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PCI/MSI: Cache Multiple Message Capable in struct msi_desc 

The Multiple Message Capable field in the MSI Message Control register
indicates how many vectors the device supports.  This field is read-only,
so cache it in msi_desc to avoid reading it repeatedly.

Since we cache the extracted field (not the entire Message Control
register), we can use msi_mask() instead of msi_capable_mask(), which is
then unused, so remove it.

[bhelgaas: fix whitespace, changelog]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Yijing Wang 2014-06-19 16:30:30 +08:00 committed by Bjorn Helgaas
parent 199596ef91
commit 31ea5d4dfe
2 changed files with 7 additions and 11 deletions
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15
drivers/pci/msi.c
View File

@ -167,11 +167,6 @@ static inline __attribute_const__ u32 msi_mask(unsigned x)
return (1 << (1 << x)) - 1;
}
static inline __attribute_const__ u32 msi_capable_mask(u16 control)
{
return msi_mask((control >> 1) & 7);
}
/*
* PCI 2.3 does not specify mask bits for each MSI interrupt. Attempting to
* mask all MSI interrupts by clearing the MSI enable bit does not work
@ -454,7 +449,8 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
arch_restore_msi_irqs(dev);
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
msi_mask_irq(entry, msi_mask(entry->msi_attrib.multi_cap),
entry->masked);
control &= ~PCI_MSI_FLAGS_QSIZE;
control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
@ -617,6 +613,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
entry->msi_attrib.maskbit = !!(control & PCI_MSI_FLAGS_MASKBIT);
entry->msi_attrib.default_irq = dev->irq; /* Save IOAPIC IRQ */
entry->msi_attrib.pos = dev->msi_cap;
entry->msi_attrib.multi_cap = (control & PCI_MSI_FLAGS_QMASK) >> 1;
if (control & PCI_MSI_FLAGS_64BIT)
entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
@ -625,7 +622,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
/* All MSIs are unmasked by default, Mask them all */
if (entry->msi_attrib.maskbit)
pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
mask = msi_capable_mask(control);
mask = msi_mask(entry->msi_attrib.multi_cap);
msi_mask_irq(entry, mask, mask);
list_add_tail(&entry->list, &dev->msi_list);
@ -870,7 +867,6 @@ void pci_msi_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;
u32 mask;
u16 ctrl;
if (!pci_msi_enable || !dev || !dev->msi_enabled)
return;
@ -883,8 +879,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
dev->msi_enabled = 0;
/* Return the device with MSI unmasked as initial states */
pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
mask = msi_capable_mask(ctrl);
mask = msi_mask(desc->msi_attrib.multi_cap);
/* Keep cached state to be restored */
arch_msi_mask_irq(desc, mask, ~mask);

3
include/linux/msi.h
View File

@ -25,7 +25,8 @@ void write_msi_msg(unsigned int irq, struct msi_msg *msg);
struct msi_desc {
struct {
__u8 is_msix : 1;
__u8 multiple: 3; /* log2 number of messages */
__u8 multiple: 3; /* log2 num of messages allocated */
__u8 multi_cap : 3; /* log2 num of messages supported */
__u8 maskbit : 1; /* mask-pending bit supported ? */
__u8 is_64 : 1; /* Address size: 0=32bit 1=64bit */
__u8 pos; /* Location of the msi capability */