From c6e5f02b5281a3166a9b7b4d66830cc234421ba5 Mon Sep 17 00:00:00 2001 From: "Saheed O. Bolarinwa" Date: Thu, 15 Oct 2020 14:30:31 -0500 Subject: [PATCH] PCI/ASPM: Remove struct aspm_register_info.support Previously we stored the "ASPM Support" field from the Link Capabilities register in the struct aspm_register_info. Read the Link Capabilities directly when needed and remove it from the struct aspm_register_info. No functional change intended. [bhelgaas: remove pci_dev cached copy since LNKCAP isn't truly read-only, add PCI_EXP_LNKCAP_ASPM_L0S & PCI_EXP_LNKCAP_ASPM_L1, check them directly instead of adding aspm_support()] Link: https://lore.kernel.org/r/20201015193039.12585-5-helgaas@kernel.org Signed-off-by: Saheed O. Bolarinwa Signed-off-by: Bjorn Helgaas --- drivers/pci/pcie/aspm.c | 25 ++++++++++++++----------- include/uapi/linux/pci_regs.h | 2 ++ 2 files changed, 16 insertions(+), 11 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 0725511..82ce34e 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -381,7 +381,6 @@ static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value) } struct aspm_register_info { - u32 support:2; u32 enabled:2; u32 latency_encoding_l0s; u32 latency_encoding_l1; @@ -400,7 +399,6 @@ static void pcie_get_aspm_reg(struct pci_dev *pdev, u32 reg32; pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, ®32); - info->support = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10; info->latency_encoding_l0s = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12; info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15; pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, ®16); @@ -550,6 +548,7 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link, static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) { struct pci_dev *child = link->downstream, *parent = link->pdev; + u32 parent_lnkcap, child_lnkcap; struct pci_bus *linkbus = parent->subordinate; struct aspm_register_info upreg, dwreg; @@ -560,24 +559,26 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) return; } - /* Get upstream/downstream components' register state */ - pcie_get_aspm_reg(parent, &upreg); - pcie_get_aspm_reg(child, &dwreg); - /* * If ASPM not supported, don't mess with the clocks and link, * bail out now. */ - if (!(upreg.support & dwreg.support)) + pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &parent_lnkcap); + pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &child_lnkcap); + if (!(parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPMS)) return; /* Configure common clock before checking latencies */ pcie_aspm_configure_common_clock(link); /* - * Re-read upstream/downstream components' register state - * after clock configuration + * Re-read upstream/downstream components' register state after + * clock configuration. L0s & L1 exit latencies in the otherwise + * read-only Link Capabilities may change depending on common clock + * configuration (PCIe r5.0, sec 7.5.3.6). */ + pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &parent_lnkcap); + pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &child_lnkcap); pcie_get_aspm_reg(parent, &upreg); pcie_get_aspm_reg(child, &dwreg); @@ -588,8 +589,9 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) * given link unless components on both sides of the link each * support L0s. */ - if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S) + if (parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPM_L0S) link->aspm_support |= ASPM_STATE_L0S; + if (dwreg.enabled & PCIE_LINK_STATE_L0S) link->aspm_enabled |= ASPM_STATE_L0S_UP; if (upreg.enabled & PCIE_LINK_STATE_L0S) @@ -598,8 +600,9 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) link->latency_dw.l0s = calc_l0s_latency(dwreg.latency_encoding_l0s); /* Setup L1 state */ - if (upreg.support & dwreg.support & PCIE_LINK_STATE_L1) + if (parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPM_L1) link->aspm_support |= ASPM_STATE_L1; + if (upreg.enabled & dwreg.enabled & PCIE_LINK_STATE_L1) link->aspm_enabled |= ASPM_STATE_L1; link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1); diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index f970141..06846ec 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -532,6 +532,8 @@ #define PCI_EXP_LNKCAP_SLS_32_0GB 0x00000005 /* LNKCAP2 SLS Vector bit 4 */ #define PCI_EXP_LNKCAP_MLW 0x000003f0 /* Maximum Link Width */ #define PCI_EXP_LNKCAP_ASPMS 0x00000c00 /* ASPM Support */ +#define PCI_EXP_LNKCAP_ASPM_L0S 0x00000400 /* ASPM L0s Support */ +#define PCI_EXP_LNKCAP_ASPM_L1 0x00000800 /* ASPM L1 Support */ #define PCI_EXP_LNKCAP_L0SEL 0x00007000 /* L0s Exit Latency */ #define PCI_EXP_LNKCAP_L1EL 0x00038000 /* L1 Exit Latency */ #define PCI_EXP_LNKCAP_CLKPM 0x00040000 /* Clock Power Management */ -- 2.7.4