Re: [PATCH v3 03/12] irqchip: vf610-mscm: support NVIC parent

Jason Cooper
2015-03-23T00:47:40Z

Stefan,

On Fri, Mar 13, 2015 at 12:36:11AM +0100, Stefan Agner wrote:
> Support the NVIC interrupt controller as node parent of the MSCM
> interrupt router. On the dual-core variants of Vybird (VF6xx), the
> NVIC interrupt controller is used by the Cortex-M4. To support
> running Linux on this core too, MSCM needs NVIC parent support too.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> drivers/irqchip/irq-vf610-mscm-ir.c | 32 ++++++++++++++++++++++++++------
> 1 file changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/irqchip/irq-vf610-mscm-ir.c b/drivers/irqchip/irq-vf610-mscm-ir.c
> index 9521057..bb0e1a3 100644
> --- a/drivers/irqchip/irq-vf610-mscm-ir.c
> +++ b/drivers/irqchip/irq-vf610-mscm-ir.c
...
> @@ -101,17 +103,25 @@ static void vf610_mscm_ir_enable(struct irq_data *data)
> writew_relaxed(chip_data->cpu_mask,
> chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
>
> - irq_chip_unmask_parent(data);
> + if (parent->chip->irq_enable)
> + parent->chip->irq_enable(parent);
> + else
> + parent->chip->irq_unmask(parent);
> +
> }
>
> static void vf610_mscm_ir_disable(struct irq_data *data)
> {
> irq_hw_number_t hwirq = data->hwirq;
> struct vf610_mscm_ir_chip_data *chip_data = data->chip_data;
> + struct irq_data *parent = data->parent_data;
>
> writew_relaxed(0x0, chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
>
> - irq_chip_mask_parent(data);
> + if (parent->chip->irq_enable)
> + parent->chip->irq_disable(parent);

copy/paste?

> @@ -143,10 +153,17 @@ static int vf610_mscm_ir_domain_alloc(struct irq_domain *domain, unsigned int vi
> domain->host_data);
>
> gic_data.np = domain->parent->of_node;
> - gic_data.args_count = 3;
> - gic_data.args[0] = GIC_SPI;
> - gic_data.args[1] = irq_data->args[0];
> - gic_data.args[2] = irq_data->args[1];
> +
> + if (mscm_ir_data->is_nvic) {
> + gic_data.args_count = 1;
> + gic_data.args[0] = irq_data->args[0];
> + } else {
> + gic_data.args_count = 3;
> + gic_data.args[0] = GIC_SPI;
> + gic_data.args[1] = irq_data->args[0];
> + gic_data.args[2] = irq_data->args[1];
> + }
> +
> return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_data);
> }
>
> @@ -199,6 +216,9 @@ static int __init vf610_mscm_ir_of_init(struct device_node *node,
> goto out_unmap;
> }
>
> + if (of_device_is_compatible(domain->parent->of_node, "arm,armv7m-nvic"))
> + mscm_ir_data->is_nvic = true;
> +

Could you walk me through how DT backwards compatibility is being
preserved/broken here? I'm not saying it's wrong, but every other conversion
to stacked domains involves a compatibility break. At the very least, I'd like
to see it discussed in the commit log.

thx,

Jason.