xpram.c

ARM S3C2410 linux2.4 内核源码

/*
 * Xpram.c -- the S/390 expanded memory RAM-disk
 *           
 * significant parts of this code are based on
 * the sbull device driver presented in
 * A. Rubini: Linux Device Drivers
 *
 * Author of XPRAM specific coding: Reinhard Buendgen
 *                                  [e-mail]
 *
 * External interfaces:
 *   Interfaces to linux kernel
 *        xpram_setup: read kernel parameters   (see init/main.c)
 *        xpram_init:  initialize device driver (see drivers/block/ll_rw_blk.c)
 *   Module interfaces
 *        init_module
 *        cleanup_module
 *   Device specific file operations
 *        xpram_iotcl
 *        xpram_open
 *        xpram_release
 *
 * "ad-hoc" partitioning:         
 *    the expanded memory can be partitioned among several devices 
 *    (with different minors). The partitioning set up can be
 *    set by kernel or module parameters (int devs & int sizes[])
 *
 *    module parameters: devs= and sizes=
 *    kernel parameters: xpram_parts=
 *      note: I did not succeed in parsing numbers 
 *            for module parameters of type string "s" ?!?
 *
 * Other kenel files/modules affected(gerp for "xpram" or "XPRAM":
 *    drivers/s390/Config.in
 *    drivers/s390/block/Makefile
 *    include/linux/blk.h
 *    include/linux/major.h
 *    init/main.c
 *    drivers/block//ll_rw_blk.c
 *
 *
 * Potential future improvements:
 *   request clustering: first coding started not yet tested or integrated
 *                       I doubt that it really pays off 
 *   generic hard disk support to replace ad-hoc partitioning
 *
 * Tested with 2.2.14 (under VM)
 */

#ifdef MODULE
#  ifndef __KERNEL__
#    define __KERNEL__
#  endif
#  define __NO_VERSION__ /* don't define kernel_version in module.h */
#endif /* MODULE */

#include <linux/module.h>
#include <linux/version.h>

#ifdef MODULE
char kernel_version [] = UTS_RELEASE; 
#endif

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,3,98))
#  define XPRAM_VERSION 24
#else
#  define XPRAM_VERSION 22
#endif 

#if (XPRAM_VERSION == 24)
#  include <linux/config.h>
#  include <linux/init.h>
#endif /* V24 */
#include <linux/sched.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#if (XPRAM_VERSION == 24)
#  include <linux/devfs_fs_kernel.h>
#endif /* V24 */
#include <linux/fs.h>     /* everything... */
#include <linux/errno.h>  /* error codes */
#include <linux/timer.h>
#include <linux/types.h>  /* size_t */
#include <linux/ctype.h>  /* isdigit, isxdigit */
#include <linux/fcntl.h>  /* O_ACCMODE */
#include <linux/hdreg.h>  /* HDIO_GETGEO */

#include <asm/system.h>   /* cli(), *_flags */
#include <asm/uaccess.h>  /* put_user */

#if (XPRAM_VERSION == 24)
#define MAJOR_NR xpram_major /* force definitions on in blk.h */
int xpram_major;   /* must be declared before including blk.h */
devfs_handle_t xpram_devfs_handle;

#define DEVICE_NR(device) MINOR(device)   /* xpram has no partition bits */
#define DEVICE_NAME "xpram"               /* name for messaging */
#define DEVICE_INTR xpram_intrptr         /* pointer to the bottom half */
#define DEVICE_NO_RANDOM                  /* no entropy to contribute */
#define DEVICE_OFF(d)                     /* do-nothing */

#include <linux/blk.h>

#include "xpram.h"        /* local definitions */

__setup("xpram_parts=", xpram_setup);
#endif /* V24 */

/*
   define the debug levels:
   - 0 No debugging output to console or syslog
   - 1 Log internal errors to syslog, ignore check conditions 
   - 2 Log internal errors and check conditions to syslog
   - 3 Log internal errors to console, log check conditions to syslog
   - 4 Log internal errors and check conditions to console
   - 5 panic on internal errors, log check conditions to console
   - 6 panic on both, internal errors and check conditions
 */
#define XPRAM_DEBUG 4

#define PRINTK_HEADER XPRAM_NAME

#if XPRAM_DEBUG > 0
#define PRINT_DEBUG(x...) printk ( KERN_DEBUG PRINTK_HEADER "debug:" x )
#define PRINT_INFO(x...) printk ( KERN_INFO PRINTK_HEADER "info:" x )
#define PRINT_WARN(x...) printk ( KERN_WARNING PRINTK_HEADER "warning:" x )
#define PRINT_ERR(x...) printk ( KERN_ERR PRINTK_HEADER "error:" x )
#define PRINT_FATAL(x...) panic ( PRINTK_HEADER "panic:"x )
#else
#define PRINT_DEBUG(x...) printk ( KERN_DEBUG PRINTK_HEADER "debug:"  x )
#define PRINT_INFO(x...) printk ( KERN_DEBUG PRINTK_HEADER "info:" x )
#define PRINT_WARN(x...) printk ( KERN_DEBUG PRINTK_HEADER "warning:" x )
#define PRINT_ERR(x...) printk ( KERN_DEBUG PRINTK_HEADER "error:" x )
#define PRINT_FATAL(x...) printk ( KERN_DEBUG PRINTK_HEADER "panic:" x )
#endif	

#if (XPRAM_VERSION == 22)
#define MAJOR_NR xpram_major /* force definitions on in blk.h */
int xpram_major;   /* must be declared before including blk.h */

#define DEVICE_NR(device) MINOR(device)   /* xpram has no partition bits */
#define DEVICE_NAME "xpram"               /* name for messaging */
#define DEVICE_INTR xpram_intrptr         /* pointer to the bottom half */
#define DEVICE_NO_RANDOM                  /* no entropy to contribute */


#define DEVICE_OFF(d) /* do-nothing */

#define DEVICE_REQUEST *xpram_dummy_device_request  /* dummy function variable 
						     * to prevent warnings 
						     */#include <linux/blk.h>

#include "xpram.h"        /* local definitions */
#endif /* V22 */

/*
 * Non-prefixed symbols are static. They are meant to be assigned at
 * load time. Prefixed symbols are not static, so they can be used in
 * debugging. They are hidden anyways by register_symtab() unless
 * XPRAM_DEBUG is defined.
 */

static int major    = XPRAM_MAJOR;
static int devs     = XPRAM_DEVS;
static int rahead   = XPRAM_RAHEAD;
static int sizes[XPRAM_MAX_DEVS] = { 0, };
static int blksize  = XPRAM_BLKSIZE;
static int hardsect = XPRAM_HARDSECT;

int xpram_devs, xpram_rahead;
int xpram_blksize, xpram_hardsect;
int xpram_mem_avail = 0;
unsigned long xpram_sizes[XPRAM_MAX_DEVS];


MODULE_PARM(devs,"i");
MODULE_PARM(sizes,"1-" __MODULE_STRING(XPRAM_MAX_DEVS) "i"); 

MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \
		 "the default is " __MODULE_STRING(XPRAM_DEVS) "\n");
MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \
		 "the defaults are 0s \n" \
		 "All devices with size 0 equally partition the "
		 "remaining space on the expanded strorage not "
		 "claimed by explicit sizes\n");



/* The following items are obtained through kmalloc() in init_module() */

Xpram_Dev *xpram_devices = NULL;
int *xpram_blksizes = NULL;
int *xpram_hardsects = NULL;
int *xpram_offsets = NULL;   /* partition offsets */

#define MIN(x,y) ((x) < (y) ? (x) : (y))
#define MAX(x,y) ((x) > (y) ? (x) : (y))

/* 
 *              compute nearest multiple of 4 , argument must be non-negative
 *              the macros used depends on XPRAM_KB_IN_PG = 4 
 */

#define NEXT4(x) ((x & 0x3) ? (x+4-(x &0x3)) : (x))   /* increment if needed */
#define LAST4(x) ((x & 0x3) ? (x-4+(x & 0x3)) : (x))  /* decrement if needed */

#if 0               /* this is probably not faster than the previous code */
#define NEXT4(x)   ((((x-1)>>2)>>2)+4)             /* increment if needed */
#define LAST4(x)   (((x+3)>>2)<<2)                 /* decrement if needed */
#endif

/* integer formats */
#define XPRAM_INVALF -1    /* invalid     */
#define XPRAM_HEXF    0    /* hexadecimal */
#define XPRAM_DECF    1    /* decimal     */

/* 
 *    parsing operations (needed for kernel parameter parsing)
 */

/* -------------------------------------------------------------------------
 * sets the string pointer after the next comma 
 *
 * argument:    strptr pointer to string
 * side effect: strptr points to endof string or to position of the next 
 *              comma 
 * ------------------------------------------------------------------------*/
static void
xpram_scan_to_next_comma (char **strptr)
{
	while ( ((**strptr) != ',') && (**strptr) )
		(*strptr)++;
}

/* -------------------------------------------------------------------------
 * interpret character as hex-digit
 *
 * argument: c charcter
 * result: c interpreted as hex-digit
 * note: can be used to read digits for any base <= 16
 * ------------------------------------------------------------------------*/
static int
xpram_get_hexdigit (char c)
{
	if ((c >= '0') && (c <= '9'))
		return c - '0';
	if ((c >= 'a') && (c <= 'f'))
		return c + 10 - 'a';
	if ((c >= 'A') && (c <= 'F'))
		return c + 10 - 'A';
	return -1;
}

/*--------------------------------------------------------------------------
 * Check format of unsigned integer
 *
 * Argument: strptr pointer to string 
 * result:   -1 if strptr does not start with a digit 
 *                (does not start an integer)
 *           0  if strptr starts a positive hex-integer with "0x" 
 *           1  if strptr start a positive decimal integer
 *
 * side effect: if strptr start a positive hex-integer then strptr is
 *              set to the character after the "0x"
 *-------------------------------------------------------------------------*/
static int
xpram_int_format(char **strptr)
{
	if ( !isdigit(**strptr) )
		return XPRAM_INVALF;
	if ( (**strptr == '0') 
	     && ( (*((*strptr)+1) == 'x') || (*((*strptr) +1) == 'X') ) 
	     && isdigit(*((*strptr)+3)) ) {
		*strptr=(*strptr)+2;
		return XPRAM_HEXF;
	} else return XPRAM_DECF;
}

/*--------------------------------------------------------------------------
 * Read non-negative decimal integer
 *
 * Argument: strptr pointer to string starting with a non-negative integer
 *           in decimal format
 * result:   the value of theinitial integer pointed to by strptr
 *
 * side effect: strptr is set to the first character following the integer
 *-------------------------------------------------------------------------*/

static int
xpram_read_decint (char ** strptr)
{
	int res=0;
	while ( isdigit(**strptr) ) {
		res = (res*10) + xpram_get_hexdigit(**strptr);
		(*strptr)++;
	}
	return res;
}

/*--------------------------------------------------------------------------
 * Read non-negative hex-integer
 *
 * Argument: strptr pointer to string starting with a non-negative integer
 *           in hexformat (without "0x" prefix)
 * result:   the value of the initial integer pointed to by strptr
 *
 * side effect: strptr is set to the first character following the integer
 *-------------------------------------------------------------------------*/

static int
xpram_read_hexint (char ** strptr)
{
	int res=0;
	while ( isxdigit(**strptr) ) {
		res = (res<<4) + xpram_get_hexdigit(**strptr);
		(*strptr)++;
	}
	return res;
}
/*--------------------------------------------------------------------------
 * Read non-negative integer
 *
 * Argument: strptr pointer to string starting with a non-negative integer
             (either in decimal- or in hex-format
 * result:   the value of the initial integer pointed to by strptr
 *           in case of a parsing error the result is -EINVAL
 *
 * side effect: strptr is set to the first character following the integer
 *-------------------------------------------------------------------------*/

static int
xpram_read_int (char ** strptr)
{
	switch (  xpram_int_format(strptr) ) {
	case XPRAM_INVALF: return -EINVAL;
	case XPRAM_HEXF:   return xpram_read_hexint(strptr);
	case XPRAM_DECF:   return xpram_read_decint(strptr);
	default: return -EINVAL;
	}
}

/*--------------------------------------------------------------------------
 * Read size
 *
 * Argument: strptr pointer to string starting with a non-negative integer
 *           followed optionally by a size modifier:
 *             k or K for kilo (default),
 *             m or M for mega
 *             g or G for giga
 * result:   the value of the initial integer pointed to by strptr
 *           multiplied by the modifier value devided by 1024
 *           in case of a parsing error the result is -EINVAL
 *
 * side effect: strptr is set to the first character following the size
 *-------------------------------------------------------------------------*/

static int
xpram_read_size (char ** strptr)
{
	int res;
  
	res=xpram_read_int(strptr);
	if ( res < 0 )return res;
	switch ( **strptr ) {
	case 'g':
	case 'G': res=res*1024;
	case 'm':
	case 'M': res=res*1024;
	case 'k' :
	case 'K' : (* strptr)++;
	}
  
	return res;
}


/*--------------------------------------------------------------------------
 * Read tail of comma separated size list  ",i1,i2,...,in"
 *
 * Arguments:strptr pointer to string. It is assumed that the string has
 *                  the format (","<size>)*
 *           maxl integer describing the maximal number of elements in the
                  list pointed to by strptr, max must be > 0.
 *           ilist array of dimension >= maxl of integers to be modified
 *
 * result:   -EINVAL if the list is longer than maxl
 *           0 otherwise
 *
 * side effects: for j=1,...,n ilist[ij] is set to the value of ij if it is
 *               a valid non-negative integer and to -EINVAL otherwise
 *               if no comma is found where it is expected an entry in
 *               ilist is set to -EINVAL
 *-------------------------------------------------------------------------*/
static int
xpram_read_size_list_tail (char ** strptr, int maxl, int * ilist)
{ 
	int i=0;
	char *str = *strptr;
	int res=0;

	while ( (*str == ',') && (i < maxl) ) {
		str++;      
		ilist[i] = xpram_read_size(&str);
		if ( ilist[i] == -EINVAL ) {
			xpram_scan_to_next_comma(&str);
			res = -EINVAL;
		}
		i++;
	}
	return res;
#if 0  /* be lenient about trailing stuff */
	if ( *str != 0 && *str != ' ' ) {
		ilist[MAX(i-1,0)] = -EINVAL;
		return -EINVAL;