Messages in this thread | | | Date | Tue, 1 Mar 2022 22:09:06 +0100 | Subject | Re: [PATCH v8 2/2] clocksource: Add Intel Keem Bay timer support | From | Daniel Lezcano <> |
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On 22/02/2022 10:56, shruthi.sanil@intel.com wrote: > From: Shruthi Sanil <shruthi.sanil@intel.com> > > The Intel Keem Bay timer driver supports clocksource and clockevent > features for the timer IP used in Intel Keem Bay SoC. > The timer block supports 1 free running counter and 8 timers. > The free running counter can be used as a clocksource and > the timers can be used as clockevent. Each timer is capable of > generating individual interrupt. > Both the features are enabled through the timer general config register. > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com> > Signed-off-by: Shruthi Sanil <shruthi.sanil@intel.com> > --- > MAINTAINERS | 6 + > drivers/clocksource/Kconfig | 11 ++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/timer-keembay.c | 230 ++++++++++++++++++++++++++++ > 4 files changed, 248 insertions(+) > create mode 100644 drivers/clocksource/timer-keembay.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 777cd6fa2b3d..73c0029dcdf7 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9796,6 +9796,12 @@ F: drivers/crypto/keembay/keembay-ocs-hcu-core.c > F: drivers/crypto/keembay/ocs-hcu.c > F: drivers/crypto/keembay/ocs-hcu.h > > +INTEL KEEM BAY TIMER DRIVER > +M: Shruthi Sanil <shruthi.sanil@intel.com> > +S: Maintained > +F: Documentation/devicetree/bindings/timer/intel,keembay-timer.yaml > +F: drivers/clocksource/timer-keembay.c > + > INTEL THUNDER BAY EMMC PHY DRIVER > M: Nandhini Srikandan <nandhini.srikandan@intel.com> > M: Rashmi A <rashmi.a@intel.com> > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index cfb8ea0df3b1..65b6cf916e5a 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -721,4 +721,15 @@ config MICROCHIP_PIT64B > modes and high resolution. It is used as a clocksource > and a clockevent. > > +config KEEMBAY_TIMER > + bool "Intel Keem Bay timer" > + depends on ARCH_KEEMBAY || COMPILE_TEST > + select TIMER_OF > + help > + This option enables the support for the Intel Keem Bay > + general purpose timer and free running counter driver. > + Each timer can generate an individual interrupt and > + supports oneshot and periodic modes. > + The 64-bit counter can be used as a clock source. > + > endmenu > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index fa5f624eadb6..dff6458ef9e5 100644 > --- a/drivers/clocksource/Makefile > +++ b/drivers/clocksource/Makefile > @@ -89,3 +89,4 @@ obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o > obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o > obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o > obj-$(CONFIG_MSC313E_TIMER) += timer-msc313e.o > +obj-$(CONFIG_KEEMBAY_TIMER) += timer-keembay.o > diff --git a/drivers/clocksource/timer-keembay.c b/drivers/clocksource/timer-keembay.c > new file mode 100644 > index 000000000000..230609c06a26 > --- /dev/null > +++ b/drivers/clocksource/timer-keembay.c > @@ -0,0 +1,230 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Intel Keem Bay Timer driver > + * > + * Copyright (C) 2020 Intel Corporation > + */ > + > +#include <linux/bitops.h> > +#include <linux/interrupt.h> > +#include <linux/io-64-nonatomic-lo-hi.h> > +#include <linux/mfd/syscon.h> > +#include <linux/module.h> > +#include <linux/of_address.h> > +#include <linux/sizes.h> > +#include <linux/slab.h> > +#include <linux/regmap.h> > + > +#include "timer-of.h" > + > +/* Timer register offset */ > +#define TIM_CNT_VAL_OFFSET 0x0 > +#define TIM_RELOAD_VAL_OFFSET 0x4 > +#define TIM_CONFIG_OFFSET 0x8 > + > +/* Bit fields of timer general config register */ > +#define TIM_CONFIG_PRESCALER_ENABLE BIT(2) > +#define TIM_CONFIG_COUNTER_ENABLE BIT(0) > + > +/* Bit fields of timer config register */ > +#define TIM_CONFIG_INTERRUPT_PENDING BIT(4) > +#define TIM_CONFIG_INTERRUPT_ENABLE BIT(2) > +#define TIM_CONFIG_RESTART BIT(1) > +#define TIM_CONFIG_ENABLE BIT(0) > + > +#define TIM_GEN_MASK GENMASK(31, 12) > +#define TIM_RATING 200 > +#define TIM_CLKSRC_MASK_BITS 64 > + > +#define TIMER_NAME_SIZE 25 > + > +static inline void keembay_timer_enable(void __iomem *base, u32 flags) > +{ > + writel(TIM_CONFIG_ENABLE | flags, base + TIM_CONFIG_OFFSET); > +} > + > +static inline void keembay_timer_disable(void __iomem *base) > +{ > + writel(0x0, base + TIM_CONFIG_OFFSET); > +} > + > +static inline void keembay_timer_update_counter(void __iomem *base, u32 val) > +{ > + writel(val, base + TIM_CNT_VAL_OFFSET); > + writel(val, base + TIM_RELOAD_VAL_OFFSET); > +} > + > +static inline void keembay_timer_clear_pending_int(void __iomem *base) > +{ > + u32 val; > + > + val = readl(base + TIM_CONFIG_OFFSET); > + val &= ~TIM_CONFIG_INTERRUPT_PENDING; > + writel(val, base + TIM_CONFIG_OFFSET); > +} > + > +static int keembay_timer_set_next_event(unsigned long evt, struct clock_event_device *ce) > +{ > + u32 flags = TIM_CONFIG_INTERRUPT_ENABLE; > + struct timer_of *to = to_timer_of(ce); > + void __iomem *tim_base = timer_of_base(to); > + > + keembay_timer_disable(tim_base); > + keembay_timer_update_counter(tim_base, evt); > + keembay_timer_enable(tim_base, flags); > + > + return 0; > +} > + > +static int keembay_timer_periodic(struct clock_event_device *ce) > +{ > + u32 flags = TIM_CONFIG_INTERRUPT_ENABLE | TIM_CONFIG_RESTART; > + struct timer_of *to = to_timer_of(ce); > + void __iomem *tim_base = timer_of_base(to); > + > + keembay_timer_disable(tim_base); > + keembay_timer_update_counter(tim_base, timer_of_period(to)); > + keembay_timer_enable(tim_base, flags); > + > + return 0; > +} > + > +static int keembay_timer_shutdown(struct clock_event_device *ce) > +{ > + struct timer_of *to = to_timer_of(ce); > + > + keembay_timer_disable(timer_of_base(to)); > + > + return 0; > +} > + > +static irqreturn_t keembay_timer_isr(int irq, void *dev_id) > +{ > + struct clock_event_device *evt = dev_id; > + struct timer_of *to = to_timer_of(evt); > + void __iomem *tim_base = timer_of_base(to); > + u32 val; > + > + val = readl(tim_base + TIM_CONFIG_OFFSET); > + > + if (val & TIM_CONFIG_RESTART) { > + /* Clear interrupt for periodic timer*/
nit: comment format is:
/* * my comment */
One line comment format is usually for the network subsystem
> + keembay_timer_clear_pending_int(tim_base); > + } else { > + /* Disable the timer for one shot timer */
comment format
> + keembay_timer_disable(tim_base); > + } > + > + evt->event_handler(evt); > + > + return IRQ_HANDLED; > +} > + > +static int __init keembay_clockevent_init(struct device_node *np) > +{ > + struct timer_of *keembay_ce_to; > + struct regmap *regmap; > + int ret; > + u32 val; > + > + regmap = device_node_to_regmap(np->parent); > + if (IS_ERR(regmap)) > + return PTR_ERR(regmap); > + > + ret = regmap_read(regmap, TIM_CONFIG_OFFSET, &val); > + if (ret) > + return ret; > + > + /* Prescaler bit must be enabled for the timer to function */
comment format
> + if (!(val & TIM_CONFIG_PRESCALER_ENABLE)) { > + pr_err("%pOF: Prescaler is not enabled\n", np); > + ret = -ENODEV; > + }
Why bail out instead of enabling the prescalar ?
> + keembay_ce_to = kzalloc(sizeof(*keembay_ce_to), GFP_KERNEL); > + if (!keembay_ce_to) > + ret = -ENOMEM;
As your convenience but I suggest global static variable initialization, that will simplify the init function regarding the error path.
> + keembay_ce_to->flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK; > + keembay_ce_to->clkevt.name = "keembay_timer"; > + keembay_ce_to->clkevt.cpumask = cpu_possible_mask; > + keembay_ce_to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | > + CLOCK_EVT_FEAT_ONESHOT | > + CLOCK_EVT_FEAT_DYNIRQ; > + keembay_ce_to->clkevt.rating = TIM_RATING; > + keembay_ce_to->clkevt.set_next_event = keembay_timer_set_next_event; > + keembay_ce_to->clkevt.set_state_periodic = keembay_timer_periodic; > + keembay_ce_to->clkevt.set_state_shutdown = keembay_timer_shutdown; > + keembay_ce_to->of_irq.handler = keembay_timer_isr; > + keembay_ce_to->of_irq.flags = IRQF_TIMER; > + > + ret = timer_of_init(np, keembay_ce_to); > + if (ret) > + goto err_keembay_ce_to_free; > + > + ret = regmap_read(regmap, TIM_RELOAD_VAL_OFFSET, &val); > + if (ret) > + goto err_keembay_ce_to_free; > + > + keembay_ce_to->of_clk.rate = keembay_ce_to->of_clk.rate / (val + 1); > + > + clockevents_config_and_register(&keembay_ce_to->clkevt, > + timer_of_rate(keembay_ce_to), > + 1, > + U32_MAX); > + > + return 0; > + > +err_keembay_ce_to_free: > + kfree(keembay_ce_to); > + > + return ret; > +} > + > +static struct timer_of keembay_cs_to = { > + .flags = TIMER_OF_BASE | TIMER_OF_CLOCK, > +}; > + > +static u64 notrace keembay_clocksource_read(struct clocksource *cs) > +{ > + return lo_hi_readq(timer_of_base(&keembay_cs_to)); > +} > + > +static struct clocksource keembay_counter = { > + .name = "keembay_sys_counter", > + .rating = TIM_RATING, > + .read = keembay_clocksource_read, > + .mask = CLOCKSOURCE_MASK(TIM_CLKSRC_MASK_BITS), > + .flags = CLOCK_SOURCE_IS_CONTINUOUS | > + CLOCK_SOURCE_SUSPEND_NONSTOP, > +}; > + > +static int __init keembay_clocksource_init(struct device_node *np) > +{ > + struct regmap *regmap; > + u32 val; > + int ret; > + > + regmap = device_node_to_regmap(np->parent); > + if (IS_ERR(regmap)) > + return PTR_ERR(regmap); > + > + ret = regmap_read(regmap, TIM_CONFIG_OFFSET, &val); > + if (ret) > + return ret; > + > + /* Free Running Counter bit must be enabled for counter to function */
comment format
> + if (!(val & TIM_CONFIG_COUNTER_ENABLE)) { > + pr_err("%pOF: free running counter is not enabled\n", np); > + return -ENODEV; > + }
Same comment as above. Why not enable the counter ?
Other than that, the driver is having a good shape
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