[PATCH RFC v5 8/8] PCI: dw-rockchip: port some suspend code from vendor kernel

[Sebastian Reichel]

Rockchip's vendor kernel does these calls before starting the actual
process of going into L2 state. I'm not sure about the rationale,
hopefully Shawn can help out with that.

Cc: Shawn Lin <shawn.lin at rock-chips.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
---
 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 3be83feccecb..fbdde82c95b6 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -74,6 +74,9 @@
 #define  PCIE_CLKREQ_NOT_READY		FIELD_PREP_WM16(BIT(0), 0)
 #define  PCIE_CLKREQ_PULL_DOWN		FIELD_PREP_WM16(GENMASK(13, 12), 1)
 
+/* General Debug Register */
+#define PCIE_CLIENT_GENERAL_DEBUG	0x104
+
 /* RASDES TBA information */
 #define PCIE_CLIENT_CDM_RASDES_TBA_INFO_CMN	0x154
 #define  PCIE_CLIENT_CDM_RASDES_TBA_L1_1	BIT(4)
@@ -776,6 +779,11 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static inline void rockchip_pcie_link_status_clear(struct rockchip_pcie *rockchip)
+{
+	rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_GENERAL_DEBUG, 0x0);
+}
+
 static int rockchip_pcie_suspend(struct device *dev)
 {
 	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
@@ -789,6 +797,11 @@ static int rockchip_pcie_suspend(struct device *dev)
 
 	rockchip->intx = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_INTR_MASK_LEGACY);
 
+	/* All sub-devices are in D3hot by PCIe stack */
+	dw_pcie_dbi_ro_wr_dis(pci);
+
+	rockchip_pcie_link_status_clear(rockchip);
+
 	ret = dw_pcie_suspend_noirq(pci);
 	if (ret)
 		return ret;

-- 
2.51.0