[1/2] core/pci: Ignore PCI slot capability on root port

Submitted by Gavin Shan on March 10, 2017, 12:25 a.m.

Details

Message ID 1489105546-28092-1-git-send-email-gwshan@linux.vnet.ibm.com
State Accepted
Headers show

Commit Message

Gavin Shan March 10, 2017, 12:25 a.m.
We are creating PCI slot on root port, where the PCI slot isn't
supported from hardware. For this case, we shouldn't read the PCI
slot capability from hardware. When bogus data returned from the
hardware, we will attempt to the PCI slot's power state or enable
surprise hotplug functionality. All of them can't be accomplished
without hardware support.

This leaves the PCI slot's capability list 0 if PCICAP_EXP_CAP_SLOT
isn't set in hardware (pcie_cap + 0x2). Otherwise, the PCI slot's
capability list is retrieved from hardware (pcie_cap + 0x14).

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 core/pcie-slot.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Gavin Shan March 29, 2017, 5:43 a.m.
On Fri, Mar 10, 2017 at 11:25:45AM +1100, Gavin Shan wrote:
>We are creating PCI slot on root port, where the PCI slot isn't
>supported from hardware. For this case, we shouldn't read the PCI
>slot capability from hardware. When bogus data returned from the
>hardware, we will attempt to the PCI slot's power state or enable
>surprise hotplug functionality. All of them can't be accomplished
>without hardware support.
>
>This leaves the PCI slot's capability list 0 if PCICAP_EXP_CAP_SLOT
>isn't set in hardware (pcie_cap + 0x2). Otherwise, the PCI slot's
>capability list is retrieved from hardware (pcie_cap + 0x14).
>
>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

ping, Stewart?

>---
> core/pcie-slot.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/core/pcie-slot.c b/core/pcie-slot.c
>index 64f0da6..aca59dd 100644
>--- a/core/pcie-slot.c
>+++ b/core/pcie-slot.c
>@@ -461,8 +461,13 @@ struct pci_slot *pcie_slot_create(struct phb *phb, struct pci_device *pd)
> 		       &slot->pcie_cap);
> 	pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_LCAP,
> 		       &slot->link_cap);
>-	pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_SLOTCAP,
>-		       &slot->slot_cap);
>+
>+	/* Leave PCI slot capability blank if PCI slot isn't supported */
>+	if (slot->pcie_cap & PCICAP_EXP_CAP_SLOT)
>+		pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_SLOTCAP,
>+			       &slot->slot_cap);
>+	else
>+		slot->slot_cap = 0;
>
> 	if (slot->slot_cap & PCICAP_EXP_SLOTCAP_HPLUG_CAP)
> 		slot->pluggable = 1;
>-- 
>2.7.4
>
Stewart Smith March 31, 2017, 7:03 a.m.
Gavin Shan <gwshan@linux.vnet.ibm.com> writes:
> We are creating PCI slot on root port, where the PCI slot isn't
> supported from hardware. For this case, we shouldn't read the PCI
> slot capability from hardware. When bogus data returned from the
> hardware, we will attempt to the PCI slot's power state or enable
> surprise hotplug functionality. All of them can't be accomplished
> without hardware support.
>
> This leaves the PCI slot's capability list 0 if PCICAP_EXP_CAP_SLOT
> isn't set in hardware (pcie_cap + 0x2). Otherwise, the PCI slot's
> capability list is retrieved from hardware (pcie_cap + 0x14).
>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> ---
>  core/pcie-slot.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

Sorry for the delay. Series Merged to master as of 7c4a326bea502fc1f3b8b767f6ff9c02b7d1b254

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diff --git a/core/pcie-slot.c b/core/pcie-slot.c
index 64f0da6..aca59dd 100644
--- a/core/pcie-slot.c
+++ b/core/pcie-slot.c
@@ -461,8 +461,13 @@  struct pci_slot *pcie_slot_create(struct phb *phb, struct pci_device *pd)
 		       &slot->pcie_cap);
 	pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_LCAP,
 		       &slot->link_cap);
-	pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_SLOTCAP,
-		       &slot->slot_cap);
+
+	/* Leave PCI slot capability blank if PCI slot isn't supported */
+	if (slot->pcie_cap & PCICAP_EXP_CAP_SLOT)
+		pci_cfg_read32(phb, pd->bdfn, ecap + PCICAP_EXP_SLOTCAP,
+			       &slot->slot_cap);
+	else
+		slot->slot_cap = 0;
 
 	if (slot->slot_cap & PCICAP_EXP_SLOTCAP_HPLUG_CAP)
 		slot->pluggable = 1;