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 <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c
index 6d3517d..82aac38 100644 (file)
--- 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;
        }