Re: [PATCH] spi: Mediatek: fix endian warnings

From: Arnd Bergmann
Date: Sat Aug 15 2015 - 16:17:07 EST


On Tuesday 11 August 2015 18:43:09 Leilk Liu wrote:
> @@ -359,9 +359,11 @@ 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(cpu_to_le32(xfer->tx_dma), mdata->base + SPI_TX_SRC_REG);
> + writel((__force u32)cpu_to_le32(xfer->tx_dma),
> + mdata->base + SPI_TX_SRC_REG);
> if (mdata->rx_sgl)
> - writel(cpu_to_le32(xfer->rx_dma), mdata->base + SPI_RX_DST_REG);
> + writel((__force u32)cpu_to_le32(xfer->rx_dma),
> + mdata->base + SPI_RX_DST_REG);
> }
>

This looks wrong: writel takes a CPU-endian argument, so the value returned
from cpu_to_le32() is not appropriate.

The warning is correct, and you have to remove the cpu_to_le32() conversion
in order to get the driver to behave correctly when the kernel is built
as big-endian.

Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/