Commit f12555d24ca636569b51c6f104aab41b2bba8c32
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6c35585273
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MIPS: Fix mdelay(1) for 64bit kernel with HZ == 1000
mdelay(1) (i.e. udelay(1000)) does not work correctly due to overflow. 1000 * 0x004189374BC6A7f0 = 0x10000000000000180 (>= 2**64) 0x004189374BC6A7ef (0x004189374BC6A7f0 - 1) is OK and it is exactly same as catchall case (0x8000000000000000UL / (500000 / HZ)). Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Showing 1 changed file with 2 additions and 4 deletions Side-by-side Diff
include/asm-mips/delay.h
| ... | ... | @@ -52,13 +52,11 @@ |
| 52 | 52 | unsigned long lo; |
| 53 | 53 | |
| 54 | 54 | /* |
| 55 | - * The common rates of 1000 and 128 are rounded wrongly by the | |
| 56 | - * catchall case for 64-bit. Excessive precission? Probably ... | |
| 55 | + * The rates of 128 is rounded wrongly by the catchall case | |
| 56 | + * for 64-bit. Excessive precission? Probably ... | |
| 57 | 57 | */ |
| 58 | 58 | #if defined(CONFIG_64BIT) && (HZ == 128) |
| 59 | 59 | usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */ |
| 60 | -#elif defined(CONFIG_64BIT) && (HZ == 1000) | |
| 61 | - usecs *= 0x004189374BC6A7f0UL; /* 2**64 / (1000000 / HZ) */ | |
| 62 | 60 | #elif defined(CONFIG_64BIT) |
| 63 | 61 | usecs *= (0x8000000000000000UL / (500000 / HZ)); |
| 64 | 62 | #else /* 32-bit junk follows here */ |