Many platforms use DesignWare controller but the PHY can be different in
different platforms. If the PHY is compliant to the ZRX-DC specification
it helps lower power consumption during power states.
If current data rate is 8.0 GT/s or higher and PHY is not compliant to
ZRX-DC specification, then after every 100ms link should transition to
recovery state during the low power states.
DesignWare controller provides GEN3_ZRXDC_NONCOMPL field in
GEN3_RELATED_OFF to specify about ZRX-DC compliant PHY.
Platforms with ZRX-DC compliant PHY can set "snps,phy-zrxdc-compliant"
property in controller DT node to specify this property to the controller.
CC: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
CC: Andrew Murray <andrew.murray@xxxxxxx>
Signed-off-by: Anvesh Salveru <anvesh.s@xxxxxxxxxxx>
Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
Acked-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
---
Change in v2:
- trivial change in patch description
drivers/pci/controller/dwc/pcie-designware.c | 7 +++++++
drivers/pci/controller/dwc/pcie-designware.h | 3 +++
2 files changed, 10 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 820488dfeaed..6560d9f765d7 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -556,4 +556,11 @@ void dw_pcie_setup(struct dw_pcie *pci)
PCIE_PL_CHK_REG_CHK_REG_START;
dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, val);
}
+
+ if (of_property_read_bool(np, "snps,phy-zrxdc-compliant")) {
+ val = dw_pcie_readl_dbi(pci, PCIE_PORT_GEN3_RELATED);
+ val &= ~PORT_LOGIC_GEN3_ZRXDC_NONCOMPL;
+ dw_pcie_writel_dbi(pci, PCIE_PORT_GEN3_RELATED, val);
+ }
+
}
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 5a18e94e52c8..427a55ec43c6 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -60,6 +60,9 @@
#define PCIE_MSI_INTR0_MASK 0x82C
#define PCIE_MSI_INTR0_STATUS 0x830
+#define PCIE_PORT_GEN3_RELATED 0x890
+#define PORT_LOGIC_GEN3_ZRXDC_NONCOMPL BIT(0)
+
#define PCIE_ATU_VIEWPORT 0x900
#define PCIE_ATU_REGION_INBOUND BIT(31)
#define PCIE_ATU_REGION_OUTBOUND 0
--
2.17.1
