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From: Michael Olbrich <m.olbrich@pengutronix.de>
Date: Tue, 31 May 2011 16:11:10 +0200
Subject: [PATCH] setup heads, cylinders and sectors
"heads per cylinder" and "sectors per track" are just a guess.
It seems to work with typical SD-Cards. And unused partitions
are shown as such now.
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
---
src/genpart.c | 24 ++++++++++++++++++------
1 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/src/genpart.c b/src/genpart.c
index 6c11b91..49be9d7 100644
--- a/src/genpart.c
+++ b/src/genpart.c
@@ -7,12 +7,12 @@ struct partition_entry {
unsigned char boot;
unsigned char start_head;
- unsigned short start_cyl_sec;
+ unsigned char start_cyl_sec[2];
unsigned char part_type;
unsigned char end_head;
- unsigned short end_cyl_sec;
+ unsigned char end_cyl_sec[2];
unsigned int relative_sectors;
unsigned int total_sectors;
@@ -35,6 +35,19 @@ void print_usage(void)
);
}
+void setup_head_cyl_sec(unsigned int lba, unsigned char *head, unsigned char *cyl_sec)
+{
+ const unsigned int hpc = 255;
+ const unsigned int spt = 63;
+ unsigned int s, c;
+
+ *head = (lba/spt)%hpc;
+ c = (lba/(spt * hpc));
+ s = (lba > 0) ?(lba%spt + 1) : 0;
+ cyl_sec[0] = ((c & 0x300) >> 2) | (s & 0xff);
+ cyl_sec[1] = (c & 0xff);
+}
+
int main(int argc, char *argv[])
{
struct partition_entry entry;
@@ -60,10 +73,6 @@ int main(int argc, char *argv[])
memset(&entry, 0, sizeof(struct partition_entry));
entry.part_type = 0x83; /* default to linux */
- entry.start_head = 0xff;
- entry.start_cyl_sec = 0xffff;
- entry.end_head = 0xff;
- entry.end_cyl_sec = 0xffff;
while ((opt = getopt_long(argc, argv, "hb:s:ct:m", long_options, NULL)) != -1) {
switch (opt) {
@@ -87,6 +96,9 @@ int main(int argc, char *argv[])
break;
}
}
+ setup_head_cyl_sec(entry.relative_sectors, &entry.start_head, entry.start_cyl_sec);
+ setup_head_cyl_sec((entry.total_sectors > 0) ? (entry.relative_sectors + entry.total_sectors - 1) : 0,
+ &entry.end_head, entry.end_cyl_sec);
if (fwrite(&entry, sizeof(struct partition_entry), 1, stdout) > 0) {
if (do_magic) {
--
1.7.5.3
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