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