diff options
Diffstat (limited to 'drivers/s390/block/xpram.c')
| -rw-r--r-- | drivers/s390/block/xpram.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/drivers/s390/block/xpram.c b/drivers/s390/block/xpram.c new file mode 100644 index 000000000..c2536f776 --- /dev/null +++ b/drivers/s390/block/xpram.c @@ -0,0 +1,481 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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; +} + +/* + * 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; +} + +/* + * 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; +} + +/* + * 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; +} + +/* + * Block device make request function. + */ +static blk_qc_t xpram_submit_bio(struct bio *bio) +{ + xpram_device_t *xdev = bio->bi_disk->private_data; + struct bio_vec bvec; + struct bvec_iter iter; + unsigned int index; + unsigned long page_addr; + unsigned long bytes; + + blk_queue_split(&bio); + + 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; +} + +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; +} + +static const struct block_device_operations xpram_devops = +{ + .owner = THIS_MODULE, + .submit_bio = xpram_submit_bio, + .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; +} + +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(NUMA_NO_NODE); + if (!xpram_queues[i]) { + put_disk(xpram_disks[i]); + goto out; + } + blk_queue_flag_set(QUEUE_FLAG_NONROT, xpram_queues[i]); + blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]); + 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; +} + +/* + * 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"); +} + +/* + * 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; +} + +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); +} + +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; +} + +module_init(xpram_init); +module_exit(xpram_exit); |