UBUNTU: Ubuntu-4.15.0-96.97

[mirror_ubuntu-bionic-kernel.git] / lib / test_firmware.c

/*
 * This module provides an interface to trigger and test firmware loading.
 *
 * It is designed to be used for basic evaluation of the firmware loading
 * subsystem (for example when validating firmware verification). It lacks
 * any extra dependencies, and will not normally be loaded by the system
 * unless explicitly requested by name.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/completion.h>
#include <linux/firmware.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/kthread.h>

#define TEST_FIRMWARE_NAME      "test-firmware.bin"
#define TEST_FIRMWARE_NUM_REQS  4

static DEFINE_MUTEX(test_fw_mutex);
static const struct firmware *test_firmware;

struct test_batched_req {
        u8 idx;
        int rc;
        bool sent;
        const struct firmware *fw;
        const char *name;
        struct completion completion;
        struct task_struct *task;
        struct device *dev;
};

/**
 * test_config - represents configuration for the test for different triggers
 *
 * @name: the name of the firmware file to look for
 * @sync_direct: when the sync trigger is used if this is true
 *      request_firmware_direct() will be used instead.
 * @send_uevent: whether or not to send a uevent for async requests
 * @num_requests: number of requests to try per test case. This is trigger
 *      specific.
 * @reqs: stores all requests information
 * @read_fw_idx: index of thread from which we want to read firmware results
 *      from through the read_fw trigger.
 * @test_result: a test may use this to collect the result from the call
 *      of the request_firmware*() calls used in their tests. In order of
 *      priority we always keep first any setup error. If no setup errors were
 *      found then we move on to the first error encountered while running the
 *      API. Note that for async calls this typically will be a successful
 *      result (0) unless of course you've used bogus parameters, or the system
 *      is out of memory.  In the async case the callback is expected to do a
 *      bit more homework to figure out what happened, unfortunately the only
 *      information passed today on error is the fact that no firmware was
 *      found so we can only assume -ENOENT on async calls if the firmware is
 *      NULL.
 *
 *      Errors you can expect:
 *
 *      API specific:
 *
 *      0:              success for sync, for async it means request was sent
 *      -EINVAL:        invalid parameters or request
 *      -ENOENT:        files not found
 *
 *      System environment:
 *
 *      -ENOMEM:        memory pressure on system
 *      -ENODEV:        out of number of devices to test
 *      -EINVAL:        an unexpected error has occurred
 * @req_firmware: if @sync_direct is true this is set to
 *      request_firmware_direct(), otherwise request_firmware()
 */
struct test_config {
        char *name;
        bool sync_direct;
        bool send_uevent;
        u8 num_requests;
        u8 read_fw_idx;

        /*
         * These below don't belong her but we'll move them once we create
         * a struct fw_test_device and stuff the misc_dev under there later.
         */
        struct test_batched_req *reqs;
        int test_result;
        int (*req_firmware)(const struct firmware **fw, const char *name,
                            struct device *device);
};

struct test_config *test_fw_config;

static ssize_t test_fw_misc_read(struct file *f, char __user *buf,
                                 size_t size, loff_t *offset)
{
        ssize_t rc = 0;

        mutex_lock(&test_fw_mutex);
        if (test_firmware)
                rc = simple_read_from_buffer(buf, size, offset,
                                             test_firmware->data,
                                             test_firmware->size);
        mutex_unlock(&test_fw_mutex);
        return rc;
}

static const struct file_operations test_fw_fops = {
        .owner          = THIS_MODULE,
        .read           = test_fw_misc_read,
};

static void __test_release_all_firmware(void)
{
        struct test_batched_req *req;
        u8 i;

        if (!test_fw_config->reqs)
                return;

        for (i = 0; i < test_fw_config->num_requests; i++) {
                req = &test_fw_config->reqs[i];
                if (req->fw)
                        release_firmware(req->fw);
        }

        vfree(test_fw_config->reqs);
        test_fw_config->reqs = NULL;
}

static void test_release_all_firmware(void)
{
        mutex_lock(&test_fw_mutex);
        __test_release_all_firmware();
        mutex_unlock(&test_fw_mutex);
}


static void __test_firmware_config_free(void)
{
        __test_release_all_firmware();
        kfree_const(test_fw_config->name);
        test_fw_config->name = NULL;
}

/*
 * XXX: move to kstrncpy() once merged.
 *
 * Users should use kfree_const() when freeing these.
 */
static int __kstrncpy(char **dst, const char *name, size_t count, gfp_t gfp)
{
        *dst = kstrndup(name, count, gfp);
        if (!*dst)
                return -ENOSPC;
        return count;
}

static int __test_firmware_config_init(void)
{
        int ret;

        ret = __kstrncpy(&test_fw_config->name, TEST_FIRMWARE_NAME,
                         strlen(TEST_FIRMWARE_NAME), GFP_KERNEL);
        if (ret < 0)
                goto out;

        test_fw_config->num_requests = TEST_FIRMWARE_NUM_REQS;
        test_fw_config->send_uevent = true;
        test_fw_config->sync_direct = false;
        test_fw_config->req_firmware = request_firmware;
        test_fw_config->test_result = 0;
        test_fw_config->reqs = NULL;

        return 0;

out:
        __test_firmware_config_free();
        return ret;
}

static ssize_t reset_store(struct device *dev,
                           struct device_attribute *attr,
                           const char *buf, size_t count)
{
        int ret;

        mutex_lock(&test_fw_mutex);

        __test_firmware_config_free();

        ret = __test_firmware_config_init();
        if (ret < 0) {
                ret = -ENOMEM;
                pr_err("could not alloc settings for config trigger: %d\n",
                       ret);
                goto out;
        }

        pr_info("reset\n");
        ret = count;

out:
        mutex_unlock(&test_fw_mutex);

        return ret;
}
static DEVICE_ATTR_WO(reset);

static ssize_t config_show(struct device *dev,
                           struct device_attribute *attr,
                           char *buf)
{
        int len = 0;

        mutex_lock(&test_fw_mutex);

        len += snprintf(buf, PAGE_SIZE,
                        "Custom trigger configuration for: %s\n",
                        dev_name(dev));

        if (test_fw_config->name)
                len += snprintf(buf+len, PAGE_SIZE,
                                "name:\t%s\n",
                                test_fw_config->name);
        else
                len += snprintf(buf+len, PAGE_SIZE,
                                "name:\tEMTPY\n");

        len += snprintf(buf+len, PAGE_SIZE,
                        "num_requests:\t%u\n", test_fw_config->num_requests);

        len += snprintf(buf+len, PAGE_SIZE,
                        "send_uevent:\t\t%s\n",
                        test_fw_config->send_uevent ?
                        "FW_ACTION_HOTPLUG" :
                        "FW_ACTION_NOHOTPLUG");
        len += snprintf(buf+len, PAGE_SIZE,
                        "sync_direct:\t\t%s\n",
                        test_fw_config->sync_direct ? "true" : "false");
        len += snprintf(buf+len, PAGE_SIZE,
                        "read_fw_idx:\t%u\n", test_fw_config->read_fw_idx);

        mutex_unlock(&test_fw_mutex);

        return len;
}
static DEVICE_ATTR_RO(config);

static ssize_t config_name_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        int ret;

        mutex_lock(&test_fw_mutex);
        kfree_const(test_fw_config->name);
        ret = __kstrncpy(&test_fw_config->name, buf, count, GFP_KERNEL);
        mutex_unlock(&test_fw_mutex);

        return ret;
}

/*
 * As per sysfs_kf_seq_show() the buf is max PAGE_SIZE.
 */
static ssize_t config_test_show_str(char *dst,
                                    char *src)
{
        int len;

        mutex_lock(&test_fw_mutex);
        len = snprintf(dst, PAGE_SIZE, "%s\n", src);
        mutex_unlock(&test_fw_mutex);

        return len;
}

static int test_dev_config_update_bool(const char *buf, size_t size,
                                       bool *cfg)
{
        int ret;

        mutex_lock(&test_fw_mutex);
        if (strtobool(buf, cfg) < 0)
                ret = -EINVAL;
        else
                ret = size;
        mutex_unlock(&test_fw_mutex);

        return ret;
}

static ssize_t
test_dev_config_show_bool(char *buf,
                          bool config)
{
        bool val;

        mutex_lock(&test_fw_mutex);
        val = config;
        mutex_unlock(&test_fw_mutex);

        return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

static ssize_t test_dev_config_show_int(char *buf, int cfg)
{
        int val;

        mutex_lock(&test_fw_mutex);
        val = cfg;
        mutex_unlock(&test_fw_mutex);

        return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

static int test_dev_config_update_u8(const char *buf, size_t size, u8 *cfg)
{
        int ret;
        long new;

        ret = kstrtol(buf, 10, &new);
        if (ret)
                return ret;

        if (new > U8_MAX)
                return -EINVAL;

        mutex_lock(&test_fw_mutex);
        *(u8 *)cfg = new;
        mutex_unlock(&test_fw_mutex);

        /* Always return full write size even if we didn't consume all */
        return size;
}

static ssize_t test_dev_config_show_u8(char *buf, u8 cfg)
{
        u8 val;

        mutex_lock(&test_fw_mutex);
        val = cfg;
        mutex_unlock(&test_fw_mutex);

        return snprintf(buf, PAGE_SIZE, "%u\n", val);
}

static ssize_t config_name_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        return config_test_show_str(buf, test_fw_config->name);
}
static DEVICE_ATTR_RW(config_name);

static ssize_t config_num_requests_store(struct device *dev,
                                         struct device_attribute *attr,
                                         const char *buf, size_t count)
{
        int rc;

        mutex_lock(&test_fw_mutex);
        if (test_fw_config->reqs) {
                pr_err("Must call release_all_firmware prior to changing config\n");
                rc = -EINVAL;
                mutex_unlock(&test_fw_mutex);
                goto out;
        }
        mutex_unlock(&test_fw_mutex);

        rc = test_dev_config_update_u8(buf, count,
                                       &test_fw_config->num_requests);

out:
        return rc;
}

static ssize_t config_num_requests_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        return test_dev_config_show_u8(buf, test_fw_config->num_requests);
}
static DEVICE_ATTR_RW(config_num_requests);

static ssize_t config_sync_direct_store(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t count)
{
        int rc = test_dev_config_update_bool(buf, count,
                                             &test_fw_config->sync_direct);

        if (rc == count)
                test_fw_config->req_firmware = test_fw_config->sync_direct ?
                                       request_firmware_direct :
                                       request_firmware;
        return rc;
}

static ssize_t config_sync_direct_show(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        return test_dev_config_show_bool(buf, test_fw_config->sync_direct);
}
static DEVICE_ATTR_RW(config_sync_direct);

static ssize_t config_send_uevent_store(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t count)
{
        return test_dev_config_update_bool(buf, count,
                                           &test_fw_config->send_uevent);
}

static ssize_t config_send_uevent_show(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        return test_dev_config_show_bool(buf, test_fw_config->send_uevent);
}
static DEVICE_ATTR_RW(config_send_uevent);

static ssize_t config_read_fw_idx_store(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t count)
{
        return test_dev_config_update_u8(buf, count,
                                         &test_fw_config->read_fw_idx);
}

static ssize_t config_read_fw_idx_show(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        return test_dev_config_show_u8(buf, test_fw_config->read_fw_idx);
}
static DEVICE_ATTR_RW(config_read_fw_idx);


static ssize_t trigger_request_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        int rc;
        char *name;

        name = kstrndup(buf, count, GFP_KERNEL);
        if (!name)
                return -ENOSPC;

        pr_info("loading '%s'\n", name);

        mutex_lock(&test_fw_mutex);
        release_firmware(test_firmware);
        test_firmware = NULL;
        rc = request_firmware(&test_firmware, name, dev);
        if (rc) {
                pr_info("load of '%s' failed: %d\n", name, rc);
                goto out;
        }
        pr_info("loaded: %zu\n", test_firmware->size);
        rc = count;

out:
        mutex_unlock(&test_fw_mutex);

        kfree(name);

        return rc;
}
static DEVICE_ATTR_WO(trigger_request);

static DECLARE_COMPLETION(async_fw_done);

static void trigger_async_request_cb(const struct firmware *fw, void *context)
{
        test_firmware = fw;
        complete(&async_fw_done);
}

static ssize_t trigger_async_request_store(struct device *dev,
                                           struct device_attribute *attr,
                                           const char *buf, size_t count)
{
        int rc;
        char *name;

        name = kstrndup(buf, count, GFP_KERNEL);
        if (!name)
                return -ENOSPC;

        pr_info("loading '%s'\n", name);

        mutex_lock(&test_fw_mutex);
        release_firmware(test_firmware);
        test_firmware = NULL;
        rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL,
                                     NULL, trigger_async_request_cb);
        if (rc) {
                pr_info("async load of '%s' failed: %d\n", name, rc);
                kfree(name);
                goto out;
        }
        /* Free 'name' ASAP, to test for race conditions */
        kfree(name);

        wait_for_completion(&async_fw_done);

        if (test_firmware) {
                pr_info("loaded: %zu\n", test_firmware->size);
                rc = count;
        } else {
                pr_err("failed to async load firmware\n");
                rc = -ENODEV;
        }

out:
        mutex_unlock(&test_fw_mutex);

        return rc;
}
static DEVICE_ATTR_WO(trigger_async_request);

static ssize_t trigger_custom_fallback_store(struct device *dev,
                                             struct device_attribute *attr,
                                             const char *buf, size_t count)
{
        int rc;
        char *name;

        name = kstrndup(buf, count, GFP_KERNEL);
        if (!name)
                return -ENOSPC;

        pr_info("loading '%s' using custom fallback mechanism\n", name);

        mutex_lock(&test_fw_mutex);
        release_firmware(test_firmware);
        test_firmware = NULL;
        rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG, name,
                                     dev, GFP_KERNEL, NULL,
                                     trigger_async_request_cb);
        if (rc) {
                pr_info("async load of '%s' failed: %d\n", name, rc);
                kfree(name);
                goto out;
        }
        /* Free 'name' ASAP, to test for race conditions */
        kfree(name);

        wait_for_completion(&async_fw_done);

        if (test_firmware) {
                pr_info("loaded: %zu\n", test_firmware->size);
                rc = count;
        } else {
                pr_err("failed to async load firmware\n");
                rc = -ENODEV;
        }

out:
        mutex_unlock(&test_fw_mutex);

        return rc;
}
static DEVICE_ATTR_WO(trigger_custom_fallback);

static int test_fw_run_batch_request(void *data)
{
        struct test_batched_req *req = data;

        if (!req) {
                test_fw_config->test_result = -EINVAL;
                return -EINVAL;
        }

        req->rc = test_fw_config->req_firmware(&req->fw, req->name, req->dev);
        if (req->rc) {
                pr_info("#%u: batched sync load failed: %d\n",
                        req->idx, req->rc);
                if (!test_fw_config->test_result)
                        test_fw_config->test_result = req->rc;
        } else if (req->fw) {
                req->sent = true;
                pr_info("#%u: batched sync loaded %zu\n",
                        req->idx, req->fw->size);
        }
        complete(&req->completion);

        req->task = NULL;

        return 0;
}

/*
 * We use a kthread as otherwise the kernel serializes all our sync requests
 * and we would not be able to mimic batched requests on a sync call. Batched
 * requests on a sync call can for instance happen on a device driver when
 * multiple cards are used and firmware loading happens outside of probe.
 */
static ssize_t trigger_batched_requests_store(struct device *dev,
                                              struct device_attribute *attr,
                                              const char *buf, size_t count)
{
        struct test_batched_req *req;
        int rc;
        u8 i;

        mutex_lock(&test_fw_mutex);

        test_fw_config->reqs = vzalloc(sizeof(struct test_batched_req) *
                                       test_fw_config->num_requests * 2);
        if (!test_fw_config->reqs) {
                rc = -ENOMEM;
                goto out_unlock;
        }

        pr_info("batched sync firmware loading '%s' %u times\n",
                test_fw_config->name, test_fw_config->num_requests);

        for (i = 0; i < test_fw_config->num_requests; i++) {
                req = &test_fw_config->reqs[i];
                if (!req) {
                        WARN_ON(1);
                        rc = -ENOMEM;
                        goto out_bail;
                }
                req->fw = NULL;
                req->idx = i;
                req->name = test_fw_config->name;
                req->dev = dev;
                init_completion(&req->completion);
                req->task = kthread_run(test_fw_run_batch_request, req,
                                             "%s-%u", KBUILD_MODNAME, req->idx);
                if (!req->task || IS_ERR(req->task)) {
                        pr_err("Setting up thread %u failed\n", req->idx);
                        req->task = NULL;
                        rc = -ENOMEM;
                        goto out_bail;
                }
        }

        rc = count;

        /*
         * We require an explicit release to enable more time and delay of
         * calling release_firmware() to improve our chances of forcing a
         * batched request. If we instead called release_firmware() right away
         * then we might miss on an opportunity of having a successful firmware
         * request pass on the opportunity to be come a batched request.
         */

out_bail:
        for (i = 0; i < test_fw_config->num_requests; i++) {
                req = &test_fw_config->reqs[i];
                if (req->task || req->sent)
                        wait_for_completion(&req->completion);
        }

        /* Override any worker error if we had a general setup error */
        if (rc < 0)
                test_fw_config->test_result = rc;

out_unlock:
        mutex_unlock(&test_fw_mutex);

        return rc;
}
static DEVICE_ATTR_WO(trigger_batched_requests);

/*
 * We wait for each callback to return with the lock held, no need to lock here
 */
static void trigger_batched_cb(const struct firmware *fw, void *context)
{
        struct test_batched_req *req = context;

        if (!req) {
                test_fw_config->test_result = -EINVAL;
                return;
        }

        /* forces *some* batched requests to queue up */
        if (!req->idx)
                ssleep(2);

        req->fw = fw;

        /*
         * Unfortunately the firmware API gives us nothing other than a null FW
         * if the firmware was not found on async requests.  Best we can do is
         * just assume -ENOENT. A better API would pass the actual return
         * value to the callback.
         */
        if (!fw && !test_fw_config->test_result)
                test_fw_config->test_result = -ENOENT;

        complete(&req->completion);
}

static
ssize_t trigger_batched_requests_async_store(struct device *dev,
                                             struct device_attribute *attr,
                                             const char *buf, size_t count)
{
        struct test_batched_req *req;
        bool send_uevent;
        int rc;
        u8 i;

        mutex_lock(&test_fw_mutex);

        test_fw_config->reqs = vzalloc(sizeof(struct test_batched_req) *
                                       test_fw_config->num_requests * 2);
        if (!test_fw_config->reqs) {
                rc = -ENOMEM;
                goto out;
        }

        pr_info("batched loading '%s' custom fallback mechanism %u times\n",
                test_fw_config->name, test_fw_config->num_requests);

        send_uevent = test_fw_config->send_uevent ? FW_ACTION_HOTPLUG :
                FW_ACTION_NOHOTPLUG;

        for (i = 0; i < test_fw_config->num_requests; i++) {
                req = &test_fw_config->reqs[i];
                if (!req) {
                        WARN_ON(1);
                        goto out_bail;
                }
                req->name = test_fw_config->name;
                req->fw = NULL;
                req->idx = i;
                init_completion(&req->completion);
                rc = request_firmware_nowait(THIS_MODULE, send_uevent,
                                             req->name,
                                             dev, GFP_KERNEL, req,
                                             trigger_batched_cb);
                if (rc) {
                        pr_info("#%u: batched async load failed setup: %d\n",
                                i, rc);
                        req->rc = rc;
                        goto out_bail;
                } else
                        req->sent = true;
        }

        rc = count;

out_bail:

        /*
         * We require an explicit release to enable more time and delay of
         * calling release_firmware() to improve our chances of forcing a
         * batched request. If we instead called release_firmware() right away
         * then we might miss on an opportunity of having a successful firmware
         * request pass on the opportunity to be come a batched request.
         */

        for (i = 0; i < test_fw_config->num_requests; i++) {
                req = &test_fw_config->reqs[i];
                if (req->sent)
                        wait_for_completion(&req->completion);
        }

        /* Override any worker error if we had a general setup error */
        if (rc < 0)
                test_fw_config->test_result = rc;

out:
        mutex_unlock(&test_fw_mutex);

        return rc;
}
static DEVICE_ATTR_WO(trigger_batched_requests_async);

static ssize_t test_result_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        return test_dev_config_show_int(buf, test_fw_config->test_result);
}
static DEVICE_ATTR_RO(test_result);

static ssize_t release_all_firmware_store(struct device *dev,
                                          struct device_attribute *attr,
                                          const char *buf, size_t count)
{
        test_release_all_firmware();
        return count;
}
static DEVICE_ATTR_WO(release_all_firmware);

static ssize_t read_firmware_show(struct device *dev,
                                  struct device_attribute *attr,
                                  char *buf)
{
        struct test_batched_req *req;
        u8 idx;
        ssize_t rc = 0;

        mutex_lock(&test_fw_mutex);

        idx = test_fw_config->read_fw_idx;
        if (idx >= test_fw_config->num_requests) {
                rc = -ERANGE;
                goto out;
        }

        if (!test_fw_config->reqs) {
                rc = -EINVAL;
                goto out;
        }

        req = &test_fw_config->reqs[idx];
        if (!req->fw) {
                pr_err("#%u: failed to async load firmware\n", idx);
                rc = -ENOENT;
                goto out;
        }

        pr_info("#%u: loaded %zu\n", idx, req->fw->size);

        if (req->fw->size > PAGE_SIZE) {
                pr_err("Testing interface must use PAGE_SIZE firmware for now\n");
                rc = -EINVAL;
        }
        memcpy(buf, req->fw->data, req->fw->size);

        rc = req->fw->size;
out:
        mutex_unlock(&test_fw_mutex);

        return rc;
}
static DEVICE_ATTR_RO(read_firmware);

#define TEST_FW_DEV_ATTR(name)          &dev_attr_##name.attr

static struct attribute *test_dev_attrs[] = {
        TEST_FW_DEV_ATTR(reset),

        TEST_FW_DEV_ATTR(config),
        TEST_FW_DEV_ATTR(config_name),
        TEST_FW_DEV_ATTR(config_num_requests),
        TEST_FW_DEV_ATTR(config_sync_direct),
        TEST_FW_DEV_ATTR(config_send_uevent),
        TEST_FW_DEV_ATTR(config_read_fw_idx),

        /* These don't use the config at all - they could be ported! */
        TEST_FW_DEV_ATTR(trigger_request),
        TEST_FW_DEV_ATTR(trigger_async_request),
        TEST_FW_DEV_ATTR(trigger_custom_fallback),

        /* These use the config and can use the test_result */
        TEST_FW_DEV_ATTR(trigger_batched_requests),
        TEST_FW_DEV_ATTR(trigger_batched_requests_async),

        TEST_FW_DEV_ATTR(release_all_firmware),
        TEST_FW_DEV_ATTR(test_result),
        TEST_FW_DEV_ATTR(read_firmware),
        NULL,
};

ATTRIBUTE_GROUPS(test_dev);

static struct miscdevice test_fw_misc_device = {
        .minor          = MISC_DYNAMIC_MINOR,
        .name           = "test_firmware",
        .fops           = &test_fw_fops,
        .groups         = test_dev_groups,
};

static int __init test_firmware_init(void)
{
        int rc;

        test_fw_config = kzalloc(sizeof(struct test_config), GFP_KERNEL);
        if (!test_fw_config)
                return -ENOMEM;

        rc = __test_firmware_config_init();
        if (rc)
                return rc;

        rc = misc_register(&test_fw_misc_device);
        if (rc) {
                kfree(test_fw_config);
                pr_err("could not register misc device: %d\n", rc);
                return rc;
        }

        pr_warn("interface ready\n");

        return 0;
}

module_init(test_firmware_init);

static void __exit test_firmware_exit(void)
{
        mutex_lock(&test_fw_mutex);
        release_firmware(test_firmware);
        misc_deregister(&test_fw_misc_device);
        __test_firmware_config_free();
        kfree(test_fw_config);
        mutex_unlock(&test_fw_mutex);

        pr_warn("removed interface\n");
}

module_exit(test_firmware_exit);

MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
MODULE_LICENSE("GPL");