[PATCH v11 0/5] Simplify PCIe native ownership detection logic

[PATCH v11 0/5] Simplify PCIe native ownership detection logic

[Kuppuswamy Sathyanarayanan]

Currently, PCIe capabilities ownership status is detected by
verifying the status of pcie_ports_native, pcie_ports_dpc_native
and _OSC negotiated results (cached in  struct pci_host_bridge
->native_* members). But this logic can be simplified, and we can
use only struct pci_host_bridge ->native_* members to detect it. 

This patchset removes the distributed checks for pcie_ports_native,
pcie_ports_dpc_native parameters.

Changes since v10:
 * Addressed format issue reported by lkp test.

Changes since v9:
 * Rebased on top of v5.10-rc1

Changes since v8:
 * Simplified setting _OSC ownwership logic
 * Moved bridge->native_ltr out of #ifdef CONFIG_PCIEPORTBUS.

Changes since v7:
 * Fixed "fix array_size.cocci warnings".

Changes since v6:
 * Created new patch for CONFIG_PCIEPORTBUS check in
   pci_init_host_bridge().
 * Added warning message for a case when pcie_ports_native
   overrides _OSC negotiation result.

Changes since v5:
 * Rebased on top of v5.8-rc1

Changes since v4:
 * Changed the patch set title (Original link: https://lkml.org/lkml/2020/5/26/1710)
 * Added AER/DPC dependency logic cleanup fixes.
 

Kuppuswamy Sathyanarayanan (5):
  PCI: Conditionally initialize host bridge native_* members
  ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.
  ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native
    is set.
  PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable
    logic
  PCI/DPC: Move AER/DPC dependency checks out of DPC driver

 drivers/acpi/pci_root.c           | 39 +++++++++++++++++++++++--------
 drivers/pci/hotplug/pciehp_core.c |  2 +-
 drivers/pci/pci-acpi.c            |  3 ---
 drivers/pci/pcie/aer.c            |  2 +-
 drivers/pci/pcie/dpc.c            |  3 ---
 drivers/pci/pcie/portdrv.h        |  2 --
 drivers/pci/pcie/portdrv_core.c   | 13 ++++-------
 drivers/pci/probe.c               |  6 +++--
 include/linux/acpi.h              |  2 ++
 include/linux/pci.h               |  2 ++
 10 files changed, 44 insertions(+), 30 deletions(-)

-- 
2.17.1

[PATCH v11 1/5] PCI: Conditionally initialize host bridge native_* members

[Kuppuswamy Sathyanarayanan]

If CONFIG_PCIEPORTBUS is not enabled in kernel then initialing
struct pci_host_bridge PCIe specific native_* members to "1" is
incorrect. So protect the PCIe specific member initialization
with CONFIG_PCIEPORTBUS.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/probe.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4289030b0fff..756fa60ca708 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -588,12 +588,14 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
 	 * may implement its own AER handling and use _OSC to prevent the
 	 * OS from interfering.
 	 */
+#ifdef CONFIG_PCIEPORTBUS
 	bridge->native_aer = 1;
 	bridge->native_pcie_hotplug = 1;
-	bridge->native_shpc_hotplug = 1;
 	bridge->native_pme = 1;
-	bridge->native_ltr = 1;
 	bridge->native_dpc = 1;
+#endif
+	bridge->native_ltr = 1;
+	bridge->native_shpc_hotplug = 1;
 
 	device_initialize(&bridge->dev);
 }
-- 
2.17.1

[PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Kuppuswamy Sathyanarayanan]

pcie_ports_native is set only if user requests native handling
of PCIe capabilities via pcie_port_setup command line option.
User input takes precedence over _OSC based control negotiation
result. So consider the _OSC negotiated result only if
pcie_ports_native is unset.

Also, since struct pci_host_bridge ->native_* members caches the
ownership status of various PCIe capabilities, use them instead
of distributed checks for pcie_ports_native.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/acpi/pci_root.c           | 35 ++++++++++++++++++++++---------
 drivers/pci/hotplug/pciehp_core.c |  2 +-
 drivers/pci/pci-acpi.c            |  3 ---
 drivers/pci/pcie/aer.c            |  2 +-
 drivers/pci/pcie/portdrv_core.c   |  9 +++-----
 include/linux/acpi.h              |  2 ++
 6 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index c12b5fb3e8fb..a9e6b782622d 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -41,6 +41,12 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
 				| OSC_PCI_CLOCK_PM_SUPPORT \
 				| OSC_PCI_MSI_SUPPORT)
 
+#define OSC_OWNER(ctrl, bit, flag) \
+	do { \
+		if (!(ctrl & bit)) \
+			flag = 0;  \
+	} while (0)
+
 static const struct acpi_device_id root_device_ids[] = {
 	{"PNP0A03", 0},
 	{"", 0},
@@ -887,6 +893,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 	struct pci_bus *bus;
 	struct pci_host_bridge *host_bridge;
 	union acpi_object *obj;
+	u32 ctrl;
 
 	info->root = root;
 	info->bridge = device;
@@ -912,18 +919,26 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 		goto out_release_info;
 
 	host_bridge = to_pci_host_bridge(bus->bridge);
-	if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
-		host_bridge->native_pcie_hotplug = 0;
+
+	if (pcie_ports_native) {
+		decode_osc_control(root, "OS forcibly taking over",
+				   OSC_PCI_EXPRESS_CONTROL_MASKS);
+	} else {
+		ctrl = root->osc_control_set;
+		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_NATIVE_HP_CONTROL,
+			  host_bridge->native_pcie_hotplug);
+		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL,
+			  host_bridge->native_aer);
+		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL,
+			  host_bridge->native_pme);
+		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
+			  host_bridge->native_ltr);
+		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
+			  host_bridge->native_dpc);
+	}
+
 	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
 		host_bridge->native_shpc_hotplug = 0;
-	if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
-		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;
-	if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
-		host_bridge->native_dpc = 0;
 
 	/*
 	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index ad3393930ecb..d1831e6bf60a 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -256,7 +256,7 @@ 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 bf03648c2072..a84f75ec6df8 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -800,9 +800,6 @@ bool pciehp_is_native(struct pci_dev *bridge)
 	if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
 		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 65dff5f3457a..79bb441139c2 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -219,7 +219,7 @@ 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;
 }
 
 int pci_enable_pcie_error_reporting(struct pci_dev *dev)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 50a9522ab07d..ccd5e0ce5605 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 	int services = 0;
 
-	if (dev->is_hotplug_bridge &&
-	    (pcie_ports_native || host->native_pcie_hotplug)) {
+	if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {
 		services |= PCIE_PORT_SERVICE_HP;
 
 		/*
@@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	}
 
 #ifdef CONFIG_PCIEAER
-	if (dev->aer_cap && pci_aer_available() &&
-	    (pcie_ports_native || host->native_aer)) {
+	if (dev->aer_cap && pci_aer_available() && host->native_aer) {
 		services |= PCIE_PORT_SERVICE_AER;
 
 		/*
@@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	 * Event Collectors can also generate PMEs, but we don't handle
 	 * those yet.
 	 */
-	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
-	    (pcie_ports_native || host->native_pme)) {
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
 		services |= PCIE_PORT_SERVICE_PME;
 
 		/*
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 39263c6b52e1..35689f4e8e1f 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -569,6 +569,8 @@ extern bool osc_pc_lpi_support_confirmed;
 #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
 #define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
 #define OSC_PCI_CONTROL_MASKS			0x000000bf
+/* Masks specific to PCIe Capabilities */
+#define OSC_PCI_EXPRESS_CONTROL_MASKS		0x000000bd
 
 #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
 #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
-- 
2.17.1

[PATCH v11 3/5] ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native is set.

[Kuppuswamy Sathyanarayanan]

pcie_ports_dpc_native is set only if user requests native handling
of PCIe DPC capability via pcie_port_setup command line option.
User input takes precedence over _OSC based control negotiation
result. So consider the _OSC negotiated result for DPC ownership
only if pcie_ports_dpc_native is unset.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/acpi/pci_root.c         | 8 ++++++--
 drivers/pci/pcie/dpc.c          | 3 ++-
 drivers/pci/pcie/portdrv.h      | 2 --
 drivers/pci/pcie/portdrv_core.c | 2 +-
 include/linux/pci.h             | 2 ++
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index a9e6b782622d..2e2bc80c42fe 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -933,8 +933,12 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
 			  host_bridge->native_pme);
 		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
 			  host_bridge->native_ltr);
-		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
-			  host_bridge->native_dpc);
+		if (pcie_ports_dpc_native)
+			dev_warn(&bus->dev, "OS forcibly taking over DPC\n");
+		else
+			OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
+				  host_bridge->native_dpc);
+
 	}
 
 	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index e05aba86a317..21f77420632b 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -283,11 +283,12 @@ void pci_dpc_init(struct pci_dev *pdev)
 static int dpc_probe(struct pcie_device *dev)
 {
 	struct pci_dev *pdev = dev->port;
+	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
 	struct device *device = &dev->device;
 	int status;
 	u16 ctl, cap;
 
-	if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native)
+	if (!pcie_aer_is_native(pdev) && !host->native_dpc)
 		return -ENOTSUPP;
 
 	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index af7cf237432a..0ac20feef24e 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -25,8 +25,6 @@
 
 #define PCIE_PORT_DEVICE_MAXSERVICES   5
 
-extern bool pcie_ports_dpc_native;
-
 #ifdef CONFIG_PCIEAER
 int pcie_aer_init(void);
 int pcie_aer_is_native(struct pci_dev *dev);
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index ccd5e0ce5605..2c0278f0fdcc 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -253,7 +253,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	 */
 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
 	    pci_aer_available() &&
-	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
+	    (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
 		services |= PCIE_PORT_SERVICE_DPC;
 
 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 22207a79762c..388121ec88b5 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1559,9 +1559,11 @@ static inline int pci_irqd_intx_xlate(struct irq_domain *d,
 #ifdef CONFIG_PCIEPORTBUS
 extern bool pcie_ports_disabled;
 extern bool pcie_ports_native;
+extern bool pcie_ports_dpc_native;
 #else
 #define pcie_ports_disabled	true
 #define pcie_ports_native	false
+#define pcie_ports_dpc_native	false
 #endif
 
 #define PCIE_LINK_STATE_L0S		BIT(0)
-- 
2.17.1

[PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable logic

[Kuppuswamy Sathyanarayanan]

In DPC service enable logic, check for
services & PCIE_PORT_SERVICE_AER implies pci_aer_available()
is true. So there is no need to explicitly check it again.

Also, passing pcie_ports=dpc-native in kernel command line
implies DPC needs to be enabled in native mode irrespective
of AER ownership status. So checking for pci_aer_available()
without checking for pcie_ports status is incorrect.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pcie/portdrv_core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 2c0278f0fdcc..e257a2ca3595 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -252,7 +252,6 @@ static int get_port_device_capability(struct pci_dev *dev)
 	 * permission to use AER.
 	 */
 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
-	    pci_aer_available() &&
 	    (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
 		services |= PCIE_PORT_SERVICE_DPC;
 
-- 
2.17.1

[PATCH v11 5/5] PCI/DPC: Move AER/DPC dependency checks out of DPC driver

[Kuppuswamy Sathyanarayanan]

Currently, AER and DPC Capabilities dependency checks is
distributed between DPC and portdrv service drivers. So move
them out of DPC driver.

Also, since services & PCIE_PORT_SERVICE_AER check already
ensures AER native ownership, no need to add additional
pcie_aer_is_native() check.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/pci/pcie/dpc.c          | 4 ----
 drivers/pci/pcie/portdrv_core.c | 1 +
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 21f77420632b..a8b922044447 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -283,14 +283,10 @@ void pci_dpc_init(struct pci_dev *pdev)
 static int dpc_probe(struct pcie_device *dev)
 {
 	struct pci_dev *pdev = dev->port;
-	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
 	struct device *device = &dev->device;
 	int status;
 	u16 ctl, cap;
 
-	if (!pcie_aer_is_native(pdev) && !host->native_dpc)
-		return -ENOTSUPP;
-
 	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
 					   dpc_handler, IRQF_SHARED,
 					   "pcie-dpc", pdev);
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index e257a2ca3595..ffa1d9fc458e 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -252,6 +252,7 @@ static int get_port_device_capability(struct pci_dev *dev)
 	 * permission to use AER.
 	 */
 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
+	    host->native_dpc &&
 	    (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
 		services |= PCIE_PORT_SERVICE_DPC;
 
-- 
2.17.1

Re: [PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable logic

[Ethan Zhao]

On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>
> In DPC service enable logic, check for
> services & PCIE_PORT_SERVICE_AER implies pci_aer_available()
How about PCIE_PORT_SERVICE_AER is not configured, but
pcie_aer_disable == 0 ？
> is true. So there is no need to explicitly check it again.
>
> Also, passing pcie_ports=dpc-native in kernel command line
> implies DPC needs to be enabled in native mode irrespective
> of AER ownership status. So checking for pci_aer_available()
> without checking for pcie_ports status is incorrect.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/pci/pcie/portdrv_core.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 2c0278f0fdcc..e257a2ca3595 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -252,7 +252,6 @@ static int get_port_device_capability(struct pci_dev *dev)
>          * permission to use AER.
>          */
>         if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
> -           pci_aer_available() &&
>             (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
>                 services |= PCIE_PORT_SERVICE_DPC;
>
> --
> 2.17.1
>

Re: [PATCH v11 1/5] PCI: Conditionally initialize host bridge native_* members

[Ethan Zhao]

On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>
> If CONFIG_PCIEPORTBUS is not enabled in kernel then initialing
> struct pci_host_bridge PCIe specific native_* members to "1" is
> incorrect. So protect the PCIe specific member initialization
> with CONFIG_PCIEPORTBUS.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/pci/probe.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 4289030b0fff..756fa60ca708 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -588,12 +588,14 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>          * may implement its own AER handling and use _OSC to prevent the
>          * OS from interfering.
>          */
> +#ifdef CONFIG_PCIEPORTBUS
>         bridge->native_aer = 1;
>         bridge->native_pcie_hotplug = 1;
> -       bridge->native_shpc_hotplug = 1;
>         bridge->native_pme = 1;
> -       bridge->native_ltr = 1;
>         bridge->native_dpc = 1;
> +#endif
  If CONFIG_PCIEPORTBUS wasn't defined, leave them to "unknown" value ?

> +       bridge->native_ltr = 1;
> +       bridge->native_shpc_hotplug = 1;
>
>         device_initialize(&bridge->dev);
>  }
> --
> 2.17.1
>

Re: [PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable logic

[Kuppuswamy, Sathyanarayanan]

On 10/27/20 11:00 PM, Ethan Zhao wrote:
> On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
> <sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>>
>> In DPC service enable logic, check for
>> services & PCIE_PORT_SERVICE_AER implies pci_aer_available()
> How about PCIE_PORT_SERVICE_AER is not configured, but
> pcie_aer_disable == 0 ？
Its not possible in current code flow. DPC service is configured
following AER service configuration.
>> is true. So there is no need to explicitly check it again.
>>
>> Also, passing pcie_ports=dpc-native in kernel command line
>> implies DPC needs to be enabled in native mode irrespective
>> of AER ownership status. So checking for pci_aer_available()
>> without checking for pcie_ports status is incorrect.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>> ---
>>   drivers/pci/pcie/portdrv_core.c | 1 -
>>   1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
>> index 2c0278f0fdcc..e257a2ca3595 100644
>> --- a/drivers/pci/pcie/portdrv_core.c
>> +++ b/drivers/pci/pcie/portdrv_core.c
>> @@ -252,7 +252,6 @@ static int get_port_device_capability(struct pci_dev *dev)
>>           * permission to use AER.
>>           */
>>          if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
>> -           pci_aer_available() &&
>>              (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
>>                  services |= PCIE_PORT_SERVICE_DPC;
>>
>> --
>> 2.17.1
>>

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v11 1/5] PCI: Conditionally initialize host bridge native_* members

[Kuppuswamy, Sathyanarayanan]

On 10/27/20 11:09 PM, Ethan Zhao wrote:
> On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
> <sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>>
>> If CONFIG_PCIEPORTBUS is not enabled in kernel then initialing
>> struct pci_host_bridge PCIe specific native_* members to "1" is
>> incorrect. So protect the PCIe specific member initialization
>> with CONFIG_PCIEPORTBUS.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>> ---
>>   drivers/pci/probe.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index 4289030b0fff..756fa60ca708 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -588,12 +588,14 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>>           * may implement its own AER handling and use _OSC to prevent the
>>           * OS from interfering.
>>           */
>> +#ifdef CONFIG_PCIEPORTBUS
>>          bridge->native_aer = 1;
>>          bridge->native_pcie_hotplug = 1;
>> -       bridge->native_shpc_hotplug = 1;
>>          bridge->native_pme = 1;
>> -       bridge->native_ltr = 1;
>>          bridge->native_dpc = 1;
>> +#endif
>    If CONFIG_PCIEPORTBUS wasn't defined, leave them to "unknown" value ?
By default all of them are 0.
> 
>> +       bridge->native_ltr = 1;
>> +       bridge->native_shpc_hotplug = 1;
>>
>>          device_initialize(&bridge->dev);
>>   }
>> --
>> 2.17.1
>>

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v11 4/5] PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable logic

[Ethan Zhao]

The current logic is
if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&
    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
services |= PCIE_PORT_SERVICE_DPC;


if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&
    (pcie_ports_dpc_native))
 services |= PCIE_PORT_SERVICE_DPC;

or

if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    pci_aer_available() &&(services & PCIE_PORT_SERVICE_AER)）
  services |= PCIE_PORT_SERVICE_DPC;

do you mean one of the possible is
if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
    (pcie_ports_dpc_native))
 services |= PCIE_PORT_SERVICE_DPC;

after your patch ? nothing about AER ?

Thanks,
Ethan

On Thu, Oct 29, 2020 at 1:14 AM Kuppuswamy, Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
>
>
>
> On 10/27/20 11:00 PM, Ethan Zhao wrote:
> > On Tue, Oct 27, 2020 at 10:00 PM Kuppuswamy Sathyanarayanan
> > <sathyanarayanan.kuppuswamy@linux.intel.com> wrote:
> >>
> >> In DPC service enable logic, check for
> >> services & PCIE_PORT_SERVICE_AER implies pci_aer_available()
> > How about PCIE_PORT_SERVICE_AER is not configured, but
> > pcie_aer_disable == 0 ？
> Its not possible in current code flow. DPC service is configured
> following AER service configuration.
> >> is true. So there is no need to explicitly check it again.
> >>
> >> Also, passing pcie_ports=dpc-native in kernel command line
> >> implies DPC needs to be enabled in native mode irrespective
> >> of AER ownership status. So checking for pci_aer_available()
> >> without checking for pcie_ports status is incorrect.
> >>
> >> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> >> ---
> >>   drivers/pci/pcie/portdrv_core.c | 1 -
> >>   1 file changed, 1 deletion(-)
> >>
> >> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> >> index 2c0278f0fdcc..e257a2ca3595 100644
> >> --- a/drivers/pci/pcie/portdrv_core.c
> >> +++ b/drivers/pci/pcie/portdrv_core.c
> >> @@ -252,7 +252,6 @@ static int get_port_device_capability(struct pci_dev *dev)
> >>           * permission to use AER.
> >>           */
> >>          if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
> >> -           pci_aer_available() &&
> >>              (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
> >>                  services |= PCIE_PORT_SERVICE_DPC;
> >>
> >> --
> >> 2.17.1
> >>
>
> --
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer

Re: [PATCH v11 0/5] Simplify PCIe native ownership detection logic

[Kuppuswamy, Sathyanarayanan]

Hi Bjorn,

On 10/26/20 7:57 PM, Kuppuswamy Sathyanarayanan wrote:
> Currently, PCIe capabilities ownership status is detected by
> verifying the status of pcie_ports_native, pcie_ports_dpc_native
> and _OSC negotiated results (cached in  struct pci_host_bridge
> ->native_* members). But this logic can be simplified, and we can
> use only struct pci_host_bridge ->native_* members to detect it.
> 
> This patchset removes the distributed checks for pcie_ports_native,
> pcie_ports_dpc_native parameters.
Any comments on this series?
> 
> Changes since v10:
>   * Addressed format issue reported by lkp test.
> 
> Changes since v9:
>   * Rebased on top of v5.10-rc1
> 
> Changes since v8:
>   * Simplified setting _OSC ownwership logic
>   * Moved bridge->native_ltr out of #ifdef CONFIG_PCIEPORTBUS.
> 
> Changes since v7:
>   * Fixed "fix array_size.cocci warnings".
> 
> Changes since v6:
>   * Created new patch for CONFIG_PCIEPORTBUS check in
>     pci_init_host_bridge().
>   * Added warning message for a case when pcie_ports_native
>     overrides _OSC negotiation result.
> 
> Changes since v5:
>   * Rebased on top of v5.8-rc1
> 
> Changes since v4:
>   * Changed the patch set title (Original link: https://lkml.org/lkml/2020/5/26/1710)
>   * Added AER/DPC dependency logic cleanup fixes.
>   
> 
> Kuppuswamy Sathyanarayanan (5):
>    PCI: Conditionally initialize host bridge native_* members
>    ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.
>    ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native
>      is set.
>    PCI/portdrv: Remove redundant pci_aer_available() check in DPC enable
>      logic
>    PCI/DPC: Move AER/DPC dependency checks out of DPC driver
> 
>   drivers/acpi/pci_root.c           | 39 +++++++++++++++++++++++--------
>   drivers/pci/hotplug/pciehp_core.c |  2 +-
>   drivers/pci/pci-acpi.c            |  3 ---
>   drivers/pci/pcie/aer.c            |  2 +-
>   drivers/pci/pcie/dpc.c            |  3 ---
>   drivers/pci/pcie/portdrv.h        |  2 --
>   drivers/pci/pcie/portdrv_core.c   | 13 ++++-------
>   drivers/pci/probe.c               |  6 +++--
>   include/linux/acpi.h              |  2 ++
>   include/linux/pci.h               |  2 ++
>   10 files changed, 44 insertions(+), 30 deletions(-)
> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Bjorn Helgaas]

On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
> pcie_ports_native is set only if user requests native handling
> of PCIe capabilities via pcie_port_setup command line option.
> User input takes precedence over _OSC based control negotiation
> result. So consider the _OSC negotiated result only if
> pcie_ports_native is unset.
> 
> Also, since struct pci_host_bridge ->native_* members caches the
> ownership status of various PCIe capabilities, use them instead
> of distributed checks for pcie_ports_native.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/acpi/pci_root.c           | 35 ++++++++++++++++++++++---------
>  drivers/pci/hotplug/pciehp_core.c |  2 +-
>  drivers/pci/pci-acpi.c            |  3 ---
>  drivers/pci/pcie/aer.c            |  2 +-
>  drivers/pci/pcie/portdrv_core.c   |  9 +++-----
>  include/linux/acpi.h              |  2 ++
>  6 files changed, 32 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index c12b5fb3e8fb..a9e6b782622d 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -41,6 +41,12 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
>  				| OSC_PCI_CLOCK_PM_SUPPORT \
>  				| OSC_PCI_MSI_SUPPORT)
>  
> +#define OSC_OWNER(ctrl, bit, flag) \
> +	do { \
> +		if (!(ctrl & bit)) \
> +			flag = 0;  \
> +	} while (0)
> +
>  static const struct acpi_device_id root_device_ids[] = {
>  	{"PNP0A03", 0},
>  	{"", 0},
> @@ -887,6 +893,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>  	struct pci_bus *bus;
>  	struct pci_host_bridge *host_bridge;
>  	union acpi_object *obj;
> +	u32 ctrl;
>  
>  	info->root = root;
>  	info->bridge = device;
> @@ -912,18 +919,26 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>  		goto out_release_info;
>  
>  	host_bridge = to_pci_host_bridge(bus->bridge);
> -	if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
> -		host_bridge->native_pcie_hotplug = 0;
> +
> +	if (pcie_ports_native) {
> +		decode_osc_control(root, "OS forcibly taking over",
> +				   OSC_PCI_EXPRESS_CONTROL_MASKS);

The only place OSC_PCI_EXPRESS_CONTROL_MASKS is used is right here, so
it's kind of pointless.

I think I'd rather have this:

  dev_info(&root->device->dev, "Ignoring PCIe-related _OSC results because \"pcie_ports=native\" specified\n");

> +	} else {
> +		ctrl = root->osc_control_set;
> +		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_NATIVE_HP_CONTROL,
> +			  host_bridge->native_pcie_hotplug);
> +		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL,
> +			  host_bridge->native_aer);
> +		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_PME_CONTROL,
> +			  host_bridge->native_pme);
> +		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
> +			  host_bridge->native_ltr);
> +		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
> +			  host_bridge->native_dpc);
> +	}
> +
>  	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
>  		host_bridge->native_shpc_hotplug = 0;
> -	if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
> -		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;
> -	if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
> -		host_bridge->native_dpc = 0;

followed by something like this after we're done fiddling with all the
host_bridge->native* bits:

  #define FLAG(x) ((x) ? '+' : '-')

  dev_info(&root->device->dev, "OS native features: SHPCHotplug%c PCIeCapability%c PCIeHotplug%c PME%c AER%c DPC%c LTR%c\n",
           FLAG(host_bridge->native_shpc_hotplug),
	   ?,
           FLAG(host_bridge->native_pcie_hotplug),
	   ...);

But I don't know how to handle OSC_PCI_EXPRESS_CAPABILITY_CONTROL
since we don't track it the same way.  Maybe we'd have to omit it from
this message for now?

>  	/*
>  	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index ad3393930ecb..d1831e6bf60a 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -256,7 +256,7 @@ 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 bf03648c2072..a84f75ec6df8 100644
> --- a/drivers/pci/pci-acpi.c
> +++ b/drivers/pci/pci-acpi.c
> @@ -800,9 +800,6 @@ bool pciehp_is_native(struct pci_dev *bridge)
>  	if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
>  		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 65dff5f3457a..79bb441139c2 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -219,7 +219,7 @@ 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;
>  }
>  
>  int pci_enable_pcie_error_reporting(struct pci_dev *dev)
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 50a9522ab07d..ccd5e0ce5605 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>  	int services = 0;
>  
> -	if (dev->is_hotplug_bridge &&
> -	    (pcie_ports_native || host->native_pcie_hotplug)) {
> +	if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {
>  		services |= PCIE_PORT_SERVICE_HP;
>  
>  		/*
> @@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	}
>  
>  #ifdef CONFIG_PCIEAER
> -	if (dev->aer_cap && pci_aer_available() &&
> -	    (pcie_ports_native || host->native_aer)) {
> +	if (dev->aer_cap && pci_aer_available() && host->native_aer) {
>  		services |= PCIE_PORT_SERVICE_AER;
>  
>  		/*
> @@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	 * Event Collectors can also generate PMEs, but we don't handle
>  	 * those yet.
>  	 */
> -	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
> -	    (pcie_ports_native || host->native_pme)) {
> +	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
>  		services |= PCIE_PORT_SERVICE_PME;
>  
>  		/*
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 39263c6b52e1..35689f4e8e1f 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -569,6 +569,8 @@ extern bool osc_pc_lpi_support_confirmed;
>  #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
>  #define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
>  #define OSC_PCI_CONTROL_MASKS			0x000000bf
> +/* Masks specific to PCIe Capabilities */
> +#define OSC_PCI_EXPRESS_CONTROL_MASKS		0x000000bd
>  
>  #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
>  #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
> -- 
> 2.17.1
> 

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Bjorn Helgaas]

On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
> pcie_ports_native is set only if user requests native handling
> of PCIe capabilities via pcie_port_setup command line option.
> User input takes precedence over _OSC based control negotiation
> result. So consider the _OSC negotiated result only if
> pcie_ports_native is unset.
> 
> Also, since struct pci_host_bridge ->native_* members caches the
> ownership status of various PCIe capabilities, use them instead
> of distributed checks for pcie_ports_native.

> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 50a9522ab07d..ccd5e0ce5605 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>  	int services = 0;
>  
> -	if (dev->is_hotplug_bridge &&
> -	    (pcie_ports_native || host->native_pcie_hotplug)) {
> +	if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {

This is a nit, but I think this and similar checks should be reordered
so we do the most generic test first, i.e.,

  if (host->native_pcie_hotplug && dev->is_hotplug_bridge)

Logically there's no point in looking at the device things if we
don't have native control.

>  		services |= PCIE_PORT_SERVICE_HP;
>  
>  		/*
> @@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	}
>  
>  #ifdef CONFIG_PCIEAER
> -	if (dev->aer_cap && pci_aer_available() &&
> -	    (pcie_ports_native || host->native_aer)) {
> +	if (dev->aer_cap && pci_aer_available() && host->native_aer) {

Can't we clear host->native_aer when pci_aer_available() returns
false?  I'd like to have all the checks about whether we have native
control to be in one place instead of being scattered.  Something like
this above:

  OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL, host_bridge->native_aer);
  if (!pci_aer_available())
    host_bridge->native_aer = 0;

So this test would become:

  if (host->native_aer && dev->aer_cap)

>  		services |= PCIE_PORT_SERVICE_AER;
>  
>  		/*
> @@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	 * Event Collectors can also generate PMEs, but we don't handle
>  	 * those yet.
>  	 */
> -	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
> -	    (pcie_ports_native || host->native_pme)) {
> +	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
>  		services |= PCIE_PORT_SERVICE_PME;

Also here:

  if (host->native_pme && pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)

Re: [PATCH v11 3/5] ACPI/PCI: Ignore _OSC DPC negotiation result if pcie_ports_dpc_native is set.

[Bjorn Helgaas]

On Mon, Oct 26, 2020 at 07:57:06PM -0700, Kuppuswamy Sathyanarayanan wrote:
> pcie_ports_dpc_native is set only if user requests native handling
> of PCIe DPC capability via pcie_port_setup command line option.
> User input takes precedence over _OSC based control negotiation
> result. So consider the _OSC negotiated result for DPC ownership
> only if pcie_ports_dpc_native is unset.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/acpi/pci_root.c         | 8 ++++++--
>  drivers/pci/pcie/dpc.c          | 3 ++-
>  drivers/pci/pcie/portdrv.h      | 2 --
>  drivers/pci/pcie/portdrv_core.c | 2 +-
>  include/linux/pci.h             | 2 ++
>  5 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index a9e6b782622d..2e2bc80c42fe 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -933,8 +933,12 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>  			  host_bridge->native_pme);
>  		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_LTR_CONTROL,
>  			  host_bridge->native_ltr);
> -		OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
> -			  host_bridge->native_dpc);
> +		if (pcie_ports_dpc_native)
> +			dev_warn(&bus->dev, "OS forcibly taking over DPC\n");
> +		else
> +			OSC_OWNER(ctrl, OSC_PCI_EXPRESS_DPC_CONTROL,
> +				  host_bridge->native_dpc);
> +
>  	}
>  
>  	if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index e05aba86a317..21f77420632b 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -283,11 +283,12 @@ void pci_dpc_init(struct pci_dev *pdev)
>  static int dpc_probe(struct pcie_device *dev)
>  {
>  	struct pci_dev *pdev = dev->port;
> +	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
>  	struct device *device = &dev->device;
>  	int status;
>  	u16 ctl, cap;
>  
> -	if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native)
> +	if (!pcie_aer_is_native(pdev) && !host->native_dpc)
>  		return -ENOTSUPP;

Wow, I don't even know what those negations mean and I don't want to
take ten minutes to figure it out.  Not your fault, obviously; it was
that way before.

"If AER is not native and DPC is not native, return -ENOTSUPP"?
In other words, "if not (AER is native OR DPC is native), return
-ENOTSUPP"?  Or "if (AER is native OR DPC is native), keep going"?

I guess this is tied up with 35a0b2378c19 ("PCI/DPC: Add
"pcie_ports=dpc-native" to allow DPC without AER control")

But we still ought to be able to consolidate some of this testing in
acpi_pci_root_create() so we only have to look at host->native_dpc
here (and maybe dev->aer_cap).

>  	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
> diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
> index af7cf237432a..0ac20feef24e 100644
> --- a/drivers/pci/pcie/portdrv.h
> +++ b/drivers/pci/pcie/portdrv.h
> @@ -25,8 +25,6 @@
>  
>  #define PCIE_PORT_DEVICE_MAXSERVICES   5
>  
> -extern bool pcie_ports_dpc_native;
> -
>  #ifdef CONFIG_PCIEAER
>  int pcie_aer_init(void);
>  int pcie_aer_is_native(struct pci_dev *dev);
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index ccd5e0ce5605..2c0278f0fdcc 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -253,7 +253,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	 */
>  	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
>  	    pci_aer_available() &&
> -	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
> +	    (host->native_dpc || (services & PCIE_PORT_SERVICE_AER)))
>  		services |= PCIE_PORT_SERVICE_DPC;
>  
>  	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 22207a79762c..388121ec88b5 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1559,9 +1559,11 @@ static inline int pci_irqd_intx_xlate(struct irq_domain *d,
>  #ifdef CONFIG_PCIEPORTBUS
>  extern bool pcie_ports_disabled;
>  extern bool pcie_ports_native;
> +extern bool pcie_ports_dpc_native;
>  #else
>  #define pcie_ports_disabled	true
>  #define pcie_ports_native	false
> +#define pcie_ports_dpc_native	false
>  #endif
>  
>  #define PCIE_LINK_STATE_L0S		BIT(0)
> -- 
> 2.17.1
> 

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Kuppuswamy, Sathyanarayanan]

Hi Bjorn,

Thanks for the review.

On 11/25/20 12:12 PM, Bjorn Helgaas wrote:
> On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
>> pcie_ports_native is set only if user requests native handling
>> of PCIe capabilities via pcie_port_setup command line option.
>> User input takes precedence over _OSC based control negotiation
>> result. So consider the _OSC negotiated result only if
>> pcie_ports_native is unset.
>>
>> Also, since struct pci_host_bridge ->native_* members caches the
>> ownership status of various PCIe capabilities, use them instead
>> of distributed checks for pcie_ports_native.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>> ---
>>   drivers/acpi/pci_root.c           | 35 ++++++++++++++++++++++---------
>>   drivers/pci/hotplug/pciehp_core.c |  2 +-
>>   drivers/pci/pci-acpi.c            |  3 ---
>>   drivers/pci/pcie/aer.c            |  2 +-
>>   drivers/pci/pcie/portdrv_core.c   |  9 +++-----
>>   include/linux/acpi.h              |  2 ++
>>   6 files changed, 32 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index c12b5fb3e8fb..a9e6b782622d 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -41,6 +41,12 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
>>   				| OSC_PCI_CLOCK_PM_SUPPORT \
>>   				| OSC_PCI_MSI_SUPPORT)

>> +
>> +	if (pcie_ports_native) {
>> +		decode_osc_control(root, "OS forcibly taking over",
>> +				   OSC_PCI_EXPRESS_CONTROL_MASKS);
> 
> The only place OSC_PCI_EXPRESS_CONTROL_MASKS is used is right here, so
> it's kind of pointless.
> 
> I think I'd rather have this:
> 
>    dev_info(&root->device->dev, "Ignoring PCIe-related _OSC results because \"pcie_ports=native\" specified\n");
I was trying to keep the same print format. In pci_root.c,
decode_os_control() is repeatedly used to print info related to
PCIe capability ownership.

But either way is fine with me. I can use the format you mentioned.
> 
> 
> followed by something like this after we're done fiddling with all the
> host_bridge->native* bits:
> 

>    #define FLAG(x) ((x) ? '+' : '-')
> 
>    dev_info(&root->device->dev, "OS native features: SHPCHotplug%c PCIeCapability%c PCIeHotplug%c PME%c AER%c DPC%c LTR%c\n",
>             FLAG(host_bridge->native_shpc_hotplug),
> 	   ?,
>             FLAG(host_bridge->native_pcie_hotplug),
> 	   ...);
> 
> But I don't know how to handle OSC_PCI_EXPRESS_CAPABILITY_CONTROL
> since we don't track it the same way.  Maybe we'd have to omit it from
> this message for now?
I will add it in next version. But for now, its not worry about
OSC_PCI_EXPRESS_CAPABILITY_CONTROL.
> 

>>   	/*
>>   	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it

>> -- 
>> 2.17.1
>>

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Bjorn Helgaas]

On Wed, Nov 25, 2020 at 02:21:49PM -0800, Kuppuswamy, Sathyanarayanan wrote:
> Hi Bjorn,
> 
> Thanks for the review.
> 
> On 11/25/20 12:12 PM, Bjorn Helgaas wrote:
> > On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
> > > pcie_ports_native is set only if user requests native handling
> > > of PCIe capabilities via pcie_port_setup command line option.
> > > User input takes precedence over _OSC based control negotiation
> > > result. So consider the _OSC negotiated result only if
> > > pcie_ports_native is unset.
> > > 
> > > Also, since struct pci_host_bridge ->native_* members caches the
> > > ownership status of various PCIe capabilities, use them instead
> > > of distributed checks for pcie_ports_native.
> > > 
> > > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> > > ---
> > >   drivers/acpi/pci_root.c           | 35 ++++++++++++++++++++++---------
> > >   drivers/pci/hotplug/pciehp_core.c |  2 +-
> > >   drivers/pci/pci-acpi.c            |  3 ---
> > >   drivers/pci/pcie/aer.c            |  2 +-
> > >   drivers/pci/pcie/portdrv_core.c   |  9 +++-----
> > >   include/linux/acpi.h              |  2 ++
> > >   6 files changed, 32 insertions(+), 21 deletions(-)
> > > 
> > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> > > index c12b5fb3e8fb..a9e6b782622d 100644
> > > --- a/drivers/acpi/pci_root.c
> > > +++ b/drivers/acpi/pci_root.c
> > > @@ -41,6 +41,12 @@ static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
> > >   				| OSC_PCI_CLOCK_PM_SUPPORT \
> > >   				| OSC_PCI_MSI_SUPPORT)
> 
> > > +
> > > +	if (pcie_ports_native) {
> > > +		decode_osc_control(root, "OS forcibly taking over",
> > > +				   OSC_PCI_EXPRESS_CONTROL_MASKS);
> > 
> > The only place OSC_PCI_EXPRESS_CONTROL_MASKS is used is right here, so
> > it's kind of pointless.
> > 
> > I think I'd rather have this:
> > 
> >    dev_info(&root->device->dev, "Ignoring PCIe-related _OSC results because \"pcie_ports=native\" specified\n");
> I was trying to keep the same print format. In pci_root.c,
> decode_os_control() is repeatedly used to print info related to
> PCIe capability ownership.
> 
> But either way is fine with me. I can use the format you mentioned.
> > 
> > 
> > followed by something like this after we're done fiddling with all the
> > host_bridge->native* bits:
> > 
> 
> >    #define FLAG(x) ((x) ? '+' : '-')
> > 
> >    dev_info(&root->device->dev, "OS native features: SHPCHotplug%c PCIeCapability%c PCIeHotplug%c PME%c AER%c DPC%c LTR%c\n",
> >             FLAG(host_bridge->native_shpc_hotplug),
> > 	   ?,
> >             FLAG(host_bridge->native_pcie_hotplug),
> > 	   ...);
> > 
> > But I don't know how to handle OSC_PCI_EXPRESS_CAPABILITY_CONTROL
> > since we don't track it the same way.  Maybe we'd have to omit it from
> > this message for now?
> I will add it in next version. But for now, its not worry about
> OSC_PCI_EXPRESS_CAPABILITY_CONTROL.

I've been fiddling with this, so let me post a v12 tonight and you can
see what you think.

> > >   	/*
> > >   	 * Evaluate the "PCI Boot Configuration" _DSM Function.  If it
> 
> > > -- 
> > > 2.17.1
> > > 
> 
> -- 
> Sathyanarayanan Kuppuswamy
> Linux Kernel Developer

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Kuppuswamy, Sathyanarayanan]

On 11/25/20 2:25 PM, Bjorn Helgaas wrote:
> I've been fiddling with this, so let me post a v12 tonight and you can
> see what you think.
Ok. I will wait for your update.

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

Re: [PATCH v11 2/5] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.

[Kuppuswamy, Sathyanarayanan]

On 11/25/20 12:28 PM, Bjorn Helgaas wrote:
> On Mon, Oct 26, 2020 at 07:57:05PM -0700, Kuppuswamy Sathyanarayanan wrote:
>> pcie_ports_native is set only if user requests native handling
>> of PCIe capabilities via pcie_port_setup command line option.
>> User input takes precedence over _OSC based control negotiation
>> result. So consider the _OSC negotiated result only if
>> pcie_ports_native is unset.
>>
>> Also, since struct pci_host_bridge ->native_* members caches the
>> ownership status of various PCIe capabilities, use them instead
>> of distributed checks for pcie_ports_native.
> 
>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
>> index 50a9522ab07d..ccd5e0ce5605 100644
>> --- a/drivers/pci/pcie/portdrv_core.c
>> +++ b/drivers/pci/pcie/portdrv_core.c
>> @@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>>   	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>>   	int services = 0;
>>   
>> -	if (dev->is_hotplug_bridge &&
>> -	    (pcie_ports_native || host->native_pcie_hotplug)) {
>> +	if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {
> 
> This is a nit, but I think this and similar checks should be reordered
> so we do the most generic test first, i.e.,
> 
>    if (host->native_pcie_hotplug && dev->is_hotplug_bridge)
ok. I can add this fix on top of your update.
> 
> Logically there's no point in looking at the device things if we
> don't have native control.
> 
>>   		services |= PCIE_PORT_SERVICE_HP;
>>   
>>   		/*
>> @@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>>   	}
>>   
>>   #ifdef CONFIG_PCIEAER
>> -	if (dev->aer_cap && pci_aer_available() &&
>> -	    (pcie_ports_native || host->native_aer)) {
>> +	if (dev->aer_cap && pci_aer_available() && host->native_aer) {
> 
> Can't we clear host->native_aer when pci_aer_available() returns
> false?  I'd like to have all the checks about whether we have native
> control to be in one place instead of being scattered.  Something like
> this above:
> 
>    OSC_OWNER(ctrl, OSC_PCI_EXPRESS_AER_CONTROL, host_bridge->native_aer);
>    if (!pci_aer_available())
>      host_bridge->native_aer = 0;
> 
> So this test would become:
> 
>    if (host->native_aer && dev->aer_cap)
We already use it in pci_root.c to confirm AER availability before
we request control over it via _OSC. So if pci_aer_available() is false
OSC_*AER_CONTROL bit in ctrl_set will be left zero (which means
->native_aer will also be zero).

490         if (pci_aer_available())
491                 control |= OSC_PCI_EXPRESS_AER_CONTROL;

So, may we don't need pci_aer_available() check here.

> 
>>   		services |= PCIE_PORT_SERVICE_AER;
>>   
>>   		/*
>> @@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
>>   	 * Event Collectors can also generate PMEs, but we don't handle
>>   	 * those yet.
>>   	 */
>> -	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
>> -	    (pcie_ports_native || host->native_pme)) {
>> +	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
>>   		services |= PCIE_PORT_SERVICE_PME;
> 
> Also here:
> 
>    if (host->native_pme && pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer