--- /dev/null
+/*
+ * 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 <asm/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 void 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;
+
+ 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++;
+ }
+ }
+ set_bit(BIO_UPTODATE, &bio->bi_flags);
+ bio_endio(bio, 0);
+ return;
+fail:
+ bio_io_error(bio);
+}
+
+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,
+ .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(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;
+}
+
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff