From: Russell King Date: Thu, 2 May 2019 16:19:18 +0000 (+0100) Subject: ARM: riscpc: fix DMA X-Git-Tag: v4.14.137~59 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff1b2beb5f0042cbfa99c82ea44a0b64b16b097a;p=thirdparty%2Fkernel%2Fstable.git ARM: riscpc: fix DMA [ Upstream commit ffd9a1ba9fdb7f2bd1d1ad9b9243d34e96756ba2 ] DMA got broken a while back in two different ways: 1) a change in the behaviour of disable_irq() to wait for the interrupt to finish executing causes us to deadlock at the end of DMA. 2) a change to avoid modifying the scatterlist left the first transfer uninitialised. DMA is only used with expansion cards, so has gone unnoticed. Fixes: fa4e99899932 ("[ARM] dma: RiscPC: don't modify DMA SG entries") Signed-off-by: Russell King Signed-off-by: Sasha Levin --- diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index fb48f3141fb4d..c4c96661eb89a 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -131,7 +131,7 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) } while (1); idma->state = ~DMA_ST_AB; - disable_irq(irq); + disable_irq_nosync(irq); return IRQ_HANDLED; } @@ -174,6 +174,9 @@ static void iomd_enable_dma(unsigned int chan, dma_t *dma) DMA_FROM_DEVICE : DMA_TO_DEVICE); } + idma->dma_addr = idma->dma.sg->dma_address; + idma->dma_len = idma->dma.sg->length; + iomd_writeb(DMA_CR_C, dma_base + CR); idma->state = DMA_ST_AB; }