Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 258 insertions, 0 deletions

diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
new file mode 100644
index 000000000..682cf08ab
--- /dev/null
+++ b/drivers/scsi/scsicam.c
@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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/slab.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/msdos_partition.h>
+#include <asm/unaligned.h>
+
+#include <scsi/scsicam.h>
+
+/**
+ * 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)
+{
+	struct address_space *mapping = dev->bd_contains->bd_inode->i_mapping;
+	unsigned char *res = NULL;
+	struct page *page;
+
+	page = read_mapping_page(mapping, 0, NULL);
+	if (IS_ERR(page))
+		return NULL;
+
+	if (!PageError(page))
+		res = kmemdup(page_address(page) + 0x1be, 66, GFP_KERNEL);
+	put_page(page);
+	return res;
+}
+EXPORT_SYMBOL(scsi_bios_ptable);
+
+/**
+ * scsi_partsize - Parse cylinders/heads/sectors from PC partition table
+ * @bdev: block device to parse
+ * @capacity: size of the disk in sectors
+ * @geom: output in form of [hds, cylinders, sectors]
+ *
+ * Determine the BIOS mapping/geometry used to create the partition
+ * table, storing the results in @geom.
+ *
+ * Returns: %false on failure, %true on success.
+ */
+bool scsi_partsize(struct block_device *bdev, sector_t capacity, int geom[3])
+{
+	int cyl, ext_cyl, end_head, end_cyl, end_sector;
+	unsigned int logical_end, physical_end, ext_physical_end;
+	struct msdos_partition *p, *largest = NULL;
+	void *buf;
+	int ret = false;
+
+	buf = scsi_bios_ptable(bdev);
+	if (!buf)
+		return false;
+
+	if (*(unsigned short *) (buf + 64) == 0xAA55) {
+		int largest_cyl = -1, i;
+
+		for (i = 0, p = buf; 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)
+			goto out_free_buf;
+
+#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_le32(&largest->start_sect)
+		    + get_unaligned_le32(&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)) {
+			geom[0] = end_head + 1;
+			geom[1] = end_sector;
+			geom[2] = (unsigned long)capacity /
+				((end_head + 1) * end_sector);
+			ret = true;
+			goto out_free_buf;
+		}
+#ifdef DEBUG
+		printk("scsicam_bios_param : logical (%u) != physical (%u)\n",
+		       logical_end, physical_end);
+#endif
+	}
+
+out_free_buf:
+	kfree(buf);
+	return ret;
+}
+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);
+}
+
+/**
+ * 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)
+{
+	u64 capacity64 = capacity;	/* Suppress gcc warning */
+	int ret = 0;
+
+	/* try to infer mapping from partition table */
+	if (scsi_partsize(bdev, capacity, ip))
+		return 0;
+
+	if (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);