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>
diff --git a/drivers/dma/fsl_dma.c b/drivers/dma/fsl_dma.c
index 33ea828..f3575af 100644
--- a/drivers/dma/fsl_dma.c
+++ b/drivers/dma/fsl_dma.c
@@ -30,6 +30,9 @@
#include <asm/io.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)
ccsr_dma_t *dma_base = (void *)(CONFIG_SYS_MPC85xx_DMA_ADDR);
#elif defined(CONFIG_MPC86xx)
@@ -77,20 +80,33 @@
int dma_xfer(void *dest, uint count, void *src) {
volatile fsl_dma_t *dma = &dma_base->dma[0];
+ uint xfer_size;
- out_be32(&dma->dar, (uint) dest);
- out_be32(&dma->sar, (uint) src);
- out_be32(&dma->bcr, count);
+ while (count) {
+ xfer_size = MIN(FSL_DMA_MAX_SIZE, count);
- /* Disable bandwidth control, use direct transfer mode */
- out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS | FSL_DMA_MR_CTM_DIRECT);
- dma_sync();
+ out_be32(&dma->dar, (uint) dest);
+ out_be32(&dma->sar, (uint) src);
+ out_be32(&dma->bcr, xfer_size);
- /* Start the transfer */
- out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS |
- FSL_DMA_MR_CTM_DIRECT |
- FSL_DMA_MR_CS);
- dma_sync();
+ /* Disable bandwidth control, use direct transfer mode */
+ out_be32(&dma->mr, FSL_DMA_MR_BWC_DIS | FSL_DMA_MR_CTM_DIRECT);
+ dma_sync();
+
+ /* 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 dma_check();
+ return 0;
}