linux-kernel - Re: [PATCH 1/3] phy: rockchip-snps-pcie3: fix bifurcation on rk3588

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Date: Thu, 04 Apr 2024 21:38:40 +0200
From: Heiko Stuebner <heiko@...ech.de>
To: Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
 Sebastian Reichel <sre@...nel.org>
Cc: Shawn Lin <shawn.lin@...k-chips.com>, Michal Tomek <mtdev79b@...il.com>,
 linux-phy@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
 linux-kernel@...r.kernel.org,
 Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH 1/3] phy: rockchip-snps-pcie3: fix bifurcation on rk3588

Am Donnerstag, 4. April 2024, 19:11:26 CEST schrieb Sebastian Reichel:
> From: Michal Tomek <mtdev79b@...il.com>
> 
> So far all RK3588 boards use fully aggregated PCIe. CM3588 is one
> of the few boards using this feature and apparently it is broken.
> 
> The PHY offers the following mapping options:
> 
>   port 0 lane 0 - always mapped to controller 0 (4L)
>   port 0 lane 1 - to controller 0 or 2 (1L0)
>   port 1 lane 0 - to controller 0 or 1 (2L)
>   port 1 lane 1 - to controller 0, 1 or 3 (1L1)
> 
> The data-lanes DT property maps these as follows:
> 
>   0 = no controller (unsupported by the HW)
>   1 = 4L
>   2 = 2L
>   3 = 1L0
>   4 = 1L1
> 
> That allows the following configurations with first column being the
> mainline data-lane mapping, second column being the downstream name,
> third column being PCIE3PHY_GRF_CMN_CON0 and PHP_GRF_PCIESEL register
> values and final column being the user visible lane setup:
> 
>   <1 1 1 1> = AGGREG = [4 0] = x4 (aggregation)
>   <1 1 2 2> = NANBNB = [0 0] = x2 x2 (no bif.)
>   <1 3 2 2> = NANBBI = [1 1] = x2 x1x1 (bif. of port 0)
>   <1 1 2 4> = NABINB = [2 2] = x1x1 x2 (bif. of port 1)
>   <1 3 2 4> = NABIBI = [3 3] = x1x1 x1x1 (bif. of both ports)
> 
> The driver currently does not program PHP_GRF_PCIESEL correctly, which
> is fixed by this patch. As a side-effect the new logic is much simpler
> than the old logic.
> 
> Fixes: 2e9bffc4f713 ("phy: rockchip: Support PCIe v3")
> Signed-off-by: Michal Tomek <mtdev79b@...il.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> ---
>  drivers/phy/rockchip/phy-rockchip-snps-pcie3.c | 24 ++++++++----------------
>  1 file changed, 8 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> index 121e5961ce11..d5bcc9c42b28 100644
> --- a/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> +++ b/drivers/phy/rockchip/phy-rockchip-snps-pcie3.c
> @@ -132,7 +132,7 @@ static const struct rockchip_p3phy_ops rk3568_ops = {
>  static int rockchip_p3phy_rk3588_init(struct rockchip_p3phy_priv *priv)
>  {
>  	u32 reg = 0;
> -	u8 mode = 0;
> +	u8 mode = RK3588_LANE_AGGREGATION; /* default */
>  	int ret;
>  
>  	/* Deassert PCIe PMA output clamp mode */
> @@ -140,28 +140,20 @@ static int rockchip_p3phy_rk3588_init(struct rockchip_p3phy_priv *priv)
>  
>  	/* Set bifurcation if needed */
>  	for (int i = 0; i < priv->num_lanes; i++) {
> -		if (!priv->lanes[i])
> -			mode |= (BIT(i) << 3);
> -
>  		if (priv->lanes[i] > 1)
> -			mode |= (BIT(i) >> 1);
> -	}
> -
> -	if (!mode)
> -		reg = RK3588_LANE_AGGREGATION;
> -	else {
> -		if (mode & (BIT(0) | BIT(1)))
> -			reg |= RK3588_BIFURCATION_LANE_0_1;
> -
> -		if (mode & (BIT(2) | BIT(3)))
> -			reg |= RK3588_BIFURCATION_LANE_2_3;
> +			mode &= ~RK3588_LANE_AGGREGATION;
> +		if (priv->lanes[i] == 3)
> +			mode |= RK3588_BIFURCATION_LANE_0_1;
> +		if (priv->lanes[i] == 4)
> +			mode |= RK3588_BIFURCATION_LANE_2_3;
>  	}
>  
> +	reg = mode;
>  	regmap_write(priv->phy_grf, RK3588_PCIE3PHY_GRF_CMN_CON0, (0x7<<16) | reg);

nit: instead of doing reg=mode, why not use mode directly?
i.e. (0x7<<16) | mode in the regmap_write call

other than that
Acked-by: Heiko Stuebner <heiko@...ech.de>

>  
>  	/* Set pcie1ln_sel in PHP_GRF_PCIESEL_CON */
>  	if (!IS_ERR(priv->pipe_grf)) {
> -		reg = (mode & (BIT(6) | BIT(7))) >> 6;
> +		reg = mode & 3;
>  		if (reg)
>  			regmap_write(priv->pipe_grf, PHP_GRF_PCIESEL_CON,
>  				     (reg << 16) | reg);
> 
>