[PATCH v2 2/3] PCI/DPC: Remove CONFIG_PCIE_EDR

Bjorn Helgaas
2024-02-22T22:15:38Z

From: Bjorn Helgaas <bhelgaas@google.com>

Previous Kconfig allowed the possibility of enabling CONFIG_PCIE_DPC
without CONFIG_PCIE_EDR. The PCI Firmware Spec, r3.3, sec 4.5.1,
table 4-5, says an ACPI OS that requests control of DPC must also
advertise support for EDR.

Remove CONFIG_PCIE_EDR and enable the EDR code with CONFIG_PCIE_DPC so that
enabling DPC also enables EDR for ACPI systems. Since EDR is an ACPI
feature, build edr.o only when CONFIG_ACPI is enabled. Stubs cover the
case when DPC is enabled without ACPI.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/acpi/pci_root.c | 2 +-
drivers/pci/pcie/Kconfig | 14 ++++----------
drivers/pci/pcie/Makefile | 5 ++++-
drivers/pci/pcie/dpc.c | 10 ----------
include/linux/pci-acpi.h | 4 ++--
5 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index efc292b6214e..bcaf3d3a5e05 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -448,7 +448,7 @@ static u32 calculate_support(void)
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))
+ if (IS_ENABLED(CONFIG_PCIE_DPC)) /* DPC => EDR support */
support |= OSC_PCI_EDR_SUPPORT;

return support;
diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig
index 8999fcebde6a..21e98289fbe9 100644
--- a/drivers/pci/pcie/Kconfig
+++ b/drivers/pci/pcie/Kconfig
@@ -137,6 +137,10 @@ config PCIE_DPC
have this capability or you do not want to use this feature,
it is safe to answer N.

+ On ACPI systems, this includes Error Disconnect Recover support,
+ the hybrid model that uses both firmware and OS to implement DPC,
+ as specified in the PCI Firmware Specification r3.3.
+
config PCIE_PTM
bool "PCI Express Precision Time Measurement support"
help
@@ -145,13 +149,3 @@ config PCIE_PTM

This is only useful if you have devices that support PTM, but it
is safe to enable even if you don't.
-
-config PCIE_EDR
- bool "PCI Express Error Disconnect Recover support"
- depends on PCIE_DPC && ACPI
- help
- This option adds Error Disconnect Recover support as specified
- in the Downstream Port Containment Related Enhancements ECN to
- the PCI Firmware Specification r3.2. Enable this if you want to
- support hybrid DPC model which uses both firmware and OS to
- implement DPC.
diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
index 8de4ed5f98f1..72657f780c33 100644
--- a/drivers/pci/pcie/Makefile
+++ b/drivers/pci/pcie/Makefile
@@ -12,4 +12,7 @@ obj-$(CONFIG_PCIEAER_INJECT) += aer_inject.o
obj-$(CONFIG_PCIE_PME) += pme.o
obj-$(CONFIG_PCIE_DPC) += dpc.o
obj-$(CONFIG_PCIE_PTM) += ptm.o
-obj-$(CONFIG_PCIE_EDR) += edr.o
+
+ifdef CONFIG_ACPI
+obj-$(CONFIG_PCIE_DPC) += edr.o
+endif
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 94111e438241..0aa79581250b 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -102,19 +102,9 @@ static bool dpc_completed(struct pci_dev *pdev)
*/
bool pci_dpc_recovered(struct pci_dev *pdev)
{
- struct pci_host_bridge *host;
-
if (!pdev->dpc_cap)
return false;

- /*
- * Synchronization between hotplug and DPC is not supported
- * if DPC is owned by firmware and EDR is not enabled.
- */
- host = pci_find_host_bridge(pdev->bus);
- if (!host->native_dpc && !IS_ENABLED(CONFIG_PCIE_EDR))
- return false;
-
/*
* Need a timeout in case DPC never completes due to failure of
* dpc_wait_rp_inactive(). The spec doesn't mandate a time limit,
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 078225b514d4..92e196ba0249 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -122,13 +122,13 @@ extern const guid_t pci_acpi_dsm_guid;
#define DSM_PCI_POWER_ON_RESET_DELAY 0x08
#define DSM_PCI_DEVICE_READINESS_DURATIONS 0x09

-#ifdef CONFIG_PCIE_EDR
+#ifdef CONFIG_PCIE_DPC
void pci_acpi_add_edr_notifier(struct pci_dev *pdev);
void pci_acpi_remove_edr_notifier(struct pci_dev *pdev);
#else
static inline void pci_acpi_add_edr_notifier(struct pci_dev *pdev) { }
static inline void pci_acpi_remove_edr_notifier(struct pci_dev *pdev) { }
-#endif /* CONFIG_PCIE_EDR */
+#endif /* CONFIG_PCIE_DPC */

int pci_acpi_set_companion_lookup_hook(struct acpi_device *(*func)(struct pci_dev *));
void pci_acpi_clear_companion_lookup_hook(void);
--
2.34.1