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fsl_dma: Add support for arbitrarily large transfers 

Support DMA transfers larger than the DMA controller's limit of
(2 ^ 26 - 1) bytes

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Peter Tyser 2009-06-30 17:15:43 -05:00 committed by Kumar Gala
parent a730393a36
commit 51402ac12b
1 changed files with 28 additions and 12 deletions
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40
drivers/dma/fsl_dma.c
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@ -30,6 +30,9 @@
#include <asm/io.h> #include <asm/io.h>
#include <asm/fsl_dma.h> #include <asm/fsl_dma.h>
/* Controller can only transfer 2^26 - 1 bytes at a time */
#define FSL_DMA_MAX_SIZE (0x3ffffff)
#if defined(CONFIG_MPC85xx) #if defined(CONFIG_MPC85xx)
ccsr_dma_t *dma_base = (void *)(CONFIG_SYS_MPC85xx_DMA_ADDR); ccsr_dma_t *dma_base = (void *)(CONFIG_SYS_MPC85xx_DMA_ADDR);
#elif defined(CONFIG_MPC86xx) #elif defined(CONFIG_MPC86xx)
@ -77,20 +80,33 @@ void dma_init(void) {
int dma_xfer(void *dest, uint count, void *src) { int dma_xfer(void *dest, uint count, void *src) {
volatile fsl_dma_t *dma = &dma_base->dma[0]; volatile fsl_dma_t *dma = &dma_base->dma[0];
uint xfer_size;
out_be32(&dma->dar, (uint) dest); while (count) {
out_be32(&dma->sar, (uint) src); xfer_size = MIN(FSL_DMA_MAX_SIZE, count);
out_be32(&dma->bcr, count);
/* Disable bandwidth control, use direct transfer mode */ out_be32(&dma->dar, (uint) dest);
out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS | FSL_DMA_MR_CTM_DIRECT); out_be32(&dma->sar, (uint) src);
dma_sync(); out_be32(&dma->bcr, xfer_size);
/* Start the transfer */ /* Disable bandwidth control, use direct transfer mode */
out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS | out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS | FSL_DMA_MR_CTM_DIRECT);
FSL_DMA_MR_CTM_DIRECT | dma_sync();
FSL_DMA_MR_CS);
dma_sync();
return dma_check(); /* Start the transfer */
out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS |
FSL_DMA_MR_CTM_DIRECT |
FSL_DMA_MR_CS);
count -= xfer_size;
src += xfer_size;
dest += xfer_size;
dma_sync();
if (dma_check())
return -1;
}
return 0;
} }