diff options
| author | Mike Frysinger <vapier@gentoo.org> | 2009-06-29 22:45:50 +0000 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2009-07-16 01:52:26 -0400 |
| commit | 532f07ca04c6f8ab0555b00cf5d42dc6f72b802f (patch) | |
| tree | 6a449019028efc5518da6abd3e18437ca60ade6c /arch/blackfin | |
| parent | fb4b5d3a379824d94fd71fc1aa78e9dbcb15b948 (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.c | 29 |
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); |