From b8acfd7c0f88c49dc0089cd40e02040187160f6a Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 19 Oct 2017 16:09:26 -0500 Subject: PCI/portdrv: Consolidate comments Consolidate some repetitive comments so we can see the code better. No functional change. Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/pcie/portdrv_core.c | 63 ++++++----------------------------------- 1 file changed, 9 insertions(+), 54 deletions(-) (limited to 'drivers/pci/pcie/portdrv_core.c') diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c index 72fcbe5567dd..accd16082348 100644 --- a/drivers/pci/pcie/portdrv_core.c +++ b/drivers/pci/pcie/portdrv_core.c @@ -56,40 +56,27 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask) { int nr_entries, entry, nvec = 0; - /* - * Allocate as many entries as the port wants, so that we can check - * which of them will be useful. Moreover, if nr_entries is correctly - * equal to the number of entries this port actually uses, we'll happily - * go through without any tricks. - */ + /* Allocate the maximum possible number of MSI/MSI-X vectors */ 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; + /* + * The Interrupt Message Number indicates which vector is used, i.e., + * the MSI-X table entry or the MSI offset between the base Message + * Data and the generated interrupt message. See PCIe r3.1, sec + * 7.8.2, 7.10.10, 7.31.2. + */ if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) { u16 reg16; - /* - * 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; if (entry >= nr_entries) goto out_free_irqs; + /* PME and hotplug share an MSI/MSI-X vector */ irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pci_irq_vector(dev, entry); irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pci_irq_vector(dev, entry); @@ -99,19 +86,6 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask) if (mask & PCIE_PORT_SERVICE_AER) { u32 reg32, pos; - /* - * 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); entry = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27; @@ -126,19 +100,6 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask) if (mask & PCIE_PORT_SERVICE_DPC) { u16 reg16, pos; - /* - * Per PCIe r4.0 (v0.9), sec 7.9.15.2, the DPC Interrupt - * Message Number in the DPC Capability register indicates - * which MSI/MSI-X vector is used for DPC. - * - * "For MSI, the [DPC Interrupt Message Number] indicates - * the offset between the base Message Data and the - * interrupt message that is generated." - * - * "For MSI-X, the [DPC 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_DPC); pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP, ®16); entry = reg16 & PCI_EXP_DPC_IRQ; @@ -150,16 +111,10 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask) nvec = max(nvec, entry + 1); } - /* - * If nvec is equal to the allocated number of entries, we can just use - * what we have. Otherwise, the port has some extra entries not for the - * services we know and we need to work around that. - */ + /* If we allocated more than we need, free them and allocate fewer */ if (nvec != nr_entries) { - /* Drop the temporary MSI-X setup */ pci_free_irq_vectors(dev); - /* Now allocate the MSI-X vectors for real */ nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec, PCI_IRQ_MSIX | PCI_IRQ_MSI); if (nr_entries < 0) -- cgit