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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/scsi/scsicam.c | |
download | kernel_samsung_espresso10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_espresso10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_espresso10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/scsi/scsicam.c')
-rw-r--r-- | drivers/scsi/scsicam.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c new file mode 100644 index 0000000..b78354f --- /dev/null +++ b/drivers/scsi/scsicam.c @@ -0,0 +1,245 @@ +/* + * 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); + +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); + +/* + * Function : int scsicam_bios_param (struct block_device *bdev, ector_t capacity, int *ip) + * + * Purpose : to determine the BIOS mapping 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; + 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) { + /* 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); + +/* + * Function : static int scsi_partsize(unsigned char *buf, unsigned long + * capacity,unsigned int *cyls, unsigned int *hds, unsigned int *secs); + * + * Purpose : to determine the BIOS mapping 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 + * + * + * 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); +} |