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authorvimal singh <vimalsingh@ti.com>2009-07-13 16:26:24 +0530
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-09-19 13:20:51 -0700
commit59e9c5ae17179fe561103fbe0808fac5976ca1bd (patch)
treecc1f155a2569d09ae5d1d232046bb188c6b38d4c /arch/arm/mach-omap2/gpmc.c
parent8bff82cbc30884fc52969608d090d874641e7196 (diff)
mtd: omap: add support for nand prefetch-read and post-write
This patch adds prefetch support to access nand flash in mpu mode. This patch also adds 8-bit nand support (omap_read/write_buf8). Prefetch can be used for both 8- and 16-bit devices. Signed-off-by: Vimal Singh <vimalsingh@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'arch/arm/mach-omap2/gpmc.c')
-rw-r--r--arch/arm/mach-omap2/gpmc.c63
1 files changed, 62 insertions, 1 deletions
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index f91934b2b09..15876828db2 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -57,6 +57,11 @@
#define GPMC_CHUNK_SHIFT 24 /* 16 MB */
#define GPMC_SECTION_SHIFT 28 /* 128 MB */
+#define PREFETCH_FIFOTHRESHOLD (0x40 << 8)
+#define CS_NUM_SHIFT 24
+#define ENABLE_PREFETCH (0x1 << 7)
+#define DMA_MPU_MODE 2
+
static struct resource gpmc_mem_root;
static struct resource gpmc_cs_mem[GPMC_CS_NUM];
static DEFINE_SPINLOCK(gpmc_mem_lock);
@@ -386,6 +391,63 @@ void gpmc_cs_free(int cs)
}
EXPORT_SYMBOL(gpmc_cs_free);
+/**
+ * gpmc_prefetch_enable - configures and starts prefetch transfer
+ * @cs: nand cs (chip select) number
+ * @dma_mode: dma mode enable (1) or disable (0)
+ * @u32_count: number of bytes to be transferred
+ * @is_write: prefetch read(0) or write post(1) mode
+ */
+int gpmc_prefetch_enable(int cs, int dma_mode,
+ unsigned int u32_count, int is_write)
+{
+ uint32_t prefetch_config1;
+
+ if (!(gpmc_read_reg(GPMC_PREFETCH_CONTROL))) {
+ /* Set the amount of bytes to be prefetched */
+ gpmc_write_reg(GPMC_PREFETCH_CONFIG2, u32_count);
+
+ /* Set dma/mpu mode, the prefetch read / post write and
+ * enable the engine. Set which cs is has requested for.
+ */
+ prefetch_config1 = ((cs << CS_NUM_SHIFT) |
+ PREFETCH_FIFOTHRESHOLD |
+ ENABLE_PREFETCH |
+ (dma_mode << DMA_MPU_MODE) |
+ (0x1 & is_write));
+ gpmc_write_reg(GPMC_PREFETCH_CONFIG1, prefetch_config1);
+ } else {
+ return -EBUSY;
+ }
+ /* Start the prefetch engine */
+ gpmc_write_reg(GPMC_PREFETCH_CONTROL, 0x1);
+
+ return 0;
+}
+EXPORT_SYMBOL(gpmc_prefetch_enable);
+
+/**
+ * gpmc_prefetch_reset - disables and stops the prefetch engine
+ */
+void gpmc_prefetch_reset(void)
+{
+ /* Stop the PFPW engine */
+ gpmc_write_reg(GPMC_PREFETCH_CONTROL, 0x0);
+
+ /* Reset/disable the PFPW engine */
+ gpmc_write_reg(GPMC_PREFETCH_CONFIG1, 0x0);
+}
+EXPORT_SYMBOL(gpmc_prefetch_reset);
+
+/**
+ * gpmc_prefetch_status - reads prefetch status of engine
+ */
+int gpmc_prefetch_status(void)
+{
+ return gpmc_read_reg(GPMC_PREFETCH_STATUS);
+}
+EXPORT_SYMBOL(gpmc_prefetch_status);
+
static void __init gpmc_mem_init(void)
{
int cs;
@@ -452,6 +514,5 @@ void __init gpmc_init(void)
l &= 0x03 << 3;
l |= (0x02 << 3) | (1 << 0);
gpmc_write_reg(GPMC_SYSCONFIG, l);
-
gpmc_mem_init();
}