omap3: nand: configurable fifo threshold to gain the throughput
Configure the FIFO THREASHOLD value different for read and write to keep busy
both filling and to drain out of FIFO at reading and writing.
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>
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 382dea8..6741743 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -60,7 +60,6 @@
#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
@@ -606,15 +605,19 @@
/**
* gpmc_prefetch_enable - configures and starts prefetch transfer
* @cs: cs (chip select) number
+ * @fifo_th: fifo threshold to be used for read/ write
* @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,
+int gpmc_prefetch_enable(int cs, int fifo_th, int dma_mode,
unsigned int u32_count, int is_write)
{
- if (!(gpmc_read_reg(GPMC_PREFETCH_CONTROL))) {
+ if (fifo_th > PREFETCH_FIFOTHRESHOLD_MAX) {
+ pr_err("gpmc: fifo threshold is not supported\n");
+ return -1;
+ } else if (!(gpmc_read_reg(GPMC_PREFETCH_CONTROL))) {
/* Set the amount of bytes to be prefetched */
gpmc_write_reg(GPMC_PREFETCH_CONFIG2, u32_count);
@@ -622,7 +625,7 @@
* enable the engine. Set which cs is has requested for.
*/
gpmc_write_reg(GPMC_PREFETCH_CONFIG1, ((cs << CS_NUM_SHIFT) |
- PREFETCH_FIFOTHRESHOLD |
+ PREFETCH_FIFOTHRESHOLD(fifo_th) |
ENABLE_PREFETCH |
(dma_mode << DMA_MPU_MODE) |
(0x1 & is_write)));