[PATCH] PCI: dw-rockchip: Enable L0S capability

[Shawn Lin]

L0S capability isn't enabled on all SoCs by default, so enabling it
in order to make ASPM L0S work on Rockchip platforms. We have been
testing it for quite a long time and the default FTS number provided
by DWC core is broken since it fits only for DWC PHY IP but not for
other types of PHY IP from other vendors.

Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
---

 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 21dc99c..56acfea 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -185,6 +185,20 @@ static int rockchip_pcie_link_up(struct dw_pcie *pci)
 static int rockchip_pcie_start_link(struct dw_pcie *pci)
 {
 	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+	u32 cap, lnkcap;
+
+	/* Enable L0S capability for all SoCs */
+	cap = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
+	if (cap) {
+		/* Default fts number(210) is broken, override it */
+		pci->n_fts[0] = 255; /* Gen1 */
+		pci->n_fts[1] = 255; /* Gen2+ */
+		lnkcap = dw_pcie_readl_dbi(pci, cap + PCI_EXP_LNKCAP);
+		lnkcap |= PCI_EXP_LNKCAP_ASPM_L0S;
+		dw_pcie_dbi_ro_wr_en(pci);
+		dw_pcie_writel_dbi(pci, cap + PCI_EXP_LNKCAP, lnkcap);
+		dw_pcie_dbi_ro_wr_dis(pci);
+	}
 
 	/* Reset device */
 	gpiod_set_value_cansleep(rockchip->rst_gpio, 0);
-- 
2.7.4