Re: [PATCH v16 10/15] clocksource/drivers/arm_arch_timer: Refactor the timer init code to prepare for GTDT

[Mark Rutland]

On Wed, Nov 16, 2016 at 09:49:03PM +0800, fu.wei@xxxxxxxxxx wrote:
> From: Fu Wei <fu.wei@xxxxxxxxxx>
> 
> The patch refactor original memory-mapped timer init code:
>     (1) Extract a subfunction for detecting a bast time frame:
>         is_best_frame.

Please leave this logic in arch_timer_mem_init(). Pulling it out gains
us nothing, but makes the patch harder to review.

>     (2) Refactor "arch_timer_mem_init", make it become a common code for
>         memory-mapped timer init.
>     (3) Add a new function "arch_timer_mem_of_init" for DT init.

These generally look fine.

Thanks,
Mark.

> Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx>
> ---
>  drivers/clocksource/arm_arch_timer.c | 162 +++++++++++++++++++++++------------
>  1 file changed, 107 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 9ddc091..0836bb9 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -923,17 +923,35 @@ static int __init arch_timer_of_init(struct device_node *np)
>  CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
>  CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
>  
> -static int __init arch_timer_mem_init(struct device_node *np)
> +static bool __init is_best_frame(void __iomem *cntctlbase, u32 cnttidr, int n)
> +{
> +	u32 cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT | CNTACR_RWVT |
> +		     CNTACR_RVOFF | CNTACR_RVCT;
> +
> +	/* Try enabling everything, and see what sticks */
> +	writel_relaxed(cntacr, cntctlbase + CNTACR(n));
> +	cntacr = readl_relaxed(cntctlbase + CNTACR(n));
> +
> +	if ((cnttidr & CNTTIDR_VIRT(n)) &&
> +	    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT)))
> +		arch_timer_mem_use_virtual = true;
> +	else if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
> +		return false;
> +
> +	return true;
> +}
> +
> +static int __init arch_timer_mem_init(struct arch_timer_mem *timer_mem)
>  {
> -	struct device_node *frame, *best_frame = NULL;
>  	void __iomem *cntctlbase, *base;
> -	unsigned int irq, ret = -EINVAL;
> +	struct arch_timer_mem_frame *best_frame = NULL;
> +	unsigned int irq;
>  	u32 cnttidr;
> +	int i, ret;
>  
> -	arch_timers_present |= ARCH_TIMER_TYPE_MEM;
> -	cntctlbase = of_iomap(np, 0);
> +	cntctlbase = ioremap(timer_mem->cntctlbase, timer_mem->size);
>  	if (!cntctlbase) {
> -		pr_err("Can't find CNTCTLBase\n");
> +		pr_err("Can't map CNTCTLBase.\n");
>  		return -ENXIO;
>  	}
>  
> @@ -943,76 +961,110 @@ static int __init arch_timer_mem_init(struct device_node *np)
>  	 * Try to find a virtual capable frame. Otherwise fall back to a
>  	 * physical capable frame.
>  	 */
> -	for_each_available_child_of_node(np, frame) {
> -		int n;
> -		u32 cntacr;
> -
> -		if (of_property_read_u32(frame, "frame-number", &n)) {
> -			pr_err("Missing frame-number\n");
> -			of_node_put(frame);
> -			goto out;
> -		}
> -
> -		/* Try enabling everything, and see what sticks */
> -		cntacr = CNTACR_RFRQ | CNTACR_RWPT | CNTACR_RPCT |
> -			 CNTACR_RWVT | CNTACR_RVOFF | CNTACR_RVCT;
> -		writel_relaxed(cntacr, cntctlbase + CNTACR(n));
> -		cntacr = readl_relaxed(cntctlbase + CNTACR(n));
> -
> -		if ((cnttidr & CNTTIDR_VIRT(n)) &&
> -		    !(~cntacr & (CNTACR_RWVT | CNTACR_RVCT))) {
> -			of_node_put(best_frame);
> -			best_frame = frame;
> -			arch_timer_mem_use_virtual = true;
> -			break;
> +	for (i = 0; i < timer_mem->num_frames; i++) {
> +		if (is_best_frame(cntctlbase, cnttidr,
> +				  timer_mem->frame[i].frame_nr)) {
> +			best_frame = &timer_mem->frame[i];
> +			if (arch_timer_mem_use_virtual)
> +				break;
>  		}
> -
> -		if (~cntacr & (CNTACR_RWPT | CNTACR_RPCT))
> -			continue;
> -
> -		of_node_put(best_frame);
> -		best_frame = of_node_get(frame);
>  	}
> +	iounmap(cntctlbase);
>  
> -	ret= -ENXIO;
> -	base = arch_counter_base = of_iomap(best_frame, 0);
> -	if (!base) {
> -		pr_err("Can't map frame's registers\n");
> -		goto out;
> +	if (!best_frame) {
> +		pr_err("Can't find frame for register\n");
> +		return -EINVAL;
>  	}
>  
>  	if (arch_timer_mem_use_virtual)
> -		irq = irq_of_parse_and_map(best_frame, ARCH_TIMER_VIRT_SPI);
> +		irq = best_frame->virt_irq;
>  	else
> -		irq = irq_of_parse_and_map(best_frame, ARCH_TIMER_PHYS_SPI);
> +		irq = best_frame->phys_irq;
>  
> -	ret = -EINVAL;
>  	if (!irq) {
>  		pr_err("Frame missing %s irq",
>  		       arch_timer_mem_use_virtual ? "virt" : "phys");
> -		goto out;
> +		return -EINVAL;
>  	}
>  
> -	/*
> -	 * Try to determine the frequency from the device tree,
> -	 * if fail, get the frequency from CNTFRQ.
> -	 */
> -	if (!arch_timer_rate &&
> -	    of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
> -		arch_timer_detect_rate(base);
> +	base = ioremap(best_frame->cntbase, best_frame->size);
> +	if (!base) {
> +		pr_err("Can't map frame's registers\n");
> +		return -ENXIO;
> +	}
> +
> +	arch_timer_detect_rate(base);
>  
>  	ret = arch_timer_mem_register(base, irq);
> -	if (ret)
> +	if (ret) {
> +		iounmap(base);
> +		return ret;
> +	}
> +
> +	arch_counter_base = base;
> +	arch_timers_present |= ARCH_TIMER_TYPE_MEM;
> +
> +	return 0;
> +}
> +
> +static int __init arch_timer_mem_of_init(struct device_node *np)
> +{
> +	struct arch_timer_mem *timer_mem;
> +	struct device_node *frame_node;
> +	struct resource res;
> +	int i, ret = -EINVAL;
> +
> +	timer_mem = kzalloc(sizeof(*timer_mem), GFP_KERNEL);
> +	if (!timer_mem)
> +		return -ENOMEM;
> +
> +	if (of_address_to_resource(np, 0, &res))
>  		goto out;
> +	timer_mem->cntctlbase = res.start;
> +	timer_mem->size = resource_size(&res);
>  
> -	return arch_timer_common_init();
> +	i = 0;
> +	for_each_available_child_of_node(np, frame_node) {
> +		int n;
> +		struct arch_timer_mem_frame *frame = &timer_mem->frame[i];
> +
> +		if (of_property_read_u32(frame_node, "frame-number", &n)) {
> +			pr_err("Missing frame-number\n");
> +			of_node_put(frame_node);
> +			goto out;
> +		}
> +		frame->frame_nr = n;
> +
> +		if (of_address_to_resource(frame_node, 0, &res)) {
> +			of_node_put(frame_node);
> +			goto out;
> +		}
> +		frame->cntbase = res.start;
> +		frame->size = resource_size(&res);
> +
> +		frame->virt_irq = irq_of_parse_and_map(frame_node,
> +						       ARCH_TIMER_VIRT_SPI);
> +		frame->phys_irq = irq_of_parse_and_map(frame_node,
> +						       ARCH_TIMER_PHYS_SPI);
> +
> +		if (++i >= ARCH_TIMER_MEM_MAX_FRAMES)
> +			break;
> +	}
> +	timer_mem->num_frames = i;
> +
> +	/* Try to determine the frequency from the device tree */
> +	if (!arch_timer_rate)
> +		of_property_read_u32(np, "clock-frequency", &arch_timer_rate);
> +
> +	ret = arch_timer_mem_init(timer_mem);
> +	if (!ret)
> +		ret = arch_timer_common_init();
>  out:
> -	iounmap(cntctlbase);
> -	of_node_put(best_frame);
> +	kfree(timer_mem);
>  	return ret;
>  }
>  CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
> -		       arch_timer_mem_init);
> +		       arch_timer_mem_of_init);
>  
>  #ifdef CONFIG_ACPI
>  static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
> -- 
> 2.7.4
>