD0,
@@ -300,6 +301,7 @@ static struct variant_data variant_stm32_sdmmcv2 = {
 	.datactrl_mask_sdio	= MCI_DPSM_ST_SDIOEN,
 	.stm32_idmabsize_mask	= GENMASK(16, 5),
 	.stm32_idmabsize_align	= BIT(5),
+	.supports_sdio_irq	= true,
 	.dma_lli		= true,
 	.busy_timeout		= true,
 	.busy_detect		= true,
@@ -328,6 +330,7 @@ static struct variant_data variant_stm32_sdmmcv3 = {
 	.datactrl_mask_sdio	= MCI_DPSM_ST_SDIOEN,
 	.stm32_idmabsize_mask	= GENMASK(16, 6),
 	.stm32_idmabsize_align	= BIT(6),
+	.supports_sdio_irq	= true,
 	.dma_lli		= true,
 	.busy_timeout		= true,
 	.busy_detect		= true,
@@ -421,8 +424,9 @@ void mmci_write_pwrreg(struct mmci_host *host, u32 pwr)
  */
 static void mmci_write_datactrlreg(struct mmci_host *host, u32 datactrl)
 {
-	/* Keep busy mode in DPSM if enabled */
-	datactrl |= host->datactrl_reg & host->variant->busy_dpsm_flag;
+	/* Keep busy mode in DPSM and SDIO mask if enabled */
+	datactrl |= host->datactrl_reg & (host->variant->busy_dpsm_flag |
+					  host->variant->datactrl_mask_sdio);
 
 	if (host->datactrl_reg != datactrl) {
 		host->datactrl_reg = datactrl;
@@ -1762,6 +1766,25 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void mmci_write_sdio_irq_bit(struct mmci_host *host, int enable)
+{
+	void __iomem *base = host->base;
+	u32 mask = readl_relaxed(base + MMCIMASK0);
+
+	if (enable)
+		writel_relaxed(mask | MCI_ST_SDIOITMASK, base + MMCIMASK0);
+	else
+		writel_relaxed(mask & ~MCI_ST_SDIOITMASK, base + MMCIMASK0);
+}
+
+static void mmci_signal_sdio_irq(struct mmci_host *host, u32 status)
+{
+	if (status & MCI_ST_SDIOIT) {
+		mmci_write_sdio_irq_bit(host, 0);
+		sdio_signal_irq(host->mmc);
+	}
+}
+
 /*
  * Handle completion of command and data transfers.
  */
@@ -1806,6 +1829,9 @@ static irqreturn_t mmci_irq(int irq, void *dev_id)
 			mmci_data_irq(host, host->data, status);
 		}
 
+		if (host->variant->supports_sdio_irq)
+			mmci_signal_sdio_irq(host, status);
+
 		/*
 		 * Busy detection has been handled by mmci_cmd_irq() above.
 		 * Clear the status bit to prevent polling in IRQ context.
@@ -2042,6 +2068,35 @@ static int mmci_sig_volt_switch(struct mmc_host *mmc, struct mmc_ios *ios)
 	return ret;
 }
 
+static void mmci_enable_sdio_irq(struct mmc_host *mmc, int enable)
+{
+	struct mmci_host *host = mmc_priv(mmc);
+	unsigned long flags;
+
+	if (enable)
+		/* Keep the SDIO mode bit if SDIO irqs are enabled */
+		pm_runtime_get_sync(mmc_dev(mmc));
+
+	spin_lock_irqsave(&host->lock, flags);
+	mmci_write_sdio_irq_bit(host, enable);
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	if (!enable) {
+		pm_runtime_mark_last_busy(mmc_dev(mmc));
+		pm_runtime_put_autosuspend(mmc_dev(mmc));
+	}
+}
+
+static void mmci_ack_sdio_irq(struct mmc_host *mmc)
+{
+	struct mmci_host *host = mmc_priv(mmc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&host->lock, flags);
+	mmci_write_sdio_irq_bit(host, 1);
+	spin_unlock_irqrestore(&host->lock, flags);
+}
+
 static struct mmc_host_ops mmci_ops = {
 	.request	= mmci_request,
 	.pre_req	= mmci_pre_request,
@@ -2317,6 +2372,16 @@ static int mmci_probe(struct amba_device *dev,
 		mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
 	}
 
+	if (variant->supports_sdio_irq && host->mmc->caps & MMC_CAP_SDIO_IRQ) {
+		mmc->caps2 |= MMC_CAP2_SDIO_IRQ_NOTHREAD;
+
+		mmci_ops.enable_sdio_irq = mmci_enable_sdio_irq;
+		mmci_ops.ack_sdio_irq	= mmci_ack_sdio_irq;
+
+		mmci_write_datactrlreg(host,
+				       host->variant->datactrl_mask_sdio);
+	}
+
 	/* Variants with mandatory busy timeout in HW needs R1B responses. */
 	if (variant->busy_timeout)
 		mmc->caps |= MMC_CAP_NEED_RSP_BUSY;

drivers/mmc/host/mmci.h

@@ -331,6 +331,7 @@ enum mmci_busy_state {
  *	       register.
  * @opendrain: bitmask identifying the OPENDRAIN bit inside MMCIPOWER register
  * @dma_lli: true if variant has dma link list feature.
+ * @supports_sdio_irq: allow SD I/O card to interrupt the host
  * @stm32_idmabsize_mask: stm32 sdmmc idma buffer size.
  * @dma_flow_controller: use peripheral as flow controller for DMA.
  */
@@ -377,6 +378,7 @@ struct variant_data {
 	u32			start_err;
 	u32			opendrain;
 	u8			dma_lli:1;
+	bool			supports_sdio_irq;
 	u32			stm32_idmabsize_mask;
 	u32			stm32_idmabsize_align;
 	bool			dma_flow_controller;