PCI MSI: Add support for multiple MSI
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>
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index adcc782..6f2e629 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -40,6 +40,13 @@
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 @@
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 @@
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 @@
} 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 @@
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 @@
/**
* 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 @@
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 @@
}
/**
- * 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 @@
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);