Re: [PATCH v9 4/4] PCI: qcom: Switch pcie_1_pipe_clk_src after PHY init in SC7280

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On 2021-09-28 21:51, Bjorn Helgaas wrote:
[+cc linux-pci; please cc drivers/pci changes there]

Sure Bjorn, I missed to add the lists. I will cc from next release.

On Tue, Sep 28, 2021 at 07:25:50PM +0530, 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.

This looks good.  Ideally the commit log would say what the patch
*does*.  I know it's in the subject, but it's nice to have it both
places so the body is complete in itself.

Again in an ideal world, I would split this into two patches:

  1) Do the boilerplate conversions to struct qcom_pcie_cfg and
  updates of qcom_pcie_match[].  This patch would have no functional
  change.

  2) Add the code to deal with pcie_1_pipe_clk_src, which should be a
  much smaller patch.

This makes it easier to see the important part of dealing with
pcie_1_pipe_clk_src and makes any future bisect much more specific.


Hi Bjorn,

Thanks for the suggestion.

I will split [Patch v9 4/4] patch into two separate changes and update in next version series.

Thanks
-Prasad


Signed-off-by: Prasad Malisetty <pmaliset@xxxxxxxxxxxxxx>
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-qcom.c | 94 ++++++++++++++++++++++++++++++----
 1 file changed, 83 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 8a7a300..7896a86 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 *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;
+	unsigned int pipe_clk_need_muxing:1;
+};
+
 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;
+	unsigned int pipe_clk_need_muxing:1;
 };

 #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->pipe_clk_need_muxing) {
+		res->pipe_clk_src = devm_clk_get(dev, "pipe_mux");
+		if (IS_ERR(res->pipe_clk_src))
+			return PTR_ERR(res->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 pcie_pipe_clk_src */
+	if (pcie->pipe_clk_need_muxing)
+		clk_set_parent(res->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 pcie_pipe_clk_src */
+	if (pcie->pipe_clk_need_muxing)
+		clk_set_parent(res->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,
+	.pipe_clk_need_muxing = 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;
 	int ret;

 	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
@@ -1488,7 +1553,13 @@ 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;
+	if (!pcie->ops) {
+		dev_err(dev, "Invalid platform data\n");
+		return -EINVAL;
+	}
+	pcie->pipe_clk_need_muxing = pcie_cfg->pipe_clk_need_muxing;

 	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
 	if (IS_ERR(pcie->reset)) {
@@ -1545,16 +1616,17 @@ 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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