mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
eb44820c28
Add Documentation/DocBook/scsi_midlayer.tmpl, add to Makefile, and update lots of kerneldoc comments in drivers/scsi/*. Updated with comments from Stefan Richter, Stephen M. Cameron, James Bottomley and Randy Dunlap. Signed-off-by: Rob Landley <rob@landley.net> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
260 lines
7.7 KiB
C
260 lines
7.7 KiB
C
/*
|
|
* scsicam.c - SCSI CAM support functions, use for HDIO_GETGEO, etc.
|
|
*
|
|
* Copyright 1993, 1994 Drew Eckhardt
|
|
* Visionary Computing
|
|
* (Unix and Linux consulting and custom programming)
|
|
* drew@Colorado.EDU
|
|
* +1 (303) 786-7975
|
|
*
|
|
* For more information, please consult the SCSI-CAM draft.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/genhd.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <asm/unaligned.h>
|
|
|
|
#include <scsi/scsicam.h>
|
|
|
|
|
|
static int setsize(unsigned long capacity, unsigned int *cyls, unsigned int *hds,
|
|
unsigned int *secs);
|
|
|
|
/**
|
|
* scsi_bios_ptable - Read PC partition table out of first sector of device.
|
|
* @dev: from this device
|
|
*
|
|
* Description: Reads the first sector from the device and returns %0x42 bytes
|
|
* starting at offset %0x1be.
|
|
* Returns: partition table in kmalloc(GFP_KERNEL) memory, or NULL on error.
|
|
*/
|
|
unsigned char *scsi_bios_ptable(struct block_device *dev)
|
|
{
|
|
unsigned char *res = kmalloc(66, GFP_KERNEL);
|
|
if (res) {
|
|
struct block_device *bdev = dev->bd_contains;
|
|
Sector sect;
|
|
void *data = read_dev_sector(bdev, 0, §);
|
|
if (data) {
|
|
memcpy(res, data + 0x1be, 66);
|
|
put_dev_sector(sect);
|
|
} else {
|
|
kfree(res);
|
|
res = NULL;
|
|
}
|
|
}
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(scsi_bios_ptable);
|
|
|
|
/**
|
|
* scsicam_bios_param - Determine geometry of a disk in cylinders/heads/sectors.
|
|
* @bdev: which device
|
|
* @capacity: size of the disk in sectors
|
|
* @ip: return value: ip[0]=heads, ip[1]=sectors, ip[2]=cylinders
|
|
*
|
|
* Description : determine the BIOS mapping/geometry used for a drive in a
|
|
* SCSI-CAM system, storing the results in ip as required
|
|
* by the HDIO_GETGEO ioctl().
|
|
*
|
|
* Returns : -1 on failure, 0 on success.
|
|
*/
|
|
|
|
int scsicam_bios_param(struct block_device *bdev, sector_t capacity, int *ip)
|
|
{
|
|
unsigned char *p;
|
|
u64 capacity64 = capacity; /* Suppress gcc warning */
|
|
int ret;
|
|
|
|
p = scsi_bios_ptable(bdev);
|
|
if (!p)
|
|
return -1;
|
|
|
|
/* try to infer mapping from partition table */
|
|
ret = scsi_partsize(p, (unsigned long)capacity, (unsigned int *)ip + 2,
|
|
(unsigned int *)ip + 0, (unsigned int *)ip + 1);
|
|
kfree(p);
|
|
|
|
if (ret == -1 && capacity64 < (1ULL << 32)) {
|
|
/* pick some standard mapping with at most 1024 cylinders,
|
|
and at most 62 sectors per track - this works up to
|
|
7905 MB */
|
|
ret = setsize((unsigned long)capacity, (unsigned int *)ip + 2,
|
|
(unsigned int *)ip + 0, (unsigned int *)ip + 1);
|
|
}
|
|
|
|
/* if something went wrong, then apparently we have to return
|
|
a geometry with more than 1024 cylinders */
|
|
if (ret || ip[0] > 255 || ip[1] > 63) {
|
|
if ((capacity >> 11) > 65534) {
|
|
ip[0] = 255;
|
|
ip[1] = 63;
|
|
} else {
|
|
ip[0] = 64;
|
|
ip[1] = 32;
|
|
}
|
|
|
|
if (capacity > 65535*63*255)
|
|
ip[2] = 65535;
|
|
else
|
|
ip[2] = (unsigned long)capacity / (ip[0] * ip[1]);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(scsicam_bios_param);
|
|
|
|
/**
|
|
* scsi_partsize - Parse cylinders/heads/sectors from PC partition table
|
|
* @buf: partition table, see scsi_bios_ptable()
|
|
* @capacity: size of the disk in sectors
|
|
* @cyls: put cylinders here
|
|
* @hds: put heads here
|
|
* @secs: put sectors here
|
|
*
|
|
* Description: determine the BIOS mapping/geometry used to create the partition
|
|
* table, storing the results in *cyls, *hds, and *secs
|
|
*
|
|
* Returns: -1 on failure, 0 on success.
|
|
*/
|
|
|
|
int scsi_partsize(unsigned char *buf, unsigned long capacity,
|
|
unsigned int *cyls, unsigned int *hds, unsigned int *secs)
|
|
{
|
|
struct partition *p = (struct partition *)buf, *largest = NULL;
|
|
int i, largest_cyl;
|
|
int cyl, ext_cyl, end_head, end_cyl, end_sector;
|
|
unsigned int logical_end, physical_end, ext_physical_end;
|
|
|
|
|
|
if (*(unsigned short *) (buf + 64) == 0xAA55) {
|
|
for (largest_cyl = -1, i = 0; i < 4; ++i, ++p) {
|
|
if (!p->sys_ind)
|
|
continue;
|
|
#ifdef DEBUG
|
|
printk("scsicam_bios_param : partition %d has system \n",
|
|
i);
|
|
#endif
|
|
cyl = p->cyl + ((p->sector & 0xc0) << 2);
|
|
if (cyl > largest_cyl) {
|
|
largest_cyl = cyl;
|
|
largest = p;
|
|
}
|
|
}
|
|
}
|
|
if (largest) {
|
|
end_cyl = largest->end_cyl + ((largest->end_sector & 0xc0) << 2);
|
|
end_head = largest->end_head;
|
|
end_sector = largest->end_sector & 0x3f;
|
|
|
|
if (end_head + 1 == 0 || end_sector == 0)
|
|
return -1;
|
|
|
|
#ifdef DEBUG
|
|
printk("scsicam_bios_param : end at h = %d, c = %d, s = %d\n",
|
|
end_head, end_cyl, end_sector);
|
|
#endif
|
|
|
|
physical_end = end_cyl * (end_head + 1) * end_sector +
|
|
end_head * end_sector + end_sector;
|
|
|
|
/* This is the actual _sector_ number at the end */
|
|
logical_end = get_unaligned(&largest->start_sect)
|
|
+ get_unaligned(&largest->nr_sects);
|
|
|
|
/* This is for >1023 cylinders */
|
|
ext_cyl = (logical_end - (end_head * end_sector + end_sector))
|
|
/ (end_head + 1) / end_sector;
|
|
ext_physical_end = ext_cyl * (end_head + 1) * end_sector +
|
|
end_head * end_sector + end_sector;
|
|
|
|
#ifdef DEBUG
|
|
printk("scsicam_bios_param : logical_end=%d physical_end=%d ext_physical_end=%d ext_cyl=%d\n"
|
|
,logical_end, physical_end, ext_physical_end, ext_cyl);
|
|
#endif
|
|
|
|
if ((logical_end == physical_end) ||
|
|
(end_cyl == 1023 && ext_physical_end == logical_end)) {
|
|
*secs = end_sector;
|
|
*hds = end_head + 1;
|
|
*cyls = capacity / ((end_head + 1) * end_sector);
|
|
return 0;
|
|
}
|
|
#ifdef DEBUG
|
|
printk("scsicam_bios_param : logical (%u) != physical (%u)\n",
|
|
logical_end, physical_end);
|
|
#endif
|
|
}
|
|
return -1;
|
|
}
|
|
EXPORT_SYMBOL(scsi_partsize);
|
|
|
|
/*
|
|
* Function : static int setsize(unsigned long capacity,unsigned int *cyls,
|
|
* unsigned int *hds, unsigned int *secs);
|
|
*
|
|
* Purpose : to determine a near-optimal int 0x13 mapping for a
|
|
* SCSI disk in terms of lost space of size capacity, storing
|
|
* the results in *cyls, *hds, and *secs.
|
|
*
|
|
* Returns : -1 on failure, 0 on success.
|
|
*
|
|
* Extracted from
|
|
*
|
|
* WORKING X3T9.2
|
|
* DRAFT 792D
|
|
* see http://www.t10.org/ftp/t10/drafts/cam/cam-r12b.pdf
|
|
*
|
|
* Revision 6
|
|
* 10-MAR-94
|
|
* Information technology -
|
|
* SCSI-2 Common access method
|
|
* transport and SCSI interface module
|
|
*
|
|
* ANNEX A :
|
|
*
|
|
* setsize() converts a read capacity value to int 13h
|
|
* head-cylinder-sector requirements. It minimizes the value for
|
|
* number of heads and maximizes the number of cylinders. This
|
|
* will support rather large disks before the number of heads
|
|
* will not fit in 4 bits (or 6 bits). This algorithm also
|
|
* minimizes the number of sectors that will be unused at the end
|
|
* of the disk while allowing for very large disks to be
|
|
* accommodated. This algorithm does not use physical geometry.
|
|
*/
|
|
|
|
static int setsize(unsigned long capacity, unsigned int *cyls, unsigned int *hds,
|
|
unsigned int *secs)
|
|
{
|
|
unsigned int rv = 0;
|
|
unsigned long heads, sectors, cylinders, temp;
|
|
|
|
cylinders = 1024L; /* Set number of cylinders to max */
|
|
sectors = 62L; /* Maximize sectors per track */
|
|
|
|
temp = cylinders * sectors; /* Compute divisor for heads */
|
|
heads = capacity / temp; /* Compute value for number of heads */
|
|
if (capacity % temp) { /* If no remainder, done! */
|
|
heads++; /* Else, increment number of heads */
|
|
temp = cylinders * heads; /* Compute divisor for sectors */
|
|
sectors = capacity / temp; /* Compute value for sectors per
|
|
track */
|
|
if (capacity % temp) { /* If no remainder, done! */
|
|
sectors++; /* Else, increment number of sectors */
|
|
temp = heads * sectors; /* Compute divisor for cylinders */
|
|
cylinders = capacity / temp; /* Compute number of cylinders */
|
|
}
|
|
}
|
|
if (cylinders == 0)
|
|
rv = (unsigned) -1; /* Give error if 0 cylinders */
|
|
|
|
*cyls = (unsigned int) cylinders; /* Stuff return values */
|
|
*secs = (unsigned int) sectors;
|
|
*hds = (unsigned int) heads;
|
|
return (rv);
|
|
}
|