Commit f9691bb9 authored May 05, 2011 by Steven Miao Committed by Mike Frysinger May 25, 2011

Blackfin: work around anomaly 05000480



Anomaly 05000480 on BF537 rev 0.0, 0.1, 0.2:
Multiple Simultaneous Urgent DMA Requests May Cause DMA System Instability

Suggested Workaround:
Program the DMA Traffic Control Period to a non-zero value.  This forces
the DMA block to group accesses together rather than allow arbitration for
each piece of data placed on the internal DMA bus.

Signed-off-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

parent 7a7a430f

arch/blackfin/kernel/bfin_dma_5xx.c

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -36,6 +36,11 @@ static int __init blackfin_dma_init(void)

	printk(KERN_INFO "Blackfin DMA Controller\n");		printk(KERN_INFO "Blackfin DMA Controller\n");


			#if ANOMALY_05000480
			bfin_write_DMAC_TC_PER(0x0111);
			#endif

	for (i = 0; i < MAX_DMA_CHANNELS; i++) {		for (i = 0; i < MAX_DMA_CHANNELS; i++) {
	atomic_set(&dma_ch[i].chan_status, 0);		atomic_set(&dma_ch[i].chan_status, 0);
	dma_ch[i].regs = dma_io_base_addr[i];		dma_ch[i].regs = dma_io_base_addr[i];