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authorAlexander Gordeev <agordeev@redhat.com>2013-12-30 08:28:16 +0100
committerBjorn Helgaas <bhelgaas@google.com>2014-01-03 17:17:55 -0700
commit302a2523c277bea0bbe8340312b09507905849ed (patch)
treea2d971a8aa28744c65dd454bfe4509a9be7be623 /drivers
parentff1aa430a2fa43189e89c7ddd559f0bee2298288 (diff)
downloadlinux-302a2523c277bea0bbe8340312b09507905849ed.tar.bz2
PCI/MSI: Add pci_enable_msi_range() and pci_enable_msix_range()
This adds pci_enable_msi_range(), which supersedes the pci_enable_msi() and pci_enable_msi_block() MSI interfaces. It also adds pci_enable_msix_range(), which supersedes the pci_enable_msix() MSI-X interface. The old interfaces have three categories of return values: negative: failure; caller should not retry positive: failure; value indicates number of interrupts that *could* have been allocated, and caller may retry with a smaller request zero: success; at least as many interrupts allocated as requested It is error-prone to handle these three cases correctly in drivers. The new functions return either a negative error code or a number of successfully allocated MSI/MSI-X interrupts, which is expected to lead to clearer device driver code. pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist unchanged, but are deprecated and may be removed after callers are updated. [bhelgaas: tweak changelog] Suggested-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/msi.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index bd18ecf74c55..e6bd8e57d92d 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1102,3 +1102,77 @@ void pci_msi_init_pci_dev(struct pci_dev *dev)
if (dev->msix_cap)
msix_set_enable(dev, 0);
}
+
+/**
+ * pci_enable_msi_range - configure device's MSI capability structure
+ * @dev: device to configure
+ * @minvec: minimal number of interrupts to configure
+ * @maxvec: maximum number of interrupts to configure
+ *
+ * This function tries to allocate a maximum possible number of interrupts in a
+ * range between @minvec and @maxvec. It returns a negative errno if an error
+ * occurs. If it succeeds, it returns the actual number of interrupts allocated
+ * 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_range(struct pci_dev *dev, int minvec, int maxvec)
+{
+ int nvec = maxvec;
+ int rc;
+
+ if (maxvec < minvec)
+ return -ERANGE;
+
+ do {
+ rc = pci_enable_msi_block(dev, nvec);
+ if (rc < 0) {
+ return rc;
+ } else if (rc > 0) {
+ if (rc < minvec)
+ return -ENOSPC;
+ nvec = rc;
+ }
+ } while (rc);
+
+ return nvec;
+}
+EXPORT_SYMBOL(pci_enable_msi_range);
+
+/**
+ * pci_enable_msix_range - configure device's MSI-X capability structure
+ * @dev: pointer to the pci_dev data structure of MSI-X device function
+ * @entries: pointer to an array of MSI-X entries
+ * @minvec: minimum number of MSI-X irqs requested
+ * @maxvec: maximum number of MSI-X irqs requested
+ *
+ * Setup the MSI-X capability structure of device function with a maximum
+ * possible number of interrupts in the range between @minvec and @maxvec
+ * upon its software driver call to request for MSI-X mode enabled on its
+ * hardware device function. It returns a negative errno if an error occurs.
+ * If it succeeds, it returns the actual number of interrupts allocated and
+ * indicates the successful configuration of MSI-X capability structure
+ * with new allocated MSI-X interrupts.
+ **/
+int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
+ int minvec, int maxvec)
+{
+ int nvec = maxvec;
+ int rc;
+
+ if (maxvec < minvec)
+ return -ERANGE;
+
+ do {
+ rc = pci_enable_msix(dev, entries, nvec);
+ if (rc < 0) {
+ return rc;
+ } else if (rc > 0) {
+ if (rc < minvec)
+ return -ENOSPC;
+ nvec = rc;
+ }
+ } while (rc);
+
+ return nvec;
+}
+EXPORT_SYMBOL(pci_enable_msix_range);