diff mbox series

[RFC,v2,1/4] PCI: hotplug: Add support for disabling in-band presence

Message ID 20190220012031.10741-2-mr.nuke.me@gmail.com (mailing list archive)
State Superseded, archived
Headers show
Series PCI: pciehp: Do not turn off slot if presence comes up after link | expand

Commit Message

Alex G. Feb. 20, 2019, 1:20 a.m. UTC
The presence detect state (PDS) is normally a logical or of in-band
and out-of-band presence. In PCIe 4.0, there is the option to disable
in-band presence so that the PDS bit always reflects the state of the
out-of-band presence.

The recommendation of the PCIe spec is to disable in-band presence
whenever supported.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
---
 drivers/pci/hotplug/pciehp.h     |  1 +
 drivers/pci/hotplug/pciehp_hpc.c | 12 +++++++++++-
 include/linux/pci.h              |  1 +
 include/uapi/linux/pci_regs.h    |  2 ++
 4 files changed, 15 insertions(+), 1 deletion(-)

Comments

Lukas Wunner Feb. 21, 2019, 7:19 a.m. UTC | #1
On Tue, Feb 19, 2019 at 07:20:27PM -0600, Alexandru Gagniuc wrote:
> @@ -846,6 +846,9 @@ struct controller *pcie_init(struct pcie_device *dev)
>  	if (pdev->is_thunderbolt)
>  		slot_cap |= PCI_EXP_SLTCAP_NCCS;
>  
> +	if (pdev->no_in_band_presence)
> +		ctrl->inband_presence_disabled = 1;
> +
>  	ctrl->slot_cap = slot_cap;
>  	mutex_init(&ctrl->ctrl_lock);
>  	mutex_init(&ctrl->state_lock);

The above hunk belongs in patch 4.


> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -413,6 +413,7 @@ struct pci_dev {
>  	unsigned int	non_compliant_bars:1;	/* Broken BARs; ignore them */
>  	unsigned int	is_probed:1;		/* Device probing in progress */
>  	unsigned int	link_active_reporting:1;/* Device capable of reporting link active */
> +	unsigned int	no_in_band_presence:1;	/* Device does not report in-band presence */
>  	unsigned int	no_vf_scan:1;		/* Don't scan for VFs after IOV enablement */
>  	pci_dev_flags_t dev_flags;
>  	atomic_t	enable_cnt;	/* pci_enable_device has been called */

Same here.

Thanks,

Lukas
Alex_Gagniuc@Dellteam.com Feb. 21, 2019, 6:05 p.m. UTC | #2
On 2/21/19 1:20 AM, Lukas Wunner wrote:
> 
> [EXTERNAL EMAIL]
> 
> On Tue, Feb 19, 2019 at 07:20:27PM -0600, Alexandru Gagniuc wrote:
>> @@ -846,6 +846,9 @@ struct controller *pcie_init(struct pcie_device *dev)
>>   	if (pdev->is_thunderbolt)
>>   		slot_cap |= PCI_EXP_SLTCAP_NCCS;
>>   
>> +	if (pdev->no_in_band_presence)
>> +		ctrl->inband_presence_disabled = 1;
>> +
>>   	ctrl->slot_cap = slot_cap;
>>   	mutex_init(&ctrl->ctrl_lock);
>>   	mutex_init(&ctrl->state_lock);
> 
> The above hunk belongs in patch 4.
> 
> 
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -413,6 +413,7 @@ struct pci_dev {
>>   	unsigned int	non_compliant_bars:1;	/* Broken BARs; ignore them */
>>   	unsigned int	is_probed:1;		/* Device probing in progress */
>>   	unsigned int	link_active_reporting:1;/* Device capable of reporting link active */
>> +	unsigned int	no_in_band_presence:1;	/* Device does not report in-band presence */
>>   	unsigned int	no_vf_scan:1;		/* Don't scan for VFs after IOV enablement */
>>   	pci_dev_flags_t dev_flags;
>>   	atomic_t	enable_cnt;	/* pci_enable_device has been called */
> 
> Same here.

:)

> Thanks,
> 
> Lukas
>
diff mbox series

Patch

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 506e1d923a1f..6f729ce4a7b9 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -98,6 +98,7 @@  struct controller {
 	struct pcie_device *pcie;
 
 	u32 slot_cap;				/* capabilities and quirks */
+	unsigned int inband_presence_disabled:1;
 
 	u16 slot_ctrl;				/* control register access */
 	struct mutex ctrl_lock;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7dd443aea5a5..f77dc7c38f9a 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -824,7 +824,7 @@  static inline void dbg_ctrl(struct controller *ctrl)
 struct controller *pcie_init(struct pcie_device *dev)
 {
 	struct controller *ctrl;
-	u32 slot_cap, link_cap;
+	u32 slot_cap, slot_cap2, link_cap;
 	u8 poweron;
 	struct pci_dev *pdev = dev->port;
 	struct pci_bus *subordinate = pdev->subordinate;
@@ -846,6 +846,9 @@  struct controller *pcie_init(struct pcie_device *dev)
 	if (pdev->is_thunderbolt)
 		slot_cap |= PCI_EXP_SLTCAP_NCCS;
 
+	if (pdev->no_in_band_presence)
+		ctrl->inband_presence_disabled = 1;
+
 	ctrl->slot_cap = slot_cap;
 	mutex_init(&ctrl->ctrl_lock);
 	mutex_init(&ctrl->state_lock);
@@ -882,6 +885,13 @@  struct controller *pcie_init(struct pcie_device *dev)
 		FLAG(link_cap, PCI_EXP_LNKCAP_DLLLARC),
 		pdev->broken_cmd_compl ? " (with Cmd Compl erratum)" : "");
 
+	pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP2, &slot_cap2);
+	if (slot_cap2 & PCI_EXP_SLTCAP2_IBPD) {
+		pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_IBPD_DISABLE,
+				      PCI_EXP_SLTCTL_IBPD_DISABLE);
+		ctrl->inband_presence_disabled = 1;
+	}
+
 	/*
 	 * If empty slot's power status is on, turn power off.  The IRQ isn't
 	 * requested yet, so avoid triggering a notification with this command.
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 65f1d8c2f082..9d08cdbca459 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -413,6 +413,7 @@  struct pci_dev {
 	unsigned int	non_compliant_bars:1;	/* Broken BARs; ignore them */
 	unsigned int	is_probed:1;		/* Device probing in progress */
 	unsigned int	link_active_reporting:1;/* Device capable of reporting link active */
+	unsigned int	no_in_band_presence:1;	/* Device does not report in-band presence */
 	unsigned int	no_vf_scan:1;		/* Don't scan for VFs after IOV enablement */
 	pci_dev_flags_t dev_flags;
 	atomic_t	enable_cnt;	/* pci_enable_device has been called */
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index e1e9888c85e6..5423dc476c77 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -597,6 +597,7 @@ 
 #define  PCI_EXP_SLTCTL_PWR_OFF        0x0400 /* Power Off */
 #define  PCI_EXP_SLTCTL_EIC	0x0800	/* Electromechanical Interlock Control */
 #define  PCI_EXP_SLTCTL_DLLSCE	0x1000	/* Data Link Layer State Changed Enable */
+#define  PCI_EXP_SLTCTL_IBPD_DISABLE	0x4000 /* In-band PD disable */
 #define PCI_EXP_SLTSTA		26	/* Slot Status */
 #define  PCI_EXP_SLTSTA_ABP	0x0001	/* Attention Button Pressed */
 #define  PCI_EXP_SLTSTA_PFD	0x0002	/* Power Fault Detected */
@@ -667,6 +668,7 @@ 
 #define PCI_EXP_LNKSTA2		50	/* Link Status 2 */
 #define PCI_CAP_EXP_ENDPOINT_SIZEOF_V2	52	/* v2 endpoints with link end here */
 #define PCI_EXP_SLTCAP2		52	/* Slot Capabilities 2 */
+#define  PCI_EXP_SLTCAP2_IBPD	0x0001	/* In-band PD Disable Supported */
 #define PCI_EXP_SLTCTL2		56	/* Slot Control 2 */
 #define PCI_EXP_SLTSTA2		58	/* Slot Status 2 */