pci: Allow read/write access to sysfs I/O port resources
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From: Alex Williamson on 23 Jul 2010 11:20 On Mon, 2010-07-19 at 09:45 -0600, Alex Williamson wrote: > PCI sysfs resource files currently only allow mmap'ing. On x86 this > works fine for memory backed BARs, but doesn't work at all for I/O > port backed BARs. Add read/write to I/O port PCI sysfs resource > files to allow userspace access to these device regions. > > Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com> > --- Any thoughts on this for -next? Thanks, Alex > v2: hopefully better commit log, remove unneeded cast, use bool > > Documentation/filesystems/sysfs-pci.txt | 7 ++- > drivers/pci/pci-sysfs.c | 68 +++++++++++++++++++++++++++++++ > 2 files changed, 73 insertions(+), 2 deletions(-) > > diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt > index 85354b3..74eaac2 100644 > --- a/Documentation/filesystems/sysfs-pci.txt > +++ b/Documentation/filesystems/sysfs-pci.txt > @@ -39,7 +39,7 @@ files, each with their own function. > local_cpus nearby CPU mask (cpumask, ro) > remove remove device from kernel's list (ascii, wo) > resource PCI resource host addresses (ascii, ro) > - resource0..N PCI resource N, if present (binary, mmap) > + resource0..N PCI resource N, if present (binary, mmap, rw[1]) > resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) > rom PCI ROM resource, if present (binary, ro) > subsystem_device PCI subsystem device (ascii, ro) > @@ -54,13 +54,16 @@ files, each with their own function. > binary - file contains binary data > cpumask - file contains a cpumask type > > +[1] rw for RESOURCE_IO (I/O port) regions only > + > The read only files are informational, writes to them will be ignored, with > the exception of the 'rom' file. Writable files can be used to perform > actions on the device (e.g. changing config space, detaching a device). > mmapable files are available via an mmap of the file at offset 0 and can be > used to do actual device programming from userspace. Note that some platforms > don't support mmapping of certain resources, so be sure to check the return > -value from any attempted mmap. > +value from any attempted mmap. The most notable of these are I/O port > +resources, which also provide read/write access. > > The 'enable' file provides a counter that indicates how many times the device > has been enabled. If the 'enable' file currently returns '4', and a '1' is > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 5935b85..f7692dc 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -778,6 +778,70 @@ pci_mmap_resource_wc(struct file *filp, struct kobject *kobj, > return pci_mmap_resource(kobj, attr, vma, 1); > } > > +static ssize_t > +pci_resource_io(struct file *filp, struct kobject *kobj, > + struct bin_attribute *attr, char *buf, > + loff_t off, size_t count, bool write) > +{ > + struct pci_dev *pdev = to_pci_dev(container_of(kobj, > + struct device, kobj)); > + struct resource *res = attr->private; > + unsigned long port = off; > + int i; > + > + for (i = 0; i < PCI_ROM_RESOURCE; i++) > + if (res == &pdev->resource[i]) > + break; > + if (i >= PCI_ROM_RESOURCE) > + return -ENODEV; > + > + port += pci_resource_start(pdev, i); > + > + if (port > pci_resource_end(pdev, i)) > + return 0; > + > + if (port + count - 1 > pci_resource_end(pdev, i)) > + return -EINVAL; > + > + switch (count) { > + case 1: > + if (write) > + outb(*(u8 *)buf, port); > + else > + *(u8 *)buf = inb(port); > + return 1; > + case 2: > + if (write) > + outw(*(u16 *)buf, port); > + else > + *(u16 *)buf = inw(port); > + return 2; > + case 4: > + if (write) > + outl(*(u32 *)buf, port); > + else > + *(u32 *)buf = inl(port); > + return 4; > + } > + return -EINVAL; > +} > + > +static ssize_t > +pci_read_resource_io(struct file *filp, struct kobject *kobj, > + struct bin_attribute *attr, char *buf, > + loff_t off, size_t count) > +{ > + return pci_resource_io(filp, kobj, attr, buf, off, count, false); > +} > + > +static ssize_t > +pci_write_resource_io(struct file *filp, struct kobject *kobj, > + struct bin_attribute *attr, char *buf, > + loff_t off, size_t count) > +{ > + return pci_resource_io(filp, kobj, attr, buf, off, count, true); > +} > + > /** > * pci_remove_resource_files - cleanup resource files > * @pdev: dev to cleanup > @@ -828,6 +892,10 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) > sprintf(res_attr_name, "resource%d", num); > res_attr->mmap = pci_mmap_resource_uc; > } > + if (pci_resource_flags(pdev, num) & IORESOURCE_IO) { > + res_attr->read = pci_read_resource_io; > + res_attr->write = pci_write_resource_io; > + } > res_attr->attr.name = res_attr_name; > res_attr->attr.mode = S_IRUSR | S_IWUSR; > res_attr->size = pci_resource_len(pdev, num); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jesse Barnes on 23 Jul 2010 12:30 On Fri, 23 Jul 2010 09:10:27 -0600 Alex Williamson <alex.williamson(a)redhat.com> wrote: > On Mon, 2010-07-19 at 09:45 -0600, Alex Williamson wrote: > > PCI sysfs resource files currently only allow mmap'ing. On x86 this > > works fine for memory backed BARs, but doesn't work at all for I/O > > port backed BARs. Add read/write to I/O port PCI sysfs resource > > files to allow userspace access to these device regions. > > > > Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com> > > --- > > Any thoughts on this for -next? Thanks, Yeah, I like it. Unless there are objections I'll pull it in. Thanks, -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Chris Wright on 23 Jul 2010 13:50 * Jesse Barnes (jbarnes(a)virtuousgeek.org) wrote: > On Fri, 23 Jul 2010 09:10:27 -0600 > Alex Williamson <alex.williamson(a)redhat.com> wrote: > > > On Mon, 2010-07-19 at 09:45 -0600, Alex Williamson wrote: > > > PCI sysfs resource files currently only allow mmap'ing. On x86 this > > > works fine for memory backed BARs, but doesn't work at all for I/O > > > port backed BARs. Add read/write to I/O port PCI sysfs resource > > > files to allow userspace access to these device regions. > > > > > > Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com> > > > --- > > > > Any thoughts on this for -next? Thanks, > > Yeah, I like it. Unless there are objections I'll pull it in. Acked-by: Chris Wright <chrisw(a)redhat.com> I think we may have some room for follow-on cleanups so consolidate the ioport read/write functions w/ other HAVE_PCI_LEGACY bits... thanks, -chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Jesse Barnes on 30 Jul 2010 12:40
On Mon, 19 Jul 2010 09:45:34 -0600 Alex Williamson <alex.williamson(a)redhat.com> wrote: > PCI sysfs resource files currently only allow mmap'ing. On x86 this > works fine for memory backed BARs, but doesn't work at all for I/O > port backed BARs. Add read/write to I/O port PCI sysfs resource > files to allow userspace access to these device regions. > > Signed-off-by: Alex Williamson <alex.williamson(a)redhat.com> Applied to linux-next, thanks. -- Jesse Barnes, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |