PCI: Introduce /sys/bus/pci/devices/.../rescan

[linux-2.6/mini2440.git] / drivers / pci / pci-sysfs.c

/*
 * drivers/pci/pci-sysfs.c
 *
 * (C) Copyright 2002-2004 Greg Kroah-Hartman <greg@kroah.com>
 * (C) Copyright 2002-2004 IBM Corp.
 * (C) Copyright 2003 Matthew Wilcox
 * (C) Copyright 2003 Hewlett-Packard
 * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
 * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
 *
 * File attributes for PCI devices
 *
 * Modeled after usb's driverfs.c 
 *
 */


#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/stat.h>
#include <linux/topology.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/pci-aspm.h>
#include "pci.h"

static int sysfs_initialized;   /* = 0 */

/* show configuration fields */
#define pci_config_attr(field, format_string)                           \
static ssize_t                                                          \
field##_show(struct device *dev, struct device_attribute *attr, char *buf)                              \
{                                                                       \
        struct pci_dev *pdev;                                           \
                                                                        \
        pdev = to_pci_dev (dev);                                        \
        return sprintf (buf, format_string, pdev->field);               \
}

pci_config_attr(vendor, "0x%04x\n");
pci_config_attr(device, "0x%04x\n");
pci_config_attr(subsystem_vendor, "0x%04x\n");
pci_config_attr(subsystem_device, "0x%04x\n");
pci_config_attr(class, "0x%06x\n");
pci_config_attr(irq, "%u\n");

static ssize_t broken_parity_status_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        return sprintf (buf, "%u\n", pdev->broken_parity_status);
}

static ssize_t broken_parity_status_store(struct device *dev,
                                          struct device_attribute *attr,
                                          const char *buf, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        unsigned long val;

        if (strict_strtoul(buf, 0, &val) < 0)
                return -EINVAL;

        pdev->broken_parity_status = !!val;

        return count;
}

static ssize_t local_cpus_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{               
        const struct cpumask *mask;
        int len;

        mask = cpumask_of_pcibus(to_pci_dev(dev)->bus);
        len = cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
        buf[len++] = '\n';
        buf[len] = '\0';
        return len;
}


static ssize_t local_cpulist_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        const struct cpumask *mask;
        int len;

        mask = cpumask_of_pcibus(to_pci_dev(dev)->bus);
        len = cpulist_scnprintf(buf, PAGE_SIZE-2, mask);
        buf[len++] = '\n';
        buf[len] = '\0';
        return len;
}

/* show resources */
static ssize_t
resource_show(struct device * dev, struct device_attribute *attr, char * buf)
{
        struct pci_dev * pci_dev = to_pci_dev(dev);
        char * str = buf;
        int i;
        int max;
        resource_size_t start, end;

        if (pci_dev->subordinate)
                max = DEVICE_COUNT_RESOURCE;
        else
                max = PCI_BRIDGE_RESOURCES;

        for (i = 0; i < max; i++) {
                struct resource *res =  &pci_dev->resource[i];
                pci_resource_to_user(pci_dev, i, res, &start, &end);
                str += sprintf(str,"0x%016llx 0x%016llx 0x%016llx\n",
                               (unsigned long long)start,
                               (unsigned long long)end,
                               (unsigned long long)res->flags);
        }
        return (str - buf);
}

static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);

        return sprintf(buf, "pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02x\n",
                       pci_dev->vendor, pci_dev->device,
                       pci_dev->subsystem_vendor, pci_dev->subsystem_device,
                       (u8)(pci_dev->class >> 16), (u8)(pci_dev->class >> 8),
                       (u8)(pci_dev->class));
}

static ssize_t is_enabled_store(struct device *dev,
                                struct device_attribute *attr, const char *buf,
                                size_t count)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        unsigned long val;
        ssize_t result = strict_strtoul(buf, 0, &val);

        if (result < 0)
                return result;

        /* this can crash the machine when done on the "wrong" device */
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        if (!val) {
                if (atomic_read(&pdev->enable_cnt) != 0)
                        pci_disable_device(pdev);
                else
                        result = -EIO;
        } else
                result = pci_enable_device(pdev);

        return result < 0 ? result : count;
}

static ssize_t is_enabled_show(struct device *dev,
                               struct device_attribute *attr, char *buf)
{
        struct pci_dev *pdev;

        pdev = to_pci_dev (dev);
        return sprintf (buf, "%u\n", atomic_read(&pdev->enable_cnt));
}

#ifdef CONFIG_NUMA
static ssize_t
numa_node_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        return sprintf (buf, "%d\n", dev->numa_node);
}
#endif

static ssize_t
msi_bus_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        if (!pdev->subordinate)
                return 0;

        return sprintf (buf, "%u\n",
                        !(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI));
}

static ssize_t
msi_bus_store(struct device *dev, struct device_attribute *attr,
              const char *buf, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        unsigned long val;

        if (strict_strtoul(buf, 0, &val) < 0)
                return -EINVAL;

        /* bad things may happen if the no_msi flag is changed
         * while some drivers are loaded */
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        /* Maybe pci devices without subordinate busses shouldn't even have this
         * attribute in the first place?  */
        if (!pdev->subordinate)
                return count;

        /* Is the flag going to change, or keep the value it already had? */
        if (!(pdev->subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI) ^
            !!val) {
                pdev->subordinate->bus_flags ^= PCI_BUS_FLAGS_NO_MSI;

                dev_warn(&pdev->dev, "forced subordinate bus to%s support MSI,"
                         " bad things could happen\n", val ? "" : " not");
        }

        return count;
}

#ifdef CONFIG_HOTPLUG
static DEFINE_MUTEX(pci_remove_rescan_mutex);
static ssize_t bus_rescan_store(struct bus_type *bus, const char *buf,
                                size_t count)
{
        unsigned long val;
        struct pci_bus *b = NULL;

        if (strict_strtoul(buf, 0, &val) < 0)
                return -EINVAL;

        if (val) {
                mutex_lock(&pci_remove_rescan_mutex);
                while ((b = pci_find_next_bus(b)) != NULL)
                        pci_rescan_bus(b);
                mutex_unlock(&pci_remove_rescan_mutex);
        }
        return count;
}

struct bus_attribute pci_bus_attrs[] = {
        __ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, bus_rescan_store),
        __ATTR_NULL
};

static ssize_t
dev_rescan_store(struct device *dev, struct device_attribute *attr,
                 const char *buf, size_t count)
{
        unsigned long val;
        struct pci_dev *pdev = to_pci_dev(dev);

        if (strict_strtoul(buf, 0, &val) < 0)
                return -EINVAL;

        if (val) {
                mutex_lock(&pci_remove_rescan_mutex);
                pci_rescan_bus(pdev->bus);
                mutex_unlock(&pci_remove_rescan_mutex);
        }
        return count;
}

static void remove_callback(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        mutex_lock(&pci_remove_rescan_mutex);
        pci_remove_bus_device(pdev);
        mutex_unlock(&pci_remove_rescan_mutex);
}

static ssize_t
remove_store(struct device *dev, struct device_attribute *dummy,
             const char *buf, size_t count)
{
        int ret = 0;
        unsigned long val;
        struct pci_dev *pdev = to_pci_dev(dev);

        if (strict_strtoul(buf, 0, &val) < 0)
                return -EINVAL;

        if (pci_is_root_bus(pdev->bus))
                return -EBUSY;

        /* An attribute cannot be unregistered by one of its own methods,
         * so we have to use this roundabout approach.
         */
        if (val)
                ret = device_schedule_callback(dev, remove_callback);
        if (ret)
                count = ret;
        return count;
}
#endif

struct device_attribute pci_dev_attrs[] = {
        __ATTR_RO(resource),
        __ATTR_RO(vendor),
        __ATTR_RO(device),
        __ATTR_RO(subsystem_vendor),
        __ATTR_RO(subsystem_device),
        __ATTR_RO(class),
        __ATTR_RO(irq),
        __ATTR_RO(local_cpus),
        __ATTR_RO(local_cpulist),
        __ATTR_RO(modalias),
#ifdef CONFIG_NUMA
        __ATTR_RO(numa_node),
#endif
        __ATTR(enable, 0600, is_enabled_show, is_enabled_store),
        __ATTR(broken_parity_status,(S_IRUGO|S_IWUSR),
                broken_parity_status_show,broken_parity_status_store),
        __ATTR(msi_bus, 0644, msi_bus_show, msi_bus_store),
#ifdef CONFIG_HOTPLUG
        __ATTR(remove, (S_IWUSR|S_IWGRP), NULL, remove_store),
        __ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, dev_rescan_store),
#endif
        __ATTR_NULL,
};

static ssize_t
boot_vga_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct pci_dev *pdev = to_pci_dev(dev);

        return sprintf(buf, "%u\n",
                !!(pdev->resource[PCI_ROM_RESOURCE].flags &
                   IORESOURCE_ROM_SHADOW));
}
struct device_attribute vga_attr = __ATTR_RO(boot_vga);

static ssize_t
pci_read_config(struct kobject *kobj, struct bin_attribute *bin_attr,
                char *buf, loff_t off, size_t count)
{
        struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
        unsigned int size = 64;
        loff_t init_off = off;
        u8 *data = (u8*) buf;

        /* Several chips lock up trying to read undefined config space */
        if (capable(CAP_SYS_ADMIN)) {
                size = dev->cfg_size;
        } else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
                size = 128;
        }

        if (off > size)
                return 0;
        if (off + count > size) {
                size -= off;
                count = size;
        } else {
                size = count;
        }

        if ((off & 1) && size) {
                u8 val;
                pci_user_read_config_byte(dev, off, &val);
                data[off - init_off] = val;
                off++;
                size--;
        }

        if ((off & 3) && size > 2) {
                u16 val;
                pci_user_read_config_word(dev, off, &val);
                data[off - init_off] = val & 0xff;
                data[off - init_off + 1] = (val >> 8) & 0xff;
                off += 2;
                size -= 2;
        }

        while (size > 3) {
                u32 val;
                pci_user_read_config_dword(dev, off, &val);
                data[off - init_off] = val & 0xff;
                data[off - init_off + 1] = (val >> 8) & 0xff;
                data[off - init_off + 2] = (val >> 16) & 0xff;
                data[off - init_off + 3] = (val >> 24) & 0xff;
                off += 4;
                size -= 4;
        }

        if (size >= 2) {
                u16 val;
                pci_user_read_config_word(dev, off, &val);
                data[off - init_off] = val & 0xff;
                data[off - init_off + 1] = (val >> 8) & 0xff;
                off += 2;
                size -= 2;
        }

        if (size > 0) {
                u8 val;
                pci_user_read_config_byte(dev, off, &val);
                data[off - init_off] = val;
                off++;
                --size;
        }

        return count;
}

static ssize_t
pci_write_config(struct kobject *kobj, struct bin_attribute *bin_attr,
                 char *buf, loff_t off, size_t count)
{
        struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
        unsigned int size = count;
        loff_t init_off = off;
        u8 *data = (u8*) buf;

        if (off > dev->cfg_size)
                return 0;
        if (off + count > dev->cfg_size) {
                size = dev->cfg_size - off;
                count = size;
        }
        
        if ((off & 1) && size) {
                pci_user_write_config_byte(dev, off, data[off - init_off]);
                off++;
                size--;
        }
        
        if ((off & 3) && size > 2) {
                u16 val = data[off - init_off];
                val |= (u16) data[off - init_off + 1] << 8;
                pci_user_write_config_word(dev, off, val);
                off += 2;
                size -= 2;
        }

        while (size > 3) {
                u32 val = data[off - init_off];
                val |= (u32) data[off - init_off + 1] << 8;
                val |= (u32) data[off - init_off + 2] << 16;
                val |= (u32) data[off - init_off + 3] << 24;
                pci_user_write_config_dword(dev, off, val);
                off += 4;
                size -= 4;
        }
        
        if (size >= 2) {
                u16 val = data[off - init_off];
                val |= (u16) data[off - init_off + 1] << 8;
                pci_user_write_config_word(dev, off, val);
                off += 2;
                size -= 2;
        }

        if (size) {
                pci_user_write_config_byte(dev, off, data[off - init_off]);
                off++;
                --size;
        }

        return count;
}

static ssize_t
read_vpd_attr(struct kobject *kobj, struct bin_attribute *bin_attr,
              char *buf, loff_t off, size_t count)
{
        struct pci_dev *dev =
                to_pci_dev(container_of(kobj, struct device, kobj));

        if (off > bin_attr->size)
                count = 0;
        else if (count > bin_attr->size - off)
                count = bin_attr->size - off;

        return pci_read_vpd(dev, off, count, buf);
}

static ssize_t
write_vpd_attr(struct kobject *kobj, struct bin_attribute *bin_attr,
               char *buf, loff_t off, size_t count)
{
        struct pci_dev *dev =
                to_pci_dev(container_of(kobj, struct device, kobj));

        if (off > bin_attr->size)
                count = 0;
        else if (count > bin_attr->size - off)
                count = bin_attr->size - off;

        return pci_write_vpd(dev, off, count, buf);
}

#ifdef HAVE_PCI_LEGACY
/**
 * pci_read_legacy_io - read byte(s) from legacy I/O port space
 * @kobj: kobject corresponding to file to read from
 * @buf: buffer to store results
 * @off: offset into legacy I/O port space
 * @count: number of bytes to read
 *
 * Reads 1, 2, or 4 bytes from legacy I/O port space using an arch specific
 * callback routine (pci_legacy_read).
 */
static ssize_t
pci_read_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
                   char *buf, loff_t off, size_t count)
{
        struct pci_bus *bus = to_pci_bus(container_of(kobj,
                                                      struct device,
                                                      kobj));

        /* Only support 1, 2 or 4 byte accesses */
        if (count != 1 && count != 2 && count != 4)
                return -EINVAL;

        return pci_legacy_read(bus, off, (u32 *)buf, count);
}

/**
 * pci_write_legacy_io - write byte(s) to legacy I/O port space
 * @kobj: kobject corresponding to file to read from
 * @buf: buffer containing value to be written
 * @off: offset into legacy I/O port space
 * @count: number of bytes to write
 *
 * Writes 1, 2, or 4 bytes from legacy I/O port space using an arch specific
 * callback routine (pci_legacy_write).
 */
static ssize_t
pci_write_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
                    char *buf, loff_t off, size_t count)
{
        struct pci_bus *bus = to_pci_bus(container_of(kobj,
                                                      struct device,
                                                      kobj));
        /* Only support 1, 2 or 4 byte accesses */
        if (count != 1 && count != 2 && count != 4)
                return -EINVAL;

        return pci_legacy_write(bus, off, *(u32 *)buf, count);
}

/**
 * pci_mmap_legacy_mem - map legacy PCI memory into user memory space
 * @kobj: kobject corresponding to device to be mapped
 * @attr: struct bin_attribute for this file
 * @vma: struct vm_area_struct passed to mmap
 *
 * Uses an arch specific callback, pci_mmap_legacy_mem_page_range, to mmap
 * legacy memory space (first meg of bus space) into application virtual
 * memory space.
 */
static int
pci_mmap_legacy_mem(struct kobject *kobj, struct bin_attribute *attr,
                    struct vm_area_struct *vma)
{
        struct pci_bus *bus = to_pci_bus(container_of(kobj,
                                                      struct device,
                                                      kobj));

        return pci_mmap_legacy_page_range(bus, vma, pci_mmap_mem);
}

/**
 * pci_mmap_legacy_io - map legacy PCI IO into user memory space
 * @kobj: kobject corresponding to device to be mapped
 * @attr: struct bin_attribute for this file
 * @vma: struct vm_area_struct passed to mmap
 *
 * Uses an arch specific callback, pci_mmap_legacy_io_page_range, to mmap
 * legacy IO space (first meg of bus space) into application virtual
 * memory space. Returns -ENOSYS if the operation isn't supported
 */
static int
pci_mmap_legacy_io(struct kobject *kobj, struct bin_attribute *attr,
                   struct vm_area_struct *vma)
{
        struct pci_bus *bus = to_pci_bus(container_of(kobj,
                                                      struct device,
                                                      kobj));

        return pci_mmap_legacy_page_range(bus, vma, pci_mmap_io);
}

/**
 * pci_adjust_legacy_attr - adjustment of legacy file attributes
 * @b: bus to create files under
 * @mmap_type: I/O port or memory
 *
 * Stub implementation. Can be overridden by arch if necessary.
 */
void __weak
pci_adjust_legacy_attr(struct pci_bus *b, enum pci_mmap_state mmap_type)
{
        return;
}

/**
 * pci_create_legacy_files - create legacy I/O port and memory files
 * @b: bus to create files under
 *
 * Some platforms allow access to legacy I/O port and ISA memory space on
 * a per-bus basis.  This routine creates the files and ties them into
 * their associated read, write and mmap files from pci-sysfs.c
 *
 * On error unwind, but don't propogate the error to the caller
 * as it is ok to set up the PCI bus without these files.
 */
void pci_create_legacy_files(struct pci_bus *b)
{
        int error;

        b->legacy_io = kzalloc(sizeof(struct bin_attribute) * 2,
                               GFP_ATOMIC);
        if (!b->legacy_io)
                goto kzalloc_err;

        b->legacy_io->attr.name = "legacy_io";
        b->legacy_io->size = 0xffff;
        b->legacy_io->attr.mode = S_IRUSR | S_IWUSR;
        b->legacy_io->read = pci_read_legacy_io;
        b->legacy_io->write = pci_write_legacy_io;
        b->legacy_io->mmap = pci_mmap_legacy_io;
        pci_adjust_legacy_attr(b, pci_mmap_io);
        error = device_create_bin_file(&b->dev, b->legacy_io);
        if (error)
                goto legacy_io_err;

        /* Allocated above after the legacy_io struct */
        b->legacy_mem = b->legacy_io + 1;
        b->legacy_mem->attr.name = "legacy_mem";
        b->legacy_mem->size = 1024*1024;
        b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
        b->legacy_mem->mmap = pci_mmap_legacy_mem;
        pci_adjust_legacy_attr(b, pci_mmap_mem);
        error = device_create_bin_file(&b->dev, b->legacy_mem);
        if (error)
                goto legacy_mem_err;

        return;

legacy_mem_err:
        device_remove_bin_file(&b->dev, b->legacy_io);
legacy_io_err:
        kfree(b->legacy_io);
        b->legacy_io = NULL;
kzalloc_err:
        printk(KERN_WARNING "pci: warning: could not create legacy I/O port "
               "and ISA memory resources to sysfs\n");
        return;
}

void pci_remove_legacy_files(struct pci_bus *b)
{
        if (b->legacy_io) {
                device_remove_bin_file(&b->dev, b->legacy_io);
                device_remove_bin_file(&b->dev, b->legacy_mem);
                kfree(b->legacy_io); /* both are allocated here */
        }
}
#endif /* HAVE_PCI_LEGACY */

#ifdef HAVE_PCI_MMAP

int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma)
{
        unsigned long nr, start, size;

        nr = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
        start = vma->vm_pgoff;
        size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
        if (start < size && size - start >= nr)
                return 1;
        WARN(1, "process \"%s\" tried to map 0x%08lx-0x%08lx on %s BAR %d (size 0x%08lx)\n",
                current->comm, start, start+nr, pci_name(pdev), resno, size);
        return 0;
}

/**
 * pci_mmap_resource - map a PCI resource into user memory space
 * @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.
 */
static int
pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
                  struct vm_area_struct *vma, int write_combine)
{
        struct pci_dev *pdev = to_pci_dev(container_of(kobj,
                                                       struct device, kobj));
        struct resource *res = (struct resource *)attr->private;
        enum pci_mmap_state mmap_type;
        resource_size_t start, end;
        int i;

        for (i = 0; i < PCI_ROM_RESOURCE; i++)
                if (res == &pdev->resource[i])
                        break;
        if (i >= PCI_ROM_RESOURCE)
                return -ENODEV;

        if (!pci_mmap_fits(pdev, i, vma))
                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, i, res, &start, &end);
        vma->vm_pgoff += start >> PAGE_SHIFT;
        mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;

        if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(start))
                return -EINVAL;

        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);
}

/**
 * pci_remove_resource_files - cleanup resource files
 * @dev: dev to cleanup
 *
 * If we created resource files for @dev, remove them from sysfs and
 * free their resources.
 */
static void
pci_remove_resource_files(struct pci_dev *pdev)
{
        int i;

        for (i = 0; i < PCI_ROM_RESOURCE; i++) {
                struct bin_attribute *res_attr;

                res_attr = pdev->res_attr[i];
                if (res_attr) {
                        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
 *
 * Walk the resources in @dev creating files for each resource available.
 */
static int pci_create_resource_files(struct pci_dev *pdev)
{
        int i;
        int retval;

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

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

                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);

                if (retval) {
                        pci_remove_resource_files(pdev);
                        return retval;
                }
        }
        return 0;
}
#else /* !HAVE_PCI_MMAP */
int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; }
void __weak pci_remove_resource_files(struct pci_dev *dev) { return; }
#endif /* HAVE_PCI_MMAP */

/**
 * pci_write_rom - used to enable access to the PCI ROM display
 * @kobj: kernel object handle
 * @buf: user input
 * @off: file offset
 * @count: number of byte in input
 *
 * writing anything except 0 enables it
 */
static ssize_t
pci_write_rom(struct kobject *kobj, struct bin_attribute *bin_attr,
              char *buf, loff_t off, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(container_of(kobj, struct device, kobj));

        if ((off ==  0) && (*buf == '0') && (count == 2))
                pdev->rom_attr_enabled = 0;
        else
                pdev->rom_attr_enabled = 1;

        return count;
}

/**
 * pci_read_rom - read a PCI ROM
 * @kobj: kernel object handle
 * @buf: where to put the data we read from the ROM
 * @off: file offset
 * @count: number of bytes to read
 *
 * Put @count bytes starting at @off into @buf from the ROM in the PCI
 * device corresponding to @kobj.
 */
static ssize_t
pci_read_rom(struct kobject *kobj, struct bin_attribute *bin_attr,
             char *buf, loff_t off, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(container_of(kobj, struct device, kobj));
        void __iomem *rom;
        size_t size;

        if (!pdev->rom_attr_enabled)
                return -EINVAL;
        
        rom = pci_map_rom(pdev, &size); /* size starts out as PCI window size */
        if (!rom || !size)
                return -EIO;
                
        if (off >= size)
                count = 0;
        else {
                if (off + count > size)
                        count = size - off;
                
                memcpy_fromio(buf, rom + off, count);
        }
        pci_unmap_rom(pdev, rom);
                
        return count;
}

static struct bin_attribute pci_config_attr = {
        .attr = {
                .name = "config",
                .mode = S_IRUGO | S_IWUSR,
        },
        .size = PCI_CFG_SPACE_SIZE,
        .read = pci_read_config,
        .write = pci_write_config,
};

static struct bin_attribute pcie_config_attr = {
        .attr = {
                .name = "config",
                .mode = S_IRUGO | S_IWUSR,
        },
        .size = PCI_CFG_SPACE_EXP_SIZE,
        .read = pci_read_config,
        .write = pci_write_config,
};

int __attribute__ ((weak)) pcibios_add_platform_entries(struct pci_dev *dev)
{
        return 0;
}

static int pci_create_capabilities_sysfs(struct pci_dev *dev)
{
        int retval;
        struct bin_attribute *attr;

        /* If the device has VPD, try to expose it in sysfs. */
        if (dev->vpd) {
                attr = kzalloc(sizeof(*attr), GFP_ATOMIC);
                if (!attr)
                        return -ENOMEM;

                attr->size = dev->vpd->len;
                attr->attr.name = "vpd";
                attr->attr.mode = S_IRUSR | S_IWUSR;
                attr->read = read_vpd_attr;
                attr->write = write_vpd_attr;
                retval = sysfs_create_bin_file(&dev->dev.kobj, attr);
                if (retval) {
                        kfree(dev->vpd->attr);
                        return retval;
                }
                dev->vpd->attr = attr;
        }

        /* Active State Power Management */
        pcie_aspm_create_sysfs_dev_files(dev);

        return 0;
}

int __must_check pci_create_sysfs_dev_files (struct pci_dev *pdev)
{
        int retval;
        int rom_size = 0;
        struct bin_attribute *attr;

        if (!sysfs_initialized)
                return -EACCES;

        if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
                retval = sysfs_create_bin_file(&pdev->dev.kobj, &pci_config_attr);
        else
                retval = sysfs_create_bin_file(&pdev->dev.kobj, &pcie_config_attr);
        if (retval)
                goto err;

        retval = pci_create_resource_files(pdev);
        if (retval)
                goto err_config_file;

        if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
                rom_size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
        else if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
                rom_size = 0x20000;

        /* If the device has a ROM, try to expose it in sysfs. */
        if (rom_size) {
                attr = kzalloc(sizeof(*attr), GFP_ATOMIC);
                if (!attr) {
                        retval = -ENOMEM;
                        goto err_resource_files;
                }
                attr->size = rom_size;
                attr->attr.name = "rom";
                attr->attr.mode = S_IRUSR;
                attr->read = pci_read_rom;
                attr->write = pci_write_rom;
                retval = sysfs_create_bin_file(&pdev->dev.kobj, attr);
                if (retval) {
                        kfree(attr);
                        goto err_resource_files;
                }
                pdev->rom_attr = attr;
        }

        if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) {
                retval = device_create_file(&pdev->dev, &vga_attr);
                if (retval)
                        goto err_rom_file;
        }

        /* add platform-specific attributes */
        retval = pcibios_add_platform_entries(pdev);
        if (retval)
                goto err_vga_file;

        /* add sysfs entries for various capabilities */
        retval = pci_create_capabilities_sysfs(pdev);
        if (retval)
                goto err_vga_file;

        return 0;

err_vga_file:
        if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
                device_remove_file(&pdev->dev, &vga_attr);
err_rom_file:
        if (rom_size) {
                sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
                kfree(pdev->rom_attr);
                pdev->rom_attr = NULL;
        }
err_resource_files:
        pci_remove_resource_files(pdev);
err_config_file:
        if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
                sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
        else
                sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);
err:
        return retval;
}

static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
{
        if (dev->vpd && dev->vpd->attr) {
                sysfs_remove_bin_file(&dev->dev.kobj, dev->vpd->attr);
                kfree(dev->vpd->attr);
        }

        pcie_aspm_remove_sysfs_dev_files(dev);
}

/**
 * pci_remove_sysfs_dev_files - cleanup PCI specific sysfs files
 * @pdev: device whose entries we should free
 *
 * Cleanup when @pdev is removed from sysfs.
 */
void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
{
        int rom_size = 0;

        if (!sysfs_initialized)
                return;

        pci_remove_capabilities_sysfs(pdev);

        if (pdev->cfg_size < PCI_CFG_SPACE_EXP_SIZE)
                sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
        else
                sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);

        pci_remove_resource_files(pdev);

        if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
                rom_size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
        else if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
                rom_size = 0x20000;

        if (rom_size && pdev->rom_attr) {
                sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr);
                kfree(pdev->rom_attr);
        }
}

static int __init pci_sysfs_init(void)
{
        struct pci_dev *pdev = NULL;
        int retval;

        sysfs_initialized = 1;
        for_each_pci_dev(pdev) {
                retval = pci_create_sysfs_dev_files(pdev);
                if (retval) {
                        pci_dev_put(pdev);
                        return retval;
                }
        }

        return 0;
}

late_initcall(pci_sysfs_init);