Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934608AbdCVN03 (ORCPT ); Wed, 22 Mar 2017 09:26:29 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:40438 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934390AbdCVNZt (ORCPT ); Wed, 22 Mar 2017 09:25:49 -0400 From: David Woodhouse To: linux-pci@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 09/17] pci: Add pci_mmap_resource_range() and use it for ARM64 Date: Wed, 22 Mar 2017 13:25:23 +0000 Message-Id: <7c16b64b4099fac734cb2c53759b9c975df3d73b.1490188942.git.dwmw2@infradead.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: References: MIME-Version: 1.0 In-Reply-To: References: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Content-Length: 8091 Lines: 221 From: David Woodhouse Starting to leave behind the legacy of the pci_mmap_page_range() interface which takes "user-visible" BAR addresses. This takes just the resource and offset. For now, both APIs coexist and depending on the platform, one is implemented as a wrapper around the other. Signed-off-by: David Woodhouse --- Documentation/filesystems/sysfs-pci.txt | 5 +- arch/arm64/include/asm/pci.h | 3 ++ drivers/pci/Makefile | 2 +- drivers/pci/mmap.c | 90 +++++++++++++++++++++++++++++++++ drivers/pci/pci-sysfs.c | 11 +--- include/linux/pci.h | 19 +++++-- 6 files changed, 115 insertions(+), 15 deletions(-) create mode 100644 drivers/pci/mmap.c diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 25b7f1c..3e1016e 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -113,7 +113,10 @@ Supporting PCI access on new platforms -------------------------------------- In order to support PCI resource mapping as described above, Linux platform -code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function. +code must define HAVE_PCI_MMAP and either provide a pci_mmap_page_range() +function or (preferably) also define ARCH_GENERIC_PCI_MMAP_RESOURCE to use +the generic implementation. + Platforms are free to only support subsets of the mmap functionality, but useful return codes should be provided. diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h index b9a7ba9..021da94 100644 --- a/arch/arm64/include/asm/pci.h +++ b/arch/arm64/include/asm/pci.h @@ -22,6 +22,9 @@ */ #define PCI_DMA_BUS_IS_PHYS (0) +#define HAVE_PCI_MMAP 1 +#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1 + extern int isa_dma_bridge_buggy; #ifdef CONFIG_PCI diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index 8db5079..3d40e41 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -4,7 +4,7 @@ obj-y += access.o bus.o probe.o host-bridge.o remove.o pci.o \ pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \ - irq.o vpd.o setup-bus.o vc.o + irq.o vpd.o setup-bus.o vc.o mmap.o obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_SYSFS) += slot.o diff --git a/drivers/pci/mmap.c b/drivers/pci/mmap.c new file mode 100644 index 0000000..bf28dae --- /dev/null +++ b/drivers/pci/mmap.c @@ -0,0 +1,90 @@ +/* + * mmap.c — generic PCI resource mmap helper + * + * Copyright © 2017 Amazon.com, Inc. or its affiliates. + * + * Author: David Woodhouse + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + + */ + +#include +#include +#include + +#ifdef HAVE_PCI_MMAP + +#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE +/* Modern setup: generic pci_mmap_resource_range(), and implement the legacy + * pci_mmap_page_range() as a wrapper round it. */ + +#ifdef HAVE_PCI_MMAP_IO +/* We don't support this (yet), so prevent archietectures from trying it. */ +#error Generic pci_mmap_io not supported +#endif + +static const struct vm_operations_struct pci_phys_vm_ops = { +#ifdef CONFIG_HAVE_IOREMAP_PROT + .access = generic_access_phys, +#endif +}; + +int pci_mmap_resource_range(struct pci_dev *pdev, int bar, + struct vm_area_struct *vma, + enum pci_mmap_state mmap_state, int write_combine) +{ + unsigned long size; + + if (mmap_state == pci_mmap_io) + return -EINVAL; + + size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1; + if (vma->vm_pgoff + vma_pages(vma) > size) + return -EINVAL; + + if (write_combine) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + else + vma->vm_page_prot = pgprot_device(vma->vm_page_prot); + + vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT); + vma->vm_ops = &pci_phys_vm_ops; + + return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, + vma->vm_end - vma->vm_start, vma->vm_page_prot); +} + +int pci_mmap_page_range(struct pci_dev *pdev, int bar, + struct vm_area_struct *vma, + enum pci_mmap_state mmap_state, int write_combine) +{ + /* Adjust vm_pgoff to be the offset within the resource */ + resource_size_t start, end; + + pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); + vma->vm_pgoff -= start >> PAGE_SHIFT; + return pci_mmap_resource_range(pdev, bar, vma, mmap_state, write_combine); +} + +#else +/* Legacy setup: Impement pci_mmap_resource_range() as a wrapper around + the architecture's pci_mmap_page_range(), converting to "user visible" + addresses as necessary. */ +int pci_mmap_resource_range(struct pci_dev *pdev, int bar, + struct vm_area_struct *vma, + enum pci_mmap_state mmap_state, int write_combine) +{ + resource_size_t start, end; + /* pci_mmap_page_range() expects the same kind of entry as coming + * from /proc/bus/pci/ which is a "user visible" value. If this is + * different from the resource itself, arch will do necessary fixup. + */ + pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); + vma->vm_pgoff += start >> PAGE_SHIFT; + return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine); +} +#endif +#endif /* HAVE_PCI_MMAP */ diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 063310a..9663d38 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1019,7 +1019,6 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr, struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); int bar = (unsigned long)attr->private; enum pci_mmap_state mmap_type; - resource_size_t start, end; struct resource *res = &pdev->resource[bar]; if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start)) @@ -1033,15 +1032,9 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr, (u64)pci_resource_len(pdev, bar)); return -EINVAL; } - - /* pci_mmap_page_range() expects the same kind of entry as coming - * from /proc/bus/pci/ which is a "user visible" value. If this is - * different from the resource itself, arch will do necessary fixup. - */ - pci_resource_to_user(pdev, bar, res, &start, &end); - vma->vm_pgoff += start >> PAGE_SHIFT; mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io; - return pci_mmap_page_range(pdev, bar, vma, mmap_type, write_combine); + + return pci_mmap_resource_range(pdev, bar, vma, mmap_type, write_combine); } static int pci_mmap_resource_uc(struct file *filp, struct kobject *kobj, diff --git a/include/linux/pci.h b/include/linux/pci.h index ebc86c1..4dfec16 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1626,10 +1626,21 @@ static inline int pci_get_new_domain_nr(void) { return -ENOSYS; } #include -/* Map a range of PCI memory or I/O space for a device into user space. - * Architectures provide this function if they set HAVE_PCI_MMAP, and - * it accepts the 'write_combine' argument when arch_can_pci_mmap_wc() - * evaluates to nonzero. */ +/* These two functions provide almost identical functionality. Depennding + * on the architecture, one will be implemented as a wrapper aroudn the + * other (in drivers/pci/mmap.c). + * + * pci_mmap_resource_range() maps a specific BAR, and vm->vm_pgoff + * is expected to be an offset within that region. + * + * pci_mmap_page_range() is the legacy architecture-specific interface, + * which accepts a "user visible" resource address converted by + * pci_resource_to_user(), as used in the legacy mmap() interface in + * /proc/bus/pci/. + */ +int pci_mmap_resource_range(struct pci_dev *dev, int bar, + struct vm_area_struct *vma, + enum pci_mmap_state mmap_state, int write_combine); int pci_mmap_page_range(struct pci_dev *pdev, int bar, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); -- 2.9.3