[PATCH v13 4/5] PCI/ACPI: Centralize pcie_ports_native checking

[Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>]

If the user booted with "pcie_ports=native", we take control of the PCIe
port services unconditionally, regardless of what _OSC says.

Centralize the testing of pcie_ports_native in acpi_pci_root_create(),
where we interpret the _OSC results, so other places only have to check
host_bridge->native_X and we don't have to sprinkle tests of
pcie_ports_native everywhere.

Rather than overriding the host_bridge->native_X flags after the fact,
fold "pcie_ports=native" into the _OSC control mask we evaluate, i.e.,
proceed as though the platform had granted control of the port services.
That way there is a single mechanism deciding each native_X flag, and we
can report exactly which features we are overriding _OSC for instead of
just noting that we are overriding something:

  acpi PNP0A08:00: _OSC: OS forcing control ("pcie_ports=native") of [PCIeHotplug PME AER DPC]

This also extends "pcie_ports=native" to host_bridge->native_dpc, which
had no pcie_ports_native fallback before.  The effect is narrow.
native_dpc is only used by pci_dpc_recovered(), and only when
CONFIG_PCIE_EDR=n, where hotplug now waits for firmware-owned DPC
recovery.

host_bridge->native_ltr is deliberately not forced.  "pcie_ports="
controls PCIe port services and LTR is not one.  There is no
PCIE_PORT_SERVICE_LTR, and native_ltr is only used by
pci_configure_ltr() to enable ASPM L1.2, so forcing it would be an ASPM
policy decision users did not ask for.

SHPC hotplug is left alone for a simpler reason: SHPC is a conventional
PCI feature rather than a PCIe one, so "pcie_ports=" has no bearing on
it.

[bhelgaas: commit log, rework OSC_PCIE_PORT_SERVICE_CONTROLS, logging]
Link: https://lore.kernel.org/r/bc87c9e675118960949043a832bed86bc22becbd.1603766889.git.sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
Changes since v12

 * Rebased to v7.3-rc3.
 * Fold "pcie_ports=native" into the _OSC control mask instead of
   overriding the native_X flags afterwards, and report which features we
   override, as agreed in the v12 review.
 * Do not force native_ltr, which v12 did.  LTR is not a PCIe port
   service, so "pcie_ports=" should not affect it.

v12 posting
https://lore.kernel.org/all/20201126011816.711106-1-helgaas@kernel.org/

 drivers/acpi/pci_root.c           | 36 +++++++++++++++++++++++++++++++
 drivers/pci/hotplug/pciehp_core.c |  2 +-
 drivers/pci/pci-acpi.c            |  3 ---
 drivers/pci/pcie/aer.c            |  6 +++---
 drivers/pci/pcie/aer_cxl_rch.c    |  2 +-
 drivers/pci/pcie/err.c            |  2 +-
 drivers/pci/pcie/portdrv.c        |  6 +++---
 7 files changed, 45 insertions(+), 12 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 756dc2f055f5..2494811dd69b 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -999,6 +999,19 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
 			flag = 0;		\
 	} while (0)
 
+#define FLAG(x)		((x) ? '+' : '-')
+
+/*
+ * _OSC control bits for the features implemented by the PCIe port driver,
+ * i.e., the ones "pcie_ports=native" applies to.  LTR and SHPC hotplug are
+ * negotiated via _OSC as well, but they are not portdrv services, so
+ * "pcie_ports=" has no bearing on them.
+ */
+#define OSC_PCIE_PORT_SERVICE_CONTROLS	(OSC_PCI_EXPRESS_NATIVE_HP_CONTROL | \
+					 OSC_PCI_EXPRESS_PME_CONTROL | \
+					 OSC_PCI_EXPRESS_AER_CONTROL | \
+					 OSC_PCI_EXPRESS_DPC_CONTROL)
+
 struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 				     struct acpi_pci_root_ops *ops,
 				     struct acpi_pci_root_info *info,
@@ -1039,6 +1052,21 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 	ctrl = root->osc_control_set;
 	ext_ctrl = root->osc_ext_control_set;
 
+	/*
+	 * If the user specified "pcie_ports=native", use the PCIe port
+	 * services regardless of what _OSC says, i.e., proceed as though the
+	 * platform had granted us control of them.  This may conflict with
+	 * firmware that expects to own those features.
+	 */
+	if (pcie_ports_native) {
+		u32 override = OSC_PCIE_PORT_SERVICE_CONTROLS & ~ctrl;
+
+		if (override)
+			decode_osc_control(root, "OS forcing control (\"pcie_ports=native\") of",
+					   override);
+		ctrl |= override;
+	}
+
 	OSC_OWNER(ctrl, OSC_PCI_EXPRESS_NATIVE_HP_CONTROL,
 		  host_bridge->native_pcie_hotplug);
 	OSC_OWNER(ctrl, OSC_PCI_SHPC_NATIVE_HP_CONTROL,
@@ -1051,6 +1079,14 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 	OSC_OWNER(ext_ctrl, OSC_CXL_ERROR_REPORTING_CONTROL,
 		  host_bridge->native_cxl_error);
 
+	dev_info(&root->device->dev, "OS native features: SHPCHotplug%c PCIeHotplug%c PME%c AER%c DPC%c LTR%c\n",
+		 FLAG(host_bridge->native_shpc_hotplug),
+		 FLAG(host_bridge->native_pcie_hotplug),
+		 FLAG(host_bridge->native_pme),
+		 FLAG(host_bridge->native_aer),
+		 FLAG(host_bridge->native_dpc),
+		 FLAG(host_bridge->native_ltr));
+
 	acpi_dev_power_up_children_with_adr(device);
 
 	pci_scan_child_bus(bus);
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 2cafd3b26f34..b42829cf1377 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -258,7 +258,7 @@ static bool pme_is_native(struct pcie_device *dev)
 	const struct pci_host_bridge *host;
 
 	host = pci_find_host_bridge(dev->port->bus);
-	return pcie_ports_native || host->native_pme;
+	return host->native_pme;
 }
 
 static void pciehp_disable_interrupt(struct pcie_device *dev)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 42d545edd7fa..1150f2fbabf4 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -812,9 +812,6 @@ bool pciehp_is_native(struct pci_dev *bridge)
 	if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE))
 		return false;
 
-	if (pcie_ports_native)
-		return true;
-
 	host = pci_find_host_bridge(bridge->bus);
 	return host->native_pcie_hotplug;
 }
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index d8dcd238fda1..e84dd686582a 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -260,7 +260,7 @@ int pcie_aer_is_native(struct pci_dev *dev)
 	if (!dev->aer_cap)
 		return 0;
 
-	return pcie_ports_native || host->native_aer;
+	return host->native_aer;
 }
 EXPORT_SYMBOL_NS_GPL(pcie_aer_is_native, "CXL");
 
@@ -1847,7 +1847,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 	 */
 	aer = root ? root->aer_cap : 0;
 
-	if ((host->native_aer || pcie_ports_native) && aer)
+	if (host->native_aer && aer)
 		aer_disable_irq(root);
 
 	if (type == PCI_EXP_TYPE_RC_EC || type == PCI_EXP_TYPE_RC_END) {
@@ -1862,7 +1862,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 			pci_is_root_bus(dev->bus) ? "Root" : "Downstream", rc);
 	}
 
-	if ((host->native_aer || pcie_ports_native) && aer) {
+	if (host->native_aer && aer) {
 		/* Clear Root Error Status */
 		pci_read_config_dword(root, aer + PCI_ERR_ROOT_STATUS, &reg32);
 		pci_write_config_dword(root, aer + PCI_ERR_ROOT_STATUS, reg32);
diff --git a/drivers/pci/pcie/aer_cxl_rch.c b/drivers/pci/pcie/aer_cxl_rch.c
index e471eefec9c4..b480dad8bbf4 100644
--- a/drivers/pci/pcie/aer_cxl_rch.c
+++ b/drivers/pci/pcie/aer_cxl_rch.c
@@ -31,7 +31,7 @@ static bool cxl_error_is_native(struct pci_dev *dev)
 {
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 
-	return (pcie_ports_native || host->native_aer);
+	return host->native_aer;
 }
 
 static int cxl_rch_handle_error_iter(struct pci_dev *dev, void *data)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index d77403d8855b..1a7fc71c79d8 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -273,7 +273,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	 * it is responsible for clearing this status.  In that case, the
 	 * signaling device may not even be visible to the OS.
 	 */
-	if (host->native_aer || pcie_ports_native) {
+	if (host->native_aer) {
 		pcie_clear_device_status(dev);
 		pci_aer_clear_nonfatal_status(dev);
 	}
diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c
index a9cbfc1d2bc7..32fc623dd410 100644
--- a/drivers/pci/pcie/portdrv.c
+++ b/drivers/pci/pcie/portdrv.c
@@ -223,7 +223,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	if (dev->is_pciehp &&
 	    (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
 	     pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM) &&
-	    (pcie_ports_native || host->native_pcie_hotplug)) {
+	    host->native_pcie_hotplug) {
 		services |= PCIE_PORT_SERVICE_HP;
 
 		/*
@@ -240,14 +240,14 @@ static int get_port_device_capability(struct pci_dev *dev)
 	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
              pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
 	    dev->aer_cap && pci_aer_available() &&
-	    (pcie_ports_native || host->native_aer))
+	    host->native_aer)
 		services |= PCIE_PORT_SERVICE_AER;
 #endif
 
 	/* Root Ports and Root Complex Event Collectors may generate PMEs */
 	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
 	     pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
-	    (pcie_ports_native || host->native_pme)) {
+	    host->native_pme) {
 		services |= PCIE_PORT_SERVICE_PME;
 
 		/*
-- 
2.43.0