540 lines
14 KiB
C
540 lines
14 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 <linux/devfs_fs_kernel.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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static struct sysdev_class xpram_sysclass = {
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set_kset_name("xpram"),
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};
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static struct sys_device xpram_sys_device = {
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.id = 0,
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.cls = &xpram_sysclass,
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};
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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 devs = XPRAM_DEVS;
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static unsigned int sizes[XPRAM_MAX_DEVS];
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module_param(devs, int, 0);
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module_param_array(sizes, int, 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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#ifndef MODULE
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/*
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* Parses the kernel parameters given in the kernel parameter line.
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* The expected format is
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* <number_of_partitions>[","<partition_size>]*
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* where
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* devices is a positive integer that initializes xpram_devs
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* each size is a non-negative integer possibly followed by a
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* magnitude (k,K,m,M,g,G), the list of sizes initialises
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* xpram_sizes
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*
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* Arguments
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* str: substring of kernel parameter line that contains xprams
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* kernel parameters.
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*
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* Result 0 on success, -EINVAL else -- only for Version > 2.3
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*
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* Side effects
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* the global variabls devs is set to the value of
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* <number_of_partitions> and sizes[i] is set to the i-th
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* partition size (if provided). A parsing error of a value
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* results in this value being set to -EINVAL.
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*/
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static int __init xpram_setup (char *str)
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{
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char *cp;
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int i;
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devs = simple_strtoul(str, &cp, 10);
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if (cp <= str || devs > XPRAM_MAX_DEVS)
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return 0;
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for (i = 0; (i < devs) && (*cp++ == ','); i++) {
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sizes[i] = simple_strtoul(cp, &cp, 10);
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if (*cp == 'g' || *cp == 'G') {
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sizes[i] <<= 20;
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cp++;
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} else if (*cp == 'm' || *cp == 'M') {
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sizes[i] <<= 10;
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cp++;
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} else if (*cp == 'k' || *cp == 'K')
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cp++;
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while (isspace(*cp)) cp++;
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}
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if (*cp == ',' && i >= devs)
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PRINT_WARN("partition sizes list has too many entries.\n");
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else if (*cp != 0)
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PRINT_WARN("ignored '%s' at end of parameter string.\n", cp);
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return 1;
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}
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__setup("xpram_parts=", xpram_setup);
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#endif
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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_ARCH_S390X
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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_ARCH_S390X
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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_ioctl (struct inode *inode, struct file *filp,
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unsigned int cmd, unsigned long arg)
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{
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struct hd_geometry __user *geo;
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unsigned long size;
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if (cmd != HDIO_GETGEO)
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return -EINVAL;
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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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geo = (struct hd_geometry __user *) arg;
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size = (xpram_pages * 8) & ~0x3f;
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put_user(size >> 6, &geo->cylinders);
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put_user(4, &geo->heads);
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put_user(16, &geo->sectors);
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put_user(4, &geo->start);
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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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.ioctl = xpram_ioctl,
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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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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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xpram_sizes[i] = (sizes[i] + 3) & -4UL;
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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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devfs_mk_dir("slram");
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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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sprintf(disk->devfs_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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devfs_remove("slram");
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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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devfs_remove("slram");
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blk_cleanup_queue(xpram_queue);
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sysdev_unregister(&xpram_sys_device);
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sysdev_class_unregister(&xpram_sysclass);
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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. */
|
|
if (xpram_present() != 0) {
|
|
PRINT_WARN("No expanded memory available\n");
|
|
return -ENODEV;
|
|
}
|
|
xpram_pages = xpram_highest_page_index();
|
|
PRINT_INFO(" %u pages expanded memory found (%lu KB).\n",
|
|
xpram_pages, (unsigned long) xpram_pages*4);
|
|
rc = xpram_setup_sizes(xpram_pages);
|
|
if (rc)
|
|
return rc;
|
|
rc = sysdev_class_register(&xpram_sysclass);
|
|
if (rc)
|
|
return rc;
|
|
|
|
rc = sysdev_register(&xpram_sys_device);
|
|
if (rc) {
|
|
sysdev_class_unregister(&xpram_sysclass);
|
|
return rc;
|
|
}
|
|
rc = xpram_setup_blkdev();
|
|
if (rc)
|
|
sysdev_unregister(&xpram_sys_device);
|
|
return rc;
|
|
}
|
|
|
|
module_init(xpram_init);
|
|
module_exit(xpram_exit);
|