projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 5b3b1688 DD |
1 | /* |
| 2 | * This file is subject to the terms and conditions of the GNU General Public | |
| 3 | * License. See the file "COPYING" in the main directory of this archive | |
| 4 | * for more details. | |
| 5 | * | |
| 6 | * Copyright (C) 2007 by Ralf Baechle | |
| 7 | */ | |
| 8 | #include <linux/clocksource.h> | |
| 9 | #include <linux/init.h> | |
| 10 | ||
| 11 | #include <asm/time.h> | |
| 12 | ||
| 13 | #include <asm/octeon/octeon.h> | |
| 14 | #include <asm/octeon/cvmx-ipd-defs.h> | |
| 15 | ||
| 16 | /* | |
| 17 | * Set the current core's cvmcount counter to the value of the | |
| 18 | * IPD_CLK_COUNT. We do this on all cores as they are brought | |
| 19 | * on-line. This allows for a read from a local cpu register to | |
| 20 | * access a synchronized counter. | |
| 21 | * | |
| 22 | */ | |
| 23 | void octeon_init_cvmcount(void) | |
| 24 | { | |
| 25 | unsigned long flags; | |
| 26 | unsigned loops = 2; | |
| 27 | ||
| 28 | /* Clobber loops so GCC will not unroll the following while loop. */ | |
| 29 | asm("" : "+r" (loops)); | |
| 30 | ||
| 31 | local_irq_save(flags); | |
| 32 | /* | |
| 33 | * Loop several times so we are executing from the cache, | |
| 34 | * which should give more deterministic timing. | |
| 35 | */ | |
| 36 | while (loops--) | |
| 37 | write_c0_cvmcount(cvmx_read_csr(CVMX_IPD_CLK_COUNT)); | |
| 38 | local_irq_restore(flags); | |
| 39 | } | |
| 40 | ||
| d0ce9a5a | 41 | static cycle_t octeon_cvmcount_read(struct clocksource *cs) |
| 5b3b1688 DD |
42 | { |
| 43 | return read_c0_cvmcount(); | |
| 44 | } | |
| 45 | ||
| 46 | static struct clocksource clocksource_mips = { | |
| 47 | .name = "OCTEON_CVMCOUNT", | |
| 48 | .read = octeon_cvmcount_read, | |
| 49 | .mask = CLOCKSOURCE_MASK(64), | |
| 50 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
| 51 | }; | |
| 52 | ||
| c6a3c851 DD |
53 | unsigned long long notrace sched_clock(void) |
| 54 | { | |
| 0e8a1d82 DD |
55 | /* 64-bit arithmatic can overflow, so use 128-bit. */ |
| 56 | #if (__GNUC__ < 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 3)) | |
| 57 | u64 t1, t2, t3; | |
| 58 | unsigned long long rv; | |
| 59 | u64 mult = clocksource_mips.mult; | |
| 60 | u64 shift = clocksource_mips.shift; | |
| 61 | u64 cnt = read_c0_cvmcount(); | |
| 62 | ||
| 63 | asm ( | |
| 64 | "dmultu\t%[cnt],%[mult]\n\t" | |
| 65 | "nor\t%[t1],$0,%[shift]\n\t" | |
| 66 | "mfhi\t%[t2]\n\t" | |
| 67 | "mflo\t%[t3]\n\t" | |
| 68 | "dsll\t%[t2],%[t2],1\n\t" | |
| 69 | "dsrlv\t%[rv],%[t3],%[shift]\n\t" | |
| 70 | "dsllv\t%[t1],%[t2],%[t1]\n\t" | |
| 71 | "or\t%[rv],%[t1],%[rv]\n\t" | |
| 72 | : [rv] "=&r" (rv), [t1] "=&r" (t1), [t2] "=&r" (t2), [t3] "=&r" (t3) | |
| 73 | : [cnt] "r" (cnt), [mult] "r" (mult), [shift] "r" (shift) | |
| 74 | : "hi", "lo"); | |
| 75 | return rv; | |
| 76 | #else | |
| 77 | /* GCC > 4.3 do it the easy way. */ | |
| 78 | unsigned int __attribute__((mode(TI))) t; | |
| 79 | t = read_c0_cvmcount(); | |
| 80 | t = t * clocksource_mips.mult; | |
| 81 | return (unsigned long long)(t >> clocksource_mips.shift); | |
| 82 | #endif | |
| c6a3c851 DD |
83 | } |
| 84 | ||
| 5b3b1688 DD |
85 | void __init plat_time_init(void) |
| 86 | { | |
| 87 | clocksource_mips.rating = 300; | |
| 88 | clocksource_set_clock(&clocksource_mips, mips_hpt_frequency); | |
| 89 | clocksource_register(&clocksource_mips); | |
| 90 | } |