linux-kernel - Re: [PATCH v5 04/11] clocksource/drivers: Add HPE GXP timer

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Message-ID: <87o80t5fqd.ffs@tglx>
Date:   Fri, 22 Apr 2022 16:56:26 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     nick.hawkins@....com, verdun@....com, nick.hawkins@....com,
        joel@....id.au, arnd@...db.de, openbmc@...ts.ozlabs.org
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 04/11] clocksource/drivers: Add HPE GXP timer

On Thu, Apr 21 2022 at 14:21, nick hawkins wrote:
> +
> +static struct gxp_timer *local_gxp_timer;

What is local about that time?

> +static void __iomem *system_clock __read_mostly;

__ro_after_init perhaps?

> +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)

Stray TAB in arguments

> +static int __init gxp_timer_init(struct device_node *node)
> +{
> +	void __iomem *base;
> +	struct clk *clk;
> +	u32 freq;
> +	int ret, irq;
> +	struct gxp_timer *gxp_timer;
> +
> +	base = of_iomap(node, 0);
> +	if (!base) {
> +		pr_err("Can't remap timer base register");
> +		ret = -ENXIO;
> +		return ret;
> +	}
> +
> +	/*Set the offset to the clock register*/
> +	system_clock = base + GXP_TIMESTAMP_OFS;
> +
> +	clk = of_clk_get(node, 0);
> +	if (IS_ERR(clk)) {
> +		pr_err("%pOFn clock not found: %d\n", node, (int)PTR_ERR(clk));
> +		ret = -EIO;
> +		goto err_iounmap;
> +	}
> +
> +	ret = clk_prepare_enable(clk);
> +
> +	freq = clk_get_rate(clk);
> +
> +	sched_clock_register(gxp_sched_read, 32, freq);
> +	clocksource_mmio_init(system_clock, node->name, freq,
> +			      300, 32, clocksource_mmio_readl_up);

So this registers sched clock and clocksource and if one of the
following fails....

> +	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;

... the error path unmaps 'system_clock'

> +	}
> +
> +	gxp_timer = kzalloc(sizeof(*gxp_timer), GFP_KERNEL);
> +	if (!gxp_timer) {
> +		ret = -ENOMEM;
> +		goto err_iounmap;
> +	}
> +
> +	gxp_timer->counter = base + GXP_TIMER_CNT_OFS;
> +	gxp_timer->control = base + GXP_TIMER_CTRL_OFS;
> +	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);
> +
> +	local_gxp_timer = gxp_timer;
> +
> +	ret = request_irq(irq, gxp_timer_interrupt, IRQF_TIMER | IRQF_SHARED,
> +			  node->name, gxp_timer);
> +	if (ret) {
> +		pr_err("%s: request_irq() failed %pe\n", "GXP Timer Tick", ERR_PTR(ret));
> +		goto err_iounmap;

... and here as a bonus leaks gxp_timer.

> +	}
> +
> +	clockevents_config_and_register(&gxp_timer->evt, TIMER0_FREQ,
> +					0xf, 0xffffffff);
> +
> +	pr_debug("gxp: system timer (irq = %d)\n", irq);
> +	return 0;
> +
> +err_iounmap:
> +	iounmap(system_clock);
> +	iounmap(base);
> +	return ret;
> +}

Thanks,

        tglx