3.16.76-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
commit ffd9a1ba9fdb7f2bd1d1ad9b9243d34e96756ba2 upstream.
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@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/arm/mach-rpc/dma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- 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 i
} 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
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;
}
