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hid-core: big-endian fix fix

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Adam Kropelin had posted 32-bit fix in June 2005 about two weeks after I
originally had posted my fixes for big endian support.  Adam has a UPS
device which reports LINEV using 32-bits.

Added comments to describe the limitations of the code.

extract() is the same version I posted earlier and tested in user space. 
Made similar changes to implement() routine.  I've written (and will
shortly post) a test for implement().  Code tested on C3600 (parisc) with
USB keyboard/mouse attached.


I've dropped test_implement.c and a few other user space test programs on
http://iou.parisc-linux.org/~grundler/tests/

-rw-r--r-- 1 grundler grundler 1750 Oct 18 09:13 test_extract.c
-rw-r--r-- 1 grundler grundler  561 Jan 25  2006 test_ffs.c
-rw-r--r-- 1 grundler users    7175 Apr  8  2005 test_fls.c
-rw-r--r-- 1 grundler grundler  206 Sep  1 15:52 test_gettimeofday.c
-rw-r--r-- 1 grundler grundler 1886 Oct 19 09:20 test_implement.c
-rw-r--r-- 1 grundler users    2707 Jun  4  2005 test_unaligned.c

I would appreciate if someone else would look at the output of
test_implement.c to make it does The Right Thing.

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-By: Adam Kropelin <akropel1@rochester.rr.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Grant Grundler 2006-10-19 15:09:51 -07:00 committed by Greg Kroah-Hartman
parent bc724b98c5
commit 68717950e1
1 changed files with 42 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
drivers/usb/input/hid-core.c
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@ -270,7 +270,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
* Read data value from item.
*/
static __inline__ __u32 item_udata(struct hid_item *item)
static u32 item_udata(struct hid_item *item)
{
switch (item->size) {
case 1: return item->data.u8;
@ -280,7 +280,7 @@ static __inline__ __u32 item_udata(struct hid_item *item)
return 0;
}
static __inline__ __s32 item_sdata(struct hid_item *item)
static s32 item_sdata(struct hid_item *item)
{
switch (item->size) {
case 1: return item->data.s8;
@ -727,7 +727,7 @@ static struct hid_device *hid_parse_report(__u8 *start, unsigned size)
* done by hand.
*/
static __inline__ __s32 snto32(__u32 value, unsigned n)
static s32 snto32(__u32 value, unsigned n)
{
switch (n) {
case 8: return ((__s8)value);
@ -741,9 +741,9 @@ static __inline__ __s32 snto32(__u32 value, unsigned n)
* Convert a signed 32-bit integer to a signed n-bit integer.
*/
static __inline__ __u32 s32ton(__s32 value, unsigned n)
static u32 s32ton(__s32 value, unsigned n)
{
__s32 a = value >> (n - 1);
s32 a = value >> (n - 1);
if (a && a != -1)
return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
return value & ((1 << n) - 1);
@ -751,30 +751,55 @@ static __inline__ __u32 s32ton(__s32 value, unsigned n)
/*
* Extract/implement a data field from/to a little endian report (bit array).
*
* Code sort-of follows HID spec:
* http://www.usb.org/developers/devclass_docs/HID1_11.pdf
*
* While the USB HID spec allows unlimited length bit fields in "report
* descriptors", most devices never use more than 16 bits.
* One model of UPS is claimed to report "LINEV" as a 32-bit field.
* Search linux-kernel and linux-usb-devel archives for "hid-core extract".
*/
static __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
{
u32 x;
u64 x;
WARN_ON(n > 32);
report += offset >> 3; /* adjust byte index */
offset &= 8 - 1;
x = get_unaligned((u32 *) report);
x = le32_to_cpu(x);
x = (x >> offset) & ((1 << n) - 1);
return x;
offset &= 7; /* now only need bit offset into one byte */
x = get_unaligned((u64 *) report);
x = le64_to_cpu(x);
x = (x >> offset) & ((1ULL << n) - 1); /* extract bit field */
return (u32) x;
}
/*
* "implement" : set bits in a little endian bit stream.
* Same concepts as "extract" (see comments above).
* The data mangled in the bit stream remains in little endian
* order the whole time. It make more sense to talk about
* endianness of register values by considering a register
* a "cached" copy of the little endiad bit stream.
*/
static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
{
u32 x;
u64 x;
u64 m = (1ULL << n) - 1;
WARN_ON(n > 32);
WARN_ON(value > m);
value &= m;
report += offset >> 3;
offset &= 8 - 1;
x = get_unaligned((u32 *)report);
x &= cpu_to_le32(~((((__u32) 1 << n) - 1) << offset));
x |= cpu_to_le32(value << offset);
put_unaligned(x,(u32 *)report);
offset &= 7;
x = get_unaligned((u64 *)report);
x &= cpu_to_le64(~(m << offset));
x |= cpu_to_le64(((u64) value) << offset);
put_unaligned(x, (u64 *) report);
}
/*