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| author | Saheed O. Bolarinwa <refactormyself@gmail.com> | 2021-11-19 20:37:30 +0100 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2021-11-19 16:46:09 -0600 |
| commit | 222578dad4731cb8932471f42a0a606116ec5398 (patch) | |
| tree | cbe66da90fef8dbe77435dbfe4b6b7ab4c2f4298 /drivers/pci/pcie | |
| parent | 43262f001b318a0c0531e252b47bc6b07794f356 (diff) | |
| download | linux-222578dad4731cb8932471f42a0a606116ec5398.tar.bz2 | |
PCI/ASPM: Stop caching link L0s, L1 exit latencies
Previously we calculated the upstream and downstream L0s and L1 exit
latencies of the link in pcie_aspm_cap_init() and cached them in struct
pcie_link_state.latency_*.
These values are only used in pcie_aspm_check_latency() where they are
compared with the acceptable latencies on the link. This path is used when
removing or changing the D state of the device, so it's relatively low
frequency.
To reduce the amount of per-link data we store, remove the latency_*
entries from struct pcie_link_state and calculate the latencies directly
where they are needed.
Link: https://lore.kernel.org/r/20211119193732.12343-3-refactormyself@gmail.com
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/pcie')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 6f128b654730..a7a1d59c338f 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -66,9 +66,6 @@ struct pcie_link_state { u32 clkpm_default:1; /* Default Clock PM state by BIOS */ u32 clkpm_disable:1; /* Clock PM disabled */ - /* Exit latencies */ - struct aspm_latency latency_up; /* Upstream direction exit latency */ - struct aspm_latency latency_dw; /* Downstream direction exit latency */ /* * Endpoint acceptable latencies. A pcie downstream port only * has one slot under it, so at most there are 8 functions. @@ -392,7 +389,8 @@ static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value) static void pcie_aspm_check_latency(struct pci_dev *endpoint) { - u32 latency, l1_switch_latency = 0; + u32 latency, lnkcap_up, lnkcap_dw, l1_switch_latency = 0; + struct aspm_latency latency_up, latency_dw; struct aspm_latency *acceptable; struct pcie_link_state *link; @@ -405,14 +403,26 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) acceptable = &link->acceptable[PCI_FUNC(endpoint->devfn)]; while (link) { + struct pci_dev *dev = pci_function_0(link->pdev->subordinate); + + /* Read direction exit latencies */ + pcie_capability_read_dword(link->pdev, PCI_EXP_LNKCAP, + &lnkcap_up); + pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, + &lnkcap_dw); + latency_up.l0s = calc_l0s_latency(lnkcap_up); + latency_up.l1 = calc_l1_latency(lnkcap_up); + latency_dw.l0s = calc_l0s_latency(lnkcap_dw); + latency_dw.l1 = calc_l1_latency(lnkcap_dw); + /* Check upstream direction L0s latency */ if ((link->aspm_capable & ASPM_STATE_L0S_UP) && - (link->latency_up.l0s > acceptable->l0s)) + (latency_up.l0s > acceptable->l0s)) link->aspm_capable &= ~ASPM_STATE_L0S_UP; /* Check downstream direction L0s latency */ if ((link->aspm_capable & ASPM_STATE_L0S_DW) && - (link->latency_dw.l0s > acceptable->l0s)) + (latency_dw.l0s > acceptable->l0s)) link->aspm_capable &= ~ASPM_STATE_L0S_DW; /* * Check L1 latency. @@ -427,7 +437,7 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) * L1 exit latencies advertised by a device include L1 * substate latencies (and hence do not do any check). */ - latency = max_t(u32, link->latency_up.l1, link->latency_dw.l1); + latency = max_t(u32, latency_up.l1, latency_dw.l1); if ((link->aspm_capable & ASPM_STATE_L1) && (latency + l1_switch_latency > acceptable->l1)) link->aspm_capable &= ~ASPM_STATE_L1; @@ -593,8 +603,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) link->aspm_enabled |= ASPM_STATE_L0S_UP; if (parent_lnkctl & PCI_EXP_LNKCTL_ASPM_L0S) link->aspm_enabled |= ASPM_STATE_L0S_DW; - link->latency_up.l0s = calc_l0s_latency(parent_lnkcap); - link->latency_dw.l0s = calc_l0s_latency(child_lnkcap); /* Setup L1 state */ if (parent_lnkcap & child_lnkcap & PCI_EXP_LNKCAP_ASPM_L1) @@ -602,8 +610,6 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) if (parent_lnkctl & child_lnkctl & PCI_EXP_LNKCTL_ASPM_L1) link->aspm_enabled |= ASPM_STATE_L1; - link->latency_up.l1 = calc_l1_latency(parent_lnkcap); - link->latency_dw.l1 = calc_l1_latency(child_lnkcap); /* Setup L1 substate */ pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP, |