sdio: core support for SDIO function interrupt

Signed-off-by: Nicolas Pitre <npitre@mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

5 files changed, 257 insertions, 1 deletions

diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 05d69fc72c18..4985807257a8 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -10,5 +10,5 @@ obj-$(CONFIG_MMC)		+= mmc_core.o
 mmc_core-y                      := core.o sysfs.o bus.o host.o \
                                    mmc.o mmc_ops.o sd.o sd_ops.o \
                                    sdio.o sdio_ops.o sdio_bus.o \
-                                   sdio_cis.o sdio_io.o
+                                   sdio_cis.o sdio_io.o sdio_irq.o
 
diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index 129f0719c391..240724454914 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -143,6 +143,14 @@ static int sdio_bus_remove(struct device *dev)
 
         drv->remove(func);
 
+        if (func->irq_handler) {
+                printk(KERN_WARNING "WARNING: driver %s did not remove "
+                        "its interrupt handler!\n", drv->name);
+                sdio_claim_host(func);
+                sdio_release_irq(func);
+                sdio_release_host(func);
+        }
+
         return 0;
 }
 
diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c
new file mode 100644
index 000000000000..01922d29241d
--- /dev/null
+++ b/drivers/mmc/core/sdio_irq.c
@@ -0,0 +1,237 @@
+/*
+ * linux/drivers/mmc/core/sdio_irq.c
+ *
+ * Author:      Nicolas Pitre
+ * Created:     June 18, 2007
+ * Copyright:   MontaVista Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+
+#include <linux/mmc/core.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/sdio_func.h>
+
+#include "sdio_ops.h"
+
+static int process_sdio_pending_irqs(struct mmc_card *card)
+{
+        int i, ret;
+        unsigned char pending;
+
+        ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTx, 0, &pending);
+        if (ret) {
+                printk(KERN_DEBUG "%s: error %d reading SDIO_CCCR_INTx\n",
+                       mmc_card_id(card), ret);
+                return ret;
+        }
+
+        for (i = 1; i <= 7; i++) {
+                if (pending & (1 << i)) {
+                        struct sdio_func *func = card->sdio_func[i - 1];
+                        if (!func) {
+                                printk(KERN_WARNING "%s: pending IRQ for "
+                                        "non-existant function\n",
+                                        sdio_func_id(func));
+                        } else if (func->irq_handler) {
+                                func->irq_handler(func);
+                        } else
+                                printk(KERN_WARNING "%s: pending IRQ with no handler\n",
+                                       sdio_func_id(func));
+                }
+        }
+
+        return 0;
+}
+
+static int sdio_irq_thread(void *_host)
+{
+        struct mmc_host *host = _host;
+        struct sched_param param = { .sched_priority = 1 };
+        unsigned long period;
+        int ret;
+
+        sched_setscheduler(current, SCHED_FIFO, &param);
+
+        /*
+         * We want to allow for SDIO cards to work even on non SDIO
+         * aware hosts.  One thing that non SDIO host cannot do is
+         * asynchronous notification of pending SDIO card interrupts
+         * hence we poll for them in that case.
+         */
+        period = msecs_to_jiffies(10);
+
+        pr_debug("%s: IRQ thread started (poll period = %lu jiffies)\n",
+                 mmc_hostname(host), period);
+
+        do {
+                /*
+                 * We claim the host here on drivers behalf for a couple
+                 * reasons:
+                 *
+                 * 1) it is already needed to retrieve the CCCR_INTx;
+                 * 2) we want the driver(s) to clear the IRQ condition ASAP;
+                 * 3) we need to control the abort condition locally.
+                 *
+                 * Just like traditional hard IRQ handlers, we expect SDIO
+                 * IRQ handlers to be quick and to the point, so that the
+                 * holding of the host lock does not cover too much work
+                 * that doesn't require that lock to be held.
+                 */
+                ret = __mmc_claim_host(host, &host->sdio_irq_thread_abort);
+                if (ret)
+                        break;
+                ret = process_sdio_pending_irqs(host->card);
+                mmc_release_host(host);
+
+                /*
+                 * Give other threads a chance to run in the presence of
+                 * errors.  FIXME: determine if due to card removal and
+                 * possibly exit this thread if so.
+                 */
+                if (ret)
+                        ssleep(1);
+
+                set_task_state(current, TASK_INTERRUPTIBLE);
+                if (!kthread_should_stop())
+                        schedule_timeout(period);
+                set_task_state(current, TASK_RUNNING);
+        } while (!kthread_should_stop());
+
+        pr_debug("%s: IRQ thread exiting with code %d\n",
+                 mmc_hostname(host), ret);
+
+        return ret;
+}
+
+static int sdio_card_irq_get(struct mmc_card *card)
+{
+        struct mmc_host *host = card->host;
+
+        BUG_ON(!host->claimed);
+
+        if (!host->sdio_irqs++) {
+                atomic_set(&host->sdio_irq_thread_abort, 0);
+                host->sdio_irq_thread =
+                        kthread_run(sdio_irq_thread, host, "ksdiorqd");
+                if (IS_ERR(host->sdio_irq_thread)) {
+                        int err = PTR_ERR(host->sdio_irq_thread);
+                        host->sdio_irqs--;
+                        return err;
+                }
+        }
+
+        return 0;
+}
+
+static int sdio_card_irq_put(struct mmc_card *card)
+{
+        struct mmc_host *host = card->host;
+
+        BUG_ON(!host->claimed);
+        BUG_ON(host->sdio_irqs < 1);
+
+        if (!--host->sdio_irqs) {
+                atomic_set(&host->sdio_irq_thread_abort, 1);
+                kthread_stop(host->sdio_irq_thread);
+        }
+
+        return 0;
+}
+
+/**
+ *      sdio_claim_irq - claim the IRQ for a SDIO function
+ *      @func: SDIO function
+ *      @handler: IRQ handler callback
+ *
+ *      Claim and activate the IRQ for the given SDIO function. The provided
+ *      handler will be called when that IRQ is asserted.  The host is always
+ *      claimed already when the handler is called so the handler must not
+ *      call sdio_claim_host() nor sdio_release_host().
+ */
+int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler)
+{
+        int ret;
+        unsigned char reg;
+
+        BUG_ON(!func);
+        BUG_ON(!func->card);
+
+        pr_debug("SDIO: Enabling IRQ for %s...\n", sdio_func_id(func));
+
+        if (func->irq_handler) {
+                pr_debug("SDIO: IRQ for %s already in use.\n", sdio_func_id(func));
+                return -EBUSY;
+        }
+
+        ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
+        if (ret)
+                return ret;
+
+        reg |= 1 << func->num;
+
+        reg |= 1; /* Master interrupt enable */
+
+        ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
+        if (ret)
+                return ret;
+
+        func->irq_handler = handler;
+        ret = sdio_card_irq_get(func->card);
+        if (ret)
+                func->irq_handler = NULL;
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(sdio_claim_irq);
+
+/**
+ *      sdio_release_irq - release the IRQ for a SDIO function
+ *      @func: SDIO function
+ *
+ *      Disable and release the IRQ for the given SDIO function.
+ */
+int sdio_release_irq(struct sdio_func *func)
+{
+        int ret;
+        unsigned char reg;
+
+        BUG_ON(!func);
+        BUG_ON(!func->card);
+
+        pr_debug("SDIO: Disabling IRQ for %s...\n", sdio_func_id(func));
+
+        if (func->irq_handler) {
+                func->irq_handler = NULL;
+                sdio_card_irq_put(func->card);
+        }
+
+        ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IENx, 0, &reg);
+        if (ret)
+                return ret;
+
+        reg &= ~(1 << func->num);
+
+        /* Disable master interrupt with the last function interrupt */
+        if (!(reg & 0xFE))
+                reg = 0;
+
+        ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IENx, reg, NULL);
+        if (ret)
+                return ret;
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(sdio_release_irq);
+
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 8e2642ebf02f..00dc1809494c 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -123,6 +123,10 @@ struct mmc_host {
         unsigned int            bus_refs;       /* reference counter */
         unsigned int            bus_dead:1;     /* bus has been released */
 
+        unsigned int            sdio_irqs;
+        struct task_struct      *sdio_irq_thread;
+        atomic_t                sdio_irq_thread_abort;
+
         unsigned long           private[0] ____cacheline_aligned;
 };
 
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index 8106d399c414..a8d268c9c276 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -16,6 +16,9 @@
 #include <linux/mod_devicetable.h>
 
 struct mmc_card;
+struct sdio_func;
+
+typedef void (sdio_irq_handler_t)(struct sdio_func *);
 
 /*
  * SDIO function CIS tuple (unknown to the core)
@@ -33,6 +36,7 @@ struct sdio_func_tuple {
 struct sdio_func {
         struct mmc_card         *card;          /* the card this device belongs to */
         struct device           dev;            /* the device */
+        sdio_irq_handler_t      *irq_handler;   /* IRQ callback */
         unsigned int            num;            /* function number */
 
         unsigned char           class;          /* standard interface class */
@@ -105,6 +109,9 @@ extern void sdio_release_host(struct sdio_func *func);
 extern int sdio_enable_func(struct sdio_func *func);
 extern int sdio_disable_func(struct sdio_func *func);
 
+extern int sdio_claim_irq(struct sdio_func *func, sdio_irq_handler_t *handler);
+extern int sdio_release_irq(struct sdio_func *func);
+
 extern unsigned char sdio_readb(struct sdio_func *func,
         unsigned int addr, int *err_ret);