Re: [PATCH v7 4/4] PCI: qcom: Switch pcie_1_pipe_clk_src after PHY init in SC7280

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Tue 14 Sep 11:19 PDT 2021, Prasad Malisetty wrote:

> On the SC7280, the clock source for gcc_pcie_1_pipe_clk_src
> must be the TCXO while gdsc is enabled. After PHY init successful
> clock source should switch to pipe clock for gcc_pcie_1_pipe_clk_src.
> 
> Signed-off-by: Prasad Malisetty <pmaliset@codeaurora.org>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 90 +++++++++++++++++++++++++++++-----
>  1 file changed, 79 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 8a7a300..380c962 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -166,6 +166,9 @@ struct qcom_pcie_resources_2_7_0 {
>  	struct regulator_bulk_data supplies[2];
>  	struct reset_control *pci_reset;
>  	struct clk *pipe_clk;
> +	struct clk *gcc_pcie_1_pipe_clk_src;

Afaict you have both 2 PCIe controllers on sc7280, so I think it seems
more reasonable to shorted this to "pipe_clk_src".

> +	struct clk *phy_pipe_clk;
> +	struct clk *ref_clk_src;
>  };
>  
>  union qcom_pcie_resources {
> @@ -189,6 +192,11 @@ struct qcom_pcie_ops {
>  	int (*config_sid)(struct qcom_pcie *pcie);
>  };
>  
> +struct qcom_pcie_cfg {
> +	const struct qcom_pcie_ops *ops;
> +	bool pcie_1_pipe_clk_src_switch;

Perhaps something little bit more generic, like pipe_clk_need_muxing?

> +};
> +
>  struct qcom_pcie {
>  	struct dw_pcie *pci;
>  	void __iomem *parf;			/* DT parf */
> @@ -197,6 +205,7 @@ struct qcom_pcie {
>  	struct phy *phy;
>  	struct gpio_desc *reset;
>  	const struct qcom_pcie_ops *ops;
> +	bool pcie_1_pipe_clk_src_switch;
>  };
>  
>  #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
> @@ -1167,6 +1176,20 @@ static int qcom_pcie_get_resources_2_7_0(struct qcom_pcie *pcie)
>  	if (ret < 0)
>  		return ret;
>  
> +	if (pcie->pcie_1_pipe_clk_src_switch) {

This looks much better, now it will easily scale to other platforms that
have inherited this need.

> +		res->gcc_pcie_1_pipe_clk_src = devm_clk_get(dev, "pipe_mux");
> +		if (IS_ERR(res->gcc_pcie_1_pipe_clk_src))
> +			return PTR_ERR(res->gcc_pcie_1_pipe_clk_src);
> +
> +		res->phy_pipe_clk = devm_clk_get(dev, "phy_pipe");
> +		if (IS_ERR(res->phy_pipe_clk))
> +			return PTR_ERR(res->phy_pipe_clk);
> +
> +		res->ref_clk_src = devm_clk_get(dev, "ref");
> +		if (IS_ERR(res->ref_clk_src))
> +			return PTR_ERR(res->ref_clk_src);
> +	}
> +
>  	res->pipe_clk = devm_clk_get(dev, "pipe");
>  	return PTR_ERR_OR_ZERO(res->pipe_clk);
>  }
> @@ -1185,6 +1208,10 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
>  		return ret;
>  	}
>  
> +	/* Set TCXO as clock source for gcc_pcie_1_pipe_clk_src */
> +	if (pcie->pcie_1_pipe_clk_src_switch)
> +		clk_set_parent(res->gcc_pcie_1_pipe_clk_src, res->ref_clk_src);
> +
>  	ret = clk_bulk_prepare_enable(res->num_clks, res->clks);
>  	if (ret < 0)
>  		goto err_disable_regulators;
> @@ -1256,6 +1283,10 @@ static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
>  {
>  	struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0;
>  
> +	/* Set pipe clock as clock source for gcc_pcie_1_pipe_clk_src */
> +	if (pcie->pcie_1_pipe_clk_src_switch)
> +		clk_set_parent(res->gcc_pcie_1_pipe_clk_src, res->phy_pipe_clk);
> +
>  	return clk_prepare_enable(res->pipe_clk);
>  }
>  
> @@ -1456,6 +1487,39 @@ static const struct qcom_pcie_ops ops_1_9_0 = {
>  	.config_sid = qcom_pcie_config_sid_sm8250,
>  };
>  
> +static const struct qcom_pcie_cfg apq8084_cfg = {
> +	.ops = &ops_1_0_0,
> +};
> +
> +static const struct qcom_pcie_cfg ipq8064_cfg = {
> +	.ops = &ops_2_1_0,
> +};
> +
> +static const struct qcom_pcie_cfg msm8996_cfg = {
> +	.ops = &ops_2_3_2,
> +};
> +
> +static const struct qcom_pcie_cfg ipq8074_cfg = {
> +	.ops = &ops_2_3_3,
> +};
> +
> +static const struct qcom_pcie_cfg ipq4019_cfg = {
> +	.ops = &ops_2_4_0,
> +};
> +
> +static const struct qcom_pcie_cfg sdm845_cfg = {
> +	.ops = &ops_2_7_0,
> +};
> +
> +static const struct qcom_pcie_cfg sm8250_cfg = {
> +	.ops = &ops_1_9_0,
> +};
> +
> +static const struct qcom_pcie_cfg sc7280_cfg = {
> +	.ops = &ops_1_9_0,
> +	.pcie_1_pipe_clk_src_switch = true,
> +};
> +
>  static const struct dw_pcie_ops dw_pcie_ops = {
>  	.link_up = qcom_pcie_link_up,
>  	.start_link = qcom_pcie_start_link,
> @@ -1467,6 +1531,7 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	struct pcie_port *pp;
>  	struct dw_pcie *pci;
>  	struct qcom_pcie *pcie;
> +	const struct qcom_pcie_cfg *pcie_cfg = NULL;

First use of this variable is an assignment, so I don't see a need for
zero initialize it.

Regards,
Bjorn

>  	int ret;
>  
>  	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> @@ -1488,7 +1553,9 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  
>  	pcie->pci = pci;
>  
> -	pcie->ops = of_device_get_match_data(dev);
> +	pcie_cfg = of_device_get_match_data(dev);
> +	pcie->ops = pcie_cfg->ops;
> +	pcie->pcie_1_pipe_clk_src_switch = pcie_cfg->pcie_1_pipe_clk_src_switch;
>  
>  	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
>  	if (IS_ERR(pcie->reset)) {
> @@ -1545,16 +1612,17 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  }
>  
>  static const struct of_device_id qcom_pcie_match[] = {
> -	{ .compatible = "qcom,pcie-apq8084", .data = &ops_1_0_0 },
> -	{ .compatible = "qcom,pcie-ipq8064", .data = &ops_2_1_0 },
> -	{ .compatible = "qcom,pcie-ipq8064-v2", .data = &ops_2_1_0 },
> -	{ .compatible = "qcom,pcie-apq8064", .data = &ops_2_1_0 },
> -	{ .compatible = "qcom,pcie-msm8996", .data = &ops_2_3_2 },
> -	{ .compatible = "qcom,pcie-ipq8074", .data = &ops_2_3_3 },
> -	{ .compatible = "qcom,pcie-ipq4019", .data = &ops_2_4_0 },
> -	{ .compatible = "qcom,pcie-qcs404", .data = &ops_2_4_0 },
> -	{ .compatible = "qcom,pcie-sdm845", .data = &ops_2_7_0 },
> -	{ .compatible = "qcom,pcie-sm8250", .data = &ops_1_9_0 },
> +	{ .compatible = "qcom,pcie-apq8084", .data = &apq8084_cfg },
> +	{ .compatible = "qcom,pcie-ipq8064", .data = &ipq8064_cfg },
> +	{ .compatible = "qcom,pcie-ipq8064-v2", .data = &ipq8064_cfg },
> +	{ .compatible = "qcom,pcie-apq8064", .data = &ipq8064_cfg },
> +	{ .compatible = "qcom,pcie-msm8996", .data = &msm8996_cfg },
> +	{ .compatible = "qcom,pcie-ipq8074", .data = &ipq8074_cfg },
> +	{ .compatible = "qcom,pcie-ipq4019", .data = &ipq4019_cfg },
> +	{ .compatible = "qcom,pcie-qcs404", .data = &ipq4019_cfg },
> +	{ .compatible = "qcom,pcie-sdm845", .data = &sdm845_cfg },
> +	{ .compatible = "qcom,pcie-sm8250", .data = &sm8250_cfg },
> +	{ .compatible = "qcom,pcie-sc7280", .data = &sc7280_cfg },
>  	{ }
>  };
>  
> -- 
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