[PATCH 09/16] ARM: imx6: convert wakeupgen to stacked domains

[stefan@agner.ch (Stefan Agner)]

On 2014-12-02 17:58, Marc Zyngier wrote:
> IMX6 has been (ab)using the gic_arch_extn to provide
> wakeup from suspend, and it makes a lot of sense to convert
> this code to use stacked domains instead.
> 
> This patch does just this, updating the DT files to actually
> reflect what the HW provides.
> 
> BIG FAT WARNING: because the DTs were so far lying by not
> exposing the fact that the GPC block is actually the first
> interrupt controller in the chain, kernels with this patch
> applied wont have any suspend-resume facility when booted
> with old DTs, and old kernels with updated DTs won't even boot.
> 

Not sure this is entirely true. I don't think that GPC block is really
in the chain of the interrupts for normal interrupt delivery. This is
tested to be _not_ true for Vybird (which has also a GPC block and seems
to be quite similar). I can mask an interrupt in GPC_IMR2 for instance
and it still gets delivered to the GIC. However, the registers need to
be unmasked to deliver wake-up events.

In the GPC_IMRx register description of Vybrid this sentence actually
states what I observe: "This register is used to mask certain interrupts
if they are not desired to be a source of
wake up during STOP mode.". However, this sentence is not there in the
i.MX6 RM. But the drawing in Chapter 27.1 (GPC, Overview) suggests to
me, that it is implemented like I see it in Vybrid. So I'm not
completely sure about this, and I don't have hardware handy to test
this...

I'm aware that the code did something different before. Not sure whether
this refactoring would look differently if my suspicion holds true. I
guess even if it is only wake-up capabilities, we would use stacked IRQ
domain and just implement the wake-up part...?

--
Stefan


> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm/boot/dts/imx6qdl.dtsi  |   6 +-
>  arch/arm/boot/dts/imx6sl.dtsi   |   5 +-
>  arch/arm/boot/dts/imx6sx.dtsi   |   5 +-
>  arch/arm/mach-imx/common.h      |   1 -
>  arch/arm/mach-imx/gpc.c         | 127 ++++++++++++++++++++++++++++++++--------
>  arch/arm/mach-imx/mach-imx6q.c  |   1 -
>  arch/arm/mach-imx/mach-imx6sl.c |   1 -
>  arch/arm/mach-imx/mach-imx6sx.c |   1 -
>  8 files changed, 116 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
> index 9596ed5..b7b4ee8 100644
> --- a/arch/arm/boot/dts/imx6qdl.dtsi
> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
> @@ -53,6 +53,7 @@
>  		interrupt-controller;
>  		reg = <0x00a01000 0x1000>,
>  		      <0x00a00100 0x100>;
> +		interrupt-parent = <&intc>;
>  	};
>  
>  	clocks {
> @@ -82,7 +83,7 @@
>  		#address-cells = <1>;
>  		#size-cells = <1>;
>  		compatible = "simple-bus";
> -		interrupt-parent = <&intc>;
> +		interrupt-parent = <&gpc>;
>  		ranges;
>  
>  		dma_apbh: dma-apbh at 00110000 {
> @@ -122,6 +123,7 @@
>  			compatible = "arm,cortex-a9-twd-timer";
>  			reg = <0x00a00600 0x20>;
>  			interrupts = <1 13 0xf01>;
> +			interrupt-parent = <&intc>;
>  			clocks = <&clks IMX6QDL_CLK_TWD>;
>  		};
>  
> @@ -680,8 +682,10 @@
>  			gpc: gpc at 020dc000 {
>  				compatible = "fsl,imx6q-gpc";
>  				reg = <0x020dc000 0x4000>;
> +				interrupt-controller;
>  				interrupts = <0 89 IRQ_TYPE_LEVEL_HIGH>,
>  					     <0 90 IRQ_TYPE_LEVEL_HIGH>;
> +				interrupt-parent = <&intc>;
>  			};
>  
>  			gpr: iomuxc-gpr at 020e0000 {
> diff --git a/arch/arm/boot/dts/imx6sl.dtsi b/arch/arm/boot/dts/imx6sl.dtsi
> index dfd83e6..802507e 100644
> --- a/arch/arm/boot/dts/imx6sl.dtsi
> +++ b/arch/arm/boot/dts/imx6sl.dtsi
> @@ -72,6 +72,7 @@
>  		interrupt-controller;
>  		reg = <0x00a01000 0x1000>,
>  		      <0x00a00100 0x100>;
> +		interrupt-parent = <&intc>;
>  	};
>  
>  	clocks {
> @@ -95,7 +96,7 @@
>  		#address-cells = <1>;
>  		#size-cells = <1>;
>  		compatible = "simple-bus";
> -		interrupt-parent = <&intc>;
> +		interrupt-parent = <&gpc>;
>  		ranges;
>  
>  		ocram: sram at 00900000 {
> @@ -597,7 +598,9 @@
>  			gpc: gpc at 020dc000 {
>  				compatible = "fsl,imx6sl-gpc", "fsl,imx6q-gpc";
>  				reg = <0x020dc000 0x4000>;
> +				interrupt-controller;
>  				interrupts = <0 89 IRQ_TYPE_LEVEL_HIGH>;
> +				interrupt-parent = <&intc>;
>  			};
>  
>  			gpr: iomuxc-gpr at 020e0000 {
> diff --git a/arch/arm/boot/dts/imx6sx.dtsi b/arch/arm/boot/dts/imx6sx.dtsi
> index f3e88c0..75ca610 100644
> --- a/arch/arm/boot/dts/imx6sx.dtsi
> +++ b/arch/arm/boot/dts/imx6sx.dtsi
> @@ -88,6 +88,7 @@
>  		interrupt-controller;
>  		reg = <0x00a01000 0x1000>,
>  		      <0x00a00100 0x100>;
> +		interrupt-parent = <&intc>;
>  	};
>  
>  	clocks {
> @@ -131,7 +132,7 @@
>  		#address-cells = <1>;
>  		#size-cells = <1>;
>  		compatible = "simple-bus";
> -		interrupt-parent = <&intc>;
> +		interrupt-parent = <&gpc>;
>  		ranges;
>  
>  		pmu {
> @@ -694,7 +695,9 @@
>  			gpc: gpc at 020dc000 {
>  				compatible = "fsl,imx6sx-gpc", "fsl,imx6q-gpc";
>  				reg = <0x020dc000 0x4000>;
> +				interrupt-controller;
>  				interrupts = <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
> +				interrupt-parent = <&intc>;
>  			};
>  
>  			iomuxc: iomuxc at 020e0000 {
> diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
> index 66662a1..ac65dd5 100644
> --- a/arch/arm/mach-imx/common.h
> +++ b/arch/arm/mach-imx/common.h
> @@ -103,7 +103,6 @@ static inline void imx_scu_map_io(void) {}
>  static inline void imx_smp_prepare(void) {}
>  #endif
>  void imx_src_init(void);
> -void imx_gpc_init(void);
>  void imx_gpc_pre_suspend(bool arm_power_off);
>  void imx_gpc_post_resume(void);
>  void imx_gpc_mask_all(void);
> diff --git a/arch/arm/mach-imx/gpc.c b/arch/arm/mach-imx/gpc.c
> index 5f3602e..240109b 100644
> --- a/arch/arm/mach-imx/gpc.c
> +++ b/arch/arm/mach-imx/gpc.c
> @@ -22,6 +22,7 @@
>  #define GPC_PGC_CPU_PDN		0x2a0
>  
>  #define IMR_NUM			4
> +#define GPC_MAX_IRQS		(IMR_NUM * 32)
>  
>  static void __iomem *gpc_base;
>  static u32 gpc_wake_irqs[IMR_NUM];
> @@ -56,17 +57,17 @@ void imx_gpc_post_resume(void)
>  
>  static int imx_gpc_irq_set_wake(struct irq_data *d, unsigned int on)
>  {
> -	unsigned int idx = d->hwirq / 32 - 1;
> +	unsigned int idx = d->hwirq / 32;
>  	u32 mask;
>  
> -	/* Sanity check for SPI irq */
> -	if (d->hwirq < 32)
> -		return -EINVAL;
> -
>  	mask = 1 << d->hwirq % 32;
>  	gpc_wake_irqs[idx] = on ? gpc_wake_irqs[idx] | mask :
>  				  gpc_wake_irqs[idx] & ~mask;
>  
> +	/*
> +	 * Do *not* call into the parent, as the GIC doesn't have any
> +	 * wake-up facility...
> +	 */
>  	return 0;
>  }
>  
> @@ -96,7 +97,7 @@ void imx_gpc_hwirq_unmask(unsigned int hwirq)
>  	void __iomem *reg;
>  	u32 val;
>  
> -	reg = gpc_base + GPC_IMR1 + (hwirq / 32 - 1) * 4;
> +	reg = gpc_base + GPC_IMR1 + hwirq / 32 * 4;
>  	val = readl_relaxed(reg);
>  	val &= ~(1 << hwirq % 32);
>  	writel_relaxed(val, reg);
> @@ -107,7 +108,7 @@ void imx_gpc_hwirq_mask(unsigned int hwirq)
>  	void __iomem *reg;
>  	u32 val;
>  
> -	reg = gpc_base + GPC_IMR1 + (hwirq / 32 - 1) * 4;
> +	reg = gpc_base + GPC_IMR1 + hwirq / 32 * 4;
>  	val = readl_relaxed(reg);
>  	val |= 1 << (hwirq % 32);
>  	writel_relaxed(val, reg);
> @@ -115,37 +116,115 @@ void imx_gpc_hwirq_mask(unsigned int hwirq)
>  
>  static void imx_gpc_irq_unmask(struct irq_data *d)
>  {
> -	/* Sanity check for SPI irq */
> -	if (d->hwirq < 32)
> -		return;
> -
>  	imx_gpc_hwirq_unmask(d->hwirq);
> +	irq_chip_unmask_parent(d);
>  }
>  
>  static void imx_gpc_irq_mask(struct irq_data *d)
>  {
> -	/* Sanity check for SPI irq */
> -	if (d->hwirq < 32)
> -		return;
> -
>  	imx_gpc_hwirq_mask(d->hwirq);
> +	irq_chip_mask_parent(d);
> +}
> +
> +static struct irq_chip imx_gpc_chip = {
> +	.name		= "GPC",
> +	.irq_eoi	= irq_chip_eoi_parent,
> +	.irq_mask	= imx_gpc_irq_mask,
> +	.irq_unmask	= imx_gpc_irq_unmask,
> +	.irq_retrigger	= irq_chip_retrigger_hierarchy,
> +	.irq_set_wake	= imx_gpc_irq_set_wake,
> +};
> +
> +static int imx_gpc_domain_xlate(struct irq_domain *domain,
> +				struct device_node *controller,
> +				const u32 *intspec,
> +				unsigned int intsize,
> +				unsigned long *out_hwirq,
> +				unsigned int *out_type)
> +{
> +	if (domain->of_node != controller)
> +		return -EINVAL;	/* Shouldn't happen, really... */
> +	if (intsize != 3)
> +		return -EINVAL;	/* Not GIC compliant */
> +	if (intspec[0] != 0)
> +		return -EINVAL;	/* No PPI should point to this domain */
> +
> +	*out_hwirq = intspec[1];
> +	*out_type = intspec[2];
> +	return 0;
> +}
> +
> +static int imx_gpc_domain_alloc(struct irq_domain *domain,
> +				  unsigned int virq,
> +				  unsigned int nr_irqs, void *data)
> +{
> +	struct of_phandle_args *args = data;
> +	struct of_phandle_args parent_args;
> +	irq_hw_number_t hwirq;
> +	int i;
> +
> +	if (args->args_count != 3)
> +		return -EINVAL;	/* Not GIC compliant */
> +	if (args->args[0] != 0)
> +		return -EINVAL;	/* No PPI should point to this domain */
> +
> +	hwirq = args->args[1];
> +	if (hwirq >= GPC_MAX_IRQS)
> +		return -EINVAL;	/* Can't deal with this */
> +
> +	for (i = 0; i < nr_irqs; i++)
> +		irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> +					      &imx_gpc_chip, NULL);
> +
> +	parent_args = *args;
> +	parent_args.np = domain->parent->of_node;
> +	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &parent_args);
>  }
>  
> -void __init imx_gpc_init(void)
> +static struct irq_domain_ops imx_gpc_domain_ops = {
> +	.xlate	= imx_gpc_domain_xlate,
> +	.alloc	= imx_gpc_domain_alloc,
> +	.free	= irq_domain_free_irqs_common,
> +};
> +
> +static int __init imx_gpc_init(struct device_node *node,
> +			       struct device_node *parent)
>  {
> -	struct device_node *np;
> +	struct irq_domain *parent_domain, *domain;
>  	int i;
>  
> -	np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-gpc");
> -	gpc_base = of_iomap(np, 0);
> -	WARN_ON(!gpc_base);
> +	if (!parent) {
> +		pr_err("%s: no parent, giving up\n", node->full_name);
> +		return -ENODEV;
> +	}
> +
> +	parent_domain = irq_find_host(parent);
> +	if (!parent_domain) {
> +		pr_err("%s: unable to obtain parent domain\n", node->full_name);
> +		return -ENXIO;
> +	}
> +
> +	gpc_base = of_iomap(node, 0);
> +	if (WARN_ON(!gpc_base))
> +	        return -ENOMEM;
> +
> +	domain = irq_domain_add_hierarchy(parent_domain, 0, GPC_MAX_IRQS,
> +					  node, &imx_gpc_domain_ops,
> +					  NULL);
> +	if (!domain) {
> +		iounmap(gpc_base);
> +		return -ENOMEM;
> +	}
>  
>  	/* Initially mask all interrupts */
>  	for (i = 0; i < IMR_NUM; i++)
>  		writel_relaxed(~0, gpc_base + GPC_IMR1 + i * 4);
>  
> -	/* Register GPC as the secondary interrupt controller behind GIC */
> -	gic_arch_extn.irq_mask = imx_gpc_irq_mask;
> -	gic_arch_extn.irq_unmask = imx_gpc_irq_unmask;
> -	gic_arch_extn.irq_set_wake = imx_gpc_irq_set_wake;
> +	return 0;
>  }
> +
> +/*
> + * We cannot use the IRQCHIP_DECLARE macro that lives in
> + * drivers/irqchip, so we're forced to roll our own. Not very nice.
> + */
> +OF_DECLARE_2(irqchip, imx_gpc, "fsl,imx6q-gpc", imx_gpc_init);
> diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
> index d51c6e9..5242a9c 100644
> --- a/arch/arm/mach-imx/mach-imx6q.c
> +++ b/arch/arm/mach-imx/mach-imx6q.c
> @@ -392,7 +392,6 @@ static void __init imx6q_init_irq(void)
>  	imx_init_revision_from_anatop();
>  	imx_init_l2cache();
>  	imx_src_init();
> -	imx_gpc_init();
>  	irqchip_init();
>  }
>  
> diff --git a/arch/arm/mach-imx/mach-imx6sl.c b/arch/arm/mach-imx/mach-imx6sl.c
> index ed263a2..49c4e22 100644
> --- a/arch/arm/mach-imx/mach-imx6sl.c
> +++ b/arch/arm/mach-imx/mach-imx6sl.c
> @@ -66,7 +66,6 @@ static void __init imx6sl_init_irq(void)
>  	imx_init_revision_from_anatop();
>  	imx_init_l2cache();
>  	imx_src_init();
> -	imx_gpc_init();
>  	irqchip_init();
>  }
>  
> diff --git a/arch/arm/mach-imx/mach-imx6sx.c b/arch/arm/mach-imx/mach-imx6sx.c
> index 3de3b73..dc0df73 100644
> --- a/arch/arm/mach-imx/mach-imx6sx.c
> +++ b/arch/arm/mach-imx/mach-imx6sx.c
> @@ -35,7 +35,6 @@ static void __init imx6sx_init_irq(void)
>  	imx_init_revision_from_anatop();
>  	imx_init_l2cache();
>  	imx_src_init();
> -	imx_gpc_init();
>  	irqchip_init();
>  }