Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/plat-versatile/sched-clock.c |
| 3 | * |
| 4 | * Copyright (C) 1999 - 2003 ARM Limited |
| 5 | * Copyright (C) 2000 Deep Blue Solutions Ltd |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 20 | */ |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 21 | #include <linux/io.h> |
Rabin Vincent | ec763f0 | 2010-11-19 21:11:02 +0530 | [diff] [blame] | 22 | #include <linux/sched.h> |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 23 | |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 24 | #include <asm/sched_clock.h> |
| 25 | #include <plat/sched_clock.h> |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 26 | |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 27 | static DEFINE_CLOCK_DATA(cd); |
| 28 | static void __iomem *ctr; |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 29 | |
| 30 | /* |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 31 | * Constants generated by clocks_calc_mult_shift(m, s, 24MHz, NSEC_PER_SEC, 60). |
| 32 | * This gives a resolution of about 41ns and a wrap period of about 178s. |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 33 | */ |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 34 | #define SC_MULT 2796202667u |
| 35 | #define SC_SHIFT 26 |
| 36 | |
Russell King | 5e06b64 | 2010-12-15 19:19:25 +0000 | [diff] [blame] | 37 | unsigned long long notrace sched_clock(void) |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 38 | { |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 39 | if (ctr) { |
| 40 | u32 cyc = readl(ctr); |
| 41 | return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, |
| 42 | SC_MULT, SC_SHIFT); |
| 43 | } else |
| 44 | return 0; |
| 45 | } |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 46 | |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 47 | static void notrace versatile_update_sched_clock(void) |
| 48 | { |
| 49 | u32 cyc = readl(ctr); |
| 50 | update_sched_clock(&cd, cyc, (u32)~0); |
| 51 | } |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 52 | |
Russell King | 1da0c89 | 2010-12-15 21:56:47 +0000 | [diff] [blame^] | 53 | void __init versatile_sched_clock_init(void __iomem *reg, unsigned long rate) |
| 54 | { |
| 55 | ctr = reg; |
| 56 | init_fixed_sched_clock(&cd, versatile_update_sched_clock, |
| 57 | 32, rate, SC_MULT, SC_SHIFT); |
Russell King | f5fc008 | 2010-01-14 20:07:35 +0000 | [diff] [blame] | 58 | } |