From: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Date: Tue, 23 May 2017 15:23:58 +0100
Subject: PCI/portdrv: Support multiple interrupts for MSI as well as MSI-X
Git-commit: a1d5f18cafe6b81696e60ca4901709d2f807362c
Patch-mainline: v4.13-rc1
References: fate#326249
Root Ports can generate several different interrupts using either MSI or
MSI-X, but we only support that for MSI-X. Ports that support MSI but not
MSI-X are currently limited to sharing a single interrupt.
Rename pcie_port_enable_msix() to pcie_port_enable_irq_vec() and extend it
to support multiple interrupts using either MSI-X (preferred) or MSI.
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
[bhelgaas: changelog, reword comments, simplify PME/hotplug no-MSI logic]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
drivers/pci/pcie/portdrv.h | 7 +--
drivers/pci/pcie/portdrv_core.c | 77 +++++++++++++++++++--------------
2 files changed, 49 insertions(+), 35 deletions(-)
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index 587aef36030d..4334fd5d7de9 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -13,10 +13,11 @@
#define PCIE_PORT_DEVICE_MAXSERVICES 5
/*
- * According to the PCI Express Base Specification 2.0, the indices of
- * the MSI-X table entries used by port services must not exceed 31
+ * The PCIe Capability Interrupt Message Number (PCIe r3.1, sec 7.8.2) must
+ * be one of the first 32 MSI-X entries. Per PCI r3.0, sec 6.8.3.1, MSI
+ * supports a maximum of 32 vectors per function.
*/
-#define PCIE_PORT_MAX_MSIX_ENTRIES 32
+#define PCIE_PORT_MAX_MSI_ENTRIES 32
#define get_descriptor_id(type, service) (((type - 4) << 8) | service)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index cea504f6f478..e00b5da07fef 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -44,14 +44,15 @@ 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_irq_vec - 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_irq_vec(struct pci_dev *dev, int *irqs, int mask)
{
int nr_entries, entry, nvec = 0;
@@ -61,8 +62,8 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* equal to the number of entries this port actually uses, we'll happily
* go through without any tricks.
*/
- nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSIX_ENTRIES,
- PCI_IRQ_MSIX);
+ nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
+ PCI_IRQ_MSIX | PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
@@ -70,14 +71,19 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
u16 reg16;
/*
- * The code below follows the PCI Express Base Specification 2.0
- * stating in Section 6.1.6 that "PME and Hot-Plug Event
- * interrupts (when both are implemented) always share the same
- * MSI or MSI-X vector, as indicated by the Interrupt Message
- * 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."
+ * Per PCIe r3.1, sec 6.1.6, "PME and Hot-Plug Event
+ * interrupts (when both are implemented) always share the
+ * same MSI or MSI-X vector, as indicated by the Interrupt
+ * Message Number field in the PCI Express Capabilities
+ * register".
+ *
+ * Per sec 7.8.2, "For MSI, the [Interrupt Message Number]
+ * indicates the offset between the base Message Data and
+ * the interrupt message that is generated."
+ *
+ * "For MSI-X, the [Interrupt Message Number] indicates
+ * which MSI-X Table entry is used to generate the
+ * interrupt message."
*/
pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
@@ -94,13 +100,17 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
u32 reg32, pos;
/*
- * The code below follows Section 7.10.10 of the PCI Express
- * Base Specification 2.0 stating that bits 31-27 of the Root
- * Error Status Register contain a value indicating which of the
- * 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."
+ * Per PCIe r3.1, sec 7.10.10, the Advanced Error Interrupt
+ * Message Number in the Root Error Status register
+ * indicates which MSI/MSI-X vector is used for AER.
+ *
+ * "For MSI, the [Advanced Error Interrupt Message Number]
+ * indicates the offset between the base Message Data and
+ * the interrupt message that is generated."
+ *
+ * "For MSI-X, the [Advanced Error Interrupt Message
+ * Number] indicates which MSI-X Table entry is used to
+ * generate the interrupt message."
*/
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, ®32);
@@ -124,7 +134,7 @@ 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);
+ PCI_IRQ_MSIX | PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
}
@@ -146,26 +156,29 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
*/
static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
{
- unsigned flags = PCI_IRQ_LEGACY | PCI_IRQ_MSI;
int ret, i;
for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
irqs[i] = -1;
/*
- * If MSI cannot be used for PCIe PME or hotplug, we have to use
- * INTx or other interrupts, e.g. system shared interrupt.
+ * If we support PME or hotplug, but we can't use MSI/MSI-X for
+ * them, we have to fall back to INTx or other interrupts, e.g., a
+ * system shared interrupt.
*/
- if (((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi()) ||
- ((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))
- return 0;
- }
+ if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
+ goto legacy_irq;
+
+ if ((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi())
+ goto legacy_irq;
+
+ /* Try to use MSI-X or MSI if supported */
+ if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
+ return 0;
- ret = pci_alloc_irq_vectors(dev, 1, 1, flags);
+legacy_irq:
+ /* fall back to legacy IRQ */
+ ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
if (ret < 0)
return -ENODEV;
--
2.19.1