pci_enable_ari will be called if an ARI pci device found, set its bridge ARI Forwarding Enable
bit in Device Control 2 Register. But the bridge ARI Forwarding Enable bit will never be cleared
when an ARI device hot removed.
1. Hot add an ARI pci device;
2. Hot remove the ARI pci device;
3. Hot add an non ARI pci device;
In this case, we could only find fun 0 of non ARI pci device because of its bridge ARI Forwarding Enable
bit set.
As PCIe Spec 2.0(6.13/441) recommends:
"Following a hot-plug event below a Downstream Port, it is strongly recommended that software
Clear the ARI Forwarding Enable bit in the Downstream Port until software determines that a
newly added component is in fact an ARI Device"
So, this patch rework pci_enable_ari to support enable/disable ARI when a new device hot add.
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
---
drivers/pci/pci.c | 21 +++++++++++++--------
drivers/pci/pci.h | 2 +-
drivers/pci/probe.c | 2 +-
3 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 5485883..38f1ad6 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2010,10 +2010,10 @@ void pci_free_cap_save_buffers(struct pci_dev *dev)
}
/**
- * pci_enable_ari - enable ARI forwarding if hardware support it
+ * pci_configure_ari - enable or disable ARI forwarding if hardware support it
* @dev: the PCI device
*/
-void pci_enable_ari(struct pci_dev *dev)
+void pci_configure_ari(struct pci_dev *dev)
{
u32 cap;
struct pci_dev *bridge;
@@ -2021,9 +2021,6 @@ void pci_enable_ari(struct pci_dev *dev)
if (pcie_ari_disabled || !pci_is_pcie(dev) || dev->devfn)
return;
- if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI))
- return;
-
bridge = dev->bus->self;
if (!bridge)
return;
@@ -2031,10 +2028,18 @@ void pci_enable_ari(struct pci_dev *dev)
pcie_capability_read_dword(bridge, PCI_EXP_DEVCAP2, &cap);
if (!(cap & PCI_EXP_DEVCAP2_ARI))
return;
-
- pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2, PCI_EXP_DEVCTL2_ARI);
- bridge->ari_enabled = 1;
+
+ if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI)) {
+ pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_ARI);
+ bridge->ari_enabled = 1;
+ } else {
+ pcie_capability_clear_word(bridge, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_ARI);
+ bridge->ari_enabled = 0;
+ }
}
+EXPORT_SYMBOL(pci_configure_ari);
/**
* pci_enable_ido - enable ID-based Ordering on a device
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index bacbcba..d6eb3d9 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -211,7 +211,7 @@ extern int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
extern int pci_resource_bar(struct pci_dev *dev, int resno,
enum pci_bar_type *type);
extern int pci_bus_add_child(struct pci_bus *bus);
-extern void pci_enable_ari(struct pci_dev *dev);
+extern void pci_configure_ari(struct pci_dev *dev);
/**
* pci_ari_enabled - query ARI forwarding status
* @bus: the PCI bus
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ec909af..bb7ecf6 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1282,7 +1282,7 @@ static void pci_init_capabilities(struct pci_dev *dev)
pci_vpd_pci22_init(dev);
/* Alternative Routing-ID Forwarding */
- pci_enable_ari(dev);
+ pci_configure_ari(dev);
/* Single Root I/O Virtualization */
pci_iov_init(dev);
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
