37ab46a3f4
Remove system device class for xpram. It creates the directory hierarchy under /sys/devices/system/xpram/xpram0. The xpram0 directory is empty and it is always created while xpram1 and following devices are always missing, independent if the devices exist or not. Since the xpram devices are listed in /proc/partitions and /sys/block/ as slram<x> the system device class for xpram is meaningless. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
467 lines
12 KiB
C
467 lines
12 KiB
C
/*
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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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#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/slab.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/sysdev.h>
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#include <linux/bio.h>
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#include <asm/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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#define PRINT_DEBUG(x...) printk(KERN_DEBUG XPRAM_NAME " debug:" x)
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#define PRINT_INFO(x...) printk(KERN_INFO XPRAM_NAME " info:" x)
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#define PRINT_WARN(x...) printk(KERN_WARNING XPRAM_NAME " warning:" x)
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#define PRINT_ERR(x...) printk(KERN_ERR XPRAM_NAME " error:" x)
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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 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 __initdata devs = XPRAM_DEVS;
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static char __initdata *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;
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__asm__ __volatile__ (
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" lhi %0,2\n" /* return unused cc 2 if pgin traps */
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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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#ifndef CONFIG_64BIT
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".section __ex_table,\"a\"\n"
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" .align 4\n"
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" .long 0b,1b\n"
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".previous"
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#else
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".section __ex_table,\"a\"\n"
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" .align 8\n"
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" .quad 0b,1b\n"
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".previous"
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#endif
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: "=&d" (cc)
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: "a" (__pa(page_addr)), "a" (xpage_index)
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: "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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PRINT_ERR("expanded storage lost!\n");
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return -ENXIO;
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}
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if (cc == 1) {
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PRINT_ERR("page in failed for page index %u.\n",
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xpage_index);
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return -EIO;
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}
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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;
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__asm__ __volatile__ (
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" lhi %0,2\n" /* return unused cc 2 if pgout traps */
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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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#ifndef CONFIG_64BIT
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".section __ex_table,\"a\"\n"
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" .align 4\n"
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" .long 0b,1b\n"
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".previous"
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#else
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".section __ex_table,\"a\"\n"
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" .align 8\n"
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" .quad 0b,1b\n"
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".previous"
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#endif
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: "=&d" (cc)
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: "a" (__pa(page_addr)), "a" (xpage_index)
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: "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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PRINT_ERR("expanded storage lost!\n");
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return -ENXIO;
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}
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if (cc == 1) {
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PRINT_ERR("page out failed for page index %u.\n",
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xpage_index);
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return -EIO;
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}
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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 __init 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 __init 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 int xpram_make_request(request_queue_t *q, struct bio *bio)
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{
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xpram_device_t *xdev = bio->bi_bdev->bd_disk->private_data;
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struct bio_vec *bvec;
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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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int i;
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if ((bio->bi_sector & 7) != 0 || (bio->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_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_sector >> 3) > 0xffffffffU - xdev->offset)
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goto fail;
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index = (bio->bi_sector >> 3) + xdev->offset;
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bio_for_each_segment(bvec, bio, i) {
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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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set_bit(BIO_UPTODATE, &bio->bi_flags);
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bytes = bio->bi_size;
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bio->bi_size = 0;
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bio->bi_end_io(bio, bytes, 0);
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return 0;
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fail:
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bio_io_error(bio, bio->bi_size);
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return 0;
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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 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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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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PRINT_ERR("invalid number %d of 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[i], 0);
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switch (sizes[i][0]) {
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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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PRINT_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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PRINT_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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PRINT_INFO(" size of partition %d to be set "
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"automatically\n",i);
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}
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PRINT_DEBUG(" memory needed (for sized partitions): %lu kB\n",
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mem_needed);
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PRINT_DEBUG(" 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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PRINT_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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PRINT_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 struct request_queue *xpram_queue;
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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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struct gendisk *disk = alloc_disk(1);
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if (!disk)
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goto out;
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xpram_disks[i] = disk;
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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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* Assign the other needed values: make request function, sizes and
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* hardsect size. All the minor devices feature the same value.
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*/
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xpram_queue = blk_alloc_queue(GFP_KERNEL);
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if (!xpram_queue) {
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rc = -ENOMEM;
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goto out_unreg;
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}
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blk_queue_make_request(xpram_queue, xpram_make_request);
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blk_queue_hardsect_size(xpram_queue, 4096);
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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_queue;
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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_unreg:
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unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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out:
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while (i--)
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put_disk(xpram_disks[i]);
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return rc;
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}
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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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put_disk(xpram_disks[i]);
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}
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unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
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blk_cleanup_queue(xpram_queue);
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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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PRINT_WARN("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();
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PRINT_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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return xpram_setup_blkdev();
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}
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module_init(xpram_init);
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module_exit(xpram_exit);
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