RE: [PATCH v2] mt76: mt7915: wed: find rx token by physical address

[Ping-Ke Shih <pkshih@realtek.com>]

Shengyu Qu <wiagn233@outlook.com> wrote:
> The token id in RxDMAD may be incorrect when it is not the last frame
> due to WED HW bug. Lookup correct token id by physical address in sdp0.
> 
> Downstream patch link:
> https://git01.mediatek.com/plugins/gitiles/openwrt/feeds/mtk-openwrt-feeds/+/737340322ab22b138fd200e02
> 0d61ffdbe3e36a9/autobuild/autobuild_5.4_mac80211_release/mt7988_wifi7_mac80211_mlo/package/kernel/mt76
> /patches/0062-mtk-wifi-mt76-mt7915-wed-find-rx-token-by-physical-a.patch
> 
> Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
> Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
> ---
> Changes since v1:
>  - Reordered code sequence to reversed Xmas tree order
>  - Renamed some variables
> ---
>  drivers/net/wireless/mediatek/mt76/dma.c | 26 +++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
> index 844af16ee5513..25893686cbe85 100644
> --- a/drivers/net/wireless/mediatek/mt76/dma.c
> +++ b/drivers/net/wireless/mediatek/mt76/dma.c
> @@ -445,8 +445,32 @@ mt76_dma_get_buf(struct mt76_dev *dev, struct mt76_queue *q, int idx,
> 
>         if (mt76_queue_is_wed_rx(q)) {
>                 u32 token = FIELD_GET(MT_DMA_CTL_TOKEN, buf1);
> -               struct mt76_txwi_cache *t = mt76_rx_token_release(dev, token);
> +               struct mt76_txwi_cache *t;
> +               bool found = false;
> +               u32 id;
> +
> +               if (*more) {
> +                       spin_lock_bh(&dev->rx_token_lock);
> +
> +                       idr_for_each_entry(&dev->rx_token, t, id) {
> +                               if (t->dma_addr == le32_to_cpu(desc->buf0)) {
> +                                       token = id;
> +                                       found = 1;

found = true;

Since you are digging how frequent this can occur, you may decide to have a
conversion function afterward, so it would be good to move this loop
into a function, like mt76_dma_get_id_from_txwi(dev, t). Then the you can
replace the implementation at that time.

By the way, I personally don't like so many indents. A function can ease
indents.

> +
> +                                       /* Write correct id back to DMA*/
> +                                       u32p_replace_bits(&buf1, id,
> +                                                         MT_DMA_CTL_TOKEN);
> +                                       WRITE_ONCE(desc->buf1, cpu_to_le32(buf1));
> +                                       break;
> +                               }
> +                       }
> +
> +                       spin_unlock_bh(&dev->rx_token_lock);
> +                       if (!found)
> +                               return NULL;
> +               }
> 
> +               t = mt76_rx_token_release(dev, token);
>                 if (!t)
>                         return NULL;
> 
> --
> 2.48.1