-----Original Message-----
From: Vinod <vkoul@kernel.org>
Sent: Tuesday, August 21, 2018 9:26 PM
To: Radhey Shyam Pandey <redacted>
Cc: dan.j.williams at intel.com; Michal Simek <redacted>; Appana
Durga Kedareswara Rao [off-list ref]; lars at metafoo.de;
dmaengine at vger.kernel.org; linux-arm-kernel at lists.infradead.org; linux-
kernel at vger.kernel.org
Subject: Re: [PATCH 3/3] dmaengine: xilinx_dma: Fix 64-bit simple CDMA
transfer

On 27-07-18, 16:20, Radhey Shyam Pandey wrote:

quoted

In AXI CDMA simple mode also pass MSB bits of source and destination
address to xilinx_write function. This fixes simple CDMA operation
mode using 64-bit addressing.

Signed-off-by: Radhey Shyam Pandey <redacted>
Signed-off-by: Michal Simek <redacted>
---
 drivers/dma/xilinx/xilinx_dma.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c
index a37871e..2e15d86 100644
--- a/drivers/dma/xilinx/xilinx_dma.c
+++ b/drivers/dma/xilinx/xilinx_dma.c

@@ -1245,8 +1245,10 @@ static void xilinx_cdma_start_transfer(struct

xilinx_dma_chan *chan)

quoted

 		hw = &segment->hw;

-		xilinx_write(chan, XILINX_CDMA_REG_SRCADDR, hw-
src_addr);
-		xilinx_write(chan, XILINX_CDMA_REG_DSTADDR, hw-
dest_addr);
+		xilinx_write(chan, XILINX_CDMA_REG_SRCADDR,

(dma_addr_t)

quoted

+			     ((u64)hw->src_addr_msb << 32 | hw->src_addr));

so this is:
        (dma_addr_t)((u64)hw->src_addr_msb << 32 | hw->src_addr)

what is src_addr data type? I think its u32. It would be better to
update xilinx_write() to take u64 and not dma_addr_t.

Yes, src_addr_msb and src_addr BD fields are u32. To explain: There is no
prob in xilinx_write it takes dma_addr_t as an arg which is 32/64 bit 
depending on _DMA_ADDR_T_64BIT. In 64bit CDMA transfer, there was a bug
i.e in the call to xilinx_write src_addr_msb 32 bits were not passed. To fix
that combine MSB and LSB 32 bits before passing it to xilinx_write.

Thanks,
Radhey

quoted

+		xilinx_write(chan, XILINX_CDMA_REG_DSTADDR,

(dma_addr_t)

quoted

+			     ((u64)hw->dest_addr_msb << 32 | hw-
dest_addr));

 		/* Start the transfer */
 		dma_ctrl_write(chan, XILINX_DMA_REG_BTT,
--
1.7.1

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--
~Vinod