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481 lines
12 KiB
481 lines
12 KiB
// 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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* [email protected] |
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* Rewrite for 2.5: Martin Schwidefsky <[email protected]> |
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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_submit_bio(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(&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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.submit_bio = xpram_submit_bio, |
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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(NUMA_NO_NODE); |
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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_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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