Subject: [PATCH 2/6] ARM: add Highbank core platform support

From: [email-masked] (Arnd Bergmann)
Date: Thu, 18 Aug 2011 17:34:25 +0200

On Tuesday 16 August 2011, Rob Herring wrote:

> +void __iomem *a9_base_addr = ((void __iomem *)(HB_MPIC_VIRT_BASE));
> +void __iomem *sregs_base;
> +
> +static struct map_desc highbank_io_desc[] __initdata = {
> +	{
> +		.virtual	= HB_MPIC_VIRT_BASE,
> +		.pfn		= 0, /* run-time */
> +		.length		= SZ_4K,
> +		.type		= MT_DEVICE,
> +	},
> +#ifdef CONFIG_DEBUG_LL
> +	{
> +		.virtual	= HB_DEBUG_LL_VIRT_BASE,
> +		.pfn		= __phys_to_pfn(HB_DEBUG_LL_PHYS_BASE),
> +		.length		= SZ_4K,
> +		.type		= MT_DEVICE,
> +	},
> +#endif
> +};
> +
> +static void __init highbank_map_io(void)
> +{
> +	unsigned long base;
> +
> +	/* Get SCU base */
> +	asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
> +
> +	highbank_io_desc[0].pfn = __phys_to_pfn(base);
> +	iotable_init(highbank_io_desc, ARRAY_SIZE(highbank_io_desc));
> +}

I really liked the way that Barry moved the io_desc out to the
drivers using them, e.g arch/arm/mach-prima2/lluart.c.

Can you do the same thing with your lluart and with the a9_base_addr?
I guess it can live locally in platsmp.c.

> +void highbank_init_irq(void)
> +{
> +	struct device_node *node;
> +	struct of_intc_desc desc;
> +	int n = 0;
> +
> +	memset(&desc, 0, sizeof(desc));
> +	desc.controller = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-gic");
> +	gic_of_init(&desc);
> +	node = desc.controller;
> +	for_each_child_of_node(node, desc.controller) {
> +		gic_of_ppi_init(&desc);
> +	}
> +
> +	for_each_compatible_node(node, NULL, "arm,pl061") {
> +		irq_domain_add_simple(node, 160 + (8 * n));
> +		n++;
> +	}

Where does the "160 + (8 * n)" come from? Is that something that should
be in a property of the gic binding?

> +#ifdef CONFIG_CACHE_L2X0
> +	l2x0_of_init(0, ~0UL);
> +#endif
> +}

Hmm, I missed that during the review of the patch that adds l2x0_of_init,
but I think the #ifdef should really be in the header file, not in the
user, so that calling l2x0_of_init when CONFIG_CACHE_L2X0 is not set
automatically turns into an empty stub.

> +static void __init highbank_timer_init(void)
> +{
> +	int irq;
> +	struct device_node *np;
> +	void __iomem *timer_base;
> +
> +	/* Map system registers */
> +	np = of_find_compatible_node(NULL, NULL, "calxeda,hb-sregs");
> +	sregs_base = of_iomap(np, 0);
> +
> +	np = of_find_compatible_node(NULL, NULL, "arm,sp804");
> +	timer_base = of_iomap(np, 0);
> +	irq = irq_of_parse_and_map(np, 0);
> +
> +	highbank_clocks_init();
> +
> +	sp804_clocksource_init(timer_base + 0x20, "timer1");
> +	sp804_clockevents_init(timer_base, irq, "timer0");
> +}

How about moving the sp804 initialization from device tree into the
arch/arm/common/timer-sp.c file?

Why do you initialize sregs_base from timer_init?

> diff --git a/arch/arm/mach-highbank/include/mach/timex.h b/arch/arm/mach-highbank/include/mach/timex.h
> new file mode 100644
> index 0000000..88dac7a
> --- /dev/null
> +++ b/arch/arm/mach-highbank/include/mach/timex.h
> @@ -0,0 +1,6 @@
> +#ifndef __MACH_TIMEX_H
> +#define __MACH_TIMEX_H
> +
> +#define CLOCK_TICK_RATE		1000000
> +
> +#endif

In 3.2, we shouldn't need this any more. We'll have to come up with a
way to remember removing the new definitions that come in in parallel
to the patch that removes the old ones.

> +#ifndef _MACH_HIGHBANK__SYSREGS_H_
> +#define _MACH_HIGHBANK__SYSREGS_H_
> +
> +extern void __iomem *sregs_base;
> +
> +#define HB_SREG_A9_PWR_REQ		0xf00
> +#define HB_SREG_A9_BOOT_STAT		0xf04
> +#define HB_SREG_A9_BOOT_DATA		0xf08
> +
> +#define HB_PWR_SUSPEND			0
> +#define HB_PWR_SOFT_RESET		1
> +#define HB_PWR_HARD_RESET		2
> +#define HB_PWR_SHUTDOWN			3
> +
> +#endif

Do these really need to be global?

I think it's better to put the base address and register definitions into a
single file and export functions to be used from elsewhere.

	Arnd