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authorMike Frysinger <vapier@gentoo.org>2009-06-29 22:45:50 +0000
committerMike Frysinger <vapier@gentoo.org>2009-07-16 01:52:26 -0400
commit532f07ca04c6f8ab0555b00cf5d42dc6f72b802f (patch)
tree6a449019028efc5518da6abd3e18437ca60ade6c /arch/blackfin
parentfb4b5d3a379824d94fd71fc1aa78e9dbcb15b948 (diff)
Blackfin: fix early_dma_memcpy() handling of busy channels
The early logic to locate a free DMA channel and then set it up was broken in a few ways that only manifested itself when we needed to set up more than 2 on chip SRAM regions (most board defaults setup 1 or 2). First, we checked the wrong status register (the destination gets updated, not the source) and second, we did the ssync before rather than after resetting a DMA config register. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin')
-rw-r--r--arch/blackfin/kernel/bfin_dma_5xx.c29
1 files changed, 14 insertions, 15 deletions
diff --git a/arch/blackfin/kernel/bfin_dma_5xx.c b/arch/blackfin/kernel/bfin_dma_5xx.c
index e0bf8cc06907..9f9b82816652 100644
--- a/arch/blackfin/kernel/bfin_dma_5xx.c
+++ b/arch/blackfin/kernel/bfin_dma_5xx.c
@@ -253,32 +253,31 @@ void __init early_dma_memcpy(void *pdst, const void *psrc, size_t size)
BUG_ON(src % 4);
BUG_ON(size % 4);
- /* Force a sync in case a previous config reset on this channel
- * occurred. This is needed so subsequent writes to DMA registers
- * are not spuriously lost/corrupted.
- */
- __builtin_bfin_ssync();
-
src_ch = 0;
/* Find an avalible memDMA channel */
while (1) {
- if (!src_ch || src_ch == (struct dma_register *)MDMA_S1_NEXT_DESC_PTR) {
- dst_ch = (struct dma_register *)MDMA_D0_NEXT_DESC_PTR;
- src_ch = (struct dma_register *)MDMA_S0_NEXT_DESC_PTR;
- } else {
+ if (src_ch == (struct dma_register *)MDMA_S0_NEXT_DESC_PTR) {
dst_ch = (struct dma_register *)MDMA_D1_NEXT_DESC_PTR;
src_ch = (struct dma_register *)MDMA_S1_NEXT_DESC_PTR;
+ } else {
+ dst_ch = (struct dma_register *)MDMA_D0_NEXT_DESC_PTR;
+ src_ch = (struct dma_register *)MDMA_S0_NEXT_DESC_PTR;
}
- if (!bfin_read16(&src_ch->cfg)) {
+ if (!bfin_read16(&src_ch->cfg))
+ break;
+ else if (bfin_read16(&dst_ch->irq_status) & DMA_DONE) {
+ bfin_write16(&src_ch->cfg, 0);
break;
- } else {
- if (bfin_read16(&src_ch->irq_status) & DMA_DONE)
- bfin_write16(&src_ch->cfg, 0);
}
-
}
+ /* Force a sync in case a previous config reset on this channel
+ * occurred. This is needed so subsequent writes to DMA registers
+ * are not spuriously lost/corrupted.
+ */
+ __builtin_bfin_ssync();
+
/* Destination */
bfin_write32(&dst_ch->start_addr, dst);
bfin_write16(&dst_ch->x_count, size >> 2);