omap3: nand: prefetch in irq mode support

This patch enable prefetch-irq mode for nand transfer(read, write)

Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 189 insertions, 9 deletions

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 60bac8e6e9fa..fbe841467175 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -11,6 +11,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 #include <linux/jiffies.h>
 #include <linux/sched.h>
 #include <linux/mtd/mtd.h>
@@ -24,6 +25,7 @@
 #include <plat/nand.h>
 
 #define DRIVER_NAME     "omap2-nand"
+#define OMAP_NAND_TIMEOUT_MS    5000
 
 #define NAND_Ecc_P1e            (1 << 0)
 #define NAND_Ecc_P2e            (1 << 1)
@@ -108,6 +110,13 @@ struct omap_nand_info {
         unsigned long                   phys_base;
         struct completion               comp;
         int                             dma_ch;
+        int                             gpmc_irq;
+        enum {
+                OMAP_NAND_IO_READ = 0,  /* read */
+                OMAP_NAND_IO_WRITE,     /* write */
+        } iomode;
+        u_char                          *buf;
+        int                                     buf_len;
 };
 
 /**
@@ -267,9 +276,10 @@ static void omap_write_buf_pref(struct mtd_info *mtd,
 {
         struct omap_nand_info *info = container_of(mtd,
                                                 struct omap_nand_info, mtd);
-        uint32_t pref_count = 0, w_count = 0;
+        uint32_t w_count = 0;
         int i = 0, ret = 0;
         u16 *p;
+        unsigned long tim, limit;
 
         /* take care of subpage writes */
         if (len % 2 != 0) {
@@ -295,9 +305,12 @@ static void omap_write_buf_pref(struct mtd_info *mtd,
                                 iowrite16(*p++, info->nand.IO_ADDR_W);
                 }
                 /* wait for data to flushed-out before reset the prefetch */
-                do {
-                        pref_count = gpmc_read_status(GPMC_PREFETCH_COUNT);
-                } while (pref_count);
+                tim = 0;
+                limit = (loops_per_jiffy *
+                                        msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+                while (gpmc_read_status(GPMC_PREFETCH_COUNT) && (tim++ < limit))
+                        cpu_relax();
+
                 /* disable and stop the PFPW engine */
                 gpmc_prefetch_reset(info->gpmc_cs);
         }
@@ -326,11 +339,11 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
 {
         struct omap_nand_info *info = container_of(mtd,
                                         struct omap_nand_info, mtd);
-        uint32_t prefetch_status = 0;
         enum dma_data_direction dir = is_write ? DMA_TO_DEVICE :
                                                         DMA_FROM_DEVICE;
         dma_addr_t dma_addr;
         int ret;
+        unsigned long tim, limit;
 
         /* The fifo depth is 64 bytes. We have a sync at each frame and frame
          * length is 64 bytes.
@@ -376,7 +389,7 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
         /*  configure and start prefetch transfer */
         ret = gpmc_prefetch_enable(info->gpmc_cs, 0x1, len, is_write);
         if (ret)
-                /* PFPW engine is busy, use cpu copy methode */
+                /* PFPW engine is busy, use cpu copy method */
                 goto out_copy;
 
         init_completion(&info->comp);
@@ -385,10 +398,11 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr,
 
         /* setup and start DMA using dma_addr */
         wait_for_completion(&info->comp);
+        tim = 0;
+        limit = (loops_per_jiffy * msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+        while (gpmc_read_status(GPMC_PREFETCH_COUNT) && (tim++ < limit))
+                cpu_relax();
 
-        do {
-                prefetch_status = gpmc_read_status(GPMC_PREFETCH_COUNT);
-        } while (prefetch_status);
         /* disable and stop the PFPW engine */
         gpmc_prefetch_reset(info->gpmc_cs);
 
@@ -436,6 +450,155 @@ static void omap_write_buf_dma_pref(struct mtd_info *mtd,
                 omap_nand_dma_transfer(mtd, (u_char *) buf, len, 0x1);
 }
 
+/*
+ * omap_nand_irq - GMPC irq handler
+ * @this_irq: gpmc irq number
+ * @dev: omap_nand_info structure pointer is passed here
+ */
+static irqreturn_t omap_nand_irq(int this_irq, void *dev)
+{
+        struct omap_nand_info *info = (struct omap_nand_info *) dev;
+        u32 bytes;
+        u32 irq_stat;
+
+        irq_stat = gpmc_read_status(GPMC_GET_IRQ_STATUS);
+        bytes = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT);
+        bytes = bytes  & 0xFFFC; /* io in multiple of 4 bytes */
+        if (info->iomode == OMAP_NAND_IO_WRITE) { /* checks for write io */
+                if (irq_stat & 0x2)
+                        goto done;
+
+                if (info->buf_len && (info->buf_len < bytes))
+                        bytes = info->buf_len;
+                else if (!info->buf_len)
+                        bytes = 0;
+                iowrite32_rep(info->nand.IO_ADDR_W,
+                                                (u32 *)info->buf, bytes >> 2);
+                info->buf = info->buf + bytes;
+                info->buf_len -= bytes;
+
+        } else {
+                ioread32_rep(info->nand.IO_ADDR_R,
+                                                (u32 *)info->buf, bytes >> 2);
+                info->buf = info->buf + bytes;
+
+                if (irq_stat & 0x2)
+                        goto done;
+        }
+        gpmc_cs_configure(info->gpmc_cs, GPMC_SET_IRQ_STATUS, irq_stat);
+
+        return IRQ_HANDLED;
+
+done:
+        complete(&info->comp);
+        /* disable irq */
+        gpmc_cs_configure(info->gpmc_cs, GPMC_ENABLE_IRQ, 0);
+
+        /* clear status */
+        gpmc_cs_configure(info->gpmc_cs, GPMC_SET_IRQ_STATUS, irq_stat);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * omap_read_buf_irq_pref - read data from NAND controller into buffer
+ * @mtd: MTD device structure
+ * @buf: buffer to store date
+ * @len: number of bytes to read
+ */
+static void omap_read_buf_irq_pref(struct mtd_info *mtd, u_char *buf, int len)
+{
+        struct omap_nand_info *info = container_of(mtd,
+                                                struct omap_nand_info, mtd);
+        int ret = 0;
+
+        if (len <= mtd->oobsize) {
+                omap_read_buf_pref(mtd, buf, len);
+                return;
+        }
+
+        info->iomode = OMAP_NAND_IO_READ;
+        info->buf = buf;
+        init_completion(&info->comp);
+
+        /*  configure and start prefetch transfer */
+        ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0);
+        if (ret)
+                /* PFPW engine is busy, use cpu copy method */
+                goto out_copy;
+
+        info->buf_len = len;
+        /* enable irq */
+        gpmc_cs_configure(info->gpmc_cs, GPMC_ENABLE_IRQ,
+                (GPMC_IRQ_FIFOEVENTENABLE | GPMC_IRQ_COUNT_EVENT));
+
+        /* waiting for read to complete */
+        wait_for_completion(&info->comp);
+
+        /* disable and stop the PFPW engine */
+        gpmc_prefetch_reset(info->gpmc_cs);
+        return;
+
+out_copy:
+        if (info->nand.options & NAND_BUSWIDTH_16)
+                omap_read_buf16(mtd, buf, len);
+        else
+                omap_read_buf8(mtd, buf, len);
+}
+
+/*
+ * omap_write_buf_irq_pref - write buffer to NAND controller
+ * @mtd: MTD device structure
+ * @buf: data buffer
+ * @len: number of bytes to write
+ */
+static void omap_write_buf_irq_pref(struct mtd_info *mtd,
+                                        const u_char *buf, int len)
+{
+        struct omap_nand_info *info = container_of(mtd,
+                                                struct omap_nand_info, mtd);
+        int ret = 0;
+        unsigned long tim, limit;
+
+        if (len <= mtd->oobsize) {
+                omap_write_buf_pref(mtd, buf, len);
+                return;
+        }
+
+        info->iomode = OMAP_NAND_IO_WRITE;
+        info->buf = (u_char *) buf;
+        init_completion(&info->comp);
+
+        /*  configure and start prefetch transfer */
+        ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x1);
+        if (ret)
+                /* PFPW engine is busy, use cpu copy method */
+                goto out_copy;
+
+        info->buf_len = len;
+        /* enable irq */
+        gpmc_cs_configure(info->gpmc_cs, GPMC_ENABLE_IRQ,
+                        (GPMC_IRQ_FIFOEVENTENABLE | GPMC_IRQ_COUNT_EVENT));
+
+        /* waiting for write to complete */
+        wait_for_completion(&info->comp);
+        /* wait for data to flushed-out before reset the prefetch */
+        tim = 0;
+        limit = (loops_per_jiffy *  msecs_to_jiffies(OMAP_NAND_TIMEOUT_MS));
+        while (gpmc_read_status(GPMC_PREFETCH_COUNT) && (tim++ < limit))
+                cpu_relax();
+
+        /* disable and stop the PFPW engine */
+        gpmc_prefetch_reset(info->gpmc_cs);
+        return;
+
+out_copy:
+        if (info->nand.options & NAND_BUSWIDTH_16)
+                omap_write_buf16(mtd, buf, len);
+        else
+                omap_write_buf8(mtd, buf, len);
+}
+
 /**
  * omap_verify_buf - Verify chip data against buffer
  * @mtd: MTD device structure
@@ -846,6 +1009,20 @@ static int __devinit omap_nand_probe(struct platform_device *pdev)
                 }
                 break;
 
+        case NAND_OMAP_PREFETCH_IRQ:
+                err = request_irq(pdata->gpmc_irq,
+                                omap_nand_irq, IRQF_SHARED, "gpmc-nand", info);
+                if (err) {
+                        dev_err(&pdev->dev, "requesting irq(%d) error:%d",
+                                                        pdata->gpmc_irq, err);
+                        goto out_release_mem_region;
+                } else {
+                        info->gpmc_irq       = pdata->gpmc_irq;
+                        info->nand.read_buf  = omap_read_buf_irq_pref;
+                        info->nand.write_buf = omap_write_buf_irq_pref;
+                }
+                break;
+
         default:
                 dev_err(&pdev->dev,
                         "xfer_type(%d) not supported!\n", pdata->xfer_type);
@@ -911,6 +1088,9 @@ static int omap_nand_remove(struct platform_device *pdev)
         if (info->dma_ch != -1)
                 omap_free_dma(info->dma_ch);
 
+        if (info->gpmc_irq)
+                free_irq(info->gpmc_irq, info);
+
         /* Release NAND device, its internal structures and partitions */
         nand_release(&info->mtd);
         iounmap(info->nand.IO_ADDR_R);