The patch caches the MSI and MSI-X capability offset in PCI device
(struct pci_dev) so that we needn't poll it from the config space
upon enabling or disabling MSI or MSI-X interrupts.
Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
---
drivers/pci/msi.c | 36 +++++++++++++++++++-----------------
include/linux/pci.h | 2 ++
2 files changed, 21 insertions(+), 17 deletions(-)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 00cc78c..3459bdf 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -111,31 +111,31 @@ void default_restore_msi_irqs(struct pci_dev *dev, int irq)
}
#endif
-static void msi_set_enable(struct pci_dev *dev, int pos, int enable)
+static void msi_set_enable(struct pci_dev *dev, int enable)
{
u16 control;
- BUG_ON(!pos);
+ BUG_ON(!dev->msi_cap);
- pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
+ pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
control &= ~PCI_MSI_FLAGS_ENABLE;
if (enable)
control |= PCI_MSI_FLAGS_ENABLE;
- pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
+ pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}
static void msix_set_enable(struct pci_dev *dev, int enable)
{
- int pos;
u16 control;
- pos = pci_find_capability(dev, PCI_CAP_ID_MSIX);
- if (pos) {
- pci_read_config_word(dev, pos + PCI_MSIX_FLAGS, &control);
+ if (dev->msix_cap) {
+ pci_read_config_word(dev,
+ dev->msix_cap + PCI_MSIX_FLAGS, &control);
control &= ~PCI_MSIX_FLAGS_ENABLE;
if (enable)
control |= PCI_MSIX_FLAGS_ENABLE;
- pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
+ pci_write_config_word(dev,
+ dev->msix_cap + PCI_MSIX_FLAGS, control);
}
}
@@ -402,7 +402,7 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
pos = entry->msi_attrib.pos;
pci_intx_for_msi(dev, 0);
- msi_set_enable(dev, pos, 0);
+ msi_set_enable(dev, 0);
arch_restore_msi_irqs(dev, dev->irq);
pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
@@ -557,7 +557,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
unsigned mask;
pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
- msi_set_enable(dev, pos, 0); /* Disable MSI during set up */
+ msi_set_enable(dev, 0); /* Disable MSI during set up */
pci_read_config_word(dev, msi_control_reg(pos), &control);
/* MSI Entry Initialization */
@@ -598,7 +598,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
/* Set MSI enabled bits */
pci_intx_for_msi(dev, 0);
- msi_set_enable(dev, pos, 1);
+ msi_set_enable(dev, 1);
dev->msi_enabled = 1;
dev->irq = entry->irq;
@@ -885,7 +885,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
desc = list_first_entry(&dev->msi_list, struct msi_desc, list);
pos = desc->msi_attrib.pos;
- msi_set_enable(dev, pos, 0);
+ msi_set_enable(dev, 0);
pci_intx_for_msi(dev, 1);
dev->msi_enabled = 0;
@@ -1048,15 +1048,17 @@ EXPORT_SYMBOL(pci_msi_enabled);
void pci_msi_init_pci_dev(struct pci_dev *dev)
{
- int pos;
INIT_LIST_HEAD(&dev->msi_list);
/* Disable the msi hardware to avoid screaming interrupts
* during boot. This is the power on reset default so
* usually this should be a noop.
*/
- pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
- if (pos)
- msi_set_enable(dev, pos, 0);
+ dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
+ if (dev->msi_cap)
+ msi_set_enable(dev, 0);
+
+ /* We needn't check if we have valid MSI-X capability here */
+ dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
msix_set_enable(dev, 0);
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2461033a..f8314c7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -249,6 +249,8 @@ struct pci_dev {
pci_power_t current_state; /* Current operating state. In ACPI-speak,
this is D0-D3, D0 being fully functional,
and D3 being off. */
+ int msi_cap; /* MSI capability offset */
+ int msix_cap; /* MSI-X capability offset */
int pm_cap; /* PM capability offset in the
configuration space */
unsigned int pme_support:5; /* Bitmask of states from which PME#
--
1.7.5.4
--
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