Thank you for your contribution! Sashiko AI review found 1 potential issue(s) 
to consider:
- [High] mtk_dp_phy_disable_all_lanes loop executes undefined behavior when val 
is 0, and incorrectly clears lane bits using the lane index instead of a 
bitmask.
--

commit 25cdd51bd1ac4d69a49e77d93a6b1374ba46dd3c
Author: AngeloGioacchino Del Regno <[email protected]>

phy: phy-mtk-dp: Support set_lanes in configure and properly cleanup

Add support for enabling a specifically requested number of lanes in the
configure callback, and disable all lanes in power off and reset
callbacks for proper hardware cleanup.

> diff --git a/drivers/phy/mediatek/phy-mtk-dp.c 
> b/drivers/phy/mediatek/phy-mtk-dp.c
> index 586e727956332..a2cd22b9da066 100644
> --- a/drivers/phy/mediatek/phy-mtk-dp.c
> +++ b/drivers/phy/mediatek/phy-mtk-dp.c
[ ... ]
> @@ -261,6 +267,35 @@ static int mtk_dp_phy_power_on(struct phy *phy)
>       return 0;
>  }
>  
> +static int mtk_dp_phy_disable_all_lanes(struct mtk_dp_phy *dp_phy)
> +{
> +     const struct mtk_dp_phy_pdata *pdata = dp_phy->pdata;
> +     const u8 *regs = pdata->regs_dig_glb;
> +     int ret;
> +     u32 val;
> +
> +     ret = regmap_read(dp_phy->regmap, pdata->off_dig_glb + 
> regs[DP_PHYD_TX_CTL_0], &val);
> +     if (ret)
> +             return ret;
> +
> +     /* Get mask of currently enabled lane */
> +     val = FIELD_GET(PHYD_TX_LN_EN, val);
> +
> +     /* Disable all lanes (needs to be done one by one, from last to first) 
> */
> +     do {
> +             u32 lane_num = fls(val) - 1;

[Severity: High]
If no lanes are currently enabled, val will be 0. Does this cause fls(0) - 1
to underflow, leading to undefined behavior when computing BIT(lane_num)?

> +             val &= ~BIT(lane_num);
> +
> +             ret = regmap_clear_bits(dp_phy->regmap,
> +                                     pdata->off_dig_glb + 
> regs[DP_PHYD_TX_CTL_0],
> +                                     FIELD_PREP(PHYD_TX_LN_EN, lane_num));

[Severity: High]
Does this incorrectly clear bits using the lane index instead of a bitmask?

For example, if lane 3 is being disabled (lane_num == 3), this passes 3 to
FIELD_PREP instead of BIT(3). This would clear lanes 0 and 1 (3 << 4) while
leaving lane 3 enabled. Should this use BIT(lane_num) instead?

> +             if (ret)
> +                     return ret;
> +     } while (val);
> +
> +     return 0;
> +}
[ ... ]

-- 
Sashiko AI review ยท 
https://sashiko.dev/#/patchset/[email protected]?part=10

Reply via email to