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    Subject[patch] PCI: export resource_wc in pci sysfs

    * Jesse Barnes <jesse.barnes@intel.com> wrote:

    > I really would have preferred a new mmap flag for this like ia64 used
    > to have, but Suresh and Venki tell me that a flag doesn't map very
    > well to what some architectures support, so I suppose a new file is
    > the way to go. Should work fine for X's needs.
    >
    > Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>

    thanks! Linus, please apply the patch below.

    Ingo

    ------------------>
    Subject: PCI: export resource_wc in pci sysfs
    From: venkatesh.pallipadi@intel.com
    Date: Tue, 18 Mar 2008 17:00:22 -0700

    For the ranges with IORESOURCE_PREFETCH, export a new resource_wc interface in
    pci /sysfs along with resource (which is uncached).

    Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
    Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
    Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    ---
    Documentation/filesystems/sysfs-pci.txt | 1
    drivers/pci/pci-sysfs.c | 82 +++++++++++++++++++++++---------
    include/linux/pci.h | 1
    3 files changed, 63 insertions(+), 21 deletions(-)

    Index: linux-x86.q/Documentation/filesystems/sysfs-pci.txt
    ===================================================================
    --- linux-x86.q.orig/Documentation/filesystems/sysfs-pci.txt
    +++ linux-x86.q/Documentation/filesystems/sysfs-pci.txt
    @@ -36,6 +36,7 @@ files, each with their own function.
    local_cpus nearby CPU mask (cpumask, ro)
    resource PCI resource host addresses (ascii, ro)
    resource0..N PCI resource N, if present (binary, mmap)
    + 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)
    subsystem_vendor PCI subsystem vendor (ascii, ro)
    Index: linux-x86.q/drivers/pci/pci-sysfs.c
    ===================================================================
    --- linux-x86.q.orig/drivers/pci/pci-sysfs.c
    +++ linux-x86.q/drivers/pci/pci-sysfs.c
    @@ -489,13 +489,14 @@ pci_mmap_legacy_mem(struct kobject *kobj
    * @kobj: kobject for mapping
    * @attr: struct bin_attribute for the file being mapped
    * @vma: struct vm_area_struct passed into the mmap
    + * @write_combine: 1 for write_combine mapping
    *
    * Use the regular PCI mapping routines to map a PCI resource into userspace.
    * FIXME: write combining? maybe automatic for prefetchable regions?
    */
    static int
    pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
    - struct vm_area_struct *vma)
    + struct vm_area_struct *vma, int write_combine)
    {
    struct pci_dev *pdev = to_pci_dev(container_of(kobj,
    struct device, kobj));
    @@ -518,7 +519,21 @@ pci_mmap_resource(struct kobject *kobj,
    vma->vm_pgoff += start >> PAGE_SHIFT;
    mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;

    - return pci_mmap_page_range(pdev, vma, mmap_type, 0);
    + return pci_mmap_page_range(pdev, vma, mmap_type, write_combine);
    +}
    +
    +static int
    +pci_mmap_resource_uc(struct kobject *kobj, struct bin_attribute *attr,
    + struct vm_area_struct *vma)
    +{
    + return pci_mmap_resource(kobj, attr, vma, 0);
    +}
    +
    +static int
    +pci_mmap_resource_wc(struct kobject *kobj, struct bin_attribute *attr,
    + struct vm_area_struct *vma)
    +{
    + return pci_mmap_resource(kobj, attr, vma, 1);
    }

    /**
    @@ -541,9 +556,46 @@ pci_remove_resource_files(struct pci_dev
    sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
    kfree(res_attr);
    }
    +
    + res_attr = pdev->res_attr_wc[i];
    + if (res_attr) {
    + sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
    + kfree(res_attr);
    + }
    }
    }

    +static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine)
    +{
    + /* allocate attribute structure, piggyback attribute name */
    + int name_len = write_combine ? 13 : 10;
    + struct bin_attribute *res_attr;
    + int retval;
    +
    + res_attr = kzalloc(sizeof(*res_attr) + name_len, GFP_ATOMIC);
    + if (res_attr) {
    + char *res_attr_name = (char *)(res_attr + 1);
    +
    + if (write_combine) {
    + pdev->res_attr_wc[num] = res_attr;
    + sprintf(res_attr_name, "resource%d_wc", num);
    + res_attr->mmap = pci_mmap_resource_wc;
    + } else {
    + pdev->res_attr[num] = res_attr;
    + sprintf(res_attr_name, "resource%d", num);
    + res_attr->mmap = pci_mmap_resource_uc;
    + }
    + res_attr->attr.name = res_attr_name;
    + res_attr->attr.mode = S_IRUSR | S_IWUSR;
    + res_attr->size = pci_resource_len(pdev, num);
    + res_attr->private = &pdev->resource[num];
    + retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
    + } else
    + retval = -ENOMEM;
    +
    + return retval;
    +}
    +
    /**
    * pci_create_resource_files - create resource files in sysfs for @dev
    * @dev: dev in question
    @@ -557,31 +609,19 @@ static int pci_create_resource_files(str

    /* Expose the PCI resources from this device as files */
    for (i = 0; i < PCI_ROM_RESOURCE; i++) {
    - struct bin_attribute *res_attr;

    /* skip empty resources */
    if (!pci_resource_len(pdev, i))
    continue;

    - /* allocate attribute structure, piggyback attribute name */
    - res_attr = kzalloc(sizeof(*res_attr) + 10, GFP_ATOMIC);
    - if (res_attr) {
    - char *res_attr_name = (char *)(res_attr + 1);
    + retval = pci_create_attr(pdev, i, 0);
    + /* for prefetchable resources, create a WC mappable file */
    + if (!retval && pdev->resource[i].flags & IORESOURCE_PREFETCH)
    + retval = pci_create_attr(pdev, i, 1);

    - pdev->res_attr[i] = res_attr;
    - sprintf(res_attr_name, "resource%d", i);
    - res_attr->attr.name = res_attr_name;
    - res_attr->attr.mode = S_IRUSR | S_IWUSR;
    - res_attr->size = pci_resource_len(pdev, i);
    - res_attr->mmap = pci_mmap_resource;
    - res_attr->private = &pdev->resource[i];
    - retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
    - if (retval) {
    - pci_remove_resource_files(pdev);
    - return retval;
    - }
    - } else {
    - return -ENOMEM;
    + if (retval) {
    + pci_remove_resource_files(pdev);
    + return retval;
    }
    }
    return 0;
    Index: linux-x86.q/include/linux/pci.h
    ===================================================================
    --- linux-x86.q.orig/include/linux/pci.h
    +++ linux-x86.q/include/linux/pci.h
    @@ -205,6 +205,7 @@ struct pci_dev {
    struct bin_attribute *rom_attr; /* attribute descriptor for sysfs ROM entry */
    int rom_attr_enabled; /* has display of the rom attribute been enabled? */
    struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */
    + struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */
    #ifdef CONFIG_PCI_MSI
    struct list_head msi_list;
    #endif

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