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Merge branch 'pci/aspm' 

- Use Latency Tolerance Reporting if already enabled by platform (Bjorn
    Helgaas)

  - Save/restore LTR info for suspend/resume (Bjorn Helgaas)

* pci/aspm:
  PCI/ASPM: Save LTR Capability for suspend/resume
  PCI/ASPM: Use LTR if already enabled by platform
This commit is contained in:
Bjorn Helgaas 2019-03-06 15:30:09 -06:00
parent 9d8e0e4b39 dbbfadf231
commit 2fcc19b341
2 changed files with 74 additions and 15 deletions
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53
drivers/pci/pci.c
View File

@ -1233,7 +1233,6 @@ static void pci_restore_pcie_state(struct pci_dev *dev)
pcie_capability_write_word(dev, PCI_EXP_SLTCTL2, cap[i++]);
}
static int pci_save_pcix_state(struct pci_dev *dev)
{
int pos;
@ -1270,6 +1269,45 @@ static void pci_restore_pcix_state(struct pci_dev *dev)
pci_write_config_word(dev, pos + PCI_X_CMD, cap[i++]);
}
static void pci_save_ltr_state(struct pci_dev *dev)
{
int ltr;
struct pci_cap_saved_state *save_state;
u16 *cap;
if (!pci_is_pcie(dev))
return;
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!ltr)
return;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state) {
pci_err(dev, "no suspend buffer for LTR; ASPM issues possible after resume\n");
return;
}
cap = (u16 *)&save_state->cap.data[0];
pci_read_config_word(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, cap++);
pci_read_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, cap++);
}
static void pci_restore_ltr_state(struct pci_dev *dev)
{
struct pci_cap_saved_state *save_state;
int ltr;
u16 *cap;
save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_LTR);
ltr = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!save_state || !ltr)
return;
cap = (u16 *)&save_state->cap.data[0];
pci_write_config_word(dev, ltr + PCI_LTR_MAX_SNOOP_LAT, *cap++);
pci_write_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, *cap++);
}
/**
* pci_save_state - save the PCI configuration space of a device before suspending
@ -1291,6 +1329,7 @@ int pci_save_state(struct pci_dev *dev)
if (i != 0)
return i;
pci_save_ltr_state(dev);
pci_save_dpc_state(dev);
return pci_save_vc_state(dev);
}
@ -1390,7 +1429,12 @@ void pci_restore_state(struct pci_dev *dev)
if (!dev->state_saved)
return;
/* PCI Express register must be restored first */
/*
* Restore max latencies (in the LTR capability) before enabling
* LTR itself (in the PCIe capability).
*/
pci_restore_ltr_state(dev);
pci_restore_pcie_state(dev);
pci_restore_pasid_state(dev);
pci_restore_pri_state(dev);
@ -2998,6 +3042,11 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev)
if (error)
pci_err(dev, "unable to preallocate PCI-X save buffer\n");
error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_LTR,
2 * sizeof(u16));
if (error)
pci_err(dev, "unable to allocate suspend buffer for LTR\n");
pci_allocate_vc_save_buffers(dev);
}

36
drivers/pci/probe.c
View File

@ -2069,11 +2069,8 @@ static void pci_configure_ltr(struct pci_dev *dev)
{
#ifdef CONFIG_PCIEASPM
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
u32 cap;
struct pci_dev *bridge;
if (!host->native_ltr)
return;
u32 cap, ctl;
if (!pci_is_pcie(dev))
return;
@ -2082,22 +2079,35 @@ static void pci_configure_ltr(struct pci_dev *dev)
if (!(cap & PCI_EXP_DEVCAP2_LTR))
return;
/*
* Software must not enable LTR in an Endpoint unless the Root
* Complex and all intermediate Switches indicate support for LTR.
* PCIe r3.1, sec 6.18.
*/
if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
dev->ltr_path = 1;
else {
pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl);
if (ctl & PCI_EXP_DEVCTL2_LTR_EN) {
if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
dev->ltr_path = 1;
return;
}
bridge = pci_upstream_bridge(dev);
if (bridge && bridge->ltr_path)
dev->ltr_path = 1;
return;
}
if (dev->ltr_path)
if (!host->native_ltr)
return;
/*
* Software must not enable LTR in an Endpoint unless the Root
* Complex and all intermediate Switches indicate support for LTR.
* PCIe r4.0, sec 6.18.
*/
if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
((bridge = pci_upstream_bridge(dev)) &&
bridge->ltr_path)) {
pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
PCI_EXP_DEVCTL2_LTR_EN);
dev->ltr_path = 1;
}
#endif
}