[10/12] pcie: qcom: add Force GEN1 support

Commit Message

Christian Marangi March 20, 2020, 6:34 p.m. UTC

From: Sham Muthayyan <[e-mail]>

Add Force GEN1 support needed in some ipq806x board
that needs to limit some pcie line to gen1 for some
hardware limitation

Signed-off-by: Sham Muthayyan <[e-mail]>
Signed-off-by: Ansuel Smith <[e-mail]>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Comments

Bjorn Helgaas March 20, 2020, 7:37 p.m. UTC | #1

On Fri, Mar 20, 2020 at 07:34:52PM +0100, Ansuel Smith wrote:
> From: Sham Muthayyan <[e-mail]>
> 
> Add Force GEN1 support needed in some ipq806x board
> that needs to limit some pcie line to gen1 for some
> hardware limitation

Usual commit log comments.

> +	uint32_t force_gen1;

unsigned int force_gen1 : 1

> +	of_property_read_u32(np, "force_gen1", &force_gen1);
> +	pcie->force_gen1 = force_gen1;

I think there's a more or less standard property you can use for this
instead of inventing a new one specific to this device.

Documentation/devicetree/bindings/pci/pci.txt:
"max-link-speed"

Patch

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index e26ba8f63d4f..03130a3206b4 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -123,6 +123,8 @@ 
 #define PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE	0x358
 #define SLV_ADDR_SPACE_SZ			0x10000000
 
+#define PCIE20_LNK_CONTROL2_LINK_STATUS2        0xA0
+
 #define DEVICE_TYPE_RC				0x4
 
 #define QCOM_PCIE_2_1_0_MAX_SUPPLY	3
@@ -223,6 +225,7 @@  struct qcom_pcie {
 	struct phy *phy;
 	struct gpio_desc *reset;
 	const struct qcom_pcie_ops *ops;
+	uint32_t force_gen1;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
@@ -515,6 +518,11 @@  static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
 
 	/* wait for clock acquisition */
 	usleep_range(1000, 1500);
+	if (pcie->force_gen1) {
+		writel_relaxed((readl_relaxed(
+			pcie->pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2) | 1),
+			pcie->pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2);
+	}
 
 
 	/* Set the Max TLP size to 2K, instead of using default of 4K */
@@ -1487,6 +1495,8 @@  static int qcom_pcie_probe(struct platform_device *pdev)
 	struct dw_pcie *pci;
 	struct qcom_pcie *pcie;
 	int ret;
+	uint32_t force_gen1 = 0;
+	struct device_node *np = pdev->dev.of_node;
 
 	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
 	if (!pcie)
@@ -1517,6 +1527,9 @@  static int qcom_pcie_probe(struct platform_device *pdev)
 		goto err_pm_runtime_put;
 	}
 
+	of_property_read_u32(np, "force_gen1", &force_gen1);
+	pcie->force_gen1 = force_gen1;
+
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
 	pcie->parf = devm_ioremap_resource(dev, res);
 	if (IS_ERR(pcie->parf)) {