path: root/drivers/s390/block/dcssblk.c

/*
 * dcssblk.c -- the S/390 block driver for dcss memory
 *
 * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
 */

#define KMSG_COMPONENT "dcssblk"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/extmem.h>
#include <asm/io.h>

#define DCSSBLK_NAME "dcssblk"
#define DCSSBLK_MINORS_PER_DISK 1
#define DCSSBLK_PARM_LEN 400
#define DCSS_BUS_ID_SIZE 20

static int dcssblk_open(struct block_device *bdev, fmode_t mode);
static int dcssblk_release(struct gendisk *disk, fmode_t mode);
static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
				 void **kaddr, unsigned long *pfn);

static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";

static int dcssblk_major;
static struct block_device_operations dcssblk_devops = {
	.owner   	= THIS_MODULE,
	.open    	= dcssblk_open,
	.release 	= dcssblk_release,
	.direct_access 	= dcssblk_direct_access,
};

struct dcssblk_dev_info {
	struct list_head lh;
	struct device dev;
	char segment_name[DCSS_BUS_ID_SIZE];
	atomic_t use_count;
	struct gendisk *gd;
	unsigned long start;
	unsigned long end;
	int segment_type;
	unsigned char save_pending;
	unsigned char is_shared;
	struct request_queue *dcssblk_queue;
	int num_of_segments;
	struct list_head seg_list;
};

struct segment_info {
	struct list_head lh;
	char segment_name[DCSS_BUS_ID_SIZE];
	unsigned long start;
	unsigned long end;
	int segment_type;
};

static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
				  size_t count);
static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
				  size_t count);
static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
				  size_t count);
static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
				  size_t count);
static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
static ssize_t dcssblk_seglist_show(struct device *dev,
				struct device_attribute *attr,
				char *buf);

static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
		   dcssblk_save_store);
static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
		   dcssblk_shared_store);
static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);

static struct device *dcssblk_root_dev;

static LIST_HEAD(dcssblk_devices);
static struct rw_semaphore dcssblk_devices_sem;

/*
 * release function for segment device.
 */
static void
dcssblk_release_segment(struct device *dev)
{
	struct dcssblk_dev_info *dev_info;
	struct segment_info *entry, *