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MSI: Give archs the option to allocate all MSI/Xs at once.

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This patch introduces an optional function, arch_setup_msi_irqs(),
(note the plural) which gives an arch the opportunity to do per-device
setup for MSI/X and then allocate all the requested MSI/Xs at once.

If that's not required by the arch, the default version simply calls
arch_setup_msi_irq() for each MSI irq required.

arch_setup_msi_irqs() is passed a pdev, attached to the pdev is a list
of msi_descs with irq == 0, it is up to the arch to connect these up to
an irq (via set_irq_msi()) or return an error. For convenience the number
of vectors and the type are passed also.

All msi_descs with irq != 0 are considered allocated, and the arch
teardown routine will be called on them when necessary.

The existing semantics of pci_enable_msix() are that if the requested
number of irqs can not be allocated, the maximum number that _could_ be
allocated is returned. To support that, we define that in case of an
error from arch_setup_msi_irqs(), the number of msi_descs with irq != 0
are considered allocated, and are counted toward the "max that could be
allocated".


Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Michael Ellerman 2007-04-18 19:39:21 +10:00 committed by Greg Kroah-Hartman
parent 7fe3730de7
commit 9c8313343c
2 changed files with 45 additions and 19 deletions
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63
drivers/pci/msi.c
View file

@ -334,13 +334,15 @@ static int msi_capability_init(struct pci_dev *dev)
msi_mask_bits_reg(pos, is_64bit_address(control)),
maskbits);
}
list_add(&entry->list, &dev->msi_list);
/* Configure MSI capability structure */
ret = arch_setup_msi_irq(dev, entry);
ret = arch_setup_msi_irqs(dev, 1, PCI_CAP_ID_MSI);
if (ret) {
list_del(&entry->list);
kfree(entry);
return ret;
}
list_add(&entry->list, &dev->msi_list);
/* Set MSI enabled bits */
pci_intx(dev, 0); /* disable intx */
@ -365,7 +367,7 @@ static int msix_capability_init(struct pci_dev *dev,
struct msix_entry *entries, int nvec)
{
struct msi_desc *entry;
int irq, pos, i, j, nr_entries, ret;
int pos, i, j, nr_entries, ret;
unsigned long phys_addr;
u32 table_offset;
u16 control;
@ -404,30 +406,33 @@ static int msix_capability_init(struct pci_dev *dev,
entry->dev = dev;
entry->mask_base = base;
/* Configure MSI-X capability structure */
ret = arch_setup_msi_irq(dev, entry);
if (ret) {
kfree(entry);
break;
}
entries[i].vector = entry->irq;
list_add(&entry->list, &dev->msi_list);
}
if (i != nvec) {
int avail = i - 1;
i--;
for (; i >= 0; i--) {
irq = (entries + i)->vector;
msi_free_irq(dev, irq);
(entries + i)->vector = 0;
ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
if (ret) {
int avail = 0;
list_for_each_entry(entry, &dev->msi_list, list) {
if (entry->irq != 0) {
avail++;
msi_free_irq(dev, entry->irq);
}
}
/* If we had some success report the number of irqs
* we succeeded in setting up.
*/
if (avail <= 0)
avail = -EBUSY;
if (avail == 0)
avail = ret;
return avail;
}
i = 0;
list_for_each_entry(entry, &dev->msi_list, list) {
entries[i].vector = entry->irq;
set_irq_msi(entry->irq, entry);
i++;
}
/* Set MSI-X enabled bits */
pci_intx(dev, 0); /* disable intx */
msix_set_enable(dev, 1);
@ -694,3 +699,23 @@ arch_msi_check_device(struct pci_dev* dev, int nvec, int type)
return 0;
}
int __attribute__ ((weak))
arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *entry)
{
return 0;
}
int __attribute__ ((weak))
arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
{
struct msi_desc *entry;
int ret;
list_for_each_entry(entry, &dev->msi_list, list) {
ret = arch_setup_msi_irq(dev, entry);
if (ret)
return ret;
}
return 0;
}

1
include/linux/msi.h
View file

@ -41,6 +41,7 @@ struct msi_desc {
*/
int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc);
void arch_teardown_msi_irq(unsigned int irq);
extern int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
extern int arch_msi_check_device(struct pci_dev* dev, int nvec, int type);