mmc: tmio_mmc: implement SDIO IRQ support

This patch implements SDIO IRQ support for mfds which
announce the TMIO_MMC_SDIO_IRQ flag for tmio_mmc.
If MMC_CAP_SDIO_IRQ is also set SDIO IRQ signalling is activated.
Tested with a b43-based wireless SDIO card and sh_mobile_sdhi.

Signed-off-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
index f442c8205b0a..81bed310ddcd 100644
--- a/drivers/mmc/host/tmio_mmc.c
+++ b/drivers/mmc/host/tmio_mmc.c
@@ -53,6 +53,8 @@
 #define CTL_SD_ERROR_DETAIL_STATUS 0x2c
 #define CTL_SD_DATA_PORT 0x30
 #define CTL_TRANSACTION_CTL 0x34
+#define CTL_SDIO_STATUS 0x36
+#define CTL_SDIO_IRQ_MASK 0x38
 #define CTL_RESET_SD 0xe0
 #define CTL_SDIO_REGS 0x100
 #define CTL_CLK_AND_WAIT_CTL 0x138
@@ -81,6 +83,12 @@
 #define TMIO_STAT_CMD_BUSY      0x40000000
 #define TMIO_STAT_ILL_ACCESS    0x80000000
 
+/* Definitions for values the CTRL_SDIO_STATUS register can take. */
+#define TMIO_SDIO_STAT_IOIRQ    0x0001
+#define TMIO_SDIO_STAT_EXPUB52  0x4000
+#define TMIO_SDIO_STAT_EXWT     0x8000
+#define TMIO_SDIO_MASK_ALL      0xc007
+
 /* Define some IRQ masks */
 /* This is the mask used at reset by the chip */
 #define TMIO_MASK_ALL           0x837f031d
@@ -122,6 +130,7 @@ struct tmio_mmc_host {
         struct mmc_data         *data;
         struct mmc_host         *mmc;
         int                     irq;
+        unsigned int            sdio_irq_enabled;
 
         /* Callbacks for clock / power control */
         void (*set_pwr)(struct platform_device *host, int state);
@@ -249,6 +258,22 @@ void pr_debug_status(u32 status)
 #define pr_debug_status(s)  do { } while (0)
 #endif
 
+static void tmio_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
+{
+        struct tmio_mmc_host *host = mmc_priv(mmc);
+
+        if (enable) {
+                host->sdio_irq_enabled = 1;
+                sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0001);
+                sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK,
+                        (TMIO_SDIO_MASK_ALL & ~TMIO_SDIO_STAT_IOIRQ));
+        } else {
+                sd_ctrl_write16(host, CTL_SDIO_IRQ_MASK, TMIO_SDIO_MASK_ALL);
+                sd_ctrl_write16(host, CTL_TRANSACTION_CTL, 0x0000);
+                host->sdio_irq_enabled = 0;
+        }
+}
+
 static void tmio_mmc_set_clock(struct tmio_mmc_host *host, int new_clock)
 {
         u32 clk = 0, clock;
@@ -268,8 +293,23 @@ static void tmio_mmc_set_clock(struct tmio_mmc_host *host, int new_clock)
 
 static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
 {
+        struct mfd_cell *cell = host->pdev->dev.platform_data;
+        struct tmio_mmc_data *pdata = cell->driver_data;
+
+        /*
+         * Testing on sh-mobile showed that SDIO IRQs are unmasked when
+         * CTL_CLK_AND_WAIT_CTL gets written, so we have to disable the
+         * device IRQ here and restore the SDIO IRQ mask before
+         * re-enabling the device IRQ.
+         */
+        if (pdata->flags & TMIO_MMC_SDIO_IRQ)
+                disable_irq(host->irq);
         sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0000);
         msleep(10);
+        if (pdata->flags & TMIO_MMC_SDIO_IRQ) {
+                tmio_mmc_enable_sdio_irq(host->mmc, host->sdio_irq_enabled);
+                enable_irq(host->irq);
+        }
         sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~0x0100 &
                 sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
         msleep(10);
@@ -277,11 +317,21 @@ static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
 
 static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
 {
+        struct mfd_cell *cell = host->pdev->dev.platform_data;
+        struct tmio_mmc_data *pdata = cell->driver_data;
+
         sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, 0x0100 |
                 sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
         msleep(10);
+        /* see comment in tmio_mmc_clk_stop above */
+        if (pdata->flags & TMIO_MMC_SDIO_IRQ)
+                disable_irq(host->irq);
         sd_ctrl_write16(host, CTL_CLK_AND_WAIT_CTL, 0x0100);
         msleep(10);
+        if (pdata->flags & TMIO_MMC_SDIO_IRQ) {
+                tmio_mmc_enable_sdio_irq(host->mmc, host->sdio_irq_enabled);
+                enable_irq(host->irq);
+        }
 }
 
 static void reset(struct tmio_mmc_host *host)
@@ -554,7 +604,10 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host,
 static irqreturn_t tmio_mmc_irq(int irq, void *devid)
 {
         struct tmio_mmc_host *host = devid;
+        struct mfd_cell *cell = host->pdev->dev.platform_data;
+        struct tmio_mmc_data *pdata = cell->driver_data;
         unsigned int ireg, irq_mask, status;
+        unsigned int sdio_ireg, sdio_irq_mask, sdio_status;
 
         pr_debug("MMC IRQ begin\n");
 
@@ -562,6 +615,29 @@ static irqreturn_t tmio_mmc_irq(int irq, void *devid)
         irq_mask = sd_ctrl_read32(host, CTL_IRQ_MASK);
         ireg = status & TMIO_MASK_IRQ & ~irq_mask;
 
+        sdio_ireg = 0;
+        if (!ireg && pdata->flags & TMIO_MMC_SDIO_IRQ) {
+                sdio_status = sd_ctrl_read16(host, CTL_SDIO_STATUS);
+                sdio_irq_mask = sd_ctrl_read16(host, CTL_SDIO_IRQ_MASK);
+                sdio_ireg = sdio_status & TMIO_SDIO_MASK_ALL & ~sdio_irq_mask;
+
+                sd_ctrl_write16(host, CTL_SDIO_STATUS, sdio_status & ~TMIO_SDIO_MASK_ALL);
+
+                if (sdio_ireg && !host->sdio_irq_enabled) {
+                        pr_warning("tmio_mmc: Spurious SDIO IRQ, disabling! 0x%04x 0x%04x 0x%04x\n",
+                                   sdio_status, sdio_irq_mask, sdio_ireg);
+                        tmio_mmc_enable_sdio_irq(host->mmc, 0);
+                        goto out;
+                }
+
+                if (host->mmc->caps & MMC_CAP_SDIO_IRQ &&
+                        sdio_ireg & TMIO_SDIO_STAT_IOIRQ)
+                        mmc_signal_sdio_irq(host->mmc);
+
+                if (sdio_ireg)
+                        goto out;
+        }
+
         pr_debug_status(status);
         pr_debug_status(ireg);
 
@@ -1047,6 +1123,7 @@ static const struct mmc_host_ops tmio_mmc_ops = {
         .set_ios        = tmio_mmc_set_ios,
         .get_ro         = tmio_mmc_get_ro,
         .get_cd         = tmio_mmc_get_cd,
+        .enable_sdio_irq = tmio_mmc_enable_sdio_irq,
 };
 
 #ifdef CONFIG_PM
@@ -1162,6 +1239,8 @@ static int __devinit tmio_mmc_probe(struct platform_device *dev)
                 goto cell_disable;
 
         disable_mmc_irqs(host, TMIO_MASK_ALL);
+        if (pdata->flags & TMIO_MMC_SDIO_IRQ)
+                tmio_mmc_enable_sdio_irq(mmc, 0);
 
         ret = request_irq(host->irq, tmio_mmc_irq, IRQF_DISABLED |
                 IRQF_TRIGGER_FALLING, dev_name(&dev->dev), host);