| Message ID | 1428424234-28572-5-git-send-email-mcoquelin.stm32@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/07/2015 06:30 PM, Maxime Coquelin wrote: > This patch adds clocksource support for ARMv7-M's System timer, > also known as SysTick. > > Tested-by: Chanwoo Choi <cw00.choi@samsung.com> > Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> > --- > drivers/clocksource/Kconfig | 7 ++++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/armv7m_systick.c | 79 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 87 insertions(+) > create mode 100644 drivers/clocksource/armv7m_systick.c > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index 1c2506f..b82e58b 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -134,6 +134,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK > help > Use ARM global timer clock source as sched_clock > > +config ARMV7M_SYSTICK > + bool > + select CLKSRC_OF if OF > + select CLKSRC_MMIO > + help > + This options enables support for the ARMv7M system timer unit > + > config ATMEL_PIT > select CLKSRC_OF if OF > def_bool SOC_AT91SAM9 || SOC_SAMA5 > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index 752d5c7..1c9a643 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -44,6 +44,7 @@ obj-$(CONFIG_MTK_TIMER) += mtk_timer.o > > obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o > obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o > +obj-$(CONFIG_ARMV7M_SYSTICK) += armv7m_systick.o > obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o > obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o > obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o > diff --git a/drivers/clocksource/armv7m_systick.c b/drivers/clocksource/armv7m_systick.c > new file mode 100644 > index 0000000..addfd2c > --- /dev/null > +++ b/drivers/clocksource/armv7m_systick.c > @@ -0,0 +1,79 @@ > +/* > + * Copyright (C) Maxime Coquelin 2015 > + * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com> > + * License terms: GNU General Public License (GPL), version 2 > + */ > + > +#include <linux/kernel.h> > +#include <linux/clocksource.h> > +#include <linux/clockchips.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > +#include <linux/clk.h> > +#include <linux/bitops.h> > + > +#define SYST_CSR 0x00 > +#define SYST_RVR 0x04 > +#define SYST_CVR 0x08 > +#define SYST_CALIB 0x0c > + > +#define SYST_CSR_ENABLE BIT(0) > + > +#define SYSTICK_LOAD_RELOAD_MASK 0x00FFFFFF > + > +static void __init system_timer_of_register(struct device_node *np) > +{ > + struct clk *clk = NULL; > + void __iomem *base; > + u32 rate; > + int ret; > + > + base = of_iomap(np, 0); > + if (!base) { > + pr_warn("system-timer: invalid base address\n"); > + return; > + } > + > + ret = of_property_read_u32(np, "clock-frequency", &rate); > + if (ret) { > + clk = of_clk_get(np, 0); > + if (IS_ERR(clk)) > + goto out_unmap; > + > + ret = clk_prepare_enable(clk); > + if (ret) > + goto out_clk_put; > + > + rate = clk_get_rate(clk); > + if (!rate) > + goto out_clk_disable; > + } > + > + writel_relaxed(SYSTICK_LOAD_RELOAD_MASK, base + SYST_RVR); > + writel_relaxed(SYST_CSR_ENABLE, base + SYST_CSR); > + > + ret = clocksource_mmio_init(base + SYST_CVR, "arm_system_timer", rate, > + 200, 24, clocksource_mmio_readl_down); > + if (ret) { > + pr_err("failed to init clocksource (%d)\n", ret); > + if (clk) > + goto out_clk_disable; > + else > + goto out_unmap; > + } > + > + pr_info("ARM System timer initialized as clocksource\n"); > + > + return; > + > +out_clk_disable: > + clk_disable_unprepare(clk); > +out_clk_put: > + clk_put(clk); > +out_unmap: > + iounmap(base); > + pr_warn("ARM System timer register failed (%d)\n", ret); > +} > + > +CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick", > + system_timer_of_register); >
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 1c2506f..b82e58b 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -134,6 +134,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK help Use ARM global timer clock source as sched_clock +config ARMV7M_SYSTICK + bool + select CLKSRC_OF if OF + select CLKSRC_MMIO + help + This options enables support for the ARMv7M system timer unit + config ATMEL_PIT select CLKSRC_OF if OF def_bool SOC_AT91SAM9 || SOC_SAMA5 diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 752d5c7..1c9a643 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_MTK_TIMER) += mtk_timer.o obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o obj-$(CONFIG_ARM_GLOBAL_TIMER) += arm_global_timer.o +obj-$(CONFIG_ARMV7M_SYSTICK) += armv7m_systick.o obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o diff --git a/drivers/clocksource/armv7m_systick.c b/drivers/clocksource/armv7m_systick.c new file mode 100644 index 0000000..addfd2c --- /dev/null +++ b/drivers/clocksource/armv7m_systick.c @@ -0,0 +1,79 @@ +/* + * Copyright (C) Maxime Coquelin 2015 + * Author: Maxime Coquelin <mcoquelin.stm32@gmail.com> + * License terms: GNU General Public License (GPL), version 2 + */ + +#include <linux/kernel.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/clk.h> +#include <linux/bitops.h> + +#define SYST_CSR 0x00 +#define SYST_RVR 0x04 +#define SYST_CVR 0x08 +#define SYST_CALIB 0x0c + +#define SYST_CSR_ENABLE BIT(0) + +#define SYSTICK_LOAD_RELOAD_MASK 0x00FFFFFF + +static void __init system_timer_of_register(struct device_node *np) +{ + struct clk *clk = NULL; + void __iomem *base; + u32 rate; + int ret; + + base = of_iomap(np, 0); + if (!base) { + pr_warn("system-timer: invalid base address\n"); + return; + } + + ret = of_property_read_u32(np, "clock-frequency", &rate); + if (ret) { + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) + goto out_unmap; + + ret = clk_prepare_enable(clk); + if (ret) + goto out_clk_put; + + rate = clk_get_rate(clk); + if (!rate) + goto out_clk_disable; + } + + writel_relaxed(SYSTICK_LOAD_RELOAD_MASK, base + SYST_RVR); + writel_relaxed(SYST_CSR_ENABLE, base + SYST_CSR); + + ret = clocksource_mmio_init(base + SYST_CVR, "arm_system_timer", rate, + 200, 24, clocksource_mmio_readl_down); + if (ret) { + pr_err("failed to init clocksource (%d)\n", ret); + if (clk) + goto out_clk_disable; + else + goto out_unmap; + } + + pr_info("ARM System timer initialized as clocksource\n"); + + return; + +out_clk_disable: + clk_disable_unprepare(clk); +out_clk_put: + clk_put(clk); +out_unmap: + iounmap(base); + pr_warn("ARM System timer register failed (%d)\n", ret); +} + +CLOCKSOURCE_OF_DECLARE(arm_systick, "arm,armv7m-systick", + system_timer_of_register);