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author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/arm/plat-omap/counter_32k.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/arm/plat-omap/counter_32k.c')
-rw-r--r-- | kernel/arch/arm/plat-omap/counter_32k.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/kernel/arch/arm/plat-omap/counter_32k.c b/kernel/arch/arm/plat-omap/counter_32k.c new file mode 100644 index 000000000..2438b9600 --- /dev/null +++ b/kernel/arch/arm/plat-omap/counter_32k.c @@ -0,0 +1,117 @@ +/* + * OMAP 32ksynctimer/counter_32k-related code + * + * Copyright (C) 2009 Texas Instruments + * Copyright (C) 2010 Nokia Corporation + * Tony Lindgren <tony@atomide.com> + * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * NOTE: This timer is not the same timer as the old OMAP1 MPU timer. + */ +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/clocksource.h> +#include <linux/sched_clock.h> + +#include <asm/mach/time.h> + +#include <plat/counter-32k.h> + +/* OMAP2_32KSYNCNT_CR_OFF: offset of 32ksync counter register */ +#define OMAP2_32KSYNCNT_REV_OFF 0x0 +#define OMAP2_32KSYNCNT_REV_SCHEME (0x3 << 30) +#define OMAP2_32KSYNCNT_CR_OFF_LOW 0x10 +#define OMAP2_32KSYNCNT_CR_OFF_HIGH 0x30 + +/* + * 32KHz clocksource ... always available, on pretty most chips except + * OMAP 730 and 1510. Other timers could be used as clocksources, with + * higher resolution in free-running counter modes (e.g. 12 MHz xtal), + * but systems won't necessarily want to spend resources that way. + */ +static void __iomem *sync32k_cnt_reg; + +static u64 notrace omap_32k_read_sched_clock(void) +{ + return sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; +} + +/** + * omap_read_persistent_clock64 - Return time from a persistent clock. + * + * Reads the time from a source which isn't disabled during PM, the + * 32k sync timer. Convert the cycles elapsed since last read into + * nsecs and adds to a monotonically increasing timespec64. + */ +static struct timespec64 persistent_ts; +static cycles_t cycles; +static unsigned int persistent_mult, persistent_shift; + +static void omap_read_persistent_clock64(struct timespec64 *ts) +{ + unsigned long long nsecs; + cycles_t last_cycles; + + last_cycles = cycles; + cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; + + nsecs = clocksource_cyc2ns(cycles - last_cycles, + persistent_mult, persistent_shift); + + timespec64_add_ns(&persistent_ts, nsecs); + + *ts = persistent_ts; +} + +/** + * omap_init_clocksource_32k - setup and register counter 32k as a + * kernel clocksource + * @pbase: base addr of counter_32k module + * @size: size of counter_32k to map + * + * Returns 0 upon success or negative error code upon failure. + * + */ +int __init omap_init_clocksource_32k(void __iomem *vbase) +{ + int ret; + + /* + * 32k sync Counter IP register offsets vary between the + * highlander version and the legacy ones. + * The 'SCHEME' bits(30-31) of the revision register is used + * to identify the version. + */ + if (readl_relaxed(vbase + OMAP2_32KSYNCNT_REV_OFF) & + OMAP2_32KSYNCNT_REV_SCHEME) + sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_HIGH; + else + sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_LOW; + + /* + * 120000 rough estimate from the calculations in + * __clocksource_update_freq_scale. + */ + clocks_calc_mult_shift(&persistent_mult, &persistent_shift, + 32768, NSEC_PER_SEC, 120000); + + ret = clocksource_mmio_init(sync32k_cnt_reg, "32k_counter", 32768, + 250, 32, clocksource_mmio_readl_up); + if (ret) { + pr_err("32k_counter: can't register clocksource\n"); + return ret; + } + + sched_clock_register(omap_32k_read_sched_clock, 32, 32768); + register_persistent_clock(NULL, omap_read_persistent_clock64); + pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n"); + + return 0; +} |