Release 4.11 drivers/s390/block/xpram.c

/*
 * Xpram.c -- the S/390 expanded memory RAM-disk
 *           
 * significant parts of this code are based on
 * the sbull device driver presented in
 * A. Rubini: Linux Device Drivers
 *
 * Author of XPRAM specific coding: Reinhard Buendgen
 *                                  buendgen@de.ibm.com
 * Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
 *
 * External interfaces:
 *   Interfaces to linux kernel
 *        xpram_setup: read kernel parameters
 *   Device specific file operations
 *        xpram_iotcl
 *        xpram_open
 *
 * "ad-hoc" partitioning:
 *    the expanded memory can be partitioned among several devices 
 *    (with different minors). The partitioning set up can be
 *    set by kernel or module parameters (int devs & int sizes[])
 *
 * Potential future improvements:
 *   generic hard disk support to replace ad-hoc partitioning
 */


#define KMSG_COMPONENT "xpram"

#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ctype.h>  /* isdigit, isxdigit */
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/hdreg.h>  /* HDIO_GETGEO */
#include <linux/device.h>
#include <linux/bio.h>
#include <linux/suspend.h>
#include <linux/platform_device.h>
#include <linux/gfp.h>
#include <linux/uaccess.h>


#define XPRAM_NAME	"xpram"

#define XPRAM_DEVS	1	
/* one partition */

#define XPRAM_MAX_DEVS	32	
/* maximal number of devices (partitions) */

typedef struct {
	
unsigned int	size;		/* size of xpram segment in pages */
	
unsigned int	offset;		/* start page of xpram segment */
} 
xpram_device_t;


static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];

static unsigned int xpram_sizes[XPRAM_MAX_DEVS];

static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];

static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];

static unsigned int xpram_pages;

static int xpram_devs;

/*
 * Parameter parsing functions.
 */

static int devs = XPRAM_DEVS;

static char *sizes[XPRAM_MAX_DEVS];

module_param(devs, int, 0);
module_param_array(sizes, charp, NULL, 0);

MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
		 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
		 "the defaults are 0s \n" \
		 "All devices with size 0 equally partition the "
		 "remaining space on the expanded strorage not "
		 "claimed by explicit sizes\n");
MODULE_LICENSE("GPL");

/*
 * Copy expanded memory page (4kB) into main memory                  
 * Arguments                                                         
 *           page_addr:    address of target page                    
 *           xpage_index:  index of expandeded memory page           
 * Return value                                                      
 *           0:            if operation succeeds
 *           -EIO:         if pgin failed
 *           -ENXIO:       if xpram has vanished
 */


static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
{
	int cc = 2;	/* return unused cc 2 if pgin traps */

	asm volatile(
                "       .insn   rre,0xb22e0000,%1,%2\n"  /* pgin %1,%2 */
		"0:     ipm     %0\n"
                "       srl     %0,28\n"
                "1:\n"
                EX_TABLE(0b,1b)
                : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
	if (cc == 3)
		return -ENXIO;
	if (cc == 2)
		return -ENXIO;
	if (cc == 1)
		return -EIO;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
41
70.69%
3
75.00%
Linus Torvalds
17
29.31%
1
25.00%
Total
58
100.00%
4
100.00%

/*
 * Copy a 4kB page of main memory to an expanded memory page          
 * Arguments                                                          
 *           page_addr:    address of source page                     
 *           xpage_index:  index of expandeded memory page            
 * Return value                                                       
 *           0:            if operation succeeds
 *           -EIO:         if pgout failed
 *           -ENXIO:       if xpram has vanished
 */


static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
{
	int cc = 2;	/* return unused cc 2 if pgin traps */

	asm volatile(
                "       .insn   rre,0xb22f0000,%1,%2\n"  /* pgout %1,%2 */
		"0:     ipm     %0\n"
                "       srl     %0,28\n"
                "1:\n"
                EX_TABLE(0b,1b)
                : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
	if (cc == 3)
		return -ENXIO;
	if (cc == 2)
		return -ENXIO;
	if (cc == 1)
		return -EIO;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
38
65.52%
3
75.00%
Linus Torvalds
20
34.48%
1
25.00%
Total
58
100.00%
4
100.00%

/*
 * Check if xpram is available.
 */


static int xpram_present(void)
{
	unsigned long mem_page;
	int rc;

	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
	if (!mem_page)
		return -ENOMEM;
	rc = xpram_page_in(mem_page, 0);
	free_page(mem_page);
	return rc ? -ENXIO : 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
35
61.40%
2
50.00%
Linus Torvalds
20
35.09%
1
25.00%
Al Viro
2
3.51%
1
25.00%
Total
57
100.00%
4
100.00%

/*
 * Return index of the last available xpram page.
 */


static unsigned long xpram_highest_page_index(void)
{
	unsigned int page_index, add_bit;
	unsigned long mem_page;

	mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
	if (!mem_page)
		return 0;

	page_index = 0;
	add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
	while (add_bit > 0) {
		if (xpram_page_in(mem_page, page_index | add_bit) == 0)
			page_index |= add_bit;
		add_bit >>= 1;
	}

	free_page (mem_page);

	return page_index;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
79
83.16%
2
66.67%
Linus Torvalds
16
16.84%
1
33.33%
Total
95
100.00%
3
100.00%

/*
 * Block device make request function.
 */


static blk_qc_t xpram_make_request(struct request_queue *q, struct bio *bio)
{
	xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
	struct bio_vec bvec;
	struct bvec_iter iter;
	unsigned int index;
	unsigned long page_addr;
	unsigned long bytes;

	blk_queue_split(q, &bio, q->bio_split);

	if ((bio->bi_iter.bi_sector & 7) != 0 ||
	    (bio->bi_iter.bi_size & 4095) != 0)
		/* Request is not page-aligned. */
		goto fail;
	if ((bio->bi_iter.bi_size >> 12) > xdev->size)
		/* Request size is no page-aligned. */
		goto fail;
	if ((bio->bi_iter.bi_sector >> 3) > 0xffffffffU - xdev->offset)
		goto fail;
	index = (bio->bi_iter.bi_sector >> 3) + xdev->offset;
	bio_for_each_segment(bvec, bio, iter) {
		page_addr = (unsigned long)
			kmap(bvec.bv_page) + bvec.bv_offset;
		bytes = bvec.bv_len;
		if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
			/* More paranoia. */
			goto fail;
		while (bytes > 0) {
			if (bio_data_dir(bio) == READ) {
				if (xpram_page_in(page_addr, index) != 0)
					goto fail;
			} else {
				if (xpram_page_out(page_addr, index) != 0)
					goto fail;
			}
			page_addr += 4096;
			bytes -= 4096;
			index++;
		}
	}
	bio_endio(bio);
	return BLK_QC_T_NONE;
fail:
	bio_io_error(bio);
	return BLK_QC_T_NONE;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
186
66.19%
3
23.08%
Linus Torvalds
43
15.30%
1
7.69%
Kent Overstreet
30
10.68%
3
23.08%
Al Viro
10
3.56%
2
15.38%
Jens Axboe
9
3.20%
2
15.38%
Martin Dalecki
2
0.71%
1
7.69%
Andrew Morton
1
0.36%
1
7.69%
Total
281
100.00%
13
100.00%



static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
	unsigned long size;

	/*
         * get geometry: we have to fake one...  trim the size to a
         * multiple of 64 (32k): tell we have 16 sectors, 4 heads,
         * whatever cylinders. Tell also that data starts at sector. 4.
         */
	size = (xpram_pages * 8) & ~0x3f;
	geo->cylinders = size >> 6;
	geo->heads = 4;
	geo->sectors = 16;
	geo->start = 4;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
38
62.30%
1
25.00%
Christoph Hellwig
15
24.59%
1
25.00%
Linus Torvalds
7
11.48%
1
25.00%
Al Viro
1
1.64%
1
25.00%
Total
61
100.00%
4
100.00%


static const struct block_device_operations xpram_devops =
{
	.owner	= THIS_MODULE,
	.getgeo	= xpram_getgeo,
};

/*
 * Setup xpram_sizes array.
 */


static int __init xpram_setup_sizes(unsigned long pages)
{
	unsigned long mem_needed;
	unsigned long mem_auto;
	unsigned long long size;
	char *sizes_end;
	int mem_auto_no;
	int i;

	/* Check number of devices. */
	if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
		pr_err("%d is not a valid number of XPRAM devices\n",devs);
		return -EINVAL;
	}
	xpram_devs = devs;

	/*
         * Copy sizes array to xpram_sizes and align partition
         * sizes to page boundary.
         */
	mem_needed = 0;
	mem_auto_no = 0;
	for (i = 0; i < xpram_devs; i++) {
		if (sizes[i]) {
			size = simple_strtoull(sizes[i], &sizes_end, 0);
			switch (*sizes_end) {
			case 'g':
			case 'G':
				size <<= 20;
				break;
			case 'm':
			case 'M':
				size <<= 10;
			}
			xpram_sizes[i] = (size + 3) & -4UL;
		}
		if (xpram_sizes[i])
			mem_needed += xpram_sizes[i];
		else
			mem_auto_no++;
	}
	
	pr_info("  number of devices (partitions): %d \n", xpram_devs);
	for (i = 0; i < xpram_devs; i++) {
		if (xpram_sizes[i])
			pr_info("  size of partition %d: %u kB\n",
				i, xpram_sizes[i]);
		else
			pr_info("  size of partition %d to be set "
				"automatically\n",i);
	}
	pr_info("  memory needed (for sized partitions): %lu kB\n",
		mem_needed);
	pr_info("  partitions to be sized automatically: %d\n",
		mem_auto_no);

	if (mem_needed > pages * 4) {
		pr_err("Not enough expanded memory available\n");
		return -EINVAL;
	}

	/*
         * partitioning:
         * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
         * else:             ; all partitions with zero xpram_sizes[i]
         *                     partition equally the remaining space
         */
	if (mem_auto_no) {
		mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
		pr_info("  automatically determined "
			"partition size: %lu kB\n", mem_auto);
		for (i = 0; i < xpram_devs; i++)
			if (xpram_sizes[i] == 0)
				xpram_sizes[i] = mem_auto;
	}
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds
142
44.94%
3
33.33%
Martin Schwidefsky
111
35.13%
3
33.33%
Heiko Carstens
56
17.72%
2
22.22%
Sebastian Ott
7
2.22%
1
11.11%
Total
316
100.00%
9
100.00%



static int __init xpram_setup_blkdev(void)
{
	unsigned long offset;
	int i, rc = -ENOMEM;

	for (i = 0; i < xpram_devs; i++) {
		xpram_disks[i] = alloc_disk(1);
		if (!xpram_disks[i])
			goto out;
		xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
		if (!xpram_queues[i]) {
			put_disk(xpram_disks[i]);
			goto out;
		}
		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, xpram_queues[i]);
		queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]);
		blk_queue_make_request(xpram_queues[i], xpram_make_request);
		blk_queue_logical_block_size(xpram_queues[i], 4096);
	}

	/*
         * Register xpram major.
         */
	rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
	if (rc < 0)
		goto out;

	/*
         * Setup device structures.
         */
	offset = 0;
	for (i = 0; i < xpram_devs; i++) {
		struct gendisk *disk = xpram_disks[i];

		xpram_devices[i].size = xpram_sizes[i] / 4;
		xpram_devices[i].offset = offset;
		offset += xpram_devices[i].size;
		disk->major = XPRAM_MAJOR;
		disk->first_minor = i;
		disk->fops = &xpram_devops;
		disk->private_data = &xpram_devices[i];
		disk->queue = xpram_queues[i];
		sprintf(disk->disk_name, "slram%d", i);
		set_capacity(disk, xpram_sizes[i] << 1);
		add_disk(disk);
	}

	return 0;
out:
	while (i--) {
		blk_cleanup_queue(xpram_queues[i]);
		put_disk(xpram_disks[i]);
	}
	return rc;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
118
38.56%
5
38.46%
Martin Schwidefsky
98
32.03%
3
23.08%
Linus Torvalds
54
17.65%
1
7.69%
Andrew Morton
15
4.90%
1
7.69%
Christian Bornträger
10
3.27%
1
7.69%
Mike Snitzer
10
3.27%
1
7.69%
Martin K. Petersen
1
0.33%
1
7.69%
Total
306
100.00%
13
100.00%

/*
 * Resume failed: Print error message and call panic.
 */


static void xpram_resume_error(const char *message)
{
	pr_err("Resuming the system failed: %s\n", message);
	panic("xpram resume error\n");
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michael Holzheu
22
95.65%
1
50.00%
Christian Bornträger
1
4.35%
1
50.00%
Total
23
100.00%
2
100.00%

/*
 * Check if xpram setup changed between suspend and resume.
 */


static int xpram_restore(struct device *dev)
{
	if (!xpram_pages)
		return 0;
	if (xpram_present() != 0)
		xpram_resume_error("xpram disappeared");
	if (xpram_pages != xpram_highest_page_index() + 1)
		xpram_resume_error("Size of xpram changed");
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michael Holzheu
48
100.00%
1
100.00%
Total
48
100.00%
1
100.00%


static const struct dev_pm_ops xpram_pm_ops = {
	.restore	= xpram_restore,
};


static struct platform_driver xpram_pdrv = {
	.driver = {
		.name	= XPRAM_NAME,
		.pm	= &xpram_pm_ops,
        },
};


static struct platform_device *xpram_pdev;

/*
 * Finally, the init/exit functions.
 */


static void __exit xpram_exit(void)
{
	int i;
	for (i = 0; i < xpram_devs; i++) {
		del_gendisk(xpram_disks[i]);
		blk_cleanup_queue(xpram_queues[i]);
		put_disk(xpram_disks[i]);
	}
	unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
	platform_device_unregister(xpram_pdev);
	platform_driver_unregister(&xpram_pdrv);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
34
49.28%
2
28.57%
Martin Schwidefsky
18
26.09%
2
28.57%
Michael Holzheu
11
15.94%
1
14.29%
Linus Torvalds
5
7.25%
1
14.29%
Greg Kroah-Hartman
1
1.45%
1
14.29%
Total
69
100.00%
7
100.00%



static int __init xpram_init(void)
{
	int rc;

	/* Find out size of expanded memory. */
	if (xpram_present() != 0) {
		pr_err("No expanded memory available\n");
		return -ENODEV;
	}
	xpram_pages = xpram_highest_page_index() + 1;
	pr_info("  %u pages expanded memory found (%lu KB).\n",
		xpram_pages, (unsigned long) xpram_pages*4);
	rc = xpram_setup_sizes(xpram_pages);
	if (rc)
		return rc;
	rc = platform_driver_register(&xpram_pdrv);
	if (rc)
		return rc;
	xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
	if (IS_ERR(xpram_pdev)) {
		rc = PTR_ERR(xpram_pdev);
		goto fail_platform_driver_unregister;
	}
	rc = xpram_setup_blkdev();
	if (rc)
		goto fail_platform_device_unregister;
	return 0;

fail_platform_device_unregister:
	platform_device_unregister(xpram_pdev);
fail_platform_driver_unregister:
	platform_driver_unregister(&xpram_pdrv);
	return rc;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michael Holzheu
77
52.03%
1
14.29%
Martin Schwidefsky
44
29.73%
3
42.86%
Linus Torvalds
25
16.89%
2
28.57%
Christian Bornträger
2
1.35%
1
14.29%
Total
148
100.00%
7
100.00%


module_init(xpram_init);

module_exit(xpram_exit);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Martin Schwidefsky
791
44.09%
8
17.39%
Linus Torvalds
442
24.64%
5
10.87%
Michael Holzheu
207
11.54%
1
2.17%
Al Viro
178
9.92%
8
17.39%
Heiko Carstens
59
3.29%
2
4.35%
Kent Overstreet
30
1.67%
3
6.52%
Andrew Morton
20
1.11%
3
6.52%
Christoph Hellwig
17
0.95%
1
2.17%
Christian Bornträger
13
0.72%
3
6.52%
Mike Snitzer
10
0.56%
1
2.17%
Jens Axboe
9
0.50%
2
4.35%
Sebastian Ott
7
0.39%
1
2.17%
Tejun Heo
3
0.17%
1
2.17%
Alexey Dobriyan
2
0.11%
2
4.35%
Martin Dalecki
2
0.11%
1
2.17%
Martin K. Petersen
1
0.06%
1
2.17%
Kay Sievers
1
0.06%
1
2.17%
Rusty Russell
1
0.06%
1
2.17%
Greg Kroah-Hartman
1
0.06%
1
2.17%
Total
1794
100.00%
46
100.00%
Directory: drivers/s390/block

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