treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / pci / pci-sysfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * (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/export.h>
#include <linux/topology.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/capability.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <linux/vgaarb.h>
#include <linux/pm_runtime.h>
#include <linux/of.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);                \
}                                                                       \
static DEVICE_ATTR_RO(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(revision, "0x%02x\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 (kstrtoul(buf, 0, &val) < 0)
                return -EINVAL;

        pdev->broken_parity_status = !!val;

        return count;
}
static DEVICE_ATTR_RW(broken_parity_status);

static ssize_t pci_dev_show_local_cpu(struct device *dev, bool list,
                                      struct device_attribute *attr, char *buf)
{
        const struct cpumask *mask;

#ifdef CONFIG_NUMA
        mask = (dev_to_node(dev) == -1) ? cpu_online_mask :
                                          cpumask_of_node(dev_to_node(dev));
#else
        mask = cpumask_of_pcibus(to_pci_dev(dev)->bus);
#endif
        return cpumap_print_to_pagebuf(list, buf, mask);
}

static ssize_t local_cpus_show(struct device *dev,
                               struct device_attribute *attr, char *buf)
{
        return pci_dev_show_local_cpu(dev, false, attr, buf);
}
static DEVICE_ATTR_RO(local_cpus);

static ssize_t local_cpulist_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        return pci_dev_show_local_cpu(dev, true, attr, buf);
}
static DEVICE_ATTR_RO(local_cpulist);

/*
 * PCI Bus Class Devices
 */
static ssize_t cpuaffinity_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        const struct cpumask *cpumask = cpumask_of_pcibus(to_pci_bus(dev));

        return cpumap_print_to_pagebuf(false, buf, cpumask);
}
static DEVICE_ATTR_RO(cpuaffinity);

static ssize_t cpulistaffinity_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        const struct cpumask *cpumask = cpumask_of_pcibus(to_pci_bus(dev));

        return cpumap_print_to_pagebuf(true, buf, cpumask);
}
static DEVICE_ATTR_RO(cpulistaffinity);

/* 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 DEVICE_ATTR_RO(resource);

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

        return sprintf(buf, "%s\n", PCIE_SPEED2STR(pcie_get_speed_cap(pdev)));
}
static DEVICE_ATTR_RO(max_link_speed);

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

        return sprintf(buf, "%u\n", pcie_get_width_cap(pdev));
}
static DEVICE_ATTR_RO(max_link_width);

static ssize_t current_link_speed_show(struct device *dev,
                                       struct device_attribute *attr, char *buf)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        u16 linkstat;
        int err;
        const char *speed;

        err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat);
        if (err)
                return -EINVAL;

        switch (linkstat & PCI_EXP_LNKSTA_CLS) {
        case PCI_EXP_LNKSTA_CLS_32_0GB:
                speed = "32 GT/s";
                break;
        case PCI_EXP_LNKSTA_CLS_16_0GB:
                speed = "16 GT/s";
                break;
        case PCI_EXP_LNKSTA_CLS_8_0GB:
                speed = "8 GT/s";
                break;
        case PCI_EXP_LNKSTA_CLS_5_0GB:
                speed = "5 GT/s";
                break;
        case PCI_EXP_LNKSTA_CLS_2_5GB:
                speed = "2.5 GT/s";
                break;
        default:
                speed = "Unknown speed";
        }

        return sprintf(buf, "%s\n", speed);
}
static DEVICE_ATTR_RO(current_link_speed);

static ssize_t current_link_width_show(struct device *dev,
                                       struct device_attribute *attr, char *buf)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        u16 linkstat;
        int err;

        err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat);
        if (err)
                return -EINVAL;

        return sprintf(buf, "%u\n",
                (linkstat & PCI_EXP_LNKSTA_NLW) >> PCI_EXP_LNKSTA_NLW_SHIFT);
}
static DEVICE_ATTR_RO(current_link_width);

static ssize_t secondary_bus_number_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        u8 sec_bus;
        int err;

        err = pci_read_config_byte(pci_dev, PCI_SECONDARY_BUS, &sec_bus);
        if (err)
                return -EINVAL;

        return sprintf(buf, "%u\n", sec_bus);
}
static DEVICE_ATTR_RO(secondary_bus_number);

static ssize_t subordinate_bus_number_show(struct device *dev,
                                           struct device_attribute *attr,
                                           char *buf)
{
        struct pci_dev *pci_dev = to_pci_dev(dev);
        u8 sub_bus;
        int err;

        err = pci_read_config_byte(pci_dev, PCI_SUBORDINATE_BUS, &sub_bus);
        if (err)
                return -EINVAL;

        return sprintf(buf, "%u\n", sub_bus);
}
static DEVICE_ATTR_RO(subordinate_bus_number);

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

        return sprintf(buf, "%u\n", pci_ari_enabled(pci_dev->bus));
}
static DEVICE_ATTR_RO(ari_enabled);

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 DEVICE_ATTR_RO(modalias);

static ssize_t enable_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 = kstrtoul(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;

        device_lock(dev);
        if (dev->driver)
                result = -EBUSY;
        else if (val)
                result = pci_enable_device(pdev);
        else if (pci_is_enabled(pdev))
                pci_disable_device(pdev);
        else
                result = -EIO;
        device_unlock(dev);

        return result < 0 ? result : count;
}

static ssize_t enable_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));
}
static DEVICE_ATTR_RW(enable);

#ifdef CONFIG_NUMA
static ssize_t numa_node_store(struct device *dev,
                               struct device_attribute *attr, const char *buf,
                               size_t count)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        int node, ret;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        ret = kstrtoint(buf, 0, &node);
        if (ret)
                return ret;

        if ((node < 0 && node != NUMA_NO_NODE) || node >= MAX_NUMNODES)
                return -EINVAL;

        if (node != NUMA_NO_NODE && !node_online(node))
                return -EINVAL;

        add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
        pci_alert(pdev, FW_BUG "Overriding NUMA node to %d.  Contact your vendor for updates.",
                  node);

        dev->numa_node = node;
        return count;
}

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

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

        return sprintf(buf, "%d\n", fls64(pdev->dma_mask));
}
static DEVICE_ATTR_RO(dma_mask_bits);

static ssize_t consistent_dma_mask_bits_show(struct device *dev,
                                             struct device_attribute *attr,
                                             char *buf)
{
        return sprintf(buf, "%d\n", fls64(dev->coherent_dma_mask));
}
static DEVICE_ATTR_RO(consistent_dma_mask_bits);

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

        return sprintf(buf, "%u\n", subordinate ?
                       !(subordinate->bus_flags & PCI_BUS_FLAGS_NO_MSI)
                           : !pdev->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);
        struct pci_bus *subordinate = pdev->subordinate;
        unsigned long val;

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

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;

        /*
         * "no_msi" and "bus_flags" only affect what happens when a driver
         * requests MSI or MSI-X.  They don't affect any drivers that have
         * already requested MSI or MSI-X.
         */
        if (!subordinate) {
                pdev->no_msi = !val;
                pci_info(pdev, "MSI/MSI-X %s for future drivers\n",
                         val ? "allowed" : "disallowed");
                return count;
        }

        if (val)
                subordinate->bus_flags &= ~PCI_BUS_FLAGS_NO_MSI;
        else
                subordinate->bus_flags |= PCI_BUS_FLAGS_NO_MSI;

        dev_info(&subordinate->dev, "MSI/MSI-X %s for future drivers of devices on this bus\n",
                 val ? "allowed" : "disallowed");
        return count;
}
static DEVICE_ATTR_RW(msi_bus);

static ssize_t rescan_store(struct bus_type *bus, const char *buf, size_t count)
{
        unsigned long val;
        struct pci_bus *b = NULL;

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

        if (val) {
                pci_lock_rescan_remove();
                while ((b = pci_find_next_bus(b)) != NULL)
                        pci_rescan_bus(b);
                pci_unlock_rescan_remove();
        }
        return count;
}
static BUS_ATTR_WO(rescan);

static struct attribute *pci_bus_attrs[] = {
        &bus_attr_rescan.attr,
        NULL,
};

static const struct attribute_group pci_bus_group = {
        .attrs = pci_bus_attrs,
};

const struct attribute_group *pci_bus_groups[] = {
        &pci_bus_group,
        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 (kstrtoul(buf, 0, &val) < 0)
                return -EINVAL;

        if (val) {
                pci_lock_rescan_remove();
                pci_rescan_bus(pdev->bus);
                pci_unlock_rescan_remove();
        }
        return count;
}
static DEVICE_ATTR_WO(dev_rescan);

static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t count)
{
        unsigned long val;

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

        if (val && device_remove_file_self(dev, attr))
                pci_stop_and_remove_bus_device_locked(to_pci_dev(dev));
        return count;
}
static DEVICE_ATTR_IGNORE_LOCKDEP(remove, 0220, NULL,
                                  remove_store);

static ssize_t bus_rescan_store(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf, size_t count)
{
        unsigned long val;
        struct pci_bus *bus = to_pci_bus(dev);

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

        if (val) {
                pci_lock_rescan_remove();
                if (!pci_is_root_bus(bus) && list_empty(&bus->devices))
                        pci_rescan_bus_bridge_resize(bus->self);
                else
                        pci_rescan_bus(bus);
                pci_unlock_rescan_remove();
        }
        return count;
}
static DEVICE_ATTR_WO(bus_rescan);

#if defined(CONFIG_PM) && defined(CONFIG_ACPI)
static ssize_t d3cold_allowed_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 (kstrtoul(buf, 0, &val) < 0)
                return -EINVAL;

        pdev->d3cold_allowed = !!val;
        if (pdev->d3cold_allowed)
                pci_d3cold_enable(pdev);
        else
                pci_d3cold_disable(pdev);

        pm_runtime_resume(dev);

        return count;
}

static ssize_t d3cold_allowed_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        return sprintf(buf, "%u\n", pdev->d3cold_allowed);
}
static DEVICE_ATTR_RW(d3cold_allowed);
#endif

#ifdef CONFIG_OF
static ssize_t devspec_show(struct device *dev,
                            struct device_attribute *attr, char *buf)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct device_node *np = pci_device_to_OF_node(pdev);

        if (np == NULL)
                return 0;
        return sprintf(buf, "%pOF", np);
}
static DEVICE_ATTR_RO(devspec);
#endif

static ssize_t driver_override_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        char *driver_override, *old, *cp;

        /* We need to keep extra room for a newline */
        if (count >= (PAGE_SIZE - 1))
                return -EINVAL;

        driver_override = kstrndup(buf, count, GFP_KERNEL);
        if (!driver_override)
                return -ENOMEM;

        cp = strchr(driver_override, '\n');
        if (cp)
                *cp = '\0';

        device_lock(dev);
        old = pdev->driver_override;
        if (strlen(driver_override)) {
                pdev->driver_override = driver_override;
        } else {
                kfree(driver_override);
                pdev->driver_override = NULL;
        }
        device_unlock(dev);

        kfree(old);

        return count;
}

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

        device_lock(dev);
        len = snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
        device_unlock(dev);
        return len;
}
static DEVICE_ATTR_RW(driver_override);

static struct attribute *pci_dev_attrs[] = {
        &dev_attr_resource.attr,
        &dev_attr_vendor.attr,
        &dev_attr_device.attr,
        &dev_attr_subsystem_vendor.attr,
        &dev_attr_subsystem_device.attr,
        &dev_attr_revision.attr,
        &dev_attr_class.attr,
        &dev_attr_irq.attr,
        &dev_attr_local_cpus.attr,
        &dev_attr_local_cpulist.attr,
        &dev_attr_modalias.attr,
#ifdef CONFIG_NUMA
        &dev_attr_numa_node.attr,
#endif
        &dev_attr_dma_mask_bits.attr,
        &dev_attr_consistent_dma_mask_bits.attr,
        &dev_attr_enable.attr,
        &dev_attr_broken_parity_status.attr,
        &dev_attr_msi_bus.attr,
#if defined(CONFIG_PM) && defined(CONFIG_ACPI)
        &dev_attr_d3cold_allowed.attr,
#endif
#ifdef CONFIG_OF
        &dev_attr_devspec.attr,
#endif
        &dev_attr_driver_override.attr,
        &dev_attr_ari_enabled.attr,
        NULL,
};

static struct attribute *pci_bridge_attrs[] = {
        &dev_attr_subordinate_bus_number.attr,
        &dev_attr_secondary_bus_number.attr,
        NULL,
};

static struct attribute *pcie_dev_attrs[] = {
        &dev_attr_current_link_speed.attr,
        &dev_attr_current_link_width.attr,
        &dev_attr_max_link_width.attr,
        &dev_attr_max_link_speed.attr,
        NULL,
};

static struct attribute *pcibus_attrs[] = {
        &dev_attr_bus_rescan.attr,
        &dev_attr_cpuaffinity.attr,
        &dev_attr_cpulistaffinity.attr,
        NULL,
};

static const struct attribute_group pcibus_group = {
        .attrs = pcibus_attrs,
};

const struct attribute_group *pcibus_groups[] = {
        &pcibus_group,
        NULL,
};

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

        if (vga_dev)
                return sprintf(buf, "%u\n", (pdev == vga_dev));

        return sprintf(buf, "%u\n",
                !!(pdev->resource[PCI_ROM_RESOURCE].flags &
                   IORESOURCE_ROM_SHADOW));
}
static DEVICE_ATTR_RO(boot_vga);

static ssize_t pci_read_config(struct file *filp, struct kobject *kobj,
                               struct bin_attribute *bin_attr, char *buf,
                               loff_t off, size_t count)
{
        struct pci_dev *dev = to_pci_dev(kobj_to_dev(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 (file_ns_capable(filp, &init_user_ns, 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;
        }

        pci_config_pm_runtime_get(dev);

        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;
        }

        pci_config_pm_runtime_put(dev);

        return count;
}

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

        ret = security_locked_down(LOCKDOWN_PCI_ACCESS);
        if (ret)
                return ret;

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

        pci_config_pm_runtime_get(dev);

        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;
        }

        pci_config_pm_runtime_put(dev);

        return count;
}

#ifdef HAVE_PCI_LEGACY
/**
 * pci_read_legacy_io - read byte(s) from legacy I/O port space
 * @filp: open sysfs file
 * @kobj: kobject corresponding to file to read from
 * @bin_attr: struct bin_attribute for this file
 * @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 file *filp, struct kobject *kobj,
                                  struct bin_attribute *bin_attr, char *buf,
                                  loff_t off, size_t count)
{
        struct pci_bus *bus = to_pci_bus(kobj_to_dev(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
 * @filp: open sysfs file
 * @kobj: kobject corresponding to file to read from
 * @bin_attr: struct bin_attribute for this file
 * @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 file *filp, struct kobject *kobj,
                                   struct bin_attribute *bin_attr, char *buf,
                                   loff_t off, size_t count)
{
        struct pci_bus *bus = to_pci_bus(kobj_to_dev(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
 * @filp: open sysfs file
 * @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 file *filp, struct kobject *kobj,
                               struct bin_attribute *attr,
                               struct vm_area_struct *vma)
{
        struct pci_bus *bus = to_pci_bus(kobj_to_dev(kobj));

        return pci_mmap_legacy_page_range(bus, vma, pci_mmap_mem);
}

/**
 * pci_mmap_legacy_io - map legacy PCI IO into user memory space
 * @filp: open sysfs file
 * @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 file *filp, struct kobject *kobj,
                              struct bin_attribute *attr,
                              struct vm_area_struct *vma)
{
        struct pci_bus *bus = to_pci_bus(kobj_to_dev(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)
{
}

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

        sysfs_bin_attr_init(b->legacy_io);
        b->legacy_io->attr.name = "legacy_io";
        b->legacy_io->size = 0xffff;
        b->legacy_io->attr.mode = 0600;
        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;
        sysfs_bin_attr_init(b->legacy_mem);
        b->legacy_mem->attr.name = "legacy_mem";
        b->legacy_mem->size = 1024*1024;
        b->legacy_mem->attr.mode = 0600;
        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:
        dev_warn(&b->dev, "could not create legacy I/O port and ISA memory resources in sysfs\n");
}

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 */

#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)
{
        unsigned long nr, start, size;
        resource_size_t pci_start = 0, pci_end;

        if (pci_resource_len(pdev, resno) == 0)
                return 0;
        nr = vma_pages(vma);
        start = vma->vm_pgoff;
        size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
        if (mmap_api == PCI_MMAP_PROCFS) {
                pci_resource_to_user(pdev, resno, &pdev->resource[resno],
                                     &pci_start, &pci_end);
                pci_start >>= PAGE_SHIFT;
        }
        if (start >= pci_start && start < pci_start + size &&
                        start + nr <= pci_start + size)
                return 1;
        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(kobj_to_dev(kobj));
        int bar = (unsigned long)attr->private;
        enum pci_mmap_state mmap_type;
        struct resource *res = &pdev->resource[bar];
        int ret;

        ret = security_locked_down(LOCKDOWN_PCI_ACCESS);
        if (ret)
                return ret;

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

        if (!pci_mmap_fits(pdev, bar, vma, PCI_MMAP_SYSFS))
                return -EINVAL;

        mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;

        return pci_mmap_resource_range(pdev, bar, vma, mmap_type, write_combine);
}

static int pci_mmap_resource_uc(struct file *filp, 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 file *filp, struct kobject *kobj,
                                struct bin_attribute *attr,
                                struct vm_area_struct *vma)
{
        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(kobj_to_dev(kobj));
        int bar = (unsigned long)attr->private;
        unsigned long port = off;

        port += pci_resource_start(pdev, bar);

        if (port > pci_resource_end(pdev, bar))
                return 0;

        if (port + count - 1 > pci_resource_end(pdev, bar))
                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)
{
        int ret;

        ret = security_locked_down(LOCKDOWN_PCI_ACCESS);
        if (ret)
                return ret;

        return pci_resource_io(filp, kobj, attr, buf, off, count, true);
}

/**
 * pci_remove_resource_files - cleanup resource files
 * @pdev: dev to cleanup
 *
 * If we created resource files for @pdev, 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_STD_NUM_BARS; 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;
        char *res_attr_name;
        int retval;

        res_attr = kzalloc(sizeof(*res_attr) + name_len, GFP_ATOMIC);
        if (!res_attr)
                return -ENOMEM;

        res_attr_name = (char *)(res_attr + 1);

        sysfs_bin_attr_init(res_attr);
        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);
                if (pci_resource_flags(pdev, num) & IORESOURCE_IO) {
                        res_attr->read = pci_read_resource_io;
                        res_attr->write = pci_write_resource_io;
                        if (arch_can_pci_mmap_io())
                                res_attr->mmap = pci_mmap_resource_uc;
                } else {
                        res_attr->mmap = pci_mmap_resource_uc;
                }
        }
        res_attr->attr.name = res_attr_name;
        res_attr->attr.mode = 0600;
        res_attr->size = pci_resource_len(pdev, num);
        res_attr->private = (void *)(unsigned long)num;
        retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
        if (retval)
                kfree(res_attr);

        return retval;
}

/**
 * pci_create_resource_files - create resource files in sysfs for @dev
 * @pdev: dev in question
 *
 * Walk the resources in @pdev 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_STD_NUM_BARS; 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 && arch_can_pci_mmap_wc() &&
                    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
 * @filp: sysfs file
 * @kobj: kernel object handle
 * @bin_attr: struct bin_attribute for this file
 * @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 file *filp, struct kobject *kobj,
                             struct bin_attribute *bin_attr, char *buf,
                             loff_t off, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(kobj_to_dev(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
 * @filp: sysfs file
 * @kobj: kernel object handle
 * @bin_attr: struct bin_attribute for this file
 * @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 file *filp, struct kobject *kobj,
                            struct bin_attribute *bin_attr, char *buf,
                            loff_t off, size_t count)
{
        struct pci_dev *pdev = to_pci_dev(kobj_to_dev(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 const struct bin_attribute pci_config_attr = {
        .attr = {
                .name = "config",
                .mode = 0644,
        },
        .size = PCI_CFG_SPACE_SIZE,
        .read = pci_read_config,
        .write = pci_write_config,
};

static const struct bin_attribute pcie_config_attr = {
        .attr = {
                .name = "config",
                .mode = 0644,
        },
        .size = PCI_CFG_SPACE_EXP_SIZE,
        .read = pci_read_config,
        .write = pci_write_config,
};

static ssize_t reset_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 = kstrtoul(buf, 0, &val);

        if (result < 0)
                return result;

        if (val != 1)
                return -EINVAL;

        pm_runtime_get_sync(dev);
        result = pci_reset_function(pdev);
        pm_runtime_put(dev);
        if (result < 0)
                return result;

        return count;
}

static DEVICE_ATTR(reset, 0200, NULL, reset_store);

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

        pcie_vpd_create_sysfs_dev_files(dev);

        if (dev->reset_fn) {
                retval = device_create_file(&dev->dev, &dev_attr_reset);
                if (retval)
                        goto error;
        }
        return 0;

error:
        pcie_vpd_remove_sysfs_dev_files(dev);
        return retval;
}

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

        if (!sysfs_initialized)
                return -EACCES;

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

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

        /* If the device has a ROM, try to expose it in sysfs. */
        rom_size = pci_resource_len(pdev, PCI_ROM_RESOURCE);
        if (rom_size) {
                attr = kzalloc(sizeof(*attr), GFP_ATOMIC);
                if (!attr) {
                        retval = -ENOMEM;
                        goto err_resource_files;
                }
                sysfs_bin_attr_init(attr);
                attr->size = rom_size;
                attr->attr.name = "rom";
                attr->attr.mode = 0600;
                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;
        }

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

        pci_create_firmware_label_files(pdev);

        return 0;

err_rom_file:
        if (pdev->rom_attr) {
                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_SIZE)
                sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);
        else
                sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
err:
        return retval;
}

static void pci_remove_capabilities_sysfs(struct pci_dev *dev)
{
        pcie_vpd_remove_sysfs_dev_files(dev);
        if (dev->reset_fn) {
                device_remove_file(&dev->dev, &dev_attr_reset);
                dev->reset_fn = 0;
        }
}

/**
 * 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)
{
        if (!sysfs_initialized)
                return;

        pci_remove_capabilities_sysfs(pdev);

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

        pci_remove_resource_files(pdev);

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

        pci_remove_firmware_label_files(pdev);
}

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);

static struct attribute *pci_dev_dev_attrs[] = {
        &dev_attr_boot_vga.attr,
        NULL,
};

static umode_t pci_dev_attrs_are_visible(struct kobject *kobj,
                                         struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (a == &dev_attr_boot_vga.attr)
                if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
                        return 0;

        return a->mode;
}

static struct attribute *pci_dev_hp_attrs[] = {
        &dev_attr_remove.attr,
        &dev_attr_dev_rescan.attr,
        NULL,
};

static umode_t pci_dev_hp_attrs_are_visible(struct kobject *kobj,
                                            struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (pdev->is_virtfn)
                return 0;

        return a->mode;
}

static umode_t pci_bridge_attrs_are_visible(struct kobject *kobj,
                                            struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (pci_is_bridge(pdev))
                return a->mode;

        return 0;
}

static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj,
                                          struct attribute *a, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);

        if (pci_is_pcie(pdev))
                return a->mode;

        return 0;
}

static const struct attribute_group pci_dev_group = {
        .attrs = pci_dev_attrs,
};

const struct attribute_group *pci_dev_groups[] = {
        &pci_dev_group,
        NULL,
};

static const struct attribute_group pci_dev_hp_attr_group = {
        .attrs = pci_dev_hp_attrs,
        .is_visible = pci_dev_hp_attrs_are_visible,
};

static const struct attribute_group pci_dev_attr_group = {
        .attrs = pci_dev_dev_attrs,
        .is_visible = pci_dev_attrs_are_visible,
};

static const struct attribute_group pci_bridge_attr_group = {
        .attrs = pci_bridge_attrs,
        .is_visible = pci_bridge_attrs_are_visible,
};

static const struct attribute_group pcie_dev_attr_group = {
        .attrs = pcie_dev_attrs,
        .is_visible = pcie_dev_attrs_are_visible,
};

static const struct attribute_group *pci_dev_attr_groups[] = {
        &pci_dev_attr_group,
        &pci_dev_hp_attr_group,
#ifdef CONFIG_PCI_IOV
        &sriov_dev_attr_group,
#endif
        &pci_bridge_attr_group,
        &pcie_dev_attr_group,
#ifdef CONFIG_PCIEAER
        &aer_stats_attr_group,
#endif
#ifdef CONFIG_PCIEASPM
        &aspm_ctrl_attr_group,
#endif
        NULL,
};

const struct device_type pci_dev_type = {
        .groups = pci_dev_attr_groups,
};