diff options
Diffstat (limited to 'drivers/pci/pcie/aspm.c')
| -rw-r--r-- | drivers/pci/pcie/aspm.c | 106 |
1 files changed, 104 insertions, 2 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index b3451cb0472b..ceb2395c37ae 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -588,6 +588,92 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) } } +static void pci_clear_and_set_dword(struct pci_dev *pdev, int pos, + u32 clear, u32 set) +{ + u32 val; + + pci_read_config_dword(pdev, pos, &val); + val &= ~clear; + val |= set; + pci_write_config_dword(pdev, pos, val); +} + +/* Configure the ASPM L1 substates */ +static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state) +{ + u32 val, enable_req; + struct pci_dev *child = link->downstream, *parent = link->pdev; + u32 up_cap_ptr = link->l1ss.up_cap_ptr; + u32 dw_cap_ptr = link->l1ss.dw_cap_ptr; + + enable_req = (link->aspm_enabled ^ state) & state; + + /* + * 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 + * parameters + * + * To keep it simple, disable all L1SS bits first, and later enable + * what is needed. + */ + + /* Disable all L1 substates */ + pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1, + PCI_L1SS_CTL1_L1SS_MASK, 0); + pci_clear_and_set_dword(parent, up_cap_ptr + 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 & (ASPM_STATE_L1_1 | ASPM_STATE_L1_2)) { + pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL, + PCI_EXP_LNKCTL_ASPM_L1, 0); + pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL, + PCI_EXP_LNKCTL_ASPM_L1, 0); + } + + if (enable_req & ASPM_STATE_L1_2_MASK) { + + /* Program T_pwr_on in both ports */ + pci_write_config_dword(parent, up_cap_ptr + PCI_L1SS_CTL2, + link->l1ss.ctl2); + pci_write_config_dword(child, dw_cap_ptr + PCI_L1SS_CTL2, + link->l1ss.ctl2); + + /* Program T_cmn_mode in parent */ + pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1, + 0xFF00, link->l1ss.ctl1); + + /* Program LTR L1.2 threshold in both ports */ + pci_clear_and_set_dword(parent, dw_cap_ptr + PCI_L1SS_CTL1, + 0xE3FF0000, link->l1ss.ctl1); + pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1, + 0xE3FF0000, link->l1ss.ctl1); + } + + val = 0; + if (state & ASPM_STATE_L1_1) + val |= PCI_L1SS_CTL1_ASPM_L1_1; + if (state & ASPM_STATE_L1_2) + val |= PCI_L1SS_CTL1_ASPM_L1_2; + if (state & ASPM_STATE_L1_1_PCIPM) + val |= PCI_L1SS_CTL1_PCIPM_L1_1; + if (state & ASPM_STATE_L1_2_PCIPM) + val |= PCI_L1SS_CTL1_PCIPM_L1_2; + + /* Enable what we need to enable */ + pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1, + PCI_L1SS_CAP_L1_PM_SS, val); + pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1, + PCI_L1SS_CAP_L1_PM_SS, val); +} + static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val) { pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL, @@ -597,11 +683,23 @@ static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val) static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) { u32 upstream = 0, dwstream = 0; - struct pci_dev *child, *parent = link->pdev; + struct pci_dev *child = link->downstream, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; - /* Nothing to do if the link is already in the requested state */ + /* Enable only the states that were not explicitly disabled */ state &= (link->aspm_capable & ~link->aspm_disable); + + /* Can't enable any substates if L1 is not enabled */ + if (!(state & ASPM_STATE_L1)) + state &= ~ASPM_STATE_L1SS; + + /* Spec says both ports must be in D0 before enabling PCI PM substates*/ + if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) { + state &= ~ASPM_STATE_L1_SS_PCIPM; + state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM); + } + + /* Nothing to do if the link is already in the requested state */ if (link->aspm_enabled == state) return; /* Convert ASPM state to upstream/downstream ASPM register state */ @@ -613,6 +711,10 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) upstream |= PCI_EXP_LNKCTL_ASPM_L1; dwstream |= PCI_EXP_LNKCTL_ASPM_L1; } + + if (link->aspm_capable & ASPM_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 |