From 302a2523c277bea0bbe8340312b09507905849ed Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Mon, 30 Dec 2013 08:28:16 +0100 Subject: PCI/MSI: Add pci_enable_msi_range() and pci_enable_msix_range() This adds pci_enable_msi_range(), which supersedes the pci_enable_msi() and pci_enable_msi_block() MSI interfaces. It also adds pci_enable_msix_range(), which supersedes the pci_enable_msix() MSI-X interface. The old interfaces have three categories of return values: negative: failure; caller should not retry positive: failure; value indicates number of interrupts that *could* have been allocated, and caller may retry with a smaller request zero: success; at least as many interrupts allocated as requested It is error-prone to handle these three cases correctly in drivers. The new functions return either a negative error code or a number of successfully allocated MSI/MSI-X interrupts, which is expected to lead to clearer device driver code. pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist unchanged, but are deprecated and may be removed after callers are updated. [bhelgaas: tweak changelog] Suggested-by: Ben Hutchings Signed-off-by: Alexander Gordeev Signed-off-by: Bjorn Helgaas Reviewed-by: Tejun Heo --- drivers/pci/msi.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) (limited to 'drivers/pci/msi.c') diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index bd18ecf..e6bd8e5 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -1102,3 +1102,77 @@ void pci_msi_init_pci_dev(struct pci_dev *dev) if (dev->msix_cap) msix_set_enable(dev, 0); } + +/** + * pci_enable_msi_range - configure device's MSI capability structure + * @dev: device to configure + * @minvec: minimal number of interrupts to configure + * @maxvec: maximum number of interrupts to configure + * + * This function tries to allocate a maximum possible number of interrupts in a + * range between @minvec and @maxvec. It returns a negative errno if an error + * occurs. If it succeeds, it returns the actual number of interrupts allocated + * and updates the @dev's irq member to the lowest new interrupt number; + * the other interrupt numbers allocated to this device are consecutive. + **/ +int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec) +{ + int nvec = maxvec; + int rc; + + if (maxvec < minvec) + return -ERANGE; + + do { + rc = pci_enable_msi_block(dev, nvec); + if (rc < 0) { + return rc; + } else if (rc > 0) { + if (rc < minvec) + return -ENOSPC; + nvec = rc; + } + } while (rc); + + return nvec; +} +EXPORT_SYMBOL(pci_enable_msi_range); + +/** + * pci_enable_msix_range - configure device's MSI-X capability structure + * @dev: pointer to the pci_dev data structure of MSI-X device function + * @entries: pointer to an array of MSI-X entries + * @minvec: minimum number of MSI-X irqs requested + * @maxvec: maximum number of MSI-X irqs requested + * + * Setup the MSI-X capability structure of device function with a maximum + * possible number of interrupts in the range between @minvec and @maxvec + * upon its software driver call to request for MSI-X mode enabled on its + * hardware device function. It returns a negative errno if an error occurs. + * If it succeeds, it returns the actual number of interrupts allocated and + * indicates the successful configuration of MSI-X capability structure + * with new allocated MSI-X interrupts. + **/ +int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, + int minvec, int maxvec) +{ + int nvec = maxvec; + int rc; + + if (maxvec < minvec) + return -ERANGE; + + do { + rc = pci_enable_msix(dev, entries, nvec); + if (rc < 0) { + return rc; + } else if (rc > 0) { + if (rc < minvec) + return -ENOSPC; + nvec = rc; + } + } while (rc); + + return nvec; +} +EXPORT_SYMBOL(pci_enable_msix_range); -- cgit v1.1