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path: root/drivers/pci/msi.c
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-rw-r--r--drivers/pci/msi.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 5099636a6e5f..00cc78c7aa04 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -845,6 +845,32 @@ int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec)
}
EXPORT_SYMBOL(pci_enable_msi_block);
+int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
+{
+ int ret, pos, nvec;
+ u16 msgctl;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
+ if (!pos)
+ return -EINVAL;
+
+ pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
+ ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
+
+ if (maxvec)
+ *maxvec = ret;
+
+ do {
+ nvec = ret;
+ ret = pci_enable_msi_block(dev, nvec);
+ } while (ret > 0);
+
+ if (ret < 0)
+ return ret;
+ return nvec;
+}
+EXPORT_SYMBOL(pci_enable_msi_block_auto);
+
void pci_msi_shutdown(struct pci_dev *dev)
{
struct msi_desc *desc;