ERR051586: Compliance with 8GT/s Receiver Impedance ECN.
The default value of GEN3_RELATED_OFF[GEN3_ZRXDC_NONCOMPL] is 1 which
makes receiver non-compliant with the ZRX-DC parameter for 2.5 GT/s when
operating at 8 GT/s or higher. It causes unnecessary timeout in L1.
Workaround: Program GEN3_RELATED_OFF[GEN3_ZRXDC_NONCOMPL] to 0.
Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
---
drivers/pci/controller/dwc/pci-imx6.c | 33 +++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index fbab5a4621aa..42683d6be9f2 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1261,6 +1261,37 @@ static void imx_pcie_host_exit(struct dw_pcie_rp *pp)
regulator_disable(imx_pcie->vpcie);
}
+static void imx_pcie_host_post_init(struct dw_pcie_rp *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct imx_pcie *imx_pcie = to_imx_pcie(pci);
+ u32 val;
+
+ switch (imx_pcie->drvdata->variant) {
+ case IMX95:
+ case IMX95_EP:
+ /*
+ * ERR051586: Compliance with 8GT/s Receiver Impedance ECN
+ *
+ * The default value of GEN3_RELATED_OFF[GEN3_ZRXDC_NONCOMPL]
+ * is 1 which makes receiver non-compliant with the ZRX-DC
+ * parameter for 2.5 GT/s when operating at 8 GT/s or higher.
+ * It causes unnecessary timeout in L1.
+ *
+ * Workaround: Program GEN3_RELATED_OFF[GEN3_ZRXDC_NONCOMPL]
+ * to 0.
+ */
+ dw_pcie_dbi_ro_wr_en(pci);
+ val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
+ val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
+ dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
+ dw_pcie_dbi_ro_wr_dis(pci);
+ break;
+ default:
+ break;
+ }
+}
+
static u64 imx_pcie_cpu_addr_fixup(struct dw_pcie *pcie, u64 cpu_addr)
{
struct imx_pcie *imx_pcie = to_imx_pcie(pcie);
@@ -1302,6 +1333,7 @@ static const struct dw_pcie_host_ops imx_pcie_host_ops = {
static const struct dw_pcie_host_ops imx_pcie_host_dw_pme_ops = {
.init = imx_pcie_host_init,
.deinit = imx_pcie_host_exit,
+ .post_init = imx_pcie_host_post_init,
};
static const struct dw_pcie_ops dw_pcie_ops = {
@@ -1401,6 +1433,7 @@ static int imx_add_pcie_ep(struct imx_pcie *imx_pcie,
struct device *dev = pci->dev;
imx_pcie_host_init(pp);
+ imx_pcie_host_post_init(pp);
ep = &pci->ep;
ep->ops = &pcie_ep_ops;
--
2.37.1
