Currently PCIe port services are assigned with different interrutps
only if MSI-x are supported by calling pcie_port_enable_msix().
If a root port supports MSI instead of MSI-x currently we fall back
to use a single shared interrupt for all the services.
This patch renames and extends pcie_port_enable_msix() to use MSI in
case MSI-x allocation fails.
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
---
drivers/pci/pcie/portdrv.h | 5 +++++
drivers/pci/pcie/portdrv_core.c | 33 +++++++++++++++++++++++++++------
2 files changed, 32 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index 587aef3..729ee90 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -18,6 +18,11 @@
*/
#define PCIE_PORT_MAX_MSIX_ENTRIES 32
+/* According to the PCI Local Bus Specification REV. 3.0 the max number
+ * of MSI vectors per function is 32
+ */
+#define PCIE_PORT_MAX_MSI_ENTRIES 32
+
#define get_descriptor_id(type, service) (((type - 4) << 8) | service)
extern struct bus_type pcie_port_bus_type;
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index cea504f..e2c7bfd 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -44,14 +44,16 @@ static void release_pcie_device(struct device *dev)
}
/**
- * pcie_port_enable_msix - try to set up MSI-X as interrupt mode for given port
+ * pcie_port_enable_msix_or_msi - try to set up MSI-X or MSI as interrupt mode
+ * for given port
* @dev: PCI Express port to handle
* @irqs: Array of interrupt vectors to populate
* @mask: Bitmask of port capabilities returned by get_port_device_capability()
*
* Return value: 0 on success, error code on failure
*/
-static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
+static
+int pcie_port_enable_msix_or_msi(struct pci_dev *dev, int *irqs, int mask)
{
int nr_entries, entry, nvec = 0;
@@ -63,6 +65,10 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
*/
nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSIX_ENTRIES,
PCI_IRQ_MSIX);
+ if (nr_entries < 0) /* MSI-x failed let's try with MSI */
+ nr_entries = pci_alloc_irq_vectors(dev, 1,
+ PCIE_PORT_MAX_MSI_ENTRIES,
+ PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
@@ -77,7 +83,13 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* Number field in the PCI Express Capabilities register", where
* according to Section 7.8.2 of the specification "For MSI-X,
* the value in this field indicates which MSI-X Table entry is
- * used to generate the interrupt message."
+ * used to generate the interrupt message." and "For MSI, the
+ * value in this field indicates the offset between the base
+ * Message Data and the interrupt message that is generated."
+ *
+ * pci_irq_vector() below is able to handle entry differently
+ * depending on MSI vs MSI-x case
+ *
*/
pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
@@ -100,7 +112,13 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* MSI/MSI-X vectors assigned to the port is going to be used
* for AER, where "For MSI-X, the value in this register
* indicates which MSI-X Table entry is used to generate the
- * interrupt message."
+ * interrupt message." and "For MSI, the value
+ * in this field indicates the offset between the base Message
+ * Data and the interrupt message that is generated."
+ *
+ * pci_irq_vector() below is able to handle entry differently
+ * depending on MSI vs MSI-x case
+ *
*/
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, ®32);
@@ -125,6 +143,9 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
/* Now allocate the MSI-X vectors for real */
nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
PCI_IRQ_MSIX);
+ if (nr_entries < 0) /* MSI-x failed, let's try MSI*/
+ nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
+ PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
}
@@ -160,8 +181,8 @@ static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi())) {
flags &= ~PCI_IRQ_MSI;
} else {
- /* Try to use MSI-X if supported */
- if (!pcie_port_enable_msix(dev, irqs, mask))
+ /* Try to use MSI-X or MSI if supported */
+ if (!pcie_port_enable_msix_or_msi(dev, irqs, mask))
return 0;
}
--
2.7.4
