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PCI/portdrv: Support multiple interrupts for MSI as well as MSI-X 

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>
This commit is contained in:
Gabriele Paoloni 2017-05-23 15:23:58 +01:00 committed by Bjorn Helgaas
parent 2ea659a9ef
commit a1d5f18caf
2 changed files with 49 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/pci/pcie/portdrv.h
View File

@ -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)

77
drivers/pci/pcie/portdrv_core.c
View File

@ -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, &reg16);
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, &reg32);
@ -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 @@ out_free_irqs:
*/
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;
ret = pci_alloc_irq_vectors(dev, 1, 1, flags);
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;
legacy_irq:
/* fall back to legacy IRQ */
ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
if (ret < 0)
return -ENODEV;