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PCI MSI: Add support for multiple MSI

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Add the new API pci_enable_msi_block() to allow drivers to
request multiple MSI and reimplement pci_enable_msi in terms of
pci_enable_msi_block.  Ensure that the architecture back ends don't
have to know about multiple MSI.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Matthew Wilcox
2009-03-17 08:54:10 -04:00
committed by Jesse Barnes
parent f2440d9acb
commit 1c8d7b0a56
7 changed files with 116 additions and 41 deletions
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91
drivers/pci/msi.c
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@@ -40,6 +40,13 @@ int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
struct msi_desc *entry;
int ret;
/*
* If an architecture wants to support multiple MSI, it needs to
* override arch_setup_msi_irqs()
*/
if (type == PCI_CAP_ID_MSI && nvec > 1)
return 1;
list_for_each_entry(entry, &dev->msi_list, list) {
ret = arch_setup_msi_irq(dev, entry);
if (ret < 0)
@@ -58,8 +65,12 @@ void arch_teardown_msi_irqs(struct pci_dev *dev)
struct msi_desc *entry;
list_for_each_entry(entry, &dev->msi_list, list) {
if (entry->irq != 0)
arch_teardown_msi_irq(entry->irq);
int i, nvec;
if (entry->irq == 0)
continue;
nvec = 1 << entry->msi_attrib.multiple;
for (i = 0; i < nvec; i++)
arch_teardown_msi_irq(entry->irq + i);
}
}
#endif
@@ -163,7 +174,8 @@ static void msi_set_mask_bit(unsigned irq, u32 flag)
msix_mask_irq(desc, flag);
readl(desc->mask_base); /* Flush write to device */
} else {
msi_mask_irq(desc, 1, flag);
unsigned offset = irq - desc->dev->irq;
msi_mask_irq(desc, 1 << offset, flag << offset);
}
}
@@ -229,6 +241,12 @@ void write_msi_msg_desc(struct irq_desc *desc, struct msi_msg *msg)
} else {
struct pci_dev *dev = entry->dev;
int pos = entry->msi_attrib.pos;
u16 msgctl;
pci_read_config_word(dev, msi_control_reg(pos), &msgctl);
msgctl &= ~PCI_MSI_FLAGS_QSIZE;
msgctl |= entry->msi_attrib.multiple << 4;
pci_write_config_word(dev, msi_control_reg(pos), msgctl);
pci_write_config_dword(dev, msi_lower_address_reg(pos),
msg->address_lo);
@@ -291,7 +309,7 @@ static void __pci_restore_msi_state(struct pci_dev *dev)
pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &control);
msi_mask_irq(entry, msi_capable_mask(control), entry->masked);
control &= ~PCI_MSI_FLAGS_QSIZE;
control |= PCI_MSI_FLAGS_ENABLE;
control |= (entry->msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
pci_write_config_word(dev, pos + PCI_MSI_FLAGS, control);
}
@@ -332,13 +350,15 @@ EXPORT_SYMBOL_GPL(pci_restore_msi_state);
/**
* msi_capability_init - configure device's MSI capability structure
* @dev: pointer to the pci_dev data structure of MSI device function
* @nvec: number of interrupts to allocate
*
* Setup the MSI capability structure of device function with a single
* MSI irq, regardless of device function is capable of handling
* multiple messages. A return of zero indicates the successful setup
* of an entry zero with the new MSI irq or non-zero for otherwise.
**/
static int msi_capability_init(struct pci_dev *dev)
* Setup the MSI capability structure of the device with the requested
* number of interrupts. A return value of zero indicates the successful
* setup of an entry with the new MSI irq. A negative return value indicates
* an error, and a positive return value indicates the number of interrupts
* which could have been allocated.
*/
static int msi_capability_init(struct pci_dev *dev, int nvec)
{
struct msi_desc *entry;
int pos, ret;
@@ -371,7 +391,7 @@ static int msi_capability_init(struct pci_dev *dev)
list_add_tail(&entry->list, &dev->msi_list);
/* Configure MSI capability structure */
ret = arch_setup_msi_irqs(dev, 1, PCI_CAP_ID_MSI);
ret = arch_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSI);
if (ret) {
msi_free_irqs(dev);
return ret;
@@ -524,35 +544,48 @@ static int pci_msi_check_device(struct pci_dev* dev, int nvec, int type)
}
/**
* pci_enable_msi - configure device's MSI capability structure
* @dev: pointer to the pci_dev data structure of MSI device function
* pci_enable_msi_block - configure device's MSI capability structure
* @dev: device to configure
* @nvec: number of interrupts to configure
*
* Setup the MSI capability structure of device function with
* a single MSI irq upon its software driver call to request for
* MSI mode enabled on its hardware device function. A return of zero
* indicates the successful setup of an entry zero with the new MSI
* irq or non-zero for otherwise.
**/
int pci_enable_msi(struct pci_dev* dev)
* Allocate IRQs for a device with the MSI capability.
* This function returns a negative errno if an error occurs. If it
* is unable to allocate the number of interrupts requested, it returns
* the number of interrupts it might be able to allocate. If it successfully
* allocates at least the number of interrupts requested, it returns 0 and
* updates the @dev's irq member to the lowest new interrupt number; the
* other interrupt numbers allocated to this device are consecutive.
*/
int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
{
int status;
int status, pos, maxvec;
u16 msgctl;
status = pci_msi_check_device(dev, 1, PCI_CAP_ID_MSI);
pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
if (!pos)
return -EINVAL;
pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
maxvec = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
if (nvec > maxvec)
return maxvec;
status = pci_msi_check_device(dev, nvec, PCI_CAP_ID_MSI);
if (status)
return status;
WARN_ON(!!dev->msi_enabled);
/* Check whether driver already requested for MSI-X irqs */
/* Check whether driver already requested MSI-X irqs */
if (dev->msix_enabled) {
dev_info(&dev->dev, "can't enable MSI "
"(MSI-X already enabled)\n");
return -EINVAL;
}
status = msi_capability_init(dev);
status = msi_capability_init(dev, nvec);
return status;
}
EXPORT_SYMBOL(pci_enable_msi);
EXPORT_SYMBOL(pci_enable_msi_block);
void pci_msi_shutdown(struct pci_dev *dev)
{
@@ -599,8 +632,12 @@ static int msi_free_irqs(struct pci_dev* dev)
struct msi_desc *entry, *tmp;
list_for_each_entry(entry, &dev->msi_list, list) {
if (entry->irq)
BUG_ON(irq_has_action(entry->irq));
int i, nvec;
if (!entry->irq)
continue;
nvec = 1 << entry->msi_attrib.multiple;
for (i = 0; i < nvec; i++)
BUG_ON(irq_has_action(entry->irq + i));
}
arch_teardown_msi_irqs(dev);