MTD: OneNAND: interrupt based wait support

  We can use the two methods to wait.
  1. polling: read interrupt status register
  2. interrupt: use kernel ineterrupt mechanism

  To use interrupt method, you first connect onenand interrupt pin to your
platform and configure interrupt properly

Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>

2 files changed, 108 insertions, 2 deletions

diff --git a/drivers/mtd/onenand/generic.c b/drivers/mtd/onenand/generic.c
index af06a80f44de..cdf80c68160f 100644
--- a/drivers/mtd/onenand/generic.c
+++ b/drivers/mtd/onenand/generic.c
@@ -63,6 +63,7 @@ static int __devinit generic_onenand_probe(struct device *dev)
         }
 
         info->onenand.mmcontrol = pdata->mmcontrol;
+        info->onenand.irq = platform_get_irq(pdev, 0);
 
         info->mtd.name = pdev->dev.bus_id;
         info->mtd.priv = &info->onenand;
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 8ed68b28afe3..aea13a388868 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/sched.h>
+#include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/onenand.h>
@@ -339,6 +340,111 @@ static int onenand_wait(struct mtd_info *mtd, int state)
         return 0;
 }
 
+/*
+ * onenand_interrupt - [DEFAULT] onenand interrupt handler
+ * @param irq           onenand interrupt number
+ * @param dev_id        interrupt data
+ *
+ * complete the work
+ */
+static irqreturn_t onenand_interrupt(int irq, void *data)
+{
+        struct onenand_chip *this = (struct onenand_chip *) data;
+
+        /* To handle shared interrupt */
+        if (!this->complete.done)
+                complete(&this->complete);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * onenand_interrupt_wait - [DEFAULT] wait until the command is done
+ * @param mtd           MTD device structure
+ * @param state         state to select the max. timeout value
+ *
+ * Wait for command done.
+ */
+static int onenand_interrupt_wait(struct mtd_info *mtd, int state)
+{
+        struct onenand_chip *this = mtd->priv;
+
+        /* To prevent soft lockup */
+        touch_softlockup_watchdog();
+
+        wait_for_completion(&this->complete);
+
+        return onenand_wait(mtd, state);
+}
+
+/*
+ * onenand_try_interrupt_wait - [DEFAULT] try interrupt wait
+ * @param mtd           MTD device structure
+ * @param state         state to select the max. timeout value
+ *
+ * Try interrupt based wait (It is used one-time)
+ */
+static int onenand_try_interrupt_wait(struct mtd_info *mtd, int state)
+{
+        struct onenand_chip *this = mtd->priv;
+        unsigned long remain, timeout;
+
+        /* We use interrupt wait first */
+        this->wait = onenand_interrupt_wait;
+
+        /* To prevent soft lockup */
+        touch_softlockup_watchdog();
+
+        timeout = msecs_to_jiffies(100);
+        remain = wait_for_completion_timeout(&this->complete, timeout);
+        if (!remain) {
+                printk(KERN_INFO "OneNAND: There's no interrupt. "
+                                "We use the normal wait\n");
+
+                /* Release the irq */
+                free_irq(this->irq, this);
+                
+                this->wait = onenand_wait;
+        }
+
+        return onenand_wait(mtd, state);
+}
+
+/*
+ * onenand_setup_wait - [OneNAND Interface] setup onenand wait method
+ * @param mtd           MTD device structure
+ *
+ * There's two method to wait onenand work
+ * 1. polling - read interrupt status register
+ * 2. interrupt - use the kernel interrupt method
+ */
+static void onenand_setup_wait(struct mtd_info *mtd)
+{
+        struct onenand_chip *this = mtd->priv;
+        int syscfg;
+
+        init_completion(&this->complete);
+
+        if (this->irq <= 0) {
+                this->wait = onenand_wait;
+                return;
+        }
+
+        if (request_irq(this->irq, &onenand_interrupt,
+                                IRQF_SHARED, "onenand", this)) {
+                /* If we can't get irq, use the normal wait */
+                this->wait = onenand_wait;
+                return;
+        }
+
+        /* Enable interrupt */
+        syscfg = this->read_word(this->base + ONENAND_REG_SYS_CFG1);
+        syscfg |= ONENAND_SYS_CFG1_IOBE;
+        this->write_word(syscfg, this->base + ONENAND_REG_SYS_CFG1);
+
+        this->wait = onenand_try_interrupt_wait;
+}
+
 /**
  * onenand_bufferram_offset - [DEFAULT] BufferRAM offset
  * @param mtd           MTD data structure
@@ -1129,7 +1235,6 @@ static void onenand_sync(struct mtd_info *mtd)
         onenand_release_device(mtd);
 }
 
-
 /**
  * onenand_block_isbad - [MTD Interface] Check whether the block at the given offset is bad
  * @param mtd           MTD device structure
@@ -1846,7 +1951,7 @@ int onenand_scan(struct mtd_info *mtd, int maxchips)
         if (!this->command)
                 this->command = onenand_command;
         if (!this->wait)
-                this->wait = onenand_wait;
+                onenand_setup_wait(mtd);
 
         if (!this->read_bufferram)
                 this->read_bufferram = onenand_read_bufferram;