From: Pali Rohár <pali@xxxxxxxxxx> commit 2b650b7ff20eb7ea8ef9031d20fb657286ab90cc upstream. Add support for reporting PCI_EXP_LNKSTA_DLLLA bit in Link Control register on emulated bridge via current LTSSM state. Also correctly indicate DLLLA capability via PCI_EXP_LNKCAP_DLLLARC bit in Link Control Capability register. Link: https://lore.kernel.org/r/20211005180952.6812-14-kabel@xxxxxxxxxx Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space") Signed-off-by: Pali Rohár <pali@xxxxxxxxxx> Signed-off-by: Marek Behún <kabel@xxxxxxxxxx> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> Reviewed-by: Marek Behún <kabel@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pci/controller/pci-aardvark.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -328,6 +328,20 @@ static inline bool advk_pcie_link_up(str return ltssm_state >= LTSSM_L0 && ltssm_state < LTSSM_DISABLED; } +static inline bool advk_pcie_link_active(struct advk_pcie *pcie) +{ + /* + * According to PCIe Base specification 3.0, Table 4-14: Link + * Status Mapped to the LTSSM, and 4.2.6.3.6 Configuration.Idle + * is Link Up mapped to LTSSM Configuration.Idle, Recovery, L0, + * L0s, L1 and L2 states. And according to 3.2.1. Data Link + * Control and Management State Machine Rules is DL Up status + * reported in DL Active state. + */ + u8 ltssm_state = advk_pcie_ltssm_state(pcie); + return ltssm_state >= LTSSM_CONFIG_IDLE && ltssm_state < LTSSM_DISABLED; +} + static inline bool advk_pcie_link_training(struct advk_pcie *pcie) { /* @@ -798,12 +812,26 @@ advk_pci_bridge_emul_pcie_conf_read(stru return PCI_BRIDGE_EMUL_HANDLED; } + case PCI_EXP_LNKCAP: { + u32 val = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg); + /* + * PCI_EXP_LNKCAP_DLLLARC bit is hardwired in aardvark HW to 0. + * But support for PCI_EXP_LNKSTA_DLLLA is emulated via ltssm + * state so explicitly enable PCI_EXP_LNKCAP_DLLLARC flag. + */ + val |= PCI_EXP_LNKCAP_DLLLARC; + *value = val; + return PCI_BRIDGE_EMUL_HANDLED; + } + case PCI_EXP_LNKCTL: { /* u32 contains both PCI_EXP_LNKCTL and PCI_EXP_LNKSTA */ u32 val = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg) & ~(PCI_EXP_LNKSTA_LT << 16); if (advk_pcie_link_training(pcie)) val |= (PCI_EXP_LNKSTA_LT << 16); + if (advk_pcie_link_active(pcie)) + val |= (PCI_EXP_LNKSTA_DLLLA << 16); *value = val; return PCI_BRIDGE_EMUL_HANDLED; } @@ -811,7 +839,6 @@ advk_pci_bridge_emul_pcie_conf_read(stru case PCI_CAP_LIST_ID: case PCI_EXP_DEVCAP: case PCI_EXP_DEVCTL: - case PCI_EXP_LNKCAP: *value = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg); return PCI_BRIDGE_EMUL_HANDLED; default:
