173bf69a7a
Update the mach-shmobile shared delay calibration code for late timers. All existing in-tree non-DT socs are however using early timers today and they are unaffected by this change. The patch modifies shmobile_setup_delay() from using lpj_fine to preset_lpj. This change allows us to preset the worst case loops-per-jiffy value to all CPU cores on the system. The old code which made use of lpj_fine did not affect the secondary CPU cores which made it impossible to boot on SMP without early timers. Needed for SMP SoCs using late timers like EMEV2 or any other mach-shmobile SMP SoC that makes use of late timers via DT. Signed-off-by: Magnus Damm <damm@opensource.se> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
/*
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* SH-Mobile Timer
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*
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* Copyright (C) 2010 Magnus Damm
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* Copyright (C) 2002 - 2009 Paul Mundt
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <linux/platform_device.h>
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#include <linux/delay.h>
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#include <asm/mach/time.h>
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#include <asm/smp_twd.h>
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void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz,
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unsigned int mult, unsigned int div)
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{
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/* calculate a worst-case loops-per-jiffy value
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* based on maximum cpu core mhz setting and the
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* __delay() implementation in arch/arm/lib/delay.S
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*
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* this will result in a longer delay than expected
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* when the cpu core runs on lower frequencies.
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*/
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unsigned int value = (1000000 * mult) / (HZ * div);
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if (!preset_lpj)
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preset_lpj = max_cpu_core_mhz * value;
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}
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static void __init shmobile_late_time_init(void)
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{
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/*
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* Make sure all compiled-in early timers register themselves.
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*
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* Run probe() for two "earlytimer" devices, these will be the
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* clockevents and clocksource devices respectively. In the event
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* that only a clockevents device is available, we -ENODEV on the
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* clocksource and the jiffies clocksource is used transparently
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* instead. No error handling is necessary here.
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*/
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early_platform_driver_register_all("earlytimer");
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early_platform_driver_probe("earlytimer", 2, 0);
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}
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void __init shmobile_earlytimer_init(void)
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{
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late_time_init = shmobile_late_time_init;
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}
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static void __init shmobile_timer_init(void)
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{
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}
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struct sys_timer shmobile_timer = {
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.init = shmobile_timer_init,
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};
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