482 lines
12 KiB
C
482 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Xpram.c -- the S/390 expanded memory RAM-disk
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*
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* significant parts of this code are based on
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* the sbull device driver presented in
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* A. Rubini: Linux Device Drivers
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*
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* Author of XPRAM specific coding: Reinhard Buendgen
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* buendgen@de.ibm.com
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* Rewrite for 2.5: Martin Schwidefsky <schwidefsky@de.ibm.com>
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*
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* External interfaces:
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* Interfaces to linux kernel
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* xpram_setup: read kernel parameters
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* Device specific file operations
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* xpram_iotcl
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* xpram_open
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*
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* "ad-hoc" partitioning:
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* the expanded memory can be partitioned among several devices
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* (with different minors). The partitioning set up can be
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* set by kernel or module parameters (int devs & int sizes[])
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*
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* Potential future improvements:
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* generic hard disk support to replace ad-hoc partitioning
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*/
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#define KMSG_COMPONENT "xpram"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/ctype.h> /* isdigit, isxdigit */
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/hdreg.h> /* HDIO_GETGEO */
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#include <linux/device.h>
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#include <linux/bio.h>
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#include <linux/suspend.h>
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#include <linux/platform_device.h>
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#include <linux/gfp.h>
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#include <linux/uaccess.h>
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#define XPRAM_NAME "xpram"
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#define XPRAM_DEVS 1 /* one partition */
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#define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */
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typedef struct {
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unsigned int size; /* size of xpram segment in pages */
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unsigned int offset; /* start page of xpram segment */
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} xpram_device_t;
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static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
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static unsigned int xpram_sizes[XPRAM_MAX_DEVS];
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static struct gendisk *xpram_disks[XPRAM_MAX_DEVS];
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static struct request_queue *xpram_queues[XPRAM_MAX_DEVS];
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static unsigned int xpram_pages;
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static int xpram_devs;
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/*
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* Parameter parsing functions.
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*/
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static int devs = XPRAM_DEVS;
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static char *sizes[XPRAM_MAX_DEVS];
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module_param(devs, int, 0);
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module_param_array(sizes, charp, NULL, 0);
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MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
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"the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
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MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
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"the defaults are 0s \n" \
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"All devices with size 0 equally partition the "
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"remaining space on the expanded strorage not "
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"claimed by explicit sizes\n");
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MODULE_LICENSE("GPL");
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/*
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* Copy expanded memory page (4kB) into main memory
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* Arguments
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* page_addr: address of target page
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* xpage_index: index of expandeded memory page
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* Return value
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* 0: if operation succeeds
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* -EIO: if pgin failed
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* -ENXIO: if xpram has vanished
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*/
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static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index)
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{
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int cc = 2; /* return unused cc 2 if pgin traps */
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asm volatile(
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" .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */
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"0: ipm %0\n"
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" srl %0,28\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
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if (cc == 3)
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return -ENXIO;
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if (cc == 2)
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return -ENXIO;
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if (cc == 1)
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return -EIO;
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return 0;
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}
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/*
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* Copy a 4kB page of main memory to an expanded memory page
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* Arguments
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* page_addr: address of source page
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* xpage_index: index of expandeded memory page
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* Return value
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* 0: if operation succeeds
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* -EIO: if pgout failed
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* -ENXIO: if xpram has vanished
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*/
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static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
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{
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int cc = 2; /* return unused cc 2 if pgin traps */
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asm volatile(
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" .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */
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"0: ipm %0\n"
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" srl %0,28\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc");
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if (cc == 3)
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return -ENXIO;
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if (cc == 2)
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return -ENXIO;
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if (cc == 1)
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return -EIO;
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return 0;
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}
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/*
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* Check if xpram is available.
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*/
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static int xpram_present(void)
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{
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unsigned long mem_page;
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int rc;
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mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
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if (!mem_page)
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return -ENOMEM;
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rc = xpram_page_in(mem_page, 0);
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free_page(mem_page);
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return rc ? -ENXIO : 0;
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}
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/*
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* Return index of the last available xpram page.
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*/
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static unsigned long xpram_highest_page_index(void)
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{
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unsigned int page_index, add_bit;
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unsigned long mem_page;
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mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
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if (!mem_page)
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return 0;
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page_index = 0;
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add_bit = 1ULL << (sizeof(unsigned int)*8 - 1);
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while (add_bit > 0) {
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if (xpram_page_in(mem_page, page_index | add_bit) == 0)
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page_index |= add_bit;
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add_bit >>= 1;
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}
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free_page (mem_page);
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return page_index;
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}
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/*
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* Block device make request function.
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*/
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static blk_qc_t xpram_make_request(struct request_queue *q, struct bio *bio)
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{
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xpram_device_t *xdev = bio->bi_disk->private_data;
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struct bio_vec bvec;
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struct bvec_iter iter;
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unsigned int index;
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unsigned long page_addr;
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unsigned long bytes;
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blk_queue_split(q, &bio);
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if ((bio->bi_iter.bi_sector & 7) != 0 ||
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(bio->bi_iter.bi_size & 4095) != 0)
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/* Request is not page-aligned. */
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goto fail;
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if ((bio->bi_iter.bi_size >> 12) > xdev->size)
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/* Request size is no page-aligned. */
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goto fail;
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if ((bio->bi_iter.bi_sector >> 3) > 0xffffffffU - xdev->offset)
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goto fail;
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index = (bio->bi_iter.bi_sector >> 3) + xdev->offset;
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bio_for_each_segment(bvec, bio, iter) {
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page_addr = (unsigned long)
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kmap(bvec.bv_page) + bvec.bv_offset;
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bytes = bvec.bv_len;
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if ((page_addr & 4095) != 0 || (bytes & 4095) != 0)
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/* More paranoia. */
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goto fail;
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while (bytes > 0) {
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if (bio_data_dir(bio) == READ) {
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if (xpram_page_in(page_addr, index) != 0)
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goto fail;
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} else {
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if (xpram_page_out(page_addr, index) != 0)
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goto fail;
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}
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page_addr += 4096;
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bytes -= 4096;
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index++;
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}
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}
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bio_endio(bio);
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return BLK_QC_T_NONE;
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fail:
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bio_io_error(bio);
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return BLK_QC_T_NONE;
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}
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static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo)
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{
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unsigned long size;
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/*
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* get geometry: we have to fake one... trim the size to a
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* multiple of 64 (32k): tell we have 16 sectors, 4 heads,
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* whatever cylinders. Tell also that data starts at sector. 4.
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*/
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size = (xpram_pages * 8) & ~0x3f;
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geo->cylinders = size >> 6;
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geo->heads = 4;
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geo->sectors = 16;
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geo->start = 4;
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return 0;
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}
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static const struct block_device_operations xpram_devops =
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{
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.owner = THIS_MODULE,
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.getgeo = xpram_getgeo,
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};
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/*
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* Setup xpram_sizes array.
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*/
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static int __init xpram_setup_sizes(unsigned long pages)
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{
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unsigned long mem_needed;
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unsigned long mem_auto;
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unsigned long long size;
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char *sizes_end;
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int mem_auto_no;
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int i;
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/* Check number of devices. */
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if (devs <= 0 || devs > XPRAM_MAX_DEVS) {
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pr_err("%d is not a valid number of XPRAM devices\n",devs);
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return -EINVAL;
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}
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xpram_devs = devs;
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/*
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* Copy sizes array to xpram_sizes and align partition
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* sizes to page boundary.
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*/
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mem_needed = 0;
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mem_auto_no = 0;
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for (i = 0; i < xpram_devs; i++) {
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if (sizes[i]) {
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size = simple_strtoull(sizes[i], &sizes_end, 0);
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switch (*sizes_end) {
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case 'g':
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case 'G':
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size <<= 20;
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break;
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case 'm':
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case 'M':
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size <<= 10;
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}
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xpram_sizes[i] = (size + 3) & -4UL;
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}
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if (xpram_sizes[i])
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mem_needed += xpram_sizes[i];
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else
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mem_auto_no++;
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}
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pr_info(" number of devices (partitions): %d \n", xpram_devs);
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for (i = 0; i < xpram_devs; i++) {
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if (xpram_sizes[i])
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pr_info(" size of partition %d: %u kB\n",
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i, xpram_sizes[i]);
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else
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pr_info(" size of partition %d to be set "
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"automatically\n",i);
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}
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pr_info(" memory needed (for sized partitions): %lu kB\n",
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mem_needed);
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pr_info(" partitions to be sized automatically: %d\n",
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mem_auto_no);
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if (mem_needed > pages * 4) {
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pr_err("Not enough expanded memory available\n");
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return -EINVAL;
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}
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/*
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* partitioning:
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* xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB
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* else: ; all partitions with zero xpram_sizes[i]
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* partition equally the remaining space
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*/
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if (mem_auto_no) {
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mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4;
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pr_info(" automatically determined "
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"partition size: %lu kB\n", mem_auto);
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for (i = 0; i < xpram_devs; i++)
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if (xpram_sizes[i] == 0)
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xpram_sizes[i] = mem_auto;
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}
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return 0;
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}
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static int __init xpram_setup_blkdev(void)
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{
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unsigned long offset;
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int i, rc = -ENOMEM;
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for (i = 0; i < xpram_devs; i++) {
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xpram_disks[i] = alloc_disk(1);
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if (!xpram_disks[i])
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goto out;
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xpram_queues[i] = blk_alloc_queue(GFP_KERNEL);
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if (!xpram_queues[i]) {
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put_disk(xpram_disks[i]);
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goto out;
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}
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blk_queue_flag_set(QUEUE_FLAG_NONROT, xpram_queues[i]);
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blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]);
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blk_queue_make_request(xpram_queues[i], xpram_make_request);
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blk_queue_logical_block_size(xpram_queues[i], 4096);
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}
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/*
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* Register xpram major.
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*/
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rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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if (rc < 0)
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goto out;
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/*
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* Setup device structures.
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*/
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offset = 0;
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for (i = 0; i < xpram_devs; i++) {
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struct gendisk *disk = xpram_disks[i];
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xpram_devices[i].size = xpram_sizes[i] / 4;
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xpram_devices[i].offset = offset;
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offset += xpram_devices[i].size;
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disk->major = XPRAM_MAJOR;
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disk->first_minor = i;
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disk->fops = &xpram_devops;
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disk->private_data = &xpram_devices[i];
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disk->queue = xpram_queues[i];
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sprintf(disk->disk_name, "slram%d", i);
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set_capacity(disk, xpram_sizes[i] << 1);
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add_disk(disk);
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}
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return 0;
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out:
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while (i--) {
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blk_cleanup_queue(xpram_queues[i]);
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put_disk(xpram_disks[i]);
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}
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return rc;
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}
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/*
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* Resume failed: Print error message and call panic.
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*/
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static void xpram_resume_error(const char *message)
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{
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pr_err("Resuming the system failed: %s\n", message);
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panic("xpram resume error\n");
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}
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/*
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* Check if xpram setup changed between suspend and resume.
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*/
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static int xpram_restore(struct device *dev)
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{
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if (!xpram_pages)
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return 0;
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if (xpram_present() != 0)
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xpram_resume_error("xpram disappeared");
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if (xpram_pages != xpram_highest_page_index() + 1)
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xpram_resume_error("Size of xpram changed");
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return 0;
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}
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static const struct dev_pm_ops xpram_pm_ops = {
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.restore = xpram_restore,
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};
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static struct platform_driver xpram_pdrv = {
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.driver = {
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.name = XPRAM_NAME,
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.pm = &xpram_pm_ops,
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},
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};
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static struct platform_device *xpram_pdev;
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/*
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* Finally, the init/exit functions.
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*/
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static void __exit xpram_exit(void)
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{
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int i;
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for (i = 0; i < xpram_devs; i++) {
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del_gendisk(xpram_disks[i]);
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blk_cleanup_queue(xpram_queues[i]);
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put_disk(xpram_disks[i]);
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}
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unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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platform_device_unregister(xpram_pdev);
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platform_driver_unregister(&xpram_pdrv);
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}
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static int __init xpram_init(void)
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{
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int rc;
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/* Find out size of expanded memory. */
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if (xpram_present() != 0) {
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pr_err("No expanded memory available\n");
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return -ENODEV;
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}
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xpram_pages = xpram_highest_page_index() + 1;
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pr_info(" %u pages expanded memory found (%lu KB).\n",
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xpram_pages, (unsigned long) xpram_pages*4);
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rc = xpram_setup_sizes(xpram_pages);
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if (rc)
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return rc;
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rc = platform_driver_register(&xpram_pdrv);
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if (rc)
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return rc;
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xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
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if (IS_ERR(xpram_pdev)) {
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rc = PTR_ERR(xpram_pdev);
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goto fail_platform_driver_unregister;
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}
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rc = xpram_setup_blkdev();
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if (rc)
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goto fail_platform_device_unregister;
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return 0;
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fail_platform_device_unregister:
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platform_device_unregister(xpram_pdev);
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fail_platform_driver_unregister:
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platform_driver_unregister(&xpram_pdrv);
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return rc;
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}
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module_init(xpram_init);
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module_exit(xpram_exit);
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