[U-Boot] [PATCH v4] zynq-gem: Use appropriate cache flush/invalidate for RX and TX

[Bin Meng]

Hi Stefan,

On Mon, Dec 17, 2018 at 3:49 PM Stefan Theil <stefan.theil at mixed-mode.de> wrote:
>
> The cache was only flushed before *transmitting* packets, but not
> when receiving them, leading to an issue where new packets were
> handed to the receive handler with old contents in cache. This
> only happens when a lot of packets are received without sending
> packages every now and then. Also flushing the receive buffers
> in the transmit function makes no sense and can be removed.
>
> Signed-off-by: Stefan Theil <stefan.theil at mixed-mode.de>
>
> ---
> Changes for v2:
>         - Use invalidate_dcache_range instead of
>           flush_dcache_range
> Changes for v3:
>         - Remove unnecessary flushing of all RX
>           buffers in zynq_gem_send
> Changes for v4:
>         - Invalidate receive buffers after allocating
>           them in zynq_gem_probe
> ---
>  drivers/net/zynq_gem.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
> index 9bd79b198a..79a22fb1ed 100644
> --- a/drivers/net/zynq_gem.c
> +++ b/drivers/net/zynq_gem.c
> @@ -570,11 +570,6 @@ static int zynq_gem_send(struct udevice *dev, void *ptr, int len)
>         addr &= ~(ARCH_DMA_MINALIGN - 1);
>         size = roundup(len, ARCH_DMA_MINALIGN);
>         flush_dcache_range(addr, addr + size);
> -
> -       addr = (ulong)priv->rxbuffers;
> -       addr &= ~(ARCH_DMA_MINALIGN - 1);
> -       size = roundup((RX_BUF * PKTSIZE_ALIGN), ARCH_DMA_MINALIGN);
> -       flush_dcache_range(addr, addr + size);
>         barrier();
>
>         /* Start transmit */
> @@ -621,6 +616,9 @@ static int zynq_gem_recv(struct udevice *dev, int flags, uchar **packetp)
>
>         *packetp = (uchar *)(uintptr_t)addr;
>
> +       invalidate_dcache_range(addr, addr + roundup(PKTSIZE_ALIGN, ARCH_DMA_MINALIGN));
> +       barrier();
> +
>         return frame_len;
>  }
>
> @@ -705,7 +703,9 @@ static int zynq_gem_probe(struct udevice *dev)
>         if (!priv->rxbuffers)
>                 return -ENOMEM;
>
> -       memset(priv->rxbuffers, 0, RX_BUF * PKTSIZE_ALIGN);
> +       u32 addr = (ulong)priv->rxbuffers;
> +       invalidate_dcache_range(addr, addr + roundup(RX_BUF * PKTSIZE_ALIGN, ARCH_DMA_MINALIGN));
> +       barrier();
>

Does this fix anything? I see no need to update this.

>         /* Align bd_space to MMU_SECTION_SHIFT */
>         bd_space = memalign(1 << MMU_SECTION_SHIFT, BD_SPACE);
> --

Regards,
Bin