]> git.karo-electronics.de Git - karo-tx-linux.git/commitdiff
mxs/spi: clear XFER_COUNT in ctrl0 field in DMA descriptor
authorJuha Lumme <juha.lumme@gmail.com>
Wed, 26 Dec 2012 05:48:51 +0000 (14:48 +0900)
committerGrant Likely <grant.likely@secretlab.ca>
Tue, 5 Feb 2013 12:45:24 +0000 (12:45 +0000)
On MX23 the XFER_COUNT part in ctrl0 field in DMA descriptor was
improperly OR'd during the construction of DMA descriptor chain, instead
of being freshly set.  Because of that too many bytes were being
expected from SPI during the last DMA cycle.  This caused a timeout
(SSP_TIMEOUT) to happen in the processing of the last DMA descriptor,
and thus reads and writes were failing.  This is a fix for the problem,
by clearing XFER_COUNT bytes in ctrl0 before setting the new XFER_COUNT
for DMA descriptor.

Signed-off-by: Juha Lumme <juha.lumme@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
drivers/spi/spi-mxs.c

index a3ede249d05dfc19010d3b69a244f5093a030cc7..e3d8b3197d22be04f0ed9db3f4c131c1e915905a 100644 (file)
@@ -241,6 +241,7 @@ static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs,
        INIT_COMPLETION(spi->c);
 
        ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
+       ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
        ctrl0 |= BM_SSP_CTRL0_DATA_XFER | mxs_spi_cs_to_reg(cs);
 
        if (*first)
@@ -256,8 +257,10 @@ static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs,
                if ((sg_count + 1 == sgs) && *last)
                        ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC;
 
-               if (ssp->devid == IMX23_SSP)
+               if (ssp->devid == IMX23_SSP) {
+                       ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
                        ctrl0 |= min;
+               }
 
                dma_xfer[sg_count].pio[0] = ctrl0;
                dma_xfer[sg_count].pio[3] = min;