root/sound/sound_firmware.c

#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/uaccess.h>

static int do_mod_firmware_load(const char *fn, char **fp)
{
        struct file* filp;
        long l;
        char *dp;
        loff_t pos;

        filp = filp_open(fn, 0, 0);
        if (IS_ERR(filp))
        {
                printk(KERN_INFO "Unable to load '%s'.\n", fn);
                return 0;
        }
        l = filp->f_dentry->d_inode->i_size;
        if (l <= 0 || l > 131072)
        {
                printk(KERN_INFO "Invalid firmware '%s'\n", fn);
                filp_close(filp, current->files);
                return 0;
        }
        dp = vmalloc(l);
        if (dp == NULL)
        {
                printk(KERN_INFO "Out of memory loading '%s'.\n", fn);
                filp_close(filp, current->files);
                return 0;
        }
        pos = 0;
        if (vfs_read(filp, dp, l, &pos) != l)
        {
                printk(KERN_INFO "Failed to read '%s'.\n", fn);
                vfree(dp);
                filp_close(filp, current->files);
                return 0;
        }
        filp_close(filp, current->files);
        *fp = dp;
        return (int) l;
}

/**
 *      mod_firmware_load - load sound driver firmware
 *      @fn: filename
 *      @fp: return for the buffer.
 *
 *      Load the firmware for a sound module (up to 128K) into a buffer.
 *      The buffer is returned in *fp. It is allocated with vmalloc so is
 *      virtually linear and not DMAable. The caller should free it with
 *      vfree when finished.
 *
 *      The length of the buffer is returned on a successful load, the
 *      value zero on a failure.
 *
 *      Caution: This API is not recommended. Firmware should be loaded via
 *      an ioctl call and a setup application. This function may disappear
 *      in future.
 */
 
int mod_firmware_load(const char *fn, char **fp)
{
        int r;
        mm_segment_t fs = get_fs();

        set_fs(get_ds());
        r = do_mod_firmware_load(fn, fp);
        set_fs(fs);
        return r;
}