Re: [PATCH v2 06/21] ARM: tegra: remove old LIC support

[Thierry Reding <thierry.reding@gmail.com>]

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On Wed, Jan 07, 2015 at 05:42:41PM +0000, Marc Zyngier wrote:
[...]
> diff --git a/arch/arm/mach-tegra/irq.c b/arch/arm/mach-tegra/irq.c
[...]
>  void __init tegra_init_irq(void)
>  {
> -	int i;
> -	void __iomem *distbase;
> -
> -	if (of_find_matching_node(NULL, tegra_ictlr_match))
> -		goto skip_extn_setup;
> -
> -	tegra_legacy_irq_syscore_init();
> -
> -	distbase = IO_ADDRESS(TEGRA_ARM_INT_DIST_BASE);
> -	num_ictlrs = readl_relaxed(distbase + GIC_DIST_CTR) & 0x1f;
> -
> -	if (num_ictlrs > ARRAY_SIZE(ictlr_reg_base)) {
> -		WARN(1, "Too many (%d) interrupt controllers found. Maximum is %d.",
> -			num_ictlrs, ARRAY_SIZE(ictlr_reg_base));
> -		num_ictlrs = ARRAY_SIZE(ictlr_reg_base);
> -	}
> -
> -	for (i = 0; i < num_ictlrs; i++) {
> -		void __iomem *ictlr = ictlr_reg_base[i];
> -		writel(~0, ictlr + ICTLR_CPU_IER_CLR);
> -		writel(0, ictlr + ICTLR_CPU_IEP_CLASS);
> -	}
> -
> -	gic_arch_extn.irq_ack = tegra_ack;
> -	gic_arch_extn.irq_eoi = tegra_eoi;
> -	gic_arch_extn.irq_mask = tegra_mask;
> -	gic_arch_extn.irq_unmask = tegra_unmask;
> -	gic_arch_extn.irq_retrigger = tegra_retrigger;
> -	gic_arch_extn.irq_set_wake = tegra_set_wake;
> -	gic_arch_extn.flags = IRQCHIP_MASK_ON_SUSPEND;
> +	if (!of_find_matching_node(NULL, tegra_ictlr_match))
> +		pr_warn("Outdated DT detected, suspend/resume will NOT work\n");

I'm not very happy about the ABI breakage here, but I also realize that
we need this change to properly describe the hardware. To make it more
obvious that people really should update their DTBs, maybe turn this
into a WARN()?

> -skip_extn_setup:
>  	tegra114_gic_cpu_pm_registration();

I'm not intimately familiar with the GIC, but is this really SoC
specific? Doesn't anybody else need this? Comparing to the GIC spec the
write of 0x1e0 to the GIC_CPU_CTRL register (which I assume corresponds
to GICC_CTLR in the spec), this simply disables the IRQ and FIQ bypass
signals for both group 0 and group 1.

Thierry

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