Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 1 | /* |
| 2 | * OMAP 32ksynctimer/counter_32k-related code |
| 3 | * |
| 4 | * Copyright (C) 2009 Texas Instruments |
| 5 | * Copyright (C) 2010 Nokia Corporation |
| 6 | * Tony Lindgren <tony@atomide.com> |
| 7 | * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com> |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License version 2 as |
| 11 | * published by the Free Software Foundation. |
| 12 | * |
| 13 | * NOTE: This timer is not the same timer as the old OMAP1 MPU timer. |
| 14 | */ |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/clk.h> |
Vasiliy Kulikov | cb9675f | 2010-11-26 17:06:02 +0000 | [diff] [blame] | 18 | #include <linux/err.h> |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 19 | #include <linux/io.h> |
Russell King | 5e06b64 | 2010-12-15 19:19:25 +0000 | [diff] [blame] | 20 | #include <linux/sched.h> |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 21 | #include <linux/clocksource.h> |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 22 | |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 23 | #include <asm/sched_clock.h> |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 24 | |
| 25 | #include <plat/common.h> |
| 26 | #include <plat/board.h> |
| 27 | |
| 28 | #include <plat/clock.h> |
| 29 | |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 30 | /* |
| 31 | * 32KHz clocksource ... always available, on pretty most chips except |
| 32 | * OMAP 730 and 1510. Other timers could be used as clocksources, with |
| 33 | * higher resolution in free-running counter modes (e.g. 12 MHz xtal), |
| 34 | * but systems won't necessarily want to spend resources that way. |
| 35 | */ |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 36 | static void __iomem *timer_32k_base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 37 | |
| 38 | #define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410 |
| 39 | |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 40 | /* |
| 41 | * Returns current time from boot in nsecs. It's OK for this to wrap |
| 42 | * around for now, as it's just a relative time stamp. |
| 43 | */ |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 44 | static DEFINE_CLOCK_DATA(cd); |
| 45 | |
| 46 | /* |
| 47 | * Constants generated by clocks_calc_mult_shift(m, s, 32768, NSEC_PER_SEC, 60). |
| 48 | * This gives a resolution of about 30us and a wrap period of about 36hrs. |
| 49 | */ |
| 50 | #define SC_MULT 4000000000u |
| 51 | #define SC_SHIFT 17 |
| 52 | |
Tony Lindgren | 4912cf04b | 2011-01-18 17:00:00 -0800 | [diff] [blame] | 53 | static inline unsigned long long notrace _omap_32k_sched_clock(void) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 54 | { |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 55 | u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0; |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 56 | return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT); |
| 57 | } |
| 58 | |
Tony Lindgren | 3d05a3e | 2011-03-29 15:54:49 -0700 | [diff] [blame] | 59 | #if defined(CONFIG_OMAP_32K_TIMER) && !defined(CONFIG_OMAP_MPU_TIMER) |
Tony Lindgren | 4912cf04b | 2011-01-18 17:00:00 -0800 | [diff] [blame] | 60 | unsigned long long notrace sched_clock(void) |
| 61 | { |
| 62 | return _omap_32k_sched_clock(); |
| 63 | } |
| 64 | #else |
| 65 | unsigned long long notrace omap_32k_sched_clock(void) |
| 66 | { |
| 67 | return _omap_32k_sched_clock(); |
| 68 | } |
| 69 | #endif |
| 70 | |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 71 | static void notrace omap_update_sched_clock(void) |
| 72 | { |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 73 | u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0; |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 74 | update_sched_clock(&cd, cyc, (u32)~0); |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 75 | } |
| 76 | |
| 77 | /** |
| 78 | * read_persistent_clock - Return time from a persistent clock. |
| 79 | * |
| 80 | * Reads the time from a source which isn't disabled during PM, the |
| 81 | * 32k sync timer. Convert the cycles elapsed since last read into |
| 82 | * nsecs and adds to a monotonically increasing timespec. |
| 83 | */ |
| 84 | static struct timespec persistent_ts; |
| 85 | static cycles_t cycles, last_cycles; |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 86 | static unsigned int persistent_mult, persistent_shift; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 87 | void read_persistent_clock(struct timespec *ts) |
| 88 | { |
| 89 | unsigned long long nsecs; |
| 90 | cycles_t delta; |
| 91 | struct timespec *tsp = &persistent_ts; |
| 92 | |
| 93 | last_cycles = cycles; |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 94 | cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 95 | delta = cycles - last_cycles; |
| 96 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 97 | nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift); |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 98 | |
| 99 | timespec_add_ns(tsp, nsecs); |
| 100 | *ts = *tsp; |
| 101 | } |
| 102 | |
Paul Walmsley | d8328f3 | 2011-01-15 21:32:01 -0700 | [diff] [blame] | 103 | int __init omap_init_clocksource_32k(void) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 104 | { |
| 105 | static char err[] __initdata = KERN_ERR |
| 106 | "%s: can't register clocksource!\n"; |
| 107 | |
| 108 | if (cpu_is_omap16xx() || cpu_class_is_omap2()) { |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 109 | u32 pbase; |
| 110 | unsigned long size = SZ_4K; |
| 111 | void __iomem *base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 112 | struct clk *sync_32k_ick; |
| 113 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 114 | if (cpu_is_omap16xx()) { |
| 115 | pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED; |
| 116 | size = SZ_1K; |
| 117 | } else if (cpu_is_omap2420()) |
| 118 | pbase = OMAP2420_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 119 | else if (cpu_is_omap2430()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 120 | pbase = OMAP2430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 121 | else if (cpu_is_omap34xx()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 122 | pbase = OMAP3430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 123 | else if (cpu_is_omap44xx()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 124 | pbase = OMAP4430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 125 | else |
| 126 | return -ENODEV; |
| 127 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 128 | /* For this to work we must have a static mapping in io.c for this area */ |
| 129 | base = ioremap(pbase, size); |
| 130 | if (!base) |
| 131 | return -ENODEV; |
| 132 | |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 133 | sync_32k_ick = clk_get(NULL, "omap_32ksync_ick"); |
Vasiliy Kulikov | cb9675f | 2010-11-26 17:06:02 +0000 | [diff] [blame] | 134 | if (!IS_ERR(sync_32k_ick)) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 135 | clk_enable(sync_32k_ick); |
| 136 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 137 | timer_32k_base = base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 138 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 139 | /* |
| 140 | * 120000 rough estimate from the calculations in |
| 141 | * __clocksource_updatefreq_scale. |
| 142 | */ |
| 143 | clocks_calc_mult_shift(&persistent_mult, &persistent_shift, |
| 144 | 32768, NSEC_PER_SEC, 120000); |
| 145 | |
| 146 | if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32, |
| 147 | clocksource_mmio_readl_up)) |
| 148 | printk(err, "32k_counter"); |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 149 | |
| 150 | init_fixed_sched_clock(&cd, omap_update_sched_clock, 32, |
| 151 | 32768, SC_MULT, SC_SHIFT); |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 152 | } |
| 153 | return 0; |
| 154 | } |