linux-kernel - [PATCH v2 2/3] PCI/DPC: Remove CONFIG_PCIE

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Message-Id: <20240222221521.32159-3-helgaas@kernel.org>
Date: Thu, 22 Feb 2024 16:15:20 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: linux-pci@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
	Matthew W Carlis <mattc@...estorage.com>,
	Keith Busch <kbusch@...nel.org>,
	Lukas Wunner <lukas@...ner.de>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>
Subject: [PATCH v2 2/3] PCI/DPC: Remove CONFIG_PCIE_EDR

From: Bjorn Helgaas <bhelgaas@...gle.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@...gle.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