Hi Marc, On Mon, Nov 19, 2018 at 05:57:12PM +0000, Marc Zyngier wrote: > On 19/11/2018 17:09, Manivannan Sadhasivam wrote: > > Add clock driver for RDA Micro RDA8810PL SoC supporting OSTIMER > > and HWTIMER. > > > > Signed-off-by: Andreas Färber <afaer...@suse.de> > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasi...@linaro.org> > > --- > > arch/arm/mach-rda/Kconfig | 1 + > > drivers/clocksource/Kconfig | 7 ++ > > drivers/clocksource/Makefile | 1 + > > drivers/clocksource/timer-rda.c | 187 ++++++++++++++++++++++++++++++++ > > 4 files changed, 196 insertions(+) > > create mode 100644 drivers/clocksource/timer-rda.c > > > > diff --git a/arch/arm/mach-rda/Kconfig b/arch/arm/mach-rda/Kconfig > > index 29012bc68ca4..1ea753f57b2d 100644 > > --- a/arch/arm/mach-rda/Kconfig > > +++ b/arch/arm/mach-rda/Kconfig > > @@ -4,5 +4,6 @@ menuconfig ARCH_RDA > > select COMMON_CLK > > select GENERIC_IRQ_CHIP > > select RDA_INTC > > + select RDA_TIMER > > help > > This enables support for the RDA Micro 8810PL SoC family. > > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > > index 55c77e44bb2d..f51eee3a72ea 100644 > > --- a/drivers/clocksource/Kconfig > > +++ b/drivers/clocksource/Kconfig > > @@ -105,6 +105,13 @@ config OWL_TIMER > > help > > Enables the support for the Actions Semi Owl timer driver. > > > > +config RDA_TIMER > > + bool "RDA timer driver" if COMPILE_TEST > > + depends on GENERIC_CLOCKEVENTS > > + select CLKSRC_MMIO > > + help > > + Enables the support for the RDA Micro timer driver. > > + > > config SUN4I_TIMER > > bool "Sun4i timer driver" if COMPILE_TEST > > depends on HAS_IOMEM > > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > > index dd9138104568..150020a90707 100644 > > --- a/drivers/clocksource/Makefile > > +++ b/drivers/clocksource/Makefile > > @@ -57,6 +57,7 @@ obj-$(CONFIG_OXNAS_RPS_TIMER) += timer-oxnas-rps.o > > obj-$(CONFIG_OWL_TIMER) += timer-owl.o > > obj-$(CONFIG_SPRD_TIMER) += timer-sprd.o > > obj-$(CONFIG_NPCM7XX_TIMER) += timer-npcm7xx.o > > +obj-$(CONFIG_RDA_TIMER) += timer-rda.o > > > > obj-$(CONFIG_ARC_TIMERS) += arc_timer.o > > obj-$(CONFIG_ARM_ARCH_TIMER) += arm_arch_timer.o > > diff --git a/drivers/clocksource/timer-rda.c > > b/drivers/clocksource/timer-rda.c > > new file mode 100644 > > index 000000000000..3aa684d92c5d > > --- /dev/null > > +++ b/drivers/clocksource/timer-rda.c > > @@ -0,0 +1,187 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * RDA8810PL SoC timer driver > > + * > > + * Copyright RDA Microelectronics Company Limited > > + * Copyright (c) 2017 Andreas Färber > > + * Copyright (c) 2018 Manivannan Sadhasivam > > + */ > > + > > +#include <linux/clockchips.h> > > +#include <linux/interrupt.h> > > +#include <linux/irq.h> > > +#include <linux/irqreturn.h> > > +#include <linux/of.h> > > +#include <linux/of_address.h> > > +#include <linux/of_irq.h> > > + > > +#define RDA_OSTIMER_LOADVAL_L 0x000 > > +#define RDA_OSTIMER_CTRL 0x004 > > +#define RDA_HWTIMER_LOCKVAL_L 0x024 > > +#define RDA_HWTIMER_LOCKVAL_H 0x028 > > +#define RDA_TIMER_IRQ_MASK_SET 0x02c > > +#define RDA_TIMER_IRQ_CLR 0x034 > > + > > +#define RDA_OSTIMER_CTRL_ENABLE BIT(24) > > +#define RDA_OSTIMER_CTRL_REPEAT BIT(28) > > +#define RDA_OSTIMER_CTRL_LOAD BIT(30) > > + > > +#define RDA_TIMER_IRQ_MASK_SET_OSTIMER BIT(0) > > + > > +#define RDA_TIMER_IRQ_CLR_OSTIMER BIT(0) > > + > > +static void __iomem *rda_timer_base; > > + > > +static u64 rda_hwtimer_read(struct clocksource *cs) > > +{ > > + u32 lo, hi; > > + > > + /* Always read low 32 bits first */ > > + lo = readl(rda_timer_base + RDA_HWTIMER_LOCKVAL_L); > > + hi = readl(rda_timer_base + RDA_HWTIMER_LOCKVAL_H); > > Please use the relaxed accessors throughout this driver. There is zero > reason to use the non-relaxed versions here. >
Okay. > Now, I'm pretty sure this thing isn't correct. > > <timer = 0x00000000ffffffff> > lo = 0xffffffff; > <tick, timer = 0x0000000100000000> > hi = 0x00000001; > > Bingo. You cannot read a 64bit counter with only two 32bit accesses. > I think the lack of description makes confusion here. In this SoC, there are two independent timers available: OSTIMER (56 bit) and HWTIMER (64 bit) with optional interrupt support. I have used OSTIMER for clockevents and HWTIMER for clocksource. Will add this information in driver. Please let me know whether I have to model these two clocksources differently! > > + > > + return ((u64)hi << 32) | lo; > > +} > > + > > +static struct clocksource rda_clocksource = { > > + .name = "rda-timer", > > + .rating = 400, > > + .read = rda_hwtimer_read, > > + .mask = CLOCKSOURCE_MASK(64), > > This is a 64bit counter? See below. > Yes, this is the HWTIMER and is 64 bit. > > + .flags = CLOCK_SOURCE_IS_CONTINUOUS, > > +}; > > + > > +static int rda_ostimer_start(bool periodic, u64 cycles) > > +{ > > + u32 ctrl, load_l; > > + > > + load_l = (u32)cycles; > > + ctrl = ((cycles >> 32) & 0xffffff); > > + ctrl |= RDA_OSTIMER_CTRL_LOAD | RDA_OSTIMER_CTRL_ENABLE; > > + if (periodic) > > + ctrl |= RDA_OSTIMER_CTRL_REPEAT; > > + > > + /* Enable ostimer interrupt first */ > > + writel(RDA_TIMER_IRQ_MASK_SET_OSTIMER, > > + rda_timer_base + RDA_TIMER_IRQ_MASK_SET); > > Is it masking or enabling the interrupt? > On this platform, we need to set corresponding bit in the RDA_TIMER_IRQ_MASK_SET register to enable an interrupt. > > + > > + /* Write low 32 bits first, high 24 bits are with ctrl */ > > You're saying that you can only write 56 bits? This contradicts the 64bt > counter thing above. > > > + writel(load_l, rda_timer_base + RDA_OSTIMER_LOADVAL_L); > > + writel(ctrl, rda_timer_base + RDA_OSTIMER_CTRL); > > + > > + return 0; > > +} > > + > > +static int rda_ostimer_stop(void) > > +{ > > + /* Disable ostimer interrupt first */ > > + writel(0, rda_timer_base + RDA_TIMER_IRQ_MASK_SET); > > + Here the register should be RDA_TIMER_IRQ_MASK_CLR. > > + writel(0, rda_timer_base + RDA_OSTIMER_CTRL); > > + > > + return 0; > > +} > > + > > +static int rda_ostimer_set_state_shutdown(struct clock_event_device *evt) > > +{ > > + rda_ostimer_stop(); > > + > > + return 0; > > +} > > + > > +static int rda_ostimer_set_state_oneshot(struct clock_event_device *evt) > > +{ > > + rda_ostimer_stop(); > > + > > + return 0; > > +} > > + > > +static int rda_ostimer_set_state_periodic(struct clock_event_device *evt) > > +{ > > + unsigned long cycles_per_jiffy; > > + > > + rda_ostimer_stop(); > > + > > + cycles_per_jiffy = ((unsigned long long)NSEC_PER_SEC / HZ * > > + evt->mult) >> evt->shift; > > + rda_ostimer_start(true, cycles_per_jiffy); > > + > > + return 0; > > +} > > + > > +static int rda_ostimer_tick_resume(struct clock_event_device *evt) > > +{ > > + return 0; > > +} > > + > > +static int rda_ostimer_set_next_event(unsigned long evt, > > + struct clock_event_device *ev) > > +{ > > + rda_ostimer_start(false, evt); > > + > > + return 0; > > +} > > + > > +static struct clock_event_device rda_clockevent = { > > + .name = "rda-ostimer", > > + .rating = 250, > > + .features = CLOCK_EVT_FEAT_PERIODIC | > > + CLOCK_EVT_FEAT_ONESHOT | > > + CLOCK_EVT_FEAT_DYNIRQ, > > + .set_state_shutdown = rda_ostimer_set_state_shutdown, > > + .set_state_oneshot = rda_ostimer_set_state_oneshot, > > + .set_state_periodic = rda_ostimer_set_state_periodic, > > + .tick_resume = rda_ostimer_tick_resume, > > + .set_next_event = rda_ostimer_set_next_event, > > +}; > > + > > +static irqreturn_t rda_ostimer_interrupt(int irq, void *dev_id) > > +{ > > + struct clock_event_device *evt = dev_id; > > + > > + /* clear timer int */ > > + writel(RDA_TIMER_IRQ_CLR_OSTIMER, rda_timer_base + RDA_TIMER_IRQ_CLR); > > + > > + if (evt->event_handler) > > + evt->event_handler(evt); > > + > > + return IRQ_HANDLED; > > +} > > + > > +static int __init rda_timer_init(struct device_node *node) > > +{ > > + unsigned long rate = 2000000; > > + int ostimer_irq, ret; > > + > > + rda_timer_base = of_io_request_and_map(node, 0, "rda-timer"); > > + if (IS_ERR(rda_timer_base)) { > > + pr_err("Can't map timer registers"); > > + return PTR_ERR(rda_timer_base); > > + } > > + > > + ostimer_irq = of_irq_get_byname(node, "ostimer"); > > + if (ostimer_irq <= 0) { > > + pr_err("Can't parse ostimer IRQ"); > > + return -EINVAL; > > Leaking IO space. > Ack. > > + } > > + > > + clocksource_register_hz(&rda_clocksource, rate); > > + > > + ret = request_irq(ostimer_irq, rda_ostimer_interrupt, IRQF_TIMER, > > + "rda-ostimer", &rda_clockevent); > > + if (ret) { > > + pr_err("failed to request irq %d\n", ostimer_irq); > > + return ret; > > Same here. > Ack. > > + } > > + > > + irq_force_affinity(ostimer_irq, cpumask_of(0)); > > Why? > Not needed, will remove it. Thanks, Mani > > + > > + rda_clockevent.cpumask = cpumask_of(0); > > + rda_clockevent.irq = ostimer_irq; > > + clockevents_config_and_register(&rda_clockevent, rate, > > + 0x2, 0xffffffff); > > + > > + return 0; > > +} > > + > > +TIMER_OF_DECLARE(rda8810pl, "rda,8810pl-timer", rda_timer_init); > > > > Thanks, > > M. > -- > Jazz is not dead. It just smells funny...