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PCI: Cache MSI/MSI-X capability offsets in struct pci_dev 

The patch caches the MSI and MSI-X capability offset in PCI device
(struct pci_dev) so that we needn't read it from the config space
upon enabling or disabling MSI or MSI-X interrupts.

[bhelgaas: moved pm_cap size change to separate patch]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Gavin Shan 2013-04-04 16:54:30 +00:00 committed by Bjorn Helgaas
parent 703860ed4e
commit e375b56181
2 changed files with 21 additions and 23 deletions
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42
drivers/pci/msi.c
View File

@ -111,32 +111,26 @@ 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);
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);
control &= ~PCI_MSIX_FLAGS_ENABLE;
if (enable)
control |= PCI_MSIX_FLAGS_ENABLE;
pci_write_config_word(dev, pos + PCI_MSIX_FLAGS, control);
}
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, dev->msix_cap + PCI_MSIX_FLAGS, control);
}
static inline __attribute_const__ u32 msi_mask(unsigned x)
@ -402,7 +396,7 @@ 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 +551,7 @@ 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 +592,7 @@ 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 +879,7 @@ 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 +1042,17 @@ 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);
msix_set_enable(dev, 0);
dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
if (dev->msi_cap)
msi_set_enable(dev, 0);
dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
if (dev->msix_cap)
msix_set_enable(dev, 0);
}

2
include/linux/pci.h
View File

@ -232,6 +232,8 @@ struct pci_dev {
u8 revision; /* PCI revision, low byte of class word */
u8 hdr_type; /* PCI header type (`multi' flag masked out) */
u8 pcie_cap; /* PCI-E capability offset */
u8 msi_cap; /* MSI capability offset */
u8 msix_cap; /* MSI-X capability offset */
u8 pcie_mpss:3; /* PCI-E Max Payload Size Supported */
u8 rom_base_reg; /* which config register controls the ROM */
u8 pin; /* which interrupt pin this device uses */