diff options
| -rw-r--r-- | arch/xtensa/Kconfig | 36 | ||||
| -rw-r--r-- | arch/xtensa/platforms/iss/Makefile | 1 | ||||
| -rw-r--r-- | arch/xtensa/platforms/iss/simdisk.c | 375 |
3 files changed, 412 insertions, 0 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig index 79f0a2acf25d..f83780f8f290 100644 --- a/arch/xtensa/Kconfig +++ b/arch/xtensa/Kconfig @@ -203,6 +203,42 @@ config BUILTIN_DTB string "DTB to build into the kernel image" depends on OF +config BLK_DEV_SIMDISK + tristate "Host file-based simulated block device support" + default n + depends on XTENSA_PLATFORM_ISS + help + Create block devices that map to files in the host file system. + Device binding to host file may be changed at runtime via proc + interface provided the device is not in use. + +config BLK_DEV_SIMDISK_COUNT + int "Number of host file-based simulated block devices" + range 1 10 + depends on BLK_DEV_SIMDISK + default 2 + help + This is the default minimal number of created block devices. + Kernel/module parameter 'simdisk_count' may be used to change this + value at runtime. More file names (but no more than 10) may be + specified as parameters, simdisk_count grows accordingly. + +config SIMDISK0_FILENAME + string "Host filename for the first simulated device" + depends on BLK_DEV_SIMDISK = y + default "" + help + Attach a first simdisk to a host file. Conventionally, this file + contains a root file system. + +config SIMDISK1_FILENAME + string "Host filename for the second simulated device" + depends on BLK_DEV_SIMDISK = y && BLK_DEV_SIMDISK_COUNT != 1 + default "" + help + Another simulated disk in a host file for a buildroot-independent + storage. + source "mm/Kconfig" source "drivers/pcmcia/Kconfig" diff --git a/arch/xtensa/platforms/iss/Makefile b/arch/xtensa/platforms/iss/Makefile index b7d1a5c0ff7f..d2369b799c50 100644 --- a/arch/xtensa/platforms/iss/Makefile +++ b/arch/xtensa/platforms/iss/Makefile @@ -6,3 +6,4 @@ obj-y = console.o setup.o obj-$(CONFIG_NET) += network.o +obj-$(CONFIG_BLK_DEV_SIMDISK) += simdisk.o diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c new file mode 100644 index 000000000000..f58ffc3b68a8 --- /dev/null +++ b/arch/xtensa/platforms/iss/simdisk.c @@ -0,0 +1,375 @@ +/* + * 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 <asm/uaccess.h> +#include <platform/simcall.h> + +#define SIMDISK_MAJOR 240 +#define SECTOR_SHIFT 9 +#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(SYS_lseek, dev->fd, offset, SEEK_SET, 0, 0); + 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 int simdisk_xfer_bio(struct simdisk *dev, struct bio *bio) +{ + int i; + struct bio_vec *bvec; + sector_t sector = bio->bi_sector; + + bio_for_each_segment(bvec, bio, i) { + char *buffer = __bio_kmap_atomic(bio, i, KM_USER0); + unsigned len = bvec->bv_len >> SECTOR_SHIFT; + + simdisk_transfer(dev, sector, len, buffer, + bio_data_dir(bio) == WRITE); + sector += len; + __bio_kunmap_atomic(bio, KM_USER0); + } + return 0; +} + +static void simdisk_make_request(struct request_queue *q, struct bio *bio) +{ + struct simdisk *dev = q->queuedata; + int status = simdisk_xfer_bio(dev, bio); + bio_endio(bio, status); +} + + +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 int simdisk_release(struct gendisk *disk, fmode_t mode) +{ + struct simdisk *dev = disk->private_data; + spin_lock(&dev->lock); + --dev->users; + spin_unlock(&dev->lock); + return 0; +} + +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(SYS_lseek, dev->fd, 0, SEEK_END, 0, 0); + 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 int proc_read_simdisk(char *page, char **start, off_t off, + int count, int *eof, void *data) +{ + int len; + struct simdisk *dev = (struct simdisk *) data; + len = sprintf(page, "%s\n", dev->filename ? dev->filename : ""); + return len; +} + +static int proc_write_simdisk(struct file *file, const char *buffer, + unsigned long count, void *data) +{ + char *tmp = kmalloc(count + 1, GFP_KERNEL); + struct simdisk *dev = (struct simdisk *) data; + int err; + + if (tmp == NULL) + return -ENOMEM; + if (copy_from_user(tmp, buffer, count)) { + err = -EFAULT; + goto out_free; + } + + err = simdisk_detach(dev); + if (err != 0) + goto out_free; + + if (count > 0 && tmp[count - 1] == '\n') + tmp[count - 1] = 0; + else + tmp[count] = 0; + + if (tmp[0]) + err = simdisk_attach(dev, tmp); + + if (err == 0) + err = count; +out_free: + kfree(tmp); + return err; +} + +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(GFP_KERNEL); + if (dev->queue == NULL) { + pr_err("blk_alloc_queue failed\n"); + goto out_alloc_queue; + } + + blk_queue_make_request(dev->queue, simdisk_make_request); + 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 = create_proc_entry(tmp, 0644, procdir); + dev->procfile->data = dev; + dev->procfile->read_proc = proc_read_simdisk; + dev->procfile->write_proc = proc_write_simdisk; + return 0; + +out_alloc_disk: + blk_cleanup_queue(dev->queue); + dev->queue = NULL; +out_alloc_queue: + simc_close(dev->fd); + return -EIO; +} + +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(simdisk_count * sizeof(struct simdisk), + 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"); |