Messages in this thread | | | Date | Wed, 6 Apr 2022 13:13:02 +0200 | Subject | Re: [PATCH v3 04/10] clocksource/drivers: Add HPE GXP timer | From | Daniel Lezcano <> |
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On 10/03/2022 20:52, nick.hawkins@hpe.com wrote: > From: Nick Hawkins <nick.hawkins@hpe.com> > > Add support for the HPE GXP SOC timer. The GXP supports several > different kinds of timers but for the purpose of this driver there > is only support for the General Timer. The timer has a 1us > resolution and is 32 bits. > > Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com> > --- > drivers/clocksource/Kconfig | 8 ++ > drivers/clocksource/Makefile | 1 + > drivers/clocksource/gxp-timer.c | 159 ++++++++++++++++++++++++++++++++ > 3 files changed, 168 insertions(+) > create mode 100644 drivers/clocksource/gxp-timer.c
Please for the sake of consistency, rename the timer to timer-qxp.c
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig > index cfb8ea0df3b1..5916dade7608 100644 > --- a/drivers/clocksource/Kconfig > +++ b/drivers/clocksource/Kconfig > @@ -617,6 +617,14 @@ config CLKSRC_ST_LPC > Enable this option to use the Low Power controller timer > as clocksource. > > +config GXP_TIMER > + bool "GXP timer driver" > + depends on ARCH_HPE > + default y > + help > + Provides a driver for the timer control found on HPE > + GXP SOCs. This is required for all GXP SOCs.
Regarding the silent option:
https://www.spinics.net/lists/arm-kernel/msg936976.html
> config ATCPIT100_TIMER > bool "ATCPIT100 timer driver" > depends on NDS32 || COMPILE_TEST > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile > index fa5f624eadb6..dbfb8c56a8a0 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_GXP_TIMER) += gxp-timer.o > diff --git a/drivers/clocksource/gxp-timer.c b/drivers/clocksource/gxp-timer.c > new file mode 100644 > index 000000000000..a24cd1cc5c04 > --- /dev/null > +++ b/drivers/clocksource/gxp-timer.c > @@ -0,0 +1,159 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P.*/ > + > +#include <linux/bitops.h> > +#include <linux/clockchips.h> > +#include <linux/clocksource.h> > +#include <linux/interrupt.h> > +#include <linux/irqreturn.h> > +#include <linux/kernel.h> > +#include <linux/module.h> This header is not needed.
> +#include <linux/of_address.h> > +#include <linux/of_irq.h> > +#include <linux/of_platform.h> > +#include <linux/slab.h> > +#include <linux/string.h> > +#include <linux/sched_clock.h> > + > +#include <asm/irq.h>
This header is not needed AFAICT.
Please double check the headers above are all needed.
> +#define TIMER0_FREQ 1000000 > + > +/*TCS Stands for Timer Control/Status: these are masks to be used in*/ > +/* the Timer Count Registers */ > +#define MASK_TCS_ENABLE 0x01 > +#define MASK_TCS_PERIOD 0x02 > +#define MASK_TCS_RELOAD 0x04 > +#define MASK_TCS_TC 0x80 > + > +struct gxp_timer { > + void __iomem *counter; > + void __iomem *control; > + struct clock_event_device evt; > +}; > + > +static void __iomem *system_clock __read_mostly; > + > +static inline struct gxp_timer *to_gxp_timer(struct clock_event_device *evt_dev) > +{ > + return container_of(evt_dev, struct gxp_timer, evt); > +} > + > +static u64 notrace gxp_sched_read(void) > +{ > + return readl_relaxed(system_clock); > +} > + > +static int gxp_time_set_next_event(unsigned long event, > + struct clock_event_device *evt_dev) > +{ > + struct gxp_timer *timer = to_gxp_timer(evt_dev);
nit: add a line to separate the declaration and the code below.
> + /* Stop counting and disable interrupt before updating */ > + writeb_relaxed(MASK_TCS_TC, timer->control); > + writel_relaxed(event, timer->counter); > + writeb_relaxed(MASK_TCS_TC | MASK_TCS_ENABLE, timer->control); > + > + return 0; > +} > + > +static irqreturn_t gxp_time_interrupt(int irq, void *dev_id)
s/gxp_time/gxp_timer/
> +{ > + struct gxp_timer *timer = dev_id; > + void (*event_handler)(struct clock_event_device *timer); > + > + if (!(readb_relaxed(timer->control) & MASK_TCS_TC)) > + return IRQ_NONE; > + > + writeb_relaxed(MASK_TCS_TC, timer->control); > + > + event_handler = READ_ONCE(timer->evt.event_handler); > + event_handler(&timer->evt);
Why READ_ONCE ?
Do timer->evt.event_handler();
Or alternatively pass the request_irq() &timer->evt and use to_gxp_timer()
> + return IRQ_HANDLED; > +} > + > +static int __init gxp_timer_init(struct device_node *node) > +{ > + void __iomem *base_counter; > + void __iomem *base_control; > + u32 freq; > + int ret, irq; > + struct gxp_timer *gxp_timer; > + > + base_counter = of_iomap(node, 0); > + if (!base_counter) { > + pr_err("Can't remap counter registers"); > + ret = -ENXIO; > + return ret;
return -ENXIO;
> + } > + > + base_control = of_iomap(node, 1); > + if (!base_control) { > + pr_err("Can't remap control registers"); > + ret = -ENXIO; > + goto err_iounmap;
> + } > + > + system_clock = of_iomap(node, 2); > + if (!system_clock) { > + pr_err("Can't remap control registers"); > + ret = -ENXIO; > + goto err_iounmap; > + } > + > + if (of_property_read_u32(node, "clock-frequency", &freq)) { > + pr_err("Can't read clock-frequency\n"); > + ret = -EIO; > + goto err_iounmap; > + } > + > + sched_clock_register(gxp_sched_read, 32, freq); > + clocksource_mmio_init(system_clock, node->name, freq, > + 300, 32, clocksource_mmio_readl_up); > + > + irq = irq_of_parse_and_map(node, 0); > + if (irq <= 0) { > + ret = -EINVAL; > + pr_err("GXP Timer Can't parse IRQ %d", irq); > + goto err_iounmap; > + } > + > + gxp_timer = kzalloc(sizeof(*gxp_timer), GFP_KERNEL); > + if (!gxp_timer) { > + ret = -ENOMEM; > + goto err_iounmap; > + } > + > + gxp_timer->counter = base_counter; > + gxp_timer->control = base_control; > + gxp_timer->evt.name = node->name; > + gxp_timer->evt.rating = 300; > + gxp_timer->evt.features = CLOCK_EVT_FEAT_ONESHOT; > + gxp_timer->evt.set_next_event = gxp_time_set_next_event; > + gxp_timer->evt.cpumask = cpumask_of(0); > +
ret = request_irq();
> + if (request_irq(irq, gxp_time_interrupt, IRQF_TIMER | IRQF_SHARED, > + node->name, gxp_timer)) { > + ret = -EIO;
Remove above ret = -EIO;
> + pr_err("%s: request_irq() failed\n", "GXP Timer Tick"); > + goto err_timer_free; > + } > + > + clockevents_config_and_register(&gxp_timer->evt, TIMER0_FREQ, > + 0xf, 0xffffffff); > + > + pr_info("gxp: system timer (irq = %d)\n", irq);
s/pr_info/pr_debug/
> + return 0; > + > + > +err_timer_free: > + kfree(gxp_timer); > + > +err_iounmap: > + iounmap(system_clock); > + iounmap(base_control); > + iounmap(base_counter); > + return ret; > +} > + > +TIMER_OF_DECLARE(gxp, "hpe,gxp-timer", gxp_timer_init);
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