Re: [PATCH-v2.6.39] spi/omap_mcspi: Fix broken last word xfer

[Michael Jones <michael.jones@matrix-vision.de>]

On 03/21/2011 03:27 PM, Jarkko Nikula wrote:
> Commit adef658 "spi/omap_mcspi: catch xfers of non-multiple SPI word size"
> broke the transmission of last word in cases where access is multiple of
> word size and word size is 16 or 32 bits.
> 
> Fix this by replacing the test "c > (word_len>>3)" in do-while loops with
> "c >= 'pointer increment size'". This ensures that the last word is
> transmitted in above case and still allow to break the loop and prevent
> variable c underflow in cases where word size != 'pointer increment size'.
> 
> Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
> Cc: Michael Jones <michael.jones@matrix-vision.de>
> ---
> I noticed the issue with wl1251 WLAN driver on Nokia N900 using today's
> vanilla head a44f99c7efdb88fa41128065c9a9445c19894e34.
> ---
>  drivers/spi/omap2_mcspi.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
> index 3a5ed06..6f86ba0 100644
> --- a/drivers/spi/omap2_mcspi.c
> +++ b/drivers/spi/omap2_mcspi.c
> @@ -517,7 +517,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
>  				dev_vdbg(&spi->dev, "read-%d %02x\n",
>  						word_len, *(rx - 1));
>  			}
> -		} while (c > (word_len>>3));
> +		} while (c);
>  	} else if (word_len <= 16) {
>  		u16		*rx;
>  		const u16	*tx;
> @@ -564,7 +564,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
>  				dev_vdbg(&spi->dev, "read-%d %04x\n",
>  						word_len, *(rx - 1));
>  			}
> -		} while (c > (word_len>>3));
> +		} while (c >= 2);
>  	} else if (word_len <= 32) {
>  		u32		*rx;
>  		const u32	*tx;
> @@ -611,7 +611,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
>  				dev_vdbg(&spi->dev, "read-%d %08x\n",
>  						word_len, *(rx - 1));
>  			}
> -		} while (c > (word_len>>3));
> +		} while (c >= 4);
>  	}
>  
>  	/* for TX_ONLY mode, be sure all words have shifted out */

Acked-by: Michael Jones <michael.jones@matrix-vision.de>

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