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https://github.com/AsahiLinux/u-boot
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a55d48174c
MIPS port has two problems in timer routines. One is now we assume CFG_HZ equals to CP0 counter frequency, but this is wrong. CFG_HZ has to be 1000 in the U-Boot system. The other is we don't have a proper time management counter like timestamp other ARCHs have. We need the 32-bit millisecond clock counter. This patch introduces timestamp and CYCLES_PER_JIFFY. timestamp is a 32-bit non-overflowing CFG_HZ counter, and CYCLES_PER_JIFFY is the number of calculated CP0 counter cycles in a CFG_HZ. STRATEGY: * Fix improper CFG_HZ value to have 1000 * Use CFG_MIPS_TIMER_FREQ for timer counter frequency, instead. * timer_init: initialize timestamp and set up the first timer expiration. Note that we don't need to initialize CP0 count/compare registers here as they have been already zeroed out on the system reset. Leave them as they are. * get_timer: calculate how many timestamps have been passed, then return base-relative timestamp. Make sure we can easily count missed timestamps regardless of CP0 count/compare value. * get_ticks: return the current timestamp, that is get_timer(0). Most parts are from good old Linux v2.6.16 kernel. v2: - Remove FIXME comments as they turned out to be trivial. - Use CP0 compare register as a global variable for expirelo. - Kill a global variable 'cycles_per_jiffy'. Use #define CYCLES_PER_JIFFY instead. Signed-off-by: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp> |
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| .. | ||
| board.c | ||
| bootm.c | ||
| Makefile | ||
| time.c | ||