[PATCH v3 1/2] PCI: cadence: Add flags for disabling ASPM support advertisement

[Yao Zi <me@ziyao.cc>]

Add flags for disabling advertisement of ASPM L0s/L1 states by clearing
corresponding bits in Link Capabilities Register through the local
management bus, allowing ASPM to be disabled on platforms which don't
support it.

Signed-off-by: Yao Zi <me@ziyao.cc>
Tested-by: Han Gao <gaohan@iscas.ac.cn>
---
 .../controller/cadence/pcie-cadence-host.c    |  7 +++++++
 drivers/pci/controller/cadence/pcie-cadence.h | 19 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
index db3154c1eccb..0bc9e6e90e0e 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -147,6 +147,13 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
 	cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
 	cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
 
+	value = cdns_pcie_rp_readl(pcie, CDNS_PCIE_RP_CAP_OFFSET + PCI_EXP_LNKCAP);
+	if (rc->quirk_broken_aspm_l0s)
+		value &= ~PCI_EXP_LNKCAP_ASPM_L0S;
+	if (rc->quirk_broken_aspm_l1)
+		value &= ~PCI_EXP_LNKCAP_ASPM_L1;
+	cdns_pcie_rp_writel(pcie, CDNS_PCIE_RP_CAP_OFFSET + PCI_EXP_LNKCAP, value);
+
 	return 0;
 }
 
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index 443033c607d7..32a5666204f5 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -115,6 +115,8 @@ struct cdns_pcie {
  * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk
  * @ecam_supported: Whether the ECAM is supported
  * @no_inbound_map: Whether inbound mapping is supported
+ * @quirk_broken_aspm_l0s: Disable ASPM L0s support as quirk.
+ * @quirk_broken_aspm_l1: Disable ASPM L1 support as quirk.
  */
 struct cdns_pcie_rc {
 	struct cdns_pcie	pcie;
@@ -127,6 +129,8 @@ struct cdns_pcie_rc {
 	unsigned int		quirk_detect_quiet_flag:1;
 	unsigned int            ecam_supported:1;
 	unsigned int            no_inbound_map:1;
+	unsigned int            quirk_broken_aspm_l0s:1;
+	unsigned int            quirk_broken_aspm_l1:1;
 };
 
 /**
@@ -344,6 +348,21 @@ static inline u16 cdns_pcie_rp_readw(struct cdns_pcie *pcie, u32 reg)
 	return cdns_pcie_read_sz(addr, 0x2);
 }
 
+static inline void cdns_pcie_rp_writel(struct cdns_pcie *pcie,
+				       u32 reg, u32 value)
+{
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+	cdns_pcie_write_sz(addr, 0x4, value);
+}
+
+static inline u32 cdns_pcie_rp_readl(struct cdns_pcie *pcie, u32 reg)
+{
+	void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
+
+	return cdns_pcie_read_sz(addr, 0x4);
+}
+
 static inline void cdns_pcie_hpa_rp_writeb(struct cdns_pcie *pcie,
 					   u32 reg, u8 value)
 {
-- 
2.53.0