PCI: qcom: Add QCS404 PCIe controller support

The QCS404 platform contains a PCIe version 2.4.0 controller and a
Qualcomm PCIe2 PHY. The driver already supports version 2.4.0, for the
IPQ4019, but this support touches clocks and resets related to the PHY
as well and there's no upstream driver for the PHY.

On QCS404 we must initialize the PHY, so a separate PHY driver is
implemented to take care of this and the controller driver is updated to
not require the PHY related resources. This is done by relying on the
fact that operations in both the clock and reset framework are NOPs when
passed NULL, so we can isolate this change to only the
qcom_pcie_get_resources_2_4_0() function.

For QCS404 we also need to enable the AHB (iface) clock, in order to
access the register space of the controller, but as this is not part of
the IPQ4019 DT binding this is only added for new users of the 2.4.0
controller.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>

drivers/pci/controller/dwc/pcie-qcom.c

@@ -112,7 +112,7 @@ struct qcom_pcie_resources_2_3_2 {
 	struct regulator_bulk_data supplies[QCOM_PCIE_2_3_2_MAX_SUPPLY];
 };
 
-#define QCOM_PCIE_2_4_0_MAX_CLOCKS	3
+#define QCOM_PCIE_2_4_0_MAX_CLOCKS	4
 struct qcom_pcie_resources_2_4_0 {
 	struct clk_bulk_data clks[QCOM_PCIE_2_4_0_MAX_CLOCKS];
 	int num_clks;
@@ -638,13 +638,16 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
 	struct qcom_pcie_resources_2_4_0 *res = &pcie->res.v2_4_0;
 	struct dw_pcie *pci = pcie->pci;
 	struct device *dev = pci->dev;
+	bool is_ipq = of_device_is_compatible(dev->of_node, "qcom,pcie-ipq4019");
 	int ret;
 
 	res->clks[0].id = "aux";
 	res->clks[1].id = "master_bus";
 	res->clks[2].id = "slave_bus";
+	res->clks[3].id = "iface";
 
-	res->num_clks = 3;
+	/* qcom,pcie-ipq4019 is defined without "iface" */
+	res->num_clks = is_ipq ? 3 : 4;
 
 	ret = devm_clk_bulk_get(dev, res->num_clks, res->clks);
 	if (ret < 0)
@@ -658,6 +661,11 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
 	if (IS_ERR(res->axi_s_reset))
 		return PTR_ERR(res->axi_s_reset);
 
+	if (is_ipq) {
+		/*
+		 * These resources relates to the PHY or are secure clocks, but
+		 * are controlled here for IPQ4019
+		 */
 		res->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
 		if (IS_ERR(res->pipe_reset))
 			return PTR_ERR(res->pipe_reset);
@@ -679,6 +687,7 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
 		res->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
 		if (IS_ERR(res->phy_reset))
 			return PTR_ERR(res->phy_reset);
+	}
 
 	res->axi_m_sticky_reset = devm_reset_control_get_exclusive(dev,
 								   "axi_m_sticky");
@@ -698,9 +707,11 @@ static int qcom_pcie_get_resources_2_4_0(struct qcom_pcie *pcie)
 	if (IS_ERR(res->ahb_reset))
 		return PTR_ERR(res->ahb_reset);
 
+	if (is_ipq) {
 		res->phy_ahb_reset = devm_reset_control_get_exclusive(dev, "phy_ahb");
 		if (IS_ERR(res->phy_ahb_reset))
 			return PTR_ERR(res->phy_ahb_reset);
+	}
 
 	return 0;
 }
@@ -1268,6 +1279,7 @@ static const struct of_device_id qcom_pcie_match[] = {
 	{ .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 },
 	{ }
 };