[PATCH 1/4] cobalt/kernel: pipeline: add abstract synthetic IRQ API

[Jan Kiszka]

On 17.01.21 16:25, Philippe Gerum wrote:
> From: Philippe Gerum <rpm at xenomai.org>
> 
> Add wrappers to create "synthetic IRQs" the I-pipe way (used to be
> called "virtual IRQs" there). Those interrupt channels can only be
> triggered by software, with per-CPU semantics. We use them to schedule
> handlers to be run on the in-band execution stage, meaning "secondary
> mode" in the Cobalt jargon.
> 
> We don't provide for executing handlers on the out-of-band stage,
> because Cobalt does not need this.
> 
> Signed-off-by: Philippe Gerum <rpm at xenomai.org>
> ---
>  include/cobalt/kernel/ipipe/pipeline/sirq.h | 58 +++++++++++++++++++++
>  1 file changed, 58 insertions(+)
>  create mode 100644 include/cobalt/kernel/ipipe/pipeline/sirq.h
> 
> diff --git a/include/cobalt/kernel/ipipe/pipeline/sirq.h b/include/cobalt/kernel/ipipe/pipeline/sirq.h
> new file mode 100644
> index 000000000..7c39244f9
> --- /dev/null
> +++ b/include/cobalt/kernel/ipipe/pipeline/sirq.h
> @@ -0,0 +1,58 @@
> +/*
> + * SPDX-License-Identifier: GPL-2.0
> + *
> + * Copyright (C) 2020 Philippe Gerum  <rpm at xenomai.org>
> + */
> +
> +#ifndef _COBALT_KERNEL_IPIPE_SIRQ_H
> +#define _COBALT_KERNEL_IPIPE_SIRQ_H
> +
> +#include <linux/ipipe.h>
> +#include <pipeline/machine.h>
> +
> +/*
> + * Wrappers to create "synthetic IRQs" the I-pipe way (used to be
> + * called "virtual IRQs" there). Those interrupt channels can only be
> + * triggered by software; they have per-CPU semantics. We use them to
> + * schedule handlers to be run on the in-band execution stage, meaning
> + * "secondary mode" in the Cobalt jargon.
> + */
> +
> +static inline
> +int pipeline_create_inband_sirq(irqreturn_t (*handler)(int irq, void *dev_id))
> +{
> +	int sirq = ipipe_alloc_virq(), ret;

Correct but uncommon style. I've broken that up into two lines.

Jan

> +
> +	if (sirq == 0)
> +		return -EAGAIN;
> +
> +	/*
> +	 * ipipe_irq_handler_t is close enough to the signature of a
> +	 * regular IRQ handler: use the latter in the generic code
> +	 * shared with Dovetail.  The extraneous return code will be
> +	 * ignored by the I-pipe core.
> +	 */
> +	ret = ipipe_request_irq(ipipe_root_domain, sirq,
> +				(ipipe_irq_handler_t)handler,
> +				NULL, NULL);
> +	if (ret) {
> +		ipipe_free_virq(sirq);
> +		return ret;
> +	}
> +
> +	return sirq;
> +}
> +
> +static inline
> +void pipeline_delete_inband_sirq(int sirq)
> +{
> +	ipipe_free_irq(ipipe_root_domain, sirq);
> +	ipipe_free_virq(sirq);
> +}
> +
> +static inline void pipeline_post_sirq(int sirq)
> +{
> +	ipipe_post_irq_root(sirq);
> +}
> +
> +#endif /* !_COBALT_KERNEL_IPIPE_SIRQ_H */
> 

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