From patchwork Fri Jan 20 00:16:52 2012
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Subject: Kernel panic when reading mtd device
Date: Thu, 19 Jan 2012 14:16:52 -0000
From: "Shawn J. Goff" <shawn7400@gmail.com>
X-Patchwork-Id: 136928
Message-Id: <CAGiDA6KjJKQcho9aiqA2KSe30tvU0JZnMgv86zSE_Pt2=JRdDA@mail.gmail.com>
To: linux-mtd@lists.infradead.org

I believe the problem is in drivers/spi/atmel_spi.c. It looks like it
needs to break the transfer down into chunks that can fit in the
buffer. It seems that this driver as it exists in the Linux4SAM tree (
https://github.com/linux4sam/linux-at91/tree/linus2639_5series_1.x )
is unfinished(?) As a quick workaround, I did the following, which
allows me to function for now.


diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index ca9dab5..825371f 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -463,7 +463,7 @@ static void atmel_spi_next_xfer(struct spi_master *master,

        as->current_transfer = xfer;

-       if (atmel_spi_use_dma(xfer)) {
+       if (atmel_spi_use_dma(xfer) && xfer->len <= BUFFER_SIZE) {
                if (!atmel_spi_next_xfer_dma(master, xfer))
                        return;
                else