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Commit b8acfd7c authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI/portdrv: Consolidate comments 



Consolidate some repetitive comments so we can see the code better.  No
functional change.

Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 7c950b9e

drivers/pci/pcie/portdrv_core.c

+9 −54
Original line number Diff line number Diff line
@@ -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, &reg16);

		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, &reg32);

		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, &reg16);

		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)