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authorKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>2020-03-23 17:26:07 -0700
committerBjorn Helgaas <bhelgaas@google.com>2020-03-28 13:19:04 -0500
commitac1c8e35a3262d04cc81b07fac6480a3539e3b0f (patch)
tree503f40fea8a536d0ffa31ceb3c93f145ada48a4a /drivers/acpi/pci_root.c
parentaea47413e7ceec6024f5a2b743cb1a4b2176bf3f (diff)
PCI/DPC: Add Error Disconnect Recover (EDR) support
Error Disconnect Recover (EDR) is a feature that allows ACPI firmware to notify OSPM that a device has been disconnected due to an error condition (ACPI v6.3, sec 5.6.6). OSPM advertises its support for EDR on PCI devices via _OSC (see [1], sec 4.5.1, table 4-4). The OSPM EDR notify handler should invalidate software state associated with disconnected devices and may attempt to recover them. OSPM communicates the status of recovery to the firmware via _OST (sec 6.3.5.2). For PCIe, firmware may use Downstream Port Containment (DPC) to support EDR. Per [1], sec 4.5.1, table 4-6, even if firmware has retained control of DPC, OSPM may read/write DPC control and status registers during the EDR notification processing window, i.e., from the time it receives an EDR notification until it clears the DPC Trigger Status. Note that per [1], sec 4.5.1 and 4.5.2.4, 1. If the OS supports EDR, it should advertise that to firmware by setting OSC_PCI_EDR_SUPPORT in _OSC Support. 2. If the OS sets OSC_PCI_EXPRESS_DPC_CONTROL in _OSC Control to request control of the DPC capability, it must also set OSC_PCI_EDR_SUPPORT in _OSC Support. Add an EDR notify handler to attempt recovery. [1] Downstream Port Containment Related Enhancements ECN, Jan 28, 2019, affecting PCI Firmware Specification, Rev. 3.2 https://members.pcisig.com/wg/PCI-SIG/document/12888 [bhelgaas: squash add/enable patches into one] Link: https://lore.kernel.org/r/90f91fe6d25c13f9d2255d2ce97ca15be307e1bb.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org>
Diffstat (limited to 'drivers/acpi/pci_root.c')
-rw-r--r--drivers/acpi/pci_root.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d1e666ef3fcc..0cb9df5462c3 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -131,6 +131,7 @@ static struct pci_osc_bit_struct pci_osc_support_bit[] = {
{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
{ OSC_PCI_MSI_SUPPORT, "MSI" },
+ { OSC_PCI_EDR_SUPPORT, "EDR" },
{ OSC_PCI_HPX_TYPE_3_SUPPORT, "HPX-Type3" },
};
@@ -141,6 +142,7 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
{ OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" },
+ { OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" },
};
static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
@@ -440,6 +442,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
if (pci_msi_enabled())
support |= OSC_PCI_MSI_SUPPORT;
+ if (IS_ENABLED(CONFIG_PCIE_EDR))
+ support |= OSC_PCI_EDR_SUPPORT;
decode_osc_support(root, "OS supports", support);
status = acpi_pci_osc_support(root, support);
@@ -487,6 +491,15 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
control |= OSC_PCI_EXPRESS_AER_CONTROL;
}
+ /*
+ * Per the Downstream Port Containment Related Enhancements ECN to
+ * the PCI Firmware Spec, r3.2, sec 4.5.1, table 4-5,
+ * OSC_PCI_EXPRESS_DPC_CONTROL indicates the OS supports both DPC
+ * and EDR.
+ */
+ if (IS_ENABLED(CONFIG_PCIE_DPC) && IS_ENABLED(CONFIG_PCIE_EDR))
+ control |= OSC_PCI_EXPRESS_DPC_CONTROL;
+
requested = control;
status = acpi_pci_osc_control_set(handle, &control,
OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
@@ -916,6 +929,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
host_bridge->native_pme = 0;
if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
host_bridge->native_ltr = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
+ host_bridge->native_dpc = 0;
/*
* Evaluate the "PCI Boot Configuration" _DSM Function. If it