linux-kernel - Re: [RFC PATCH v5 3/4] phy: rockchip-pcie: Enable all four lanes

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Message-ID: <4c2c9a15-50bc-4a89-b5fe-d9014657fca7@arm.com>
Date: Fri, 20 Jun 2025 13:04:46 +0100
From: Robin Murphy <robin.murphy@....com>
To: Geraldo Nascimento <geraldogabriel@...il.com>,
 linux-rockchip@...ts.infradead.org
Cc: Shawn Lin <shawn.lin@...k-chips.com>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>,
 Krzysztof Wilczyński <kw@...ux.com>,
 Manivannan Sadhasivam <mani@...nel.org>, Rob Herring <robh@...nel.org>,
 Bjorn Helgaas <bhelgaas@...gle.com>, Heiko Stuebner <heiko@...ech.de>,
 Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
 Rick wertenbroek <rick.wertenbroek@...il.com>,
 linux-phy@...ts.infradead.org, linux-pci@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v5 3/4] phy: rockchip-pcie: Enable all four lanes

On 2025-06-13 6:03 pm, Geraldo Nascimento wrote:
> Current code enables only Lane 0 because pwr_cnt will be incremented
> on first call to the function. Use for-loop to enable all 4 lanes
> through GRF.

If this was really necessary, then surely it would also need the 
equivalent changes in rockchip_pcie_phy_power_off() too?

However, I'm not sure it *is* necessary - the NVMe on my RK3399 board 
happily claims to be using an x4 link, so I stuck a print of inst->index 
in this function, and sure enough I do see it being called for each 
instance already:

[    1.737479] phy phy-ff770000.syscon:pcie-phy.1: power_on 0
[    1.738810] phy phy-ff770000.syscon:pcie-phy.2: power_on 1
[    1.745193] phy phy-ff770000.syscon:pcie-phy.3: power_on 2
[    1.745196] phy phy-ff770000.syscon:pcie-phy.4: power_on 3

Thanks,
Robin.

> Signed-off-by: Geraldo Nascimento <geraldogabriel@...il.com>
> ---
>   drivers/phy/rockchip/phy-rockchip-pcie.c | 12 +++++++-----
>   1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-pcie.c b/drivers/phy/rockchip/phy-rockchip-pcie.c
> index bd44af36c67a..48bcc7d2b33b 100644
> --- a/drivers/phy/rockchip/phy-rockchip-pcie.c
> +++ b/drivers/phy/rockchip/phy-rockchip-pcie.c
> @@ -176,11 +176,13 @@ static int rockchip_pcie_phy_power_on(struct phy *phy)
>   				   PHY_CFG_ADDR_MASK,
>   				   PHY_CFG_ADDR_SHIFT));
>   
> -	regmap_write(rk_phy->reg_base,
> -		     rk_phy->phy_data->pcie_laneoff,
> -		     HIWORD_UPDATE(!PHY_LANE_IDLE_OFF,
> -				   PHY_LANE_IDLE_MASK,
> -				   PHY_LANE_IDLE_A_SHIFT + inst->index));
> +	for (int i=0; i < PHY_MAX_LANE_NUM; i++) {
> +		regmap_write(rk_phy->reg_base,
> +			     rk_phy->phy_data->pcie_laneoff,
> +			     HIWORD_UPDATE(!PHY_LANE_IDLE_OFF,
> +					   PHY_LANE_IDLE_MASK,
> +					   PHY_LANE_IDLE_A_SHIFT + i));
> +	}
>   
>   	/*
>   	 * No documented timeout value for phy operation below,