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Merge branch 'pci/aspm'

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- disable ASPM L1.2 substate if we don't have LTR (Bjorn Helgaas)

  - respect platform ownership of LTR (Bjorn Helgaas)

* pci/aspm:
  PCI/ACPI: Request LTR control from platform before using it
  PCI/ASPM: Disable ASPM L1.2 Substate if we don't have LTR
This commit is contained in:
Bjorn Helgaas 2018-06-06 16:10:05 -05:00
commit 08b5b2f783
5 changed files with 23 additions and 1 deletions
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6
drivers/acpi/pci_root.c
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@ -153,6 +153,7 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
{ OSC_PCI_EXPRESS_PME_CONTROL, "PME" },
{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
{ OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" },
};
static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
@ -475,6 +476,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
| OSC_PCI_EXPRESS_PME_CONTROL;
if (IS_ENABLED(CONFIG_PCIEASPM))
control |= OSC_PCI_EXPRESS_LTR_CONTROL;
if (pci_aer_available()) {
if (aer_acpi_firmware_first())
dev_info(&device->dev,
@ -905,6 +909,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
host_bridge->native_aer = 0;
if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
host_bridge->native_pme = 0;
if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
host_bridge->native_ltr = 0;
pci_scan_child_bus(bus);
pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,

9
drivers/pci/pcie/aspm.c
View File

@ -400,6 +400,15 @@ static void pcie_get_aspm_reg(struct pci_dev *pdev,
info->l1ss_cap = 0;
return;
}
/*
* If we don't have LTR for the entire path from the Root Complex
* to this device, we can't use ASPM L1.2 because it relies on the
* LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18.
*/
if (!pdev->ltr_path)
info->l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2;
pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL1,
&info->l1ss_ctl1);
pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL2,

5
drivers/pci/probe.c
View File

@ -554,6 +554,7 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
bridge->native_aer = 1;
bridge->native_hotplug = 1;
bridge->native_pme = 1;
bridge->native_ltr = 1;
return bridge;
}
@ -1954,9 +1955,13 @@ static void pci_configure_relaxed_ordering(struct pci_dev *dev)
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;
if (!pci_is_pcie(dev))
return;

3
include/linux/acpi.h
View File

@ -506,7 +506,8 @@ extern bool osc_pc_lpi_support_confirmed;
#define OSC_PCI_EXPRESS_PME_CONTROL 0x00000004
#define OSC_PCI_EXPRESS_AER_CONTROL 0x00000008
#define OSC_PCI_EXPRESS_CAPABILITY_CONTROL 0x00000010
#define OSC_PCI_CONTROL_MASKS 0x0000001f
#define OSC_PCI_EXPRESS_LTR_CONTROL 0x00000020
#define OSC_PCI_CONTROL_MASKS 0x0000003f
#define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002
#define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004

1
include/linux/pci.h
View File

@ -473,6 +473,7 @@ struct pci_host_bridge {
unsigned int native_aer:1; /* OS may use PCIe AER */
unsigned int native_hotplug:1; /* OS may use PCIe hotplug */
unsigned int native_pme:1; /* OS may use PCIe PME */
unsigned int native_ltr:1; /* OS may use PCIe LTR */
/* Resource alignment requirements */
resource_size_t (*align_resource)(struct pci_dev *dev,
const struct resource *res,