diff options
| -rw-r--r-- | Documentation/filesystems/sysfs-pci.txt | 10 | ||||
| -rw-r--r-- | arch/arm64/include/asm/pci.h | 2 | ||||
| -rw-r--r-- | drivers/pci/Makefile | 2 | ||||
| -rw-r--r-- | drivers/pci/mmap.c | 95 | ||||
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 13 | ||||
| -rw-r--r-- | drivers/pci/pci.h | 4 | ||||
| -rw-r--r-- | include/linux/pci.h | 19 |
7 files changed, 125 insertions, 20 deletions
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 46b95d82c4fd..06f1d64c6f70 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -113,9 +113,13 @@ 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. -Platforms are free to only support subsets of the mmap functionality, but -useful return codes should be provided. +code should ideally define ARCH_GENERIC_PCI_MMAP_RESOURCE and use the generic +implementation of that functionality. To support the historical interface of +mmap() through files in /proc/bus/pci, platforms may also set HAVE_PCI_MMAP. + +Alternatively, platforms which set HAVE_PCI_MMAP may provide their own +implementation of pci_mmap_page_range() instead of defining +ARCH_GENERIC_PCI_MMAP_RESOURCE. Platforms which support write-combining maps of PCI resources must define arch_can_pci_mmap_wc() which shall evaluate to non-zero at runtime when diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h index b9a7ba9ca44c..1fc19744ffe9 100644 --- a/arch/arm64/include/asm/pci.h +++ b/arch/arm64/include/asm/pci.h @@ -22,6 +22,8 @@ */ #define PCI_DMA_BUS_IS_PHYS (0) +#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 8db5079f09a7..3d40e415a171 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 000000000000..b7aca9c89c31 --- /dev/null +++ b/drivers/pci/mmap.c @@ -0,0 +1,95 @@ +/* + * mmap.c — generic PCI resource mmap helper + * + * Copyright © 2017 Amazon.com, Inc. or its affiliates. + * + * Author: David Woodhouse <dwmw2@infradead.org> + * + * 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 <linux/kernel.h> +#include <linux/mm.h> +#include <linux/pci.h> + +#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE + +/* + * Modern setup: generic pci_mmap_resource_range(), and implement the legacy + * pci_mmap_page_range() (if needed) as a wrapper round it. + */ + +#ifdef HAVE_PCI_MMAP +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) +{ + resource_size_t start, end; + + pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); + + /* Adjust vm_pgoff to be the offset within the resource */ + vma->vm_pgoff -= start >> PAGE_SHIFT; + return pci_mmap_resource_range(pdev, bar, vma, mmap_state, + write_combine); +} +#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); +} + +#elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */ + +/* + * 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 diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index bfd9efe637c4..10feb98a2b1d 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -980,7 +980,7 @@ void pci_remove_legacy_files(struct pci_bus *b) } #endif /* HAVE_PCI_LEGACY */ -#ifdef HAVE_PCI_MMAP +#if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE) int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma, enum pci_mmap_api mmap_api) @@ -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/drivers/pci/pci.h b/drivers/pci/pci.h index 8dd38e69d6f2..8e5ca2dec7e7 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -21,14 +21,14 @@ void pci_create_firmware_label_files(struct pci_dev *pdev); void pci_remove_firmware_label_files(struct pci_dev *pdev); #endif void pci_cleanup_rom(struct pci_dev *dev); -#ifdef HAVE_PCI_MMAP + enum pci_mmap_api { PCI_MMAP_SYSFS, /* mmap on /sys/bus/pci/devices/<BDF>/resource<N> */ PCI_MMAP_PROCFS /* mmap on /proc/bus/pci/<BDF> */ }; int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai, enum pci_mmap_api mmap_api); -#endif + int pci_probe_reset_function(struct pci_dev *dev); /** diff --git a/include/linux/pci.h b/include/linux/pci.h index 7173a677d6dd..98a72abcf361 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 <asm/pci.h> -/* 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 around 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); |
