Dear all,
Is there any issue I need to resolve so that the patch can be merged?
Thanks in advance,
Jisheng
On Wed, 10 Dec 2014 22:26:41 -0800
Jisheng Zhang <jszhang@xxxxxxxxxxx> wrote:
> readl/writel is too expensive especially on Cortex A9 w/ outer L2 cache.
> This introduces i2c read/write errors on Marvell BG2/BG2Q SoCs when there
> are heavy L2 cache maintenance operations at the same time.
>
> The driver does not perform DMA, so it's safe to use the relaxed version.
> From another side, the relaxed io accessor macros are available on all
> architectures now, so we can use the relaxed versions instead.
>
> Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-core.c
> b/drivers/i2c/busses/i2c-designware-core.c index 23628b7..e279948 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -170,10 +170,10 @@ u32 dw_readl(struct dw_i2c_dev *dev, int offset)
> u32 value;
>
> if (dev->accessor_flags & ACCESS_16BIT)
> - value = readw(dev->base + offset) |
> - (readw(dev->base + offset + 2) << 16);
> + value = readw_relaxed(dev->base + offset) |
> + (readw_relaxed(dev->base + offset + 2) << 16);
> else
> - value = readl(dev->base + offset);
> + value = readl_relaxed(dev->base + offset);
>
> if (dev->accessor_flags & ACCESS_SWAP)
> return swab32(value);
> @@ -187,10 +187,10 @@ void dw_writel(struct dw_i2c_dev *dev, u32 b, int
> offset) b = swab32(b);
>
> if (dev->accessor_flags & ACCESS_16BIT) {
> - writew((u16)b, dev->base + offset);
> - writew((u16)(b >> 16), dev->base + offset + 2);
> + writew_relaxed((u16)b, dev->base + offset);
> + writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
> } else {
> - writel(b, dev->base + offset);
> + writel_relaxed(b, dev->base + offset);
> }
> }
>
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