[2/3] clocksource: add DB8500 PRCMU Timer support

Message ID	1306830661-9546-1-git-send-email-mattias.wallin@stericsson.com (mailing list archive)
State	New, archived
Headers	show Received: from canuck.infradead.org (canuck.infradead.org [134.117.69.58]) by demeter2.kernel.org (8.14.4/8.14.3) with ESMTP id p4VDMPSM009099 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <patchwork-linux-arm@patchwork.kernel.org>; Tue, 31 May 2011 13:22:46 GMT From: Mattias Wallin <mattias.wallin@stericsson.com> To: Thomas Gleixner <tglx@linutronix.de>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org> Subject: [PATCH 2/3] clocksource: add DB8500 PRCMU Timer support Date: Tue, 31 May 2011 10:31:01 +0200 Message-ID: <1306830661-9546-1-git-send-email-mattias.wallin@stericsson.com> MIME-Version: 1.0 summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.126.144.143 listed in list.dnswl.org] Cc: Lee Jones <lee.jones@linaro.org>, Mattias Wallin <mattias.wallin@stericsson.com> Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 96c9219..d7ee415 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -3,3 +3,18 @@ config CLKSRC_I8253 config CLKSRC_MMIO bool + +config CLKSRC_DB8500_PRCMU + bool "Clocksource PRCMU Timer" + depends on MFD_DB8500_PRCMU + default y + help + Use the always on PRCMU Timer as clocksource + +config CLKSRC_DB8500_PRCMU_SCHED_CLOCK + bool "Clocksource PRCMU Timer sched_clock" + depends on (CLKSRC_DB8500_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 b995942..f2308ba 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o obj-$(CONFIG_CLKSRC_I8253) += i8253.o obj-$(CONFIG_CLKSRC_MMIO) += mmio.o +obj-$(CONFIG_CLKSRC_DB8500_PRCMU) += clksrc-db8500-prcmu.o diff --git a/drivers/clocksource/clksrc-db8500-prcmu.c b/drivers/clocksource/clksrc-db8500-prcmu.c new file mode 100644 index 0000000..07a4d1a --- /dev/null +++ b/drivers/clocksource/clksrc-db8500-prcmu.c @@ -0,0 +1,89 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * License Terms: GNU General Public License v2 + * Author: Mattias Wallin <mattias.wallin@stericsson.com> for ST-Ericsson + * sched_clock implementation is based on: + * plat-nomadik/timer.c Linus Walleij <linus.walleij@stericsson.com> + * + * Clocksource DB8500 PRCMU Timer + * The PRCMU in the DB8500 chip has 5 timers which + * are available in an always-on power domain. + * Timer 4 is dedicated to our always-on clock source. + */ +#include <linux/clockchips.h> +#include <linux/clksrc-db8500-prcmu.h> +#include <asm/sched_clock.h> +#include <mach/setup.h> +#include <mach/db8500-regs.h> +#include <mach/hardware.h> + +#define RATE_32K (32768) + +#define TIMER_MODE_CONTINOUS (0x1) +#define TIMER_DOWNCOUNT_VAL (0xffffffff) + +/* PRCMU Timer 4 */ +#define PRCMU_TIMER_4_REF (prcmu_base + 0x450) +#define PRCMU_TIMER_4_DOWNCOUNT (prcmu_base + 0x454) +#define PRCMU_TIMER_4_MODE (prcmu_base + 0x458) + +static __iomem void *prcmu_base; + +#define SCHED_CLOCK_MIN_WRAP (131072) /* 2^32 / 32768 */ + +static cycle_t clksrc_db8500_prcmu_read(struct clocksource *cs) +{ + u32 count, count2; + + do { + count = readl(PRCMU_TIMER_4_DOWNCOUNT); + count2 = readl(PRCMU_TIMER_4_DOWNCOUNT); + } while (count2 != count); + + /* Negate because the timer is a decrementing counter */ + return ~count; +} + +static struct clocksource clocksource_db8500_prcmu = { + .name = "clksrc-db8500-prcmu-timer4", + .rating = 300, + .read = clksrc_db8500_prcmu_read, + .shift = 10, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +#ifdef CONFIG_CS_DB8500_PRCMU_SCHED_CLOCK +static DEFINE_CLOCK_DATA(cd); + +static void notrace clksrc_db8500_prcmu_update_sched_clock(void) +{ + u32 cyc = clksrc_db8500_prcmu_read(&clocksource_db8500_prcmu); + update_sched_clock(&cd, cyc, (u32)~0); +} +#endif + +void __init clksrc_db8500_prcmu_init(void) +{ + prcmu_base = __io_address(U8500_PRCMU_BASE); + + /* + * 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(PRCMU_TIMER_4_MODE) != TIMER_MODE_CONTINOUS) { + writel(TIMER_MODE_CONTINOUS, PRCMU_TIMER_4_MODE); + writel(TIMER_DOWNCOUNT_VAL, PRCMU_TIMER_4_REF); + } +#ifdef CONFIG_CS_DB8500_PRCMU_SCHED_CLOCK + init_sched_clock(&cd, clksrc_db8500_prcmu_update_sched_clock, + 32, RATE_32K); +#endif + clocksource_calc_mult_shift(&clocksource_db8500_prcmu, + RATE_32K, SCHED_CLOCK_MIN_WRAP); + clocksource_register(&clocksource_db8500_prcmu); +} + diff --git a/include/linux/clksrc-db8500-prcmu.h b/include/linux/clksrc-db8500-prcmu.h new file mode 100644 index 0000000..42b8587 --- /dev/null +++ b/include/linux/clksrc-db8500-prcmu.h @@ -0,0 +1,17 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * License Terms: GNU General Public License v2 + * Author: Mattias Wallin <mattias.wallin@stericsson.com> + * + */ +#ifndef __CLKSRC_DB8500_PRCMU_H +#define __CLKSRC_DB8500_PRCMU_H + +#ifdef CONFIG_CLKSRC_DB8500_PRCMU +void __init clksrc_db8500_prcmu_init(void); +#else +void __init clksrc_db8500_prcmu_init(void) {} +#endif + +#endif

[2/3] clocksource: add DB8500 PRCMU Timer support

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