From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932374AbcFNT7h (ORCPT ); Tue, 14 Jun 2016 15:59:37 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:38004 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932276AbcFNT7c (ORCPT ); Tue, 14 Jun 2016 15:59:32 -0400 From: Christoph Hellwig To: tglx@linutronix.de, axboe@fb.com Cc: linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 07/13] pci: Provide sensible irq vector alloc/free routines Date: Tue, 14 Jun 2016 21:59:00 +0200 Message-Id: <1465934346-20648-8-git-send-email-hch@lst.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1465934346-20648-1-git-send-email-hch@lst.de> References: <1465934346-20648-1-git-send-email-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a helper to allocate a range of interrupt vectors, which will transparently use MSI-X and MSI if available or fallback to legacy vectors. The interrupts are available in a core managed array in the pci_dev structure, and can also be released using a similar helper. The next patch will also add automatic spreading of MSI / MSI-X vectors to this function. Signed-off-by: Christoph Hellwig --- drivers/pci/msi.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 18 +++++++++ 2 files changed, 128 insertions(+) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index a080f44..a33adec 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -4,6 +4,7 @@ * * Copyright (C) 2003-2004 Intel * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com) + * Copyright (c) 2016 Christoph Hellwig. */ #include @@ -1120,6 +1121,115 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, } EXPORT_SYMBOL(pci_enable_msix_range); +static unsigned int pci_nr_irq_vectors(struct pci_dev *pdev) +{ + int nr_entries; + + nr_entries = pci_msix_vec_count(pdev); + if (nr_entries <= 0 && pci_msi_supported(pdev, 1)) + nr_entries = pci_msi_vec_count(pdev); + if (nr_entries <= 0) + nr_entries = 1; + return nr_entries; +} + +static int pci_enable_msix_range_wrapper(struct pci_dev *pdev, u32 *irqs, + unsigned int min_vecs, unsigned int max_vecs) +{ + struct msix_entry *msix_entries; + int vecs, i; + + msix_entries = kcalloc(max_vecs, sizeof(struct msix_entry), GFP_KERNEL); + if (!msix_entries) + return -ENOMEM; + + for (i = 0; i < max_vecs; i++) + msix_entries[i].entry = i; + + vecs = pci_enable_msix_range(pdev, msix_entries, min_vecs, max_vecs); + if (vecs > 0) { + for (i = 0; i < vecs; i++) + irqs[i] = msix_entries[i].vector; + } + + kfree(msix_entries); + return vecs; +} + +/** + * pci_alloc_irq_vectors - allocate multiple IRQs for a device + * @dev: PCI device to operate on + * @min_vecs: minimum number of vectors required (must be >= 1) + * @max_vecs: maximum (desired) number of vectors + * @flags: flags or quirks for the allocation + * + * Allocate up to @max_vecs interrupt vectors for @dev, using MSI-X or MSI + * vectors if available, and fall back to a single legacy vector + * if neither is available. Return the number of vectors allocated, + * (which might be smaller than @max_vecs) if successful, or a negative + * error code on error. The Linux irq numbers for the allocated + * vectors are stored in pdev->irqs. If less than @min_vecs interrupt + * vectors are available for @dev the function will fail with -ENOSPC. + */ +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs, + unsigned int max_vecs, unsigned int flags) +{ + unsigned int vecs, i; + u32 *irqs; + + max_vecs = min(max_vecs, pci_nr_irq_vectors(dev)); + + irqs = kcalloc(max_vecs, sizeof(u32), GFP_KERNEL); + if (!irqs) + return -ENOMEM; + + if (!(flags & PCI_IRQ_NOMSIX)) { + vecs = pci_enable_msix_range_wrapper(dev, irqs, min_vecs, + max_vecs); + if (vecs > 0) + goto done; + } + + vecs = pci_enable_msi_range(dev, min_vecs, max_vecs); + if (vecs > 0) { + for (i = 0; i < vecs; i++) + irqs[i] = dev->irq + i; + goto done; + } + + if (min_vecs > 1) + return -ENOSPC; + + /* use legacy irq */ + kfree(irqs); + dev->irqs = &dev->irq; + return 1; + +done: + dev->irqs = irqs; + return vecs; +} +EXPORT_SYMBOL(pci_alloc_irq_vectors); + +/** + * pci_free_irq_vectors - free previously allocated IRQs for a device + * @dev: PCI device to operate on + * + * Undoes the allocations and enabling in pci_alloc_irq_vectors(). + */ +void pci_free_irq_vectors(struct pci_dev *dev) +{ + if (dev->msix_enabled) + pci_disable_msix(dev); + else if (dev->msi_enabled) + pci_disable_msi(dev); + + if (dev->irqs != &dev->irq) + kfree(dev->irqs); +} +EXPORT_SYMBOL(pci_free_irq_vectors); + + struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc) { return to_pci_dev(desc->dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index b67e4df..84a20fc 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -320,6 +320,7 @@ struct pci_dev { * directly, use the values stored here. They might be different! */ unsigned int irq; + unsigned int *irqs; struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */ bool match_driver; /* Skip attaching driver */ @@ -1237,6 +1238,8 @@ resource_size_t pcibios_iov_resource_alignment(struct pci_dev *dev, int resno); int pci_set_vga_state(struct pci_dev *pdev, bool decode, unsigned int command_bits, u32 flags); +#define PCI_IRQ_NOMSIX (1 << 0) /* don't try to use MSI-X interrupts */ + /* kmem_cache style wrapper around pci_alloc_consistent() */ #include @@ -1284,6 +1287,9 @@ static inline int pci_enable_msix_exact(struct pci_dev *dev, return rc; return 0; } +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs, + unsigned int max_vecs, unsigned int flags); +void pci_free_irq_vectors(struct pci_dev *dev); #else static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; } static inline void pci_msi_shutdown(struct pci_dev *dev) { } @@ -1307,6 +1313,18 @@ static inline int pci_enable_msix_range(struct pci_dev *dev, static inline int pci_enable_msix_exact(struct pci_dev *dev, struct msix_entry *entries, int nvec) { return -ENOSYS; } +static inline int pci_alloc_irq_vectors(struct pci_dev *dev, + unsigned int min_vecs, unsigned int max_vecs, + unsigned int flags) +{ + if (min_vecs > 1) + return -ENOSPC; + dev->irqs = &dev->irq; + return 1; +} +static inline void pci_free_irq_vectors(struct pci_dev *dev) +{ +} #endif #ifdef CONFIG_PCIEPORTBUS -- 2.1.4