hd-geometry: Move disk geometry guessing back from block.c

Commit f3d54fc4 factored it out of hw/ide.c for reuse.  Sensible,
except it was put into block.c.  Device-specific functionality should
be kept in device code, not the block layer.  Move it to
hw/hd-geometry.c, and make stylistic changes required to keep
checkpatch.pl happy.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 162 insertions, 0 deletions

diff --git a/hw/hd-geometry.c b/hw/hd-geometry.c
new file mode 100644
index 0000000..c45eafd
--- /dev/null
+++ b/hw/hd-geometry.c
@@ -0,0 +1,162 @@
+/*
+ * Hard disk geometry utilities
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ * Copyright (c) 2003 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "block.h"
+#include "hw/block-common.h"
+
+struct partition {
+        uint8_t boot_ind;           /* 0x80 - active */
+        uint8_t head;               /* starting head */
+        uint8_t sector;             /* starting sector */
+        uint8_t cyl;                /* starting cylinder */
+        uint8_t sys_ind;            /* What partition type */
+        uint8_t end_head;           /* end head */
+        uint8_t end_sector;         /* end sector */
+        uint8_t end_cyl;            /* end cylinder */
+        uint32_t start_sect;        /* starting sector counting from 0 */
+        uint32_t nr_sects;          /* nr of sectors in partition */
+} QEMU_PACKED;
+
+/* try to guess the disk logical geometry from the MSDOS partition table.
+   Return 0 if OK, -1 if could not guess */
+static int guess_disk_lchs(BlockDriverState *bs,
+                           int *pcylinders, int *pheads, int *psectors)
+{
+    uint8_t buf[BDRV_SECTOR_SIZE];
+    int i, heads, sectors, cylinders;
+    struct partition *p;
+    uint32_t nr_sects;
+    uint64_t nb_sectors;
+
+    bdrv_get_geometry(bs, &nb_sectors);
+
+    /**
+     * The function will be invoked during startup not only in sync I/O mode,
+     * but also in async I/O mode. So the I/O throttling function has to
+     * be disabled temporarily here, not permanently.
+     */
+    if (bdrv_read_unthrottled(bs, 0, buf, 1) < 0) {
+        return -1;
+    }
+    /* test msdos magic */
+    if (buf[510] != 0x55 || buf[511] != 0xaa) {
+        return -1;
+    }
+    for (i = 0; i < 4; i++) {
+        p = ((struct partition *)(buf + 0x1be)) + i;
+        nr_sects = le32_to_cpu(p->nr_sects);
+        if (nr_sects && p->end_head) {
+            /* We make the assumption that the partition terminates on
+               a cylinder boundary */
+            heads = p->end_head + 1;
+            sectors = p->end_sector & 63;
+            if (sectors == 0) {
+                continue;
+            }
+            cylinders = nb_sectors / (heads * sectors);
+            if (cylinders < 1 || cylinders > 16383) {
+                continue;
+            }
+            *pheads = heads;
+            *psectors = sectors;
+            *pcylinders = cylinders;
+#if 0
+            printf("guessed geometry: LCHS=%d %d %d\n",
+                   cylinders, heads, sectors);
+#endif
+            return 0;
+        }
+    }
+    return -1;
+}
+
+void hd_geometry_guess(BlockDriverState *bs,
+                       int *pcyls, int *pheads, int *psecs)
+{
+    int translation, lba_detected = 0;
+    int cylinders, heads, secs;
+    uint64_t nb_sectors;
+
+    /* if a geometry hint is available, use it */
+    bdrv_get_geometry(bs, &nb_sectors);
+    bdrv_get_geometry_hint(bs, &cylinders, &heads, &secs);
+    translation = bdrv_get_translation_hint(bs);
+    if (cylinders != 0) {
+        *pcyls = cylinders;
+        *pheads = heads;
+        *psecs = secs;
+    } else {
+        if (guess_disk_lchs(bs, &cylinders, &heads, &secs) == 0) {
+            if (heads > 16) {
+                /* if heads > 16, it means that a BIOS LBA
+                   translation was active, so the default
+                   hardware geometry is OK */
+                lba_detected = 1;
+                goto default_geometry;
+            } else {
+                *pcyls = cylinders;
+                *pheads = heads;
+                *psecs = secs;
+                /* disable any translation to be in sync with
+                   the logical geometry */
+                if (translation == BIOS_ATA_TRANSLATION_AUTO) {
+                    bdrv_set_translation_hint(bs,
+                                              BIOS_ATA_TRANSLATION_NONE);
+                }
+            }
+        } else {
+        default_geometry:
+            /* if no geometry, use a standard physical disk geometry */
+            cylinders = nb_sectors / (16 * 63);
+
+            if (cylinders > 16383) {
+                cylinders = 16383;
+            } else if (cylinders < 2) {
+                cylinders = 2;
+            }
+            *pcyls = cylinders;
+            *pheads = 16;
+            *psecs = 63;
+            if ((lba_detected == 1)
+                && (translation == BIOS_ATA_TRANSLATION_AUTO)) {
+                if ((*pcyls * *pheads) <= 131072) {
+                    bdrv_set_translation_hint(bs,
+                                              BIOS_ATA_TRANSLATION_LARGE);
+                } else {
+                    bdrv_set_translation_hint(bs,
+                                              BIOS_ATA_TRANSLATION_LBA);
+                }
+            }
+        }
+        bdrv_set_geometry_hint(bs, *pcyls, *pheads, *psecs);
+    }
+}