From: Sham Muthayyan <smuthayy@xxxxxxxxxxxxxx>
Some SoC based on ipq8064/5 needs to be limited to pci GEN1 speed due to
some hardware limitations. Add support for speed setting defined by the
max-link-speed binding. If not defined the max speed is set to GEN2 by
default.
Signed-off-by: Sham Muthayyan <smuthayy@xxxxxxxxxxxxxx>
Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-qcom.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 259b627bf890..c40921589122 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/types.h>
+#include "../../pci.h"
#include "pcie-designware.h"
#define PCIE20_PARF_SYS_CTRL 0x00
@@ -99,6 +100,8 @@
#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
@@ -195,6 +198,7 @@ struct qcom_pcie {
struct phy *phy;
struct gpio_desc *reset;
const struct qcom_pcie_ops *ops;
+ int gen;
};
#define to_qcom_pcie(x) dev_get_drvdata((x)->dev)
@@ -395,6 +399,11 @@ static int qcom_pcie_init_2_1_0(struct qcom_pcie *pcie)
/* wait for clock acquisition */
usleep_range(1000, 1500);
+ if (pcie->gen == 1) {
+ val = readl(pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2);
+ val |= PCI_EXP_LNKSTA_CLS_2_5GB;
+ writel(val, pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2);
+ }
/* Set the Max TLP size to 2K, instead of using default of 4K */
writel(CFG_REMOTE_RD_REQ_BRIDGE_SIZE_2K,
@@ -1397,6 +1406,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
goto err_pm_runtime_put;
}
+ pcie->gen = of_pci_get_max_link_speed(pdev->dev.of_node);
+ if (pcie->gen < 0)
+ pcie->gen = 2;
+
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
pcie->parf = devm_ioremap_resource(dev, res);
if (IS_ERR(pcie->parf)) {
--
2.27.0.rc0
