[v6,2/9] PCI/ACPI: Add _OSC based negotiation support for DPC
diff mbox series

Message ID 6cd9661f4b7250e0d988eea4b668e2e2f6dae7a8.1564177080.git.sathyanarayanan.kuppuswamy@linux.intel.com
State Superseded
Delegated to: Bjorn Helgaas
Headers show
Series
  • Add Error Disconnect Recover (EDR) support
Related show

Commit Message

Kuppuswamy Sathyanarayanan July 26, 2019, 9:43 p.m. UTC
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

As per PCI firmware specification r3.2 Downstream Port Containment
Related Enhancements ECN, sec 4.5.1, table 4-6, OS can use bit 7 of _OSC
Control Field to negotiate control over Downstream Port Containment
(DPC) configuration of PCIe port.

After _OSC negotiation, firmware will Set this bit to grant OS control
over PCIe DPC configuration and Clear it if this feature was requested
and denied, or was not requested.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/acpi/pci_root.c         | 6 ++++++
 drivers/pci/pcie/portdrv_core.c | 3 ++-
 drivers/pci/probe.c             | 1 +
 include/linux/acpi.h            | 3 ++-
 include/linux/pci.h             | 2 +-
 5 files changed, 12 insertions(+), 3 deletions(-)

Comments

Bjorn Helgaas Aug. 15, 2019, 10:17 p.m. UTC | #1
On Fri, Jul 26, 2019 at 02:43:12PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> As per PCI firmware specification r3.2 Downstream Port Containment
> Related Enhancements ECN, sec 4.5.1, table 4-6, OS can use bit 7 of _OSC
> Control Field to negotiate control over Downstream Port Containment
> (DPC) configuration of PCIe port.
> 
> After _OSC negotiation, firmware will Set this bit to grant OS control
> over PCIe DPC configuration and Clear it if this feature was requested
> and denied, or was not requested.
> 
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/acpi/pci_root.c         | 6 ++++++
>  drivers/pci/pcie/portdrv_core.c | 3 ++-
>  drivers/pci/probe.c             | 1 +
>  include/linux/acpi.h            | 3 ++-
>  include/linux/pci.h             | 2 +-
>  5 files changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 314a187ed572..73b08f40b0da 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -142,6 +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,
> @@ -488,6 +489,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
>  			control |= OSC_PCI_EXPRESS_AER_CONTROL;
>  	}
>  
> +	if (IS_ENABLED(CONFIG_PCIE_DPC))
> +		control |= OSC_PCI_EXPRESS_DPC_CONTROL;

Sec 4.5.2.4 says:

  If the OS sets bit 7 of the Control field, it must set bit 7 of the
  Support field, indicating support for the Error Disconnect Recover
  event.

I see that you do set bit 7 (OSC_PCI_EDR_SUPPORT) in the Support field
in a later patch, but I don't think we should have this intermediate
state where we set OSC_PCI_EXPRESS_DPC_CONTROL in Control but not
OSC_PCI_EDR_SUPPORT in Support.

>  	requested = control;
>  	status = acpi_pci_osc_control_set(handle, &control,
>  					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
> @@ -917,6 +921,8 @@ 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
> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
> index 308c3e0c4a34..58c40fe7856f 100644
> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -252,7 +252,8 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	}
>  
>  	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
> -	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
> +	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER &&
> +	    (pcie_ports_native || host->native_dpc))
>  		services |= PCIE_PORT_SERVICE_DPC;
>  
>  	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index a3c7338fad86..cf8acdd62089 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -601,6 +601,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>  	bridge->native_shpc_hotplug = 1;
>  	bridge->native_pme = 1;
>  	bridge->native_ltr = 1;
> +	bridge->native_dpc = 1;
>  }
>  
>  struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 9426b9aaed86..8959ed322e15 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -525,7 +525,8 @@ extern bool osc_pc_lpi_support_confirmed;
>  #define OSC_PCI_EXPRESS_AER_CONTROL		0x00000008
>  #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL	0x00000010
>  #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
> -#define OSC_PCI_CONTROL_MASKS			0x0000003f
> +#define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
> +#define OSC_PCI_CONTROL_MASKS			0x000000ff

You added 0x80, but 0x3f | 0x80 == 0xbf, not 0xff, so I expected
OSC_PCI_CONTROL_MASKS would change to 0xbf.  Why the difference?

>  #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
>  #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 9e700d9f9f28..9145136ca728 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -510,7 +510,7 @@ struct pci_host_bridge {
>  	unsigned int	native_pme:1;		/* OS may use PCIe PME */
>  	unsigned int	native_ltr:1;		/* OS may use PCIe LTR */
>  	unsigned int	preserve_config:1;	/* Preserve FW resource setup */
> -
> +	unsigned int	native_dpc:1;		/* OS may use PCIe DPC */

Please put this next to the other "native_*" bits and preserve the
blank line.

>  	/* Resource alignment requirements */
>  	resource_size_t (*align_resource)(struct pci_dev *dev,
>  			const struct resource *res,
> -- 
> 2.21.0
>
Kuppuswamy Sathyanarayanan Aug. 15, 2019, 11:44 p.m. UTC | #2
On 8/15/19 3:17 PM, Bjorn Helgaas wrote:
> On Fri, Jul 26, 2019 at 02:43:12PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>
>> As per PCI firmware specification r3.2 Downstream Port Containment
>> Related Enhancements ECN, sec 4.5.1, table 4-6, OS can use bit 7 of _OSC
>> Control Field to negotiate control over Downstream Port Containment
>> (DPC) configuration of PCIe port.
>>
>> After _OSC negotiation, firmware will Set this bit to grant OS control
>> over PCIe DPC configuration and Clear it if this feature was requested
>> and denied, or was not requested.
>>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>> Cc: Len Brown <lenb@kernel.org>
>> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>> ---
>>   drivers/acpi/pci_root.c         | 6 ++++++
>>   drivers/pci/pcie/portdrv_core.c | 3 ++-
>>   drivers/pci/probe.c             | 1 +
>>   include/linux/acpi.h            | 3 ++-
>>   include/linux/pci.h             | 2 +-
>>   5 files changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index 314a187ed572..73b08f40b0da 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -142,6 +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,
>> @@ -488,6 +489,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
>>   			control |= OSC_PCI_EXPRESS_AER_CONTROL;
>>   	}
>>   
>> +	if (IS_ENABLED(CONFIG_PCIE_DPC))
>> +		control |= OSC_PCI_EXPRESS_DPC_CONTROL;
> Sec 4.5.2.4 says:
>
>    If the OS sets bit 7 of the Control field, it must set bit 7 of the
>    Support field, indicating support for the Error Disconnect Recover
>    event.

I think the correct dependency should be , if OS indicates support for 
EDR then it must
set bit 7 of the Control field to indicate support for DPC. As per DPC 
control bit definition, setting
this bit indicates requesting control of DPC for OS (not EDR).

I will ask the spec author for clarification. But for now I will go with 
spec requirement, I will merge this
patch with "Expose EDR support via _OSC to BIOS" patch and push it to 
the end of the patch set.

>
> I see that you do set bit 7 (OSC_PCI_EDR_SUPPORT) in the Support field
> in a later patch, but I don't think we should have this intermediate
> state where we set OSC_PCI_EXPRESS_DPC_CONTROL in Control but not
> OSC_PCI_EDR_SUPPORT in Support.
>
>>   	requested = control;
>>   	status = acpi_pci_osc_control_set(handle, &control,
>>   					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
>> @@ -917,6 +921,8 @@ 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
>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
>> index 308c3e0c4a34..58c40fe7856f 100644
>> --- a/drivers/pci/pcie/portdrv_core.c
>> +++ b/drivers/pci/pcie/portdrv_core.c
>> @@ -252,7 +252,8 @@ static int get_port_device_capability(struct pci_dev *dev)
>>   	}
>>   
>>   	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
>> -	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
>> +	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER &&
>> +	    (pcie_ports_native || host->native_dpc))
>>   		services |= PCIE_PORT_SERVICE_DPC;
>>   
>>   	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index a3c7338fad86..cf8acdd62089 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -601,6 +601,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
>>   	bridge->native_shpc_hotplug = 1;
>>   	bridge->native_pme = 1;
>>   	bridge->native_ltr = 1;
>> +	bridge->native_dpc = 1;
>>   }
>>   
>>   struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>> index 9426b9aaed86..8959ed322e15 100644
>> --- a/include/linux/acpi.h
>> +++ b/include/linux/acpi.h
>> @@ -525,7 +525,8 @@ extern bool osc_pc_lpi_support_confirmed;
>>   #define OSC_PCI_EXPRESS_AER_CONTROL		0x00000008
>>   #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL	0x00000010
>>   #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
>> -#define OSC_PCI_CONTROL_MASKS			0x0000003f
>> +#define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
>> +#define OSC_PCI_CONTROL_MASKS			0x000000ff
> You added 0x80, but 0x3f | 0x80 == 0xbf, not 0xff, so I expected
> OSC_PCI_CONTROL_MASKS would change to 0xbf.  Why the difference?
Good catch. Even though spec has support for bit[6], it should be
masked till OS supports it. I will fix it in next version.
>
>>   #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
>>   #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index 9e700d9f9f28..9145136ca728 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -510,7 +510,7 @@ struct pci_host_bridge {
>>   	unsigned int	native_pme:1;		/* OS may use PCIe PME */
>>   	unsigned int	native_ltr:1;		/* OS may use PCIe LTR */
>>   	unsigned int	preserve_config:1;	/* Preserve FW resource setup */
>> -
>> +	unsigned int	native_dpc:1;		/* OS may use PCIe DPC */
> Please put this next to the other "native_*" bits and preserve the
> blank line.
ok.
>
>>   	/* Resource alignment requirements */
>>   	resource_size_t (*align_resource)(struct pci_dev *dev,
>>   			const struct resource *res,
>> -- 
>> 2.21.0
>>

Patch
diff mbox series

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 314a187ed572..73b08f40b0da 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -142,6 +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,
@@ -488,6 +489,9 @@  static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
 			control |= OSC_PCI_EXPRESS_AER_CONTROL;
 	}
 
+	if (IS_ENABLED(CONFIG_PCIE_DPC))
+		control |= OSC_PCI_EXPRESS_DPC_CONTROL;
+
 	requested = control;
 	status = acpi_pci_osc_control_set(handle, &control,
 					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
@@ -917,6 +921,8 @@  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
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 308c3e0c4a34..58c40fe7856f 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -252,7 +252,8 @@  static int get_port_device_capability(struct pci_dev *dev)
 	}
 
 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
-	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
+	    pci_aer_available() && services & PCIE_PORT_SERVICE_AER &&
+	    (pcie_ports_native || host->native_dpc))
 		services |= PCIE_PORT_SERVICE_DPC;
 
 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index a3c7338fad86..cf8acdd62089 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -601,6 +601,7 @@  static void pci_init_host_bridge(struct pci_host_bridge *bridge)
 	bridge->native_shpc_hotplug = 1;
 	bridge->native_pme = 1;
 	bridge->native_ltr = 1;
+	bridge->native_dpc = 1;
 }
 
 struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 9426b9aaed86..8959ed322e15 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -525,7 +525,8 @@  extern bool osc_pc_lpi_support_confirmed;
 #define OSC_PCI_EXPRESS_AER_CONTROL		0x00000008
 #define OSC_PCI_EXPRESS_CAPABILITY_CONTROL	0x00000010
 #define OSC_PCI_EXPRESS_LTR_CONTROL		0x00000020
-#define OSC_PCI_CONTROL_MASKS			0x0000003f
+#define OSC_PCI_EXPRESS_DPC_CONTROL		0x00000080
+#define OSC_PCI_CONTROL_MASKS			0x000000ff
 
 #define ACPI_GSB_ACCESS_ATTRIB_QUICK		0x00000002
 #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV         0x00000004
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9e700d9f9f28..9145136ca728 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -510,7 +510,7 @@  struct pci_host_bridge {
 	unsigned int	native_pme:1;		/* OS may use PCIe PME */
 	unsigned int	native_ltr:1;		/* OS may use PCIe LTR */
 	unsigned int	preserve_config:1;	/* Preserve FW resource setup */
-
+	unsigned int	native_dpc:1;		/* OS may use PCIe DPC */
 	/* Resource alignment requirements */
 	resource_size_t (*align_resource)(struct pci_dev *dev,
 			const struct resource *res,