Hi Jason,
I don't look closely yet, but find some comments below:
Jason McMullan wrote:
include/configs/dbau1x00.h | 3 ++- include/configs/gth2.h | 3 ++- include/configs/incaip.h | 3 ++- include/configs/pb1x00.h | 3 ++- include/configs/purple.h | 3 ++- include/configs/qemu-mips.h | 3 ++- include/configs/tb0229.h | 3 ++-
Ok.
diff --git a/lib_mips/time.c b/lib_mips/time.c index cd8dc72..4807f1a 100644 --- a/lib_mips/time.c +++ b/lib_mips/time.c @@ -23,23 +23,57 @@
#include <common.h>
+/* CFG_MIPS_CLOCK is the number of ticks per second of the MIPS C0 Clock timer.
- For most implementations, this is the same as the CPU speed in HZ
- divided by 2. Some embedded MIPS implementations may use a /4
- or /1 divider, so see your CPU reference manual for specific details.
- */
+#ifndef CFG_MIPS_CLOCK +#error CFG_MIPS_CLOCK must be set in the board configuration file +#endif
+static struct {
- uint32_t lo;
- uint32_t hi;
+} mips_ticks; /* Last number of ticks seen */
See below.
+/* Input is in CFG_HZ ticks */ static inline void mips_compare_set(u32 v) {
- v *= (CFG_MIPS_CLOCK / CFG_HZ); asm volatile ("mtc0 %0, $11" : : "r" (v));
}
I tend to remove these mips_{count,compare}_{get,set} functions because they can be (and should be) replaced {read,write}_32bit_ cp0_register, IMO.
And I want to handle (CFG_MIPS_CLOCK/CFG_HZ) stuffs or something like that at udelay() side.
+/* Returns CFG_HZ ticks
- NOTE: This must be called at least once every
few seconds to be reliable.- */
static inline u32 mips_count_get(void) { u32 count;
asm volatile ("mfc0 %0, $9" : "=r" (count) :);
- /* Handle 32-bit timer overflow */
- if (count < mips_ticks.lo) {
mips_ticks.hi++;- }
- mips_ticks.lo = count;
- count =(mips_ticks.lo / (CFG_MIPS_CLOCK / CFG_HZ)) +
(mips_ticks.hi * (0x100000000ULL / (CFG_MIPS_CLOCK / CFG_HZ)));- return count;
}
I disagree with having this structure. Basic strategy for MIPS COUNT/ COMPARE handling is, let them overflow (os should I say wrap-around) as they are. All we need is the Delta, not the numbers of overflows.
@@ -75,7 +109,7 @@ void udelay (unsigned long usec) ulong tmo; ulong start = get_timer(0);
- tmo = usec * (CFG_HZ / 1000000);
- tmo = usec * CFG_HZ / 1000; while ((ulong)((mips_count_get() - start)) < tmo) /*NOP*/;
}
Again, what is needed is `the Delta' between CP0.COUNT(Previous) and CP0.COUNT(Current). This can be always achieved by
delta = COUNT(Curr) - COUNT(Prev)
regardless of COUNT value. Even if `(u32)0x00010000 - (u32)0xFFFFFFFF', it works.
I'll look around until this weekend. Sorry for inconvinience, and thank you for working on this.
Shinya