-----Original Message-----
From: Vinod <vkoul@kernel.org>
Sent: Wednesday, August 29, 2018 9:31 AM
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 28-08-18, 14:03, Radhey Shyam Pandey wrote:

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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

[off-list ref]

quoted

quoted

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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

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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

quoted

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.

Yeah that part was clear but the implementation can be better..

Thanks! Separate fields for source address are needed due to CDMA BD structure. 
Please suggest if it doesn't look ok.

--
~Vinod