diff options
Diffstat (limited to 'drivers/pci/pcie/aspm.c')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 98 |
1 files changed, 56 insertions, 42 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index cee2365e54b8..28567d457613 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -805,6 +805,15 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &parent_lnkctl); pcie_capability_read_word(child, PCI_EXP_LNKCTL, &child_lnkctl); + /* Disable L0s/L1 before updating L1SS config */ + if (FIELD_GET(PCI_EXP_LNKCTL_ASPMC, child_lnkctl) || + FIELD_GET(PCI_EXP_LNKCTL_ASPMC, parent_lnkctl)) { + pcie_capability_write_word(child, PCI_EXP_LNKCTL, + child_lnkctl & ~PCI_EXP_LNKCTL_ASPMC); + pcie_capability_write_word(parent, PCI_EXP_LNKCTL, + parent_lnkctl & ~PCI_EXP_LNKCTL_ASPMC); + } + /* * Setup L0s state * @@ -829,6 +838,13 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) aspm_l1ss_init(link); + /* Restore L0s/L1 if they were enabled */ + if (FIELD_GET(PCI_EXP_LNKCTL_ASPMC, child_lnkctl) || + FIELD_GET(PCI_EXP_LNKCTL_ASPMC, parent_lnkctl)) { + pcie_capability_write_word(parent, PCI_EXP_LNKCTL, parent_lnkctl); + pcie_capability_write_word(child, PCI_EXP_LNKCTL, child_lnkctl); + } + /* Save default state */ link->aspm_default = link->aspm_enabled; @@ -845,25 +861,28 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) } } -/* Configure the ASPM L1 substates */ +/* Configure the ASPM L1 substates. Caller must disable L1 first. */ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state) { - u32 val, enable_req; + u32 val; struct pci_dev *child = link->downstream, *parent = link->pdev; - enable_req = (link->aspm_enabled ^ state) & state; + val = 0; + if (state & PCIE_LINK_STATE_L1_1) + val |= PCI_L1SS_CTL1_ASPM_L1_1; + if (state & PCIE_LINK_STATE_L1_2) + val |= PCI_L1SS_CTL1_ASPM_L1_2; + if (state & PCIE_LINK_STATE_L1_1_PCIPM) + val |= PCI_L1SS_CTL1_PCIPM_L1_1; + if (state & PCIE_LINK_STATE_L1_2_PCIPM) + val |= PCI_L1SS_CTL1_PCIPM_L1_2; /* - * Here are the rules specified in the PCIe spec for enabling L1SS: - * - When enabling L1.x, enable bit at parent first, then at child - * - When disabling L1.x, disable bit at child first, then at parent - * - When enabling ASPM L1.x, need to disable L1 - * (at child followed by parent). - * - The ASPM/PCIPM L1.2 must be disabled while programming timing + * PCIe r6.2, sec 5.5.4, rules for enabling L1 PM Substates: + * - Clear L1.x enable bits at child first, then at parent + * - Set L1.x enable bits at parent first, then at child + * - ASPM/PCIPM L1.2 must be disabled while programming timing * parameters - * - * To keep it simple, disable all L1SS bits first, and later enable - * what is needed. */ /* Disable all L1 substates */ @@ -871,26 +890,6 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state) PCI_L1SS_CTL1_L1SS_MASK, 0); pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1, PCI_L1SS_CTL1_L1SS_MASK, 0); - /* - * If needed, disable L1, and it gets enabled later - * in pcie_config_aspm_link(). - */ - if (enable_req & (PCIE_LINK_STATE_L1_1 | PCIE_LINK_STATE_L1_2)) { - pcie_capability_clear_word(child, PCI_EXP_LNKCTL, - PCI_EXP_LNKCTL_ASPM_L1); - pcie_capability_clear_word(parent, PCI_EXP_LNKCTL, - PCI_EXP_LNKCTL_ASPM_L1); - } - - val = 0; - if (state & PCIE_LINK_STATE_L1_1) - val |= PCI_L1SS_CTL1_ASPM_L1_1; - if (state & PCIE_LINK_STATE_L1_2) - val |= PCI_L1SS_CTL1_ASPM_L1_2; - if (state & PCIE_LINK_STATE_L1_1_PCIPM) - val |= PCI_L1SS_CTL1_PCIPM_L1_1; - if (state & PCIE_LINK_STATE_L1_2_PCIPM) - val |= PCI_L1SS_CTL1_PCIPM_L1_2; /* Enable what we need to enable */ pci_clear_and_set_config_dword(parent, parent->l1ss + PCI_L1SS_CTL1, @@ -937,21 +936,30 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) dwstream |= PCI_EXP_LNKCTL_ASPM_L1; } + /* + * Per PCIe r6.2, sec 5.5.4, setting either or both of the enable + * bits for ASPM L1 PM Substates must be done while ASPM L1 is + * disabled. Disable L1 here and apply new configuration after L1SS + * configuration has been completed. + * + * Per sec 7.5.3.7, when disabling ASPM L1, software must disable + * it in the Downstream component prior to disabling it in the + * Upstream component, and ASPM L1 must be enabled in the Upstream + * component prior to enabling it in the Downstream component. + * + * Sec 7.5.3.7 also recommends programming the same ASPM Control + * value for all functions of a multi-function device. + */ + list_for_each_entry(child, &linkbus->devices, bus_list) + pcie_config_aspm_dev(child, 0); + pcie_config_aspm_dev(parent, 0); + if (link->aspm_capable & PCIE_LINK_STATE_L1SS) pcie_config_aspm_l1ss(link, state); - /* - * Spec 2.0 suggests all functions should be configured the - * same setting for ASPM. Enabling ASPM L1 should be done in - * upstream component first and then downstream, and vice - * versa for disabling ASPM L1. Spec doesn't mention L0S. - */ - if (state & PCIE_LINK_STATE_L1) - pcie_config_aspm_dev(parent, upstream); + pcie_config_aspm_dev(parent, upstream); list_for_each_entry(child, &linkbus->devices, bus_list) pcie_config_aspm_dev(child, dwstream); - if (!(state & PCIE_LINK_STATE_L1)) - pcie_config_aspm_dev(parent, upstream); link->aspm_enabled = state; @@ -1442,6 +1450,9 @@ static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked) * touch the LNKCTL register. Also note that this does not enable states * disabled by pci_disable_link_state(). Return 0 or a negative errno. * + * Note: Ensure devices are in D0 before enabling PCI-PM L1 PM Substates, per + * PCIe r6.0, sec 5.5.4. + * * @pdev: PCI device * @state: Mask of ASPM link states to enable */ @@ -1458,6 +1469,9 @@ EXPORT_SYMBOL(pci_enable_link_state); * can't touch the LNKCTL register. Also note that this does not enable states * disabled by pci_disable_link_state(). Return 0 or a negative errno. * + * Note: Ensure devices are in D0 before enabling PCI-PM L1 PM Substates, per + * PCIe r6.0, sec 5.5.4. + * * @pdev: PCI device * @state: Mask of ASPM link states to enable * |