diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/clocksource/Kconfig | 15 | ||||
| -rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/clksrc-dbx500-prcmu.c | 104 |
3 files changed, 120 insertions, 0 deletions
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 34e9c4f88926..999d6a03e436 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -15,3 +15,18 @@ config CLKSRC_MMIO config DW_APB_TIMER bool + +config CLKSRC_DBX500_PRCMU + bool "Clocksource PRCMU Timer" + depends on UX500_SOC_DB5500 || UX500_SOC_DB8500 + default y + help + Use the always on PRCMU Timer as clocksource + +config CLKSRC_DBX500_PRCMU_SCHED_CLOCK + bool "Clocksource PRCMU Timer sched_clock" + depends on (CLKSRC_DBX500_PRCMU && !NOMADIK_MTU_SCHED_CLOCK) + select HAVE_SCHED_CLOCK + default y + help + Use the always on PRCMU Timer as sched_clock diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 85ad1646a7b7..8d81a1d32653 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -9,3 +9,4 @@ obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o obj-$(CONFIG_CLKBLD_I8253) += i8253.o obj-$(CONFIG_CLKSRC_MMIO) += mmio.o obj-$(CONFIG_DW_APB_TIMER) += dw_apb_timer.o +obj-$(CONFIG_CLKSRC_DBX500_PRCMU) += clksrc-dbx500-prcmu.o
\ No newline at end of file diff --git a/drivers/clocksource/clksrc-dbx500-prcmu.c b/drivers/clocksource/clksrc-dbx500-prcmu.c new file mode 100644 index 000000000000..0ac5093a053a --- /dev/null +++ b/drivers/clocksource/clksrc-dbx500-prcmu.c @@ -0,0 +1,104 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * License Terms: GNU General Public License v2 + * Author: Mattias Wallin <mattias.wallin@stericsson.com> for ST-Ericsson + * Author: Sundar Iyer for ST-Ericsson + * sched_clock implementation is based on: + * plat-nomadik/timer.c Linus Walleij <linus.walleij@stericsson.com> + * + * DBx500-PRCMU Timer + * The PRCMU has 5 timers which are available in a always-on + * power domain. We use the Timer 4 for our always-on clock + * source on DB8500 and Timer 3 on DB5500. + */ +#include <linux/clockchips.h> +#include <linux/clksrc-dbx500-prcmu.h> + +#include <asm/sched_clock.h> + +#include <mach/setup.h> +#include <mach/hardware.h> + +#define RATE_32K 32768 + +#define TIMER_MODE_CONTINOUS 0x1 +#define TIMER_DOWNCOUNT_VAL 0xffffffff + +#define PRCMU_TIMER_REF 0 +#define PRCMU_TIMER_DOWNCOUNT 0x4 +#define PRCMU_TIMER_MODE 0x8 + +#define SCHED_CLOCK_MIN_WRAP 131072 /* 2^32 / 32768 */ + +void __iomem *clksrc_dbx500_timer_base; + +static cycle_t clksrc_dbx500_prcmu_read(struct clocksource *cs) +{ + u32 count, count2; + + do { + count = readl(clksrc_dbx500_timer_base + + PRCMU_TIMER_DOWNCOUNT); + count2 = readl(clksrc_dbx500_timer_base + + PRCMU_TIMER_DOWNCOUNT); + } while (count2 != count); + + /* Negate because the timer is a decrementing counter */ + return ~count; +} + +static struct clocksource clocksource_dbx500_prcmu = { + .name = "dbx500-prcmu-timer", + .rating = 300, + .read = clksrc_dbx500_prcmu_read, + .shift = 10, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK +static DEFINE_CLOCK_DATA(cd); + +unsigned long long notrace sched_clock(void) +{ + u32 cyc; + + if (unlikely(!clksrc_dbx500_timer_base)) + return 0; + + cyc = clksrc_dbx500_prcmu_read(&clocksource_dbx500_prcmu); + + return cyc_to_sched_clock(&cd, cyc, (u32)~0); +} + +static void notrace clksrc_dbx500_prcmu_update_sched_clock(void) +{ + u32 cyc = clksrc_dbx500_prcmu_read(&clocksource_dbx500_prcmu); + update_sched_clock(&cd, cyc, (u32)~0); +} +#endif + +void __init clksrc_dbx500_prcmu_init(void) +{ + /* + * The A9 sub system expects the timer to be configured as + * a continous looping timer. + * The PRCMU should configure it but if it for some reason + * don't we do it here. + */ + if (readl(clksrc_dbx500_timer_base + PRCMU_TIMER_MODE) != + TIMER_MODE_CONTINOUS) { + writel(TIMER_MODE_CONTINOUS, + clksrc_dbx500_timer_base + PRCMU_TIMER_MODE); + writel(TIMER_DOWNCOUNT_VAL, + clksrc_dbx500_timer_base + PRCMU_TIMER_REF); + } +#ifdef CONFIG_CLKSRC_DBX500_PRCMU_SCHED_CLOCK + init_sched_clock(&cd, clksrc_dbx500_prcmu_update_sched_clock, + 32, RATE_32K); +#endif + clocksource_calc_mult_shift(&clocksource_dbx500_prcmu, + RATE_32K, SCHED_CLOCK_MIN_WRAP); + clocksource_register(&clocksource_dbx500_prcmu); +} |