373 строки
8.2 KiB
C
373 строки
8.2 KiB
C
/*
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* arch/xtensa/platforms/iss/simdisk.c
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2001-2013 Tensilica Inc.
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* Authors Victor Prupis
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/blkdev.h>
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#include <linux/bio.h>
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#include <linux/proc_fs.h>
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#include <linux/uaccess.h>
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#include <platform/simcall.h>
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#define SIMDISK_MAJOR 240
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#define SIMDISK_MINORS 1
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#define MAX_SIMDISK_COUNT 10
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struct simdisk {
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const char *filename;
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spinlock_t lock;
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struct request_queue *queue;
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struct gendisk *gd;
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struct proc_dir_entry *procfile;
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int users;
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unsigned long size;
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int fd;
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};
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static int simdisk_count = CONFIG_BLK_DEV_SIMDISK_COUNT;
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module_param(simdisk_count, int, S_IRUGO);
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MODULE_PARM_DESC(simdisk_count, "Number of simdisk units.");
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static int n_files;
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static const char *filename[MAX_SIMDISK_COUNT] = {
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#ifdef CONFIG_SIMDISK0_FILENAME
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CONFIG_SIMDISK0_FILENAME,
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#ifdef CONFIG_SIMDISK1_FILENAME
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CONFIG_SIMDISK1_FILENAME,
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#endif
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#endif
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};
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static int simdisk_param_set_filename(const char *val,
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const struct kernel_param *kp)
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{
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if (n_files < ARRAY_SIZE(filename))
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filename[n_files++] = val;
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else
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return -EINVAL;
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return 0;
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}
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static const struct kernel_param_ops simdisk_param_ops_filename = {
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.set = simdisk_param_set_filename,
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};
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module_param_cb(filename, &simdisk_param_ops_filename, &n_files, 0);
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MODULE_PARM_DESC(filename, "Backing storage filename.");
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static int simdisk_major = SIMDISK_MAJOR;
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static void simdisk_transfer(struct simdisk *dev, unsigned long sector,
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unsigned long nsect, char *buffer, int write)
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{
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unsigned long offset = sector << SECTOR_SHIFT;
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unsigned long nbytes = nsect << SECTOR_SHIFT;
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if (offset > dev->size || dev->size - offset < nbytes) {
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pr_notice("Beyond-end %s (%ld %ld)\n",
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write ? "write" : "read", offset, nbytes);
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return;
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}
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spin_lock(&dev->lock);
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while (nbytes > 0) {
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unsigned long io;
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simc_lseek(dev->fd, offset, SEEK_SET);
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READ_ONCE(*buffer);
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if (write)
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io = simc_write(dev->fd, buffer, nbytes);
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else
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io = simc_read(dev->fd, buffer, nbytes);
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if (io == -1) {
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pr_err("SIMDISK: IO error %d\n", errno);
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break;
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}
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buffer += io;
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offset += io;
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nbytes -= io;
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}
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spin_unlock(&dev->lock);
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}
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static blk_qc_t simdisk_make_request(struct request_queue *q, struct bio *bio)
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{
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struct simdisk *dev = q->queuedata;
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struct bio_vec bvec;
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struct bvec_iter iter;
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sector_t sector = bio->bi_iter.bi_sector;
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bio_for_each_segment(bvec, bio, iter) {
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char *buffer = kmap_atomic(bvec.bv_page) + bvec.bv_offset;
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unsigned len = bvec.bv_len >> SECTOR_SHIFT;
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simdisk_transfer(dev, sector, len, buffer,
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bio_data_dir(bio) == WRITE);
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sector += len;
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kunmap_atomic(buffer);
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}
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bio_endio(bio);
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return BLK_QC_T_NONE;
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}
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static int simdisk_open(struct block_device *bdev, fmode_t mode)
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{
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struct simdisk *dev = bdev->bd_disk->private_data;
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spin_lock(&dev->lock);
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if (!dev->users)
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check_disk_change(bdev);
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++dev->users;
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spin_unlock(&dev->lock);
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return 0;
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}
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static void simdisk_release(struct gendisk *disk, fmode_t mode)
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{
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struct simdisk *dev = disk->private_data;
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spin_lock(&dev->lock);
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--dev->users;
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spin_unlock(&dev->lock);
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}
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static const struct block_device_operations simdisk_ops = {
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.owner = THIS_MODULE,
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.open = simdisk_open,
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.release = simdisk_release,
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};
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static struct simdisk *sddev;
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static struct proc_dir_entry *simdisk_procdir;
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static int simdisk_attach(struct simdisk *dev, const char *filename)
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{
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int err = 0;
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filename = kstrdup(filename, GFP_KERNEL);
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if (filename == NULL)
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return -ENOMEM;
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spin_lock(&dev->lock);
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if (dev->fd != -1) {
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err = -EBUSY;
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goto out;
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}
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dev->fd = simc_open(filename, O_RDWR, 0);
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if (dev->fd == -1) {
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pr_err("SIMDISK: Can't open %s: %d\n", filename, errno);
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err = -ENODEV;
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goto out;
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}
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dev->size = simc_lseek(dev->fd, 0, SEEK_END);
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set_capacity(dev->gd, dev->size >> SECTOR_SHIFT);
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dev->filename = filename;
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pr_info("SIMDISK: %s=%s\n", dev->gd->disk_name, dev->filename);
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out:
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if (err)
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kfree(filename);
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spin_unlock(&dev->lock);
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return err;
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}
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static int simdisk_detach(struct simdisk *dev)
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{
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int err = 0;
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spin_lock(&dev->lock);
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if (dev->users != 0) {
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err = -EBUSY;
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} else if (dev->fd != -1) {
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if (simc_close(dev->fd)) {
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pr_err("SIMDISK: error closing %s: %d\n",
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dev->filename, errno);
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err = -EIO;
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} else {
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pr_info("SIMDISK: %s detached from %s\n",
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dev->gd->disk_name, dev->filename);
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dev->fd = -1;
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kfree(dev->filename);
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dev->filename = NULL;
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}
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}
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spin_unlock(&dev->lock);
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return err;
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}
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static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
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size_t size, loff_t *ppos)
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{
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struct simdisk *dev = PDE_DATA(file_inode(file));
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const char *s = dev->filename;
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if (s) {
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ssize_t n = simple_read_from_buffer(buf, size, ppos,
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s, strlen(s));
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if (n < 0)
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return n;
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buf += n;
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size -= n;
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}
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return simple_read_from_buffer(buf, size, ppos, "\n", 1);
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}
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static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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char *tmp = memdup_user_nul(buf, count);
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struct simdisk *dev = PDE_DATA(file_inode(file));
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int err;
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if (IS_ERR(tmp))
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return PTR_ERR(tmp);
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err = simdisk_detach(dev);
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if (err != 0)
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goto out_free;
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if (count > 0 && tmp[count - 1] == '\n')
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tmp[count - 1] = 0;
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if (tmp[0])
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err = simdisk_attach(dev, tmp);
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if (err == 0)
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err = count;
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out_free:
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kfree(tmp);
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return err;
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}
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static const struct file_operations fops = {
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.read = proc_read_simdisk,
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.write = proc_write_simdisk,
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.llseek = default_llseek,
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};
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static int __init simdisk_setup(struct simdisk *dev, int which,
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struct proc_dir_entry *procdir)
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{
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char tmp[2] = { '0' + which, 0 };
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dev->fd = -1;
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dev->filename = NULL;
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spin_lock_init(&dev->lock);
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dev->users = 0;
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dev->queue = blk_alloc_queue(GFP_KERNEL);
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if (dev->queue == NULL) {
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pr_err("blk_alloc_queue failed\n");
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goto out_alloc_queue;
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}
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blk_queue_make_request(dev->queue, simdisk_make_request);
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dev->queue->queuedata = dev;
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dev->gd = alloc_disk(SIMDISK_MINORS);
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if (dev->gd == NULL) {
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pr_err("alloc_disk failed\n");
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goto out_alloc_disk;
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}
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dev->gd->major = simdisk_major;
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dev->gd->first_minor = which;
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dev->gd->fops = &simdisk_ops;
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dev->gd->queue = dev->queue;
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dev->gd->private_data = dev;
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snprintf(dev->gd->disk_name, 32, "simdisk%d", which);
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set_capacity(dev->gd, 0);
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add_disk(dev->gd);
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dev->procfile = proc_create_data(tmp, 0644, procdir, &fops, dev);
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return 0;
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out_alloc_disk:
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blk_cleanup_queue(dev->queue);
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dev->queue = NULL;
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out_alloc_queue:
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simc_close(dev->fd);
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return -EIO;
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}
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static int __init simdisk_init(void)
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{
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int i;
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if (register_blkdev(simdisk_major, "simdisk") < 0) {
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pr_err("SIMDISK: register_blkdev: %d\n", simdisk_major);
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return -EIO;
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}
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pr_info("SIMDISK: major: %d\n", simdisk_major);
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if (n_files > simdisk_count)
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simdisk_count = n_files;
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if (simdisk_count > MAX_SIMDISK_COUNT)
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simdisk_count = MAX_SIMDISK_COUNT;
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sddev = kmalloc_array(simdisk_count, sizeof(*sddev), GFP_KERNEL);
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if (sddev == NULL)
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goto out_unregister;
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simdisk_procdir = proc_mkdir("simdisk", 0);
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if (simdisk_procdir == NULL)
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goto out_free_unregister;
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for (i = 0; i < simdisk_count; ++i) {
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if (simdisk_setup(sddev + i, i, simdisk_procdir) == 0) {
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if (filename[i] != NULL && filename[i][0] != 0 &&
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(n_files == 0 || i < n_files))
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simdisk_attach(sddev + i, filename[i]);
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}
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}
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return 0;
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out_free_unregister:
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kfree(sddev);
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out_unregister:
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unregister_blkdev(simdisk_major, "simdisk");
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return -ENOMEM;
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}
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module_init(simdisk_init);
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static void simdisk_teardown(struct simdisk *dev, int which,
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struct proc_dir_entry *procdir)
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{
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char tmp[2] = { '0' + which, 0 };
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simdisk_detach(dev);
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if (dev->gd)
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del_gendisk(dev->gd);
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if (dev->queue)
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blk_cleanup_queue(dev->queue);
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remove_proc_entry(tmp, procdir);
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}
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static void __exit simdisk_exit(void)
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{
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int i;
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for (i = 0; i < simdisk_count; ++i)
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simdisk_teardown(sddev + i, i, simdisk_procdir);
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remove_proc_entry("simdisk", 0);
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kfree(sddev);
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unregister_blkdev(simdisk_major, "simdisk");
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}
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module_exit(simdisk_exit);
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MODULE_ALIAS_BLOCKDEV_MAJOR(SIMDISK_MAJOR);
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MODULE_LICENSE("GPL");
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