From a1d5f18cafe6b81696e60ca4901709d2f807362c Mon Sep 17 00:00:00 2001 From: Gabriele Paoloni Date: Tue, 23 May 2017 15:23:58 +0100 Subject: [PATCH] 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 [bhelgaas: changelog, reword comments, simplify PME/hotplug no-MSI logic] Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- 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 @@ 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; + + 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; -- 2.20.1