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omap3: nand: configurable fifo threshold to gain the throughput

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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>
This commit is contained in:
Sukumar Ghorai
2011-01-28 15:42:07 +05:30
committed by Tony Lindgren
parent 4e07037616
commit 317379a975
3 changed files with 25 additions and 13 deletions
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11
arch/arm/mach-omap2/gpmc.c
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@ -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 @@ EXPORT_SYMBOL(gpmc_nand_write);
/**
* 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 @@ int gpmc_prefetch_enable(int cs, int dma_mode,
* 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)));