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PCI/portdrv: Factor out Interrupt Message Number lookup 

Factor out Interrupt Message Number lookup from the MSI/MSI-X interrupt
setup.  One side effect is that we only have to check once to see if we
have enough vectors for all the services.  No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Bjorn Helgaas 2017-10-20 08:48:06 -05:00
parent b8acfd7c0f
commit 3321eafd2a
1 changed files with 63 additions and 49 deletions
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112
drivers/pci/pcie/portdrv_core.c
View File

@ -43,6 +43,53 @@ static void release_pcie_device(struct device *dev)
kfree(to_pcie_device(dev));
}
/*
* Fill in *pme, *aer, *dpc with the relevant Interrupt Message Numbers if
* services are enabled in "mask". Return the number of MSI/MSI-X vectors
* required to accommodate the largest Message Number.
*/
static int pcie_message_numbers(struct pci_dev *dev, int mask,
u32 *pme, u32 *aer, u32 *dpc)
{
u32 nvec = 0, pos, reg32;
u16 reg16;
/*
* 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)) {
pcie_capability_read_word(dev, PCI_EXP_FLAGS, &reg16);
*pme = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
nvec = *pme + 1;
}
if (mask & PCIE_PORT_SERVICE_AER) {
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
if (pos) {
pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS,
&reg32);
*aer = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
nvec = max(nvec, *aer + 1);
}
}
if (mask & PCIE_PORT_SERVICE_DPC) {
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
if (pos) {
pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP,
&reg16);
*dpc = reg16 & PCI_EXP_DPC_IRQ;
nvec = max(nvec, *dpc + 1);
}
}
return nvec;
}
/**
* pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
* for given port
@ -54,7 +101,8 @@ static void release_pcie_device(struct device *dev)
*/
static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
{
int nr_entries, entry, nvec = 0;
int nr_entries, nvec;
u32 pme = 0, aer = 0, dpc = 0;
/* Allocate the maximum possible number of MSI/MSI-X vectors */
nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
@ -62,54 +110,24 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
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.
*/
/* See how many and which Interrupt Message Numbers we actually use */
nvec = pcie_message_numbers(dev, mask, &pme, &aer, &dpc);
if (nvec > nr_entries) {
pci_free_irq_vectors(dev);
return -EIO;
}
/* PME and hotplug share an MSI/MSI-X vector */
if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
u16 reg16;
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);
nvec = max(nvec, entry + 1);
irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pci_irq_vector(dev, pme);
irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pci_irq_vector(dev, pme);
}
if (mask & PCIE_PORT_SERVICE_AER) {
u32 reg32, pos;
if (mask & PCIE_PORT_SERVICE_AER)
irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, aer);
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;
if (entry >= nr_entries)
goto out_free_irqs;
irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, entry);
nvec = max(nvec, entry + 1);
}
if (mask & PCIE_PORT_SERVICE_DPC) {
u16 reg16, pos;
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;
if (entry >= nr_entries)
goto out_free_irqs;
irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, entry);
nvec = max(nvec, entry + 1);
}
if (mask & PCIE_PORT_SERVICE_DPC)
irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, dpc);
/* If we allocated more than we need, free them and allocate fewer */
if (nvec != nr_entries) {
@ -122,10 +140,6 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
}
return 0;
out_free_irqs:
pci_free_irq_vectors(dev);
return -EIO;
}
/**