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authorGrant Grundler <grundler@parisc-linux.org>2006-10-19 15:09:51 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2006-11-03 11:57:18 -0800
commit68717950e11eab8ff754b2721d23e9cb3a47b56f (patch)
treea64053d0288df2151769b9a038ede7ca5bf66b64 /drivers/usb/input
parentbc724b98c5e782c2d6781428ed87768daa34921d (diff)
hid-core: big-endian fix fix
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>
Diffstat (limited to 'drivers/usb/input')
-rw-r--r--drivers/usb/input/hid-core.c59
1 files changed, 42 insertions, 17 deletions
diff --git a/drivers/usb/input/hid-core.c b/drivers/usb/input/hid-core.c
index 45f44fe33bf..6d42036c906 100644
--- a/drivers/usb/input/hid-core.c
+++ b/drivers/usb/input/hid-core.c
@@ -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);
}
/*