Re: [PATCH 3/4] phy: rockchip-samsung-dcphy: model TX and RX as separate PHYs

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Concurrent or unsupported PHY configuration clobbers the shared `samsung->lanes` driver state before verifying the direction is supported.
--

--- Patch [3]: [PATCH 3/4] phy: rockchip-samsung-dcphy: model TX and RX as separate PHYs ---
commit 242b9435d09e0133de4658156f3cc224aa2f84c9
Author: Jason Yang <jason98166@gmail.com>

phy: rockchip-samsung-dcphy: model TX and RX as separate PHYs

This commit models the MIPI DSI transmitter and MIPI CSI receiver as separate
PHYs that share the same hardware block. It registers one struct phy per
direction and adds a per-provider mutex to serialize access to the shared
state.

> diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
> --- a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
> +++ b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c

[ ... ]

> @@ -1488,11 +1521,15 @@ samsung_mipi_dcphy_pll_calc_rate(struct samsung_mipi_dcphy *samsung,
>  static int samsung_mipi_dcphy_configure(struct phy *phy,
>  					union phy_configure_opts *opts)
>  {
> -	struct samsung_mipi_dcphy *samsung = phy_get_drvdata(phy);
> +	struct samsung_mipi_dcphy_dir *pd = phy_get_drvdata(phy);
> +	struct samsung_mipi_dcphy *samsung = pd->parent;
>  	unsigned long long target_rate = opts->mipi_dphy.hs_clk_rate;
>  
>  	samsung->lanes = opts->mipi_dphy.lanes > 4 ? 4 : opts->mipi_dphy.lanes;
>  
> +	if (pd->dir == RK_DCPHY_DIR_RX)
> +		return -EOPNOTSUPP;
> +

[Severity: High]
Does this code modify the shared samsung->lanes state before checking if
the direction is supported?

Since this is done without holding samsung->lock, can a consumer
configuring the RX PHY clobber the active TX PHY's lane count?

If the lane count is corrupted, it looks like it could lead to incorrect lane
power-down sequences when the TX PHY is disabled later, potentially leaving
MIPI lanes actively driven.

Should the pd->dir check and the lock acquisition happen before updating
samsung->lanes?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260721-dcphy-rx-v1-v1-0-4fc83c0ccac9@gmail.com?part=3