// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2012
 *
 * Author(s):
 *   Jan Glauber <jang@linux.vnet.ibm.com>
 */

#define pr_fmt(fmt) "zpci: " fmt

#include <linux/kernel.h>
#include <linux/stat.h>
#include <linux/pci.h>

#include "../../../drivers/pci/pci.h"

#include <asm/sclp.h>

#define zpci_attr(name, fmt, member)                                    \
static ssize_t name##_show(struct device *dev,                          \
                           struct device_attribute *attr, char *buf)    \
{                                                                       \
        struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));               \
                                                                        \
        return sysfs_emit(buf, fmt, zdev->member);                              \
}                                                                       \
static DEVICE_ATTR_RO(name)

zpci_attr(function_id, "0x%08x\n", fid);
zpci_attr(function_handle, "0x%08x\n", fh);
zpci_attr(pchid, "0x%04x\n", pchid);
zpci_attr(pfgid, "0x%02x\n", pfgid);
zpci_attr(vfn, "0x%04x\n", vfn);
zpci_attr(pft, "0x%02x\n", pft);
zpci_attr(port, "%d\n", port);
zpci_attr(fidparm, "0x%02x\n", fidparm);
zpci_attr(uid, "0x%x\n", uid);
zpci_attr(segment0, "0x%02x\n", pfip[0]);
zpci_attr(segment1, "0x%02x\n", pfip[1]);
zpci_attr(segment2, "0x%02x\n", pfip[2]);
zpci_attr(segment3, "0x%02x\n", pfip[3]);

#define ZPCI_FW_ATTR_RO(_name)                                          \
        static struct kobj_attribute _name##_attr = __ATTR_RO(_name)

static ssize_t mio_enabled_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));

        return sysfs_emit(buf, zpci_use_mio(zdev) ? "1\n" : "0\n");
}
static DEVICE_ATTR_RO(mio_enabled);

static int _do_recover(struct pci_dev *pdev, struct zpci_dev *zdev)
{
        int ret;

        pci_stop_and_remove_bus_device(pdev);
        if (zdev_enabled(zdev)) {
                ret = zpci_disable_device(zdev);
                /*
                 * Due to a z/VM vs LPAR inconsistency in the error
                 * state the FH may indicate an enabled device but
                 * disable says the device is already disabled don't
                 * treat it as an error here.
                 */
                if (ret == -EINVAL)
                        ret = 0;
                if (ret)
                        return ret;
        }

        ret = zpci_reenable_device(zdev);

        return ret;
}

static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
                             const char *buf, size_t count)
{
        struct kernfs_node *kn;
        struct pci_dev *pdev = to_pci_dev(dev);
        struct zpci_dev *zdev = to_zpci(pdev);
        int ret = 0;

        /* Can't use device_remove_self() here as that would lead us to lock
         * the pci_rescan_remove_lock while holding the device' kernfs lock.
         * This would create a possible deadlock with disable_slot() which is
         * not directly protected by the device' kernfs lock but takes it
         * during the device removal which happens under
         * pci_rescan_remove_lock.
         *
         * This is analogous to sdev_store_delete() in
         * drivers/scsi/scsi_sysfs.c
         */
        kn = sysfs_break_active_protection(&dev->kobj, &attr->attr);
        WARN_ON_ONCE(!kn);

        /* Device needs to be configured and state must not change */
        mutex_lock(&zdev->state_lock);
        if (zdev->state != ZPCI_FN_STATE_CONFIGURED)
                goto out;

        /* device_remove_file() serializes concurrent calls ignoring all but
         * the first
         */
        device_remove_file(dev, attr);

        /* A concurrent call to recover_store() may slip between
         * sysfs_break_active_protection() and the sysfs file removal.
         * Once it unblocks from pci_lock_rescan_remove() the original pdev
         * will already be removed.
         */
        pci_lock_rescan_remove();
        if (pci_dev_is_added(pdev)) {
                ret = _do_recover(pdev, zdev);
        }
        pci_rescan_bus(zdev->zbus->bus);
        pci_unlock_rescan_remove();

out:
        mutex_unlock(&zdev->state_lock);
        if (kn)
                sysfs_unbreak_active_protection(kn);
        return ret ? ret : count;
}
static DEVICE_ATTR_WO(recover);

static ssize_t util_string_read(struct file *filp, struct kobject *kobj,
                                const struct bin_attribute *attr, char *buf,
                                loff_t off, size_t count)
{
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);
        struct zpci_dev *zdev = to_zpci(pdev);

        return memory_read_from_buffer(buf, count, &off, zdev->util_str,
                                       sizeof(zdev->util_str));
}
static const BIN_ATTR_RO(util_string, CLP_UTIL_STR_LEN);

static ssize_t report_error_write(struct file *filp, struct kobject *kobj,
                                  const struct bin_attribute *attr, char *buf,
                                  loff_t off, size_t count)
{
        struct zpci_report_error_header *report = (void *) buf;
        struct device *dev = kobj_to_dev(kobj);
        struct pci_dev *pdev = to_pci_dev(dev);
        struct zpci_dev *zdev = to_zpci(pdev);
        int ret;

        if (off || (count < sizeof(*report)))
                return -EINVAL;

        ret = sclp_pci_report(report, zdev->fh, zdev->fid);

        return ret ? ret : count;
}
static const BIN_ATTR(report_error, S_IWUSR, NULL, report_error_write, PAGE_SIZE);

static ssize_t uid_is_unique_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        return sysfs_emit(buf, "%d\n", zpci_unique_uid ? 1 : 0);
}
static DEVICE_ATTR_RO(uid_is_unique);

static ssize_t uid_checking_show(struct kobject *kobj,
                                 struct kobj_attribute *attr, char *buf)
{
        return sysfs_emit(buf, "%d\n", zpci_unique_uid ? 1 : 0);
}
ZPCI_FW_ATTR_RO(uid_checking);

/* analogous to smbios index */
static ssize_t index_show(struct device *dev,
                          struct device_attribute *attr, char *buf)
{
        struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
        u32 index = ~0;

        if (zpci_unique_uid)
                index = zdev->uid;

        return sysfs_emit(buf, "%u\n", index);
}
static DEVICE_ATTR_RO(index);

static umode_t zpci_index_is_visible(struct kobject *kobj,
                                     struct attribute *attr, int n)
{
        return zpci_unique_uid ? attr->mode : 0;
}

static struct attribute *zpci_ident_attrs[] = {
        &dev_attr_index.attr,
        NULL,
};

const struct attribute_group zpci_ident_attr_group = {
        .attrs = zpci_ident_attrs,
        .is_visible = zpci_index_is_visible,
};

static const struct bin_attribute *const zpci_bin_attrs[] = {
        &bin_attr_util_string,
        &bin_attr_report_error,
        NULL,
};

static struct attribute *zpci_dev_attrs[] = {
        &dev_attr_function_id.attr,
        &dev_attr_function_handle.attr,
        &dev_attr_pchid.attr,
        &dev_attr_pfgid.attr,
        &dev_attr_pft.attr,
        &dev_attr_port.attr,
        &dev_attr_fidparm.attr,
        &dev_attr_vfn.attr,
        &dev_attr_uid.attr,
        &dev_attr_recover.attr,
        &dev_attr_mio_enabled.attr,
        &dev_attr_uid_is_unique.attr,
        NULL,
};

const struct attribute_group zpci_attr_group = {
        .attrs = zpci_dev_attrs,
        .bin_attrs = zpci_bin_attrs,
};

static struct attribute *pfip_attrs[] = {
        &dev_attr_segment0.attr,
        &dev_attr_segment1.attr,
        &dev_attr_segment2.attr,
        &dev_attr_segment3.attr,
        NULL,
};

const struct attribute_group pfip_attr_group = {
        .name = "pfip",
        .attrs = pfip_attrs,
};

static struct attribute *clp_fw_attrs[] = {
        &uid_checking_attr.attr,
        NULL,
};

static struct attribute_group clp_fw_attr_group = {
        .name = "clp",
        .attrs = clp_fw_attrs,
};

int __init __zpci_fw_sysfs_init(void)
{
        return sysfs_create_group(firmware_kobj, &clp_fw_attr_group);
}