s3cmci: add SDIO IRQ support

diff -puN drivers/mmc/host/s3cmci.c~s3cmci-add-sdio-irq-support drivers/mmc/host/s3cmci.c
@@ -190,7 +190,33 @@ static inline u32 disable_imask(struct s
 
 static inline void clear_imask(struct s3cmci_host *host)
 {
-	writel(0, host->base + host->sdiimsk);
+	u32 mask = readl(host->base + host->sdiimsk);
+
+	/* preserve the SDIO IRQ mask state */
+	mask &= S3C2410_SDIIMSK_SDIOIRQ;
+	writel(mask, host->base + host->sdiimsk);
+}
+
+/**
+ * s3cmci_check_sdio_irq - test whether the SDIO IRQ is being signalled
+ * @host: The host to check.
+ *
+ * Test to see if the SDIO interrupt is being signalled in case the
+ * controller has failed to re-detect a card interrupt. Read GPE8 and
+ * see if it is low and if so, signal a SDIO interrupt.
+ *
+ * This is currently called if a request is finished (we assume that the
+ * bus is now idle) and when the SDIO IRQ is enabled in case the IRQ is
+ * already being indicated.
+*/
+static void s3cmci_check_sdio_irq(struct s3cmci_host *host)
+{
+	if (host->sdio_irqen) {
+		if (gpio_get_value(S3C2410_GPE(8)) == 0) {
+			printk(KERN_DEBUG "%s: signalling irq\n", __func__);
+			mmc_signal_sdio_irq(host->mmc);
+		}
+	}
 }
 
 static inline int get_data_buffer(struct s3cmci_host *host,

@@ -238,6 +264,64 @@ static inline u32 fifo_free(struct s3cmc
 	return 63 - fifostat;
 }
 
+/**
+ * s3cmci_enable_irq - enable IRQ, after having disabled it.
+ * @host: The device state.
+ * @more: True if more IRQs are expected from transfer.
+ *
+ * Enable the main IRQ if needed after it has been disabled.
+ *
+ * The IRQ can be one of the following states:
+ *	- disabled during IDLE
+ *	- disabled whilst processing data
+ *	- enabled during transfer
+ *	- enabled whilst awaiting SDIO interrupt detection
+ */
+static void s3cmci_enable_irq(struct s3cmci_host *host, bool more)
+{
+	unsigned long flags;
+	bool enable = false;
+
+	local_irq_save(flags);
+
+	host->irq_enabled = more;
+	host->irq_disabled = false;
+
+	enable = more | host->sdio_irqen;
+
+	if (host->irq_state != enable) {
+		host->irq_state = enable;
+
+		if (enable)
+			enable_irq(host->irq);
+		else
+			disable_irq(host->irq);
+	}
+
+	local_irq_restore(flags);
+}
+
+/**
+ *
+ */
+static void s3cmci_disable_irq(struct s3cmci_host *host, bool transfer)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	//printk(KERN_DEBUG "%s: transfer %d\n", __func__, transfer);
+
+	host->irq_disabled = transfer;
+
+	if (transfer && host->irq_state) {
+		host->irq_state = false;
+		disable_irq(host->irq);
+	}
+
+	local_irq_restore(flags);
+}
+
 static void do_pio_read(struct s3cmci_host *host)
 {
 	int res;

@@ -374,8 +458,7 @@ static void pio_tasklet(unsigned long da
 {
 	struct s3cmci_host *host = (struct s3cmci_host *) data;
 
-
-	disable_irq(host->irq);
+	s3cmci_disable_irq(host, true);
 
 	if (host->pio_active == XFER_WRITE)
 		do_pio_write(host);

@@ -395,9 +478,10 @@ static void pio_tasklet(unsigned long da
 				host->mrq->data->error = -EINVAL;
 		}
 
+		s3cmci_enable_irq(host, false);
 		finalize_request(host);
 	} else
-		enable_irq(host->irq);
+		s3cmci_enable_irq(host, true);
 }
 
 /*

@@ -432,17 +516,27 @@ static irqreturn_t s3cmci_irq(int irq, v
 	struct s3cmci_host *host = dev_id;
 	struct mmc_command *cmd;
 	u32 mci_csta, mci_dsta, mci_fsta, mci_dcnt, mci_imsk;
-	u32 mci_cclear, mci_dclear;
+	u32 mci_cclear = 0, mci_dclear;
 	unsigned long iflags;
 
+	mci_dsta = readl(host->base + S3C2410_SDIDSTA);
+	mci_imsk = readl(host->base + host->sdiimsk);
+
+	if (mci_dsta & S3C2410_SDIDSTA_SDIOIRQDETECT) {
+		if (mci_imsk & S3C2410_SDIIMSK_SDIOIRQ) {
+			mci_dclear = S3C2410_SDIDSTA_SDIOIRQDETECT;
+			writel(mci_dclear, host->base + S3C2410_SDIDSTA);
+
+			mmc_signal_sdio_irq(host->mmc);
+			return IRQ_HANDLED;
+		}
+	}
+
 	spin_lock_irqsave(&host->complete_lock, iflags);
 
 	mci_csta = readl(host->base + S3C2410_SDICMDSTAT);
-	mci_dsta = readl(host->base + S3C2410_SDIDSTA);
 	mci_dcnt = readl(host->base + S3C2410_SDIDCNT);
 	mci_fsta = readl(host->base + S3C2410_SDIFSTA);
-	mci_imsk = readl(host->base + host->sdiimsk);
-	mci_cclear = 0;
 	mci_dclear = 0;
 
 	if ((host->complete_what == COMPLETION_NONE) ||

@@ -776,6 +870,8 @@ static void finalize_request(struct s3cm
 request_done:
 	host->complete_what = COMPLETION_NONE;
 	host->mrq = NULL;
+
+	s3cmci_check_sdio_irq(host);
 	mmc_request_done(host->mmc, mrq);
 }
 

@@ -1037,7 +1133,7 @@ static void s3cmci_send_request(struct m
 	s3cmci_send_command(host, cmd);
 
 	/* Enable Interrupt */
-	enable_irq(host->irq);
+	s3cmci_enable_irq(host, true);
 }
 
 static int s3cmci_card_present(struct mmc_host *mmc)

@@ -1178,11 +1274,52 @@ static int s3cmci_get_ro(struct mmc_host
 	return ret;
 }
 
+static void s3cmci_enable_sdio_irq(struct mmc_host *mmc, int enable)
+{
+	struct s3cmci_host *host = mmc_priv(mmc);
+	unsigned long flags;
+	u32 con;
+
+	local_irq_save(flags);
+
+	con = readl(host->base + S3C2410_SDICON);
+	host->sdio_irqen = enable;
+
+	if (enable == host->sdio_irqen)
+		goto same_state;
+
+	if (enable) {
+		con |= S3C2410_SDICON_SDIOIRQ;
+		enable_imask(host, S3C2410_SDIIMSK_SDIOIRQ);
+
+		if (!host->irq_state && !host->irq_disabled) {
+			host->irq_state = true;
+			enable_irq(host->irq);
+		}
+	} else {
+		disable_imask(host, S3C2410_SDIIMSK_SDIOIRQ);
+		con &= ~S3C2410_SDICON_SDIOIRQ;
+
+		if (!host->irq_enabled && host->irq_state) {
+			disable_irq_nosync(host->irq);
+			host->irq_state = false;
+		}
+	}
+
+	writel(con, host->base + S3C2410_SDICON);
+
+ same_state:
+	local_irq_restore(flags);
+
+	s3cmci_check_sdio_irq(host);
+}
+
 static struct mmc_host_ops s3cmci_ops = {
 	.request	= s3cmci_request,
 	.set_ios	= s3cmci_set_ios,
 	.get_ro		= s3cmci_get_ro,
 	.get_cd		= s3cmci_card_present,
+	.enable_sdio_irq = s3cmci_enable_sdio_irq,
 };
 
 static struct s3c24xx_mci_pdata s3cmci_def_pdata = {

@@ -1257,6 +1394,9 @@ static int s3cmci_state_show(struct seq_
 	seq_printf(seq, "Prescale = %d\n", host->prescaler);
 	seq_printf(seq, "is2440 = %d\n", host->is2440);
 	seq_printf(seq, "IRQ = %d\n", host->irq);
+	seq_printf(seq, "IRQ enabled = %d\n", host->irq_enabled);
+	seq_printf(seq, "IRQ disabled = %d\n", host->irq_disabled);
+	seq_printf(seq, "IRQ state = %d\n", host->irq_state);
 	seq_printf(seq, "CD IRQ = %d\n", host->irq_cd);
 	seq_printf(seq, "Do DMA = %d\n", host->dodma);
 	seq_printf(seq, "SDIIMSK at %d\n", host->sdiimsk);

@@ -1468,6 +1608,7 @@ static int __devinit s3cmci_probe(struct
 	 * ensure we don't lock the system with un-serviceable requests. */
 
 	disable_irq(host->irq);
+	host->irq_state = false;
 
 	if (host->pdata->gpio_detect) {
 		ret = gpio_request(host->pdata->gpio_detect, "s3cmci detect");

@@ -1526,7 +1667,7 @@ static int __devinit s3cmci_probe(struct
 
 	mmc->ops 	= &s3cmci_ops;
 	mmc->ocr_avail	= MMC_VDD_32_33 | MMC_VDD_33_34;
-	mmc->caps	= MMC_CAP_4_BIT_DATA;
+	mmc->caps	= MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
 	mmc->f_min 	= host->clk_rate / (host->clk_div * 256);
 	mmc->f_max 	= host->clk_rate / host->clk_div;
 

diff -puN drivers/mmc/host/s3cmci.h~s3cmci-add-sdio-irq-support drivers/mmc/host/s3cmci.h
@@ -42,6 +42,11 @@ struct s3cmci_host {
 	int			dodma;
 	int			dmatogo;
 
+	bool			irq_disabled;
+	bool			irq_enabled;
+	bool			irq_state;
+	int			sdio_irqen;
+
 	struct mmc_request	*mrq;
 	int			cmd_is_stop;