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 - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 20 | #include <linux/clocksource.h> |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 21 | |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 22 | #include <asm/sched_clock.h> |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 23 | |
| 24 | #include <plat/common.h> |
| 25 | #include <plat/board.h> |
| 26 | |
| 27 | #include <plat/clock.h> |
| 28 | |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 29 | /* |
| 30 | * 32KHz clocksource ... always available, on pretty most chips except |
| 31 | * OMAP 730 and 1510. Other timers could be used as clocksources, with |
| 32 | * higher resolution in free-running counter modes (e.g. 12 MHz xtal), |
| 33 | * but systems won't necessarily want to spend resources that way. |
| 34 | */ |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 35 | static void __iomem *timer_32k_base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 36 | |
| 37 | #define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410 |
| 38 | |
Marc Zyngier | 2f0778af | 2011-12-15 12:19:23 +0100 | [diff] [blame] | 39 | static u32 notrace omap_32k_read_sched_clock(void) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 40 | { |
Marc Zyngier | 2f0778af | 2011-12-15 12:19:23 +0100 | [diff] [blame] | 41 | return timer_32k_base ? __raw_readl(timer_32k_base) : 0; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 42 | } |
| 43 | |
| 44 | /** |
| 45 | * read_persistent_clock - Return time from a persistent clock. |
| 46 | * |
| 47 | * Reads the time from a source which isn't disabled during PM, the |
| 48 | * 32k sync timer. Convert the cycles elapsed since last read into |
| 49 | * nsecs and adds to a monotonically increasing timespec. |
| 50 | */ |
| 51 | static struct timespec persistent_ts; |
| 52 | static cycles_t cycles, last_cycles; |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 53 | static unsigned int persistent_mult, persistent_shift; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 54 | void read_persistent_clock(struct timespec *ts) |
| 55 | { |
| 56 | unsigned long long nsecs; |
| 57 | cycles_t delta; |
| 58 | struct timespec *tsp = &persistent_ts; |
| 59 | |
| 60 | last_cycles = cycles; |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 61 | cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 62 | delta = cycles - last_cycles; |
| 63 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 64 | nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift); |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 65 | |
| 66 | timespec_add_ns(tsp, nsecs); |
| 67 | *ts = *tsp; |
| 68 | } |
| 69 | |
Paul Walmsley | d8328f3 | 2011-01-15 21:32:01 -0700 | [diff] [blame] | 70 | int __init omap_init_clocksource_32k(void) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 71 | { |
| 72 | static char err[] __initdata = KERN_ERR |
| 73 | "%s: can't register clocksource!\n"; |
| 74 | |
| 75 | if (cpu_is_omap16xx() || cpu_class_is_omap2()) { |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 76 | u32 pbase; |
| 77 | unsigned long size = SZ_4K; |
| 78 | void __iomem *base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 79 | struct clk *sync_32k_ick; |
| 80 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 81 | if (cpu_is_omap16xx()) { |
| 82 | pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED; |
| 83 | size = SZ_1K; |
| 84 | } else if (cpu_is_omap2420()) |
| 85 | pbase = OMAP2420_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 86 | else if (cpu_is_omap2430()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 87 | pbase = OMAP2430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 88 | else if (cpu_is_omap34xx()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 89 | pbase = OMAP3430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 90 | else if (cpu_is_omap44xx()) |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 91 | pbase = OMAP4430_32KSYNCT_BASE + 0x10; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 92 | else |
| 93 | return -ENODEV; |
| 94 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 95 | /* For this to work we must have a static mapping in io.c for this area */ |
| 96 | base = ioremap(pbase, size); |
| 97 | if (!base) |
| 98 | return -ENODEV; |
| 99 | |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 100 | sync_32k_ick = clk_get(NULL, "omap_32ksync_ick"); |
Vasiliy Kulikov | cb9675f | 2010-11-26 17:06:02 +0000 | [diff] [blame] | 101 | if (!IS_ERR(sync_32k_ick)) |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 102 | clk_enable(sync_32k_ick); |
| 103 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 104 | timer_32k_base = base; |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 105 | |
Russell King - ARM Linux | 354a183 | 2011-07-10 23:05:34 -0700 | [diff] [blame] | 106 | /* |
| 107 | * 120000 rough estimate from the calculations in |
| 108 | * __clocksource_updatefreq_scale. |
| 109 | */ |
| 110 | clocks_calc_mult_shift(&persistent_mult, &persistent_shift, |
| 111 | 32768, NSEC_PER_SEC, 120000); |
| 112 | |
| 113 | if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32, |
| 114 | clocksource_mmio_readl_up)) |
| 115 | printk(err, "32k_counter"); |
Russell King | dc548fb | 2010-12-15 21:53:51 +0000 | [diff] [blame] | 116 | |
Marc Zyngier | 2f0778af | 2011-12-15 12:19:23 +0100 | [diff] [blame] | 117 | setup_sched_clock(omap_32k_read_sched_clock, 32, 32768); |
Paul Walmsley | aa218da | 2010-10-08 11:40:19 -0600 | [diff] [blame] | 118 | } |
| 119 | return 0; |
| 120 | } |