| Message ID | 1439467601-10209-1-git-send-email-leilk.liu@mediatek.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 39ba928f8b34720b60c68d4c1bb274ae219ab39e |
| Headers | show |
On Thursday 13 August 2015 20:06:41 Leilk Liu wrote: > diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c > index ae645fa..519f50c 100644 > --- a/drivers/spi/spi-mt65xx.c > +++ b/drivers/spi/spi-mt65xx.c > @@ -359,11 +359,9 @@ static void mtk_spi_setup_dma_addr(struct spi_master *master, > struct mtk_spi *mdata = spi_master_get_devdata(master); > > if (mdata->tx_sgl) > - writel((__force u32)cpu_to_le32(xfer->tx_dma), > - mdata->base + SPI_TX_SRC_REG); > + writel(xfer->tx_dma, mdata->base + SPI_TX_SRC_REG); > if (mdata->rx_sgl) > - writel((__force u32)cpu_to_le32(xfer->rx_dma), > - mdata->base + SPI_RX_DST_REG); > + writel(xfer->rx_dma, mdata->base + SPI_RX_DST_REG); > } > > static int mtk_spi_fifo_transfer(struct spi_master *master, > -- > This change looks good, but after I've briefly looked at the current driver, I found at least one more location that looks like an endianess bug: +static int mtk_spi_fifo_transfer(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ ... + + for (i = 0; i < cnt; i++) + writel(*((u32 *)xfer->tx_buf + i), + mdata->base + SPI_TX_DATA_REG); + + mtk_spi_enable_transfer(master); + + return 1; +} Here, you write data into a FIFO register using an accessor that converts to little-endian. In contrast, the DMA based accessor apparently has no byte swap, so most likely one of the two is broken on big-endian systems. My guess is that the look above is wrong, and you need to use iowrite32_rep() instead, so you always write into the FIFO in the byte stream order (first byte to last byte) rather than swapping 32-bit entities. The other suspicious part is this: + reg_val |= (chip_config->tx_endian << SPI_CMD_TX_ENDIAN_OFFSET); + reg_val |= (chip_config->rx_endian << SPI_CMD_RX_ENDIAN_OFFSET); It's not clear what the tx_endian/rx_endian bits refer to and why you can't just always set the register interface to little-endian. If it's set to big-endian, you probably need to add more byte swaps in the driver. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index ae645fa..519f50c 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -359,11 +359,9 @@ static void mtk_spi_setup_dma_addr(struct spi_master *master, struct mtk_spi *mdata = spi_master_get_devdata(master); if (mdata->tx_sgl) - writel((__force u32)cpu_to_le32(xfer->tx_dma), - mdata->base + SPI_TX_SRC_REG); + writel(xfer->tx_dma, mdata->base + SPI_TX_SRC_REG); if (mdata->rx_sgl) - writel((__force u32)cpu_to_le32(xfer->rx_dma), - mdata->base + SPI_RX_DST_REG); + writel(xfer->rx_dma, mdata->base + SPI_RX_DST_REG); } static int mtk_spi_fifo_transfer(struct spi_master *master,
writel() already does a cpu_to_le32 conversion, so remove cpu_to_le32(). Signed-off-by: Leilk Liu <leilk.liu@mediatek.com> --- drivers/spi/spi-mt65xx.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)