linux-kernel - Re: [PATCHv3 4/6] irqchip/irq-pruss-intc: Implement irq_{get,set}_irqchip

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Message-ID: <658e3a8d3374eca91387932a9a246add@kernel.org>
Date:   Thu, 02 Jul 2020 18:54:26 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>
Cc:     tglx@...utronix.de, jason@...edaemon.net, s-anna@...com,
        robh+dt@...nel.org, lee.jones@...aro.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        david@...hnology.com, wmills@...com
Subject: Re: [PATCHv3 4/6] irqchip/irq-pruss-intc: Implement
 irq_{get,set}_irqchip_state ops

On 2020-07-02 15:17, Grzegorz Jaszczyk wrote:
> From: David Lechner <david@...hnology.com>
> 
> This implements the irq_get_irqchip_state and irq_set_irqchip_state
> callbacks for the TI PRUSS INTC driver. The set callback can be used
> by drivers to "kick" a PRU by enabling a PRU system event.

"enabling"? That'd be unmasking an interrupt, which isn't what this
does. "injecting", maybe?

> 
> Example:
>      irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true);

Nice example.

What this example does explain is how you are actually going to kick
a PRU via this interface. For that to happen, you'd have to have on
the Linux side an interrupt that is actually routed to a PRU.
And from what I have understood of the previous patches, this can't
be the case. What didi I miss?

> 
> Signed-off-by: David Lechner <david@...hnology.com>
> Signed-off-by: Suman Anna <s-anna@...com>
> Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@...aro.org>
> Reviewed-by: Lee Jones <lee.jones@...aro.org>
> ---
> v2->v3:
> - Get rid of unnecessary pruss_intc_check_write() and use
>   pruss_intc_write_reg directly.
> v1->v2:
> - https://patchwork.kernel.org/patch/11069769/
> ---
>  drivers/irqchip/irq-pruss-intc.c | 43 
> ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 41 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-pruss-intc.c 
> b/drivers/irqchip/irq-pruss-intc.c
> index 49c936f..19b3d38 100644
> --- a/drivers/irqchip/irq-pruss-intc.c
> +++ b/drivers/irqchip/irq-pruss-intc.c
> @@ -7,6 +7,7 @@
>   *	Suman Anna <s-anna@...com>
>   */
> 
> +#include <linux/interrupt.h>
>  #include <linux/irq.h>
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/irqdomain.h>
> @@ -39,8 +40,7 @@
>  #define PRU_INTC_HIEISR		0x0034
>  #define PRU_INTC_HIDISR		0x0038
>  #define PRU_INTC_GPIR		0x0080
> -#define PRU_INTC_SRSR0		0x0200
> -#define PRU_INTC_SRSR1		0x0204
> +#define PRU_INTC_SRSR(x)	(0x0200 + (x) * 4)
>  #define PRU_INTC_SECR0		0x0280
>  #define PRU_INTC_SECR1		0x0284
>  #define PRU_INTC_ESR0		0x0300
> @@ -145,6 +145,43 @@ static void pruss_intc_irq_relres(struct irq_data 
> *data)
>  	module_put(THIS_MODULE);
>  }
> 
> +static int pruss_intc_irq_get_irqchip_state(struct irq_data *data,
> +					    enum irqchip_irq_state which,
> +					    bool *state)
> +{
> +	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
> +	u32 reg, mask, srsr;
> +
> +	if (which != IRQCHIP_STATE_PENDING)
> +		return -EINVAL;
> +
> +	reg = PRU_INTC_SRSR(data->hwirq / 32);

I assume the register file scales as more interrupts are added in the
subsequent patch?

> +	mask = BIT(data->hwirq % 32);
> +
> +	srsr = pruss_intc_read_reg(intc, reg);
> +
> +	*state = !!(srsr & mask);
> +
> +	return 0;
> +}
> +
> +static int pruss_intc_irq_set_irqchip_state(struct irq_data *data,
> +					    enum irqchip_irq_state which,
> +					    bool state)
> +{
> +	struct pruss_intc *intc = irq_data_get_irq_chip_data(data);
> +
> +	if (which != IRQCHIP_STATE_PENDING)
> +		return -EINVAL;
> +
> +	if (state)
> +		pruss_intc_write_reg(intc, PRU_INTC_SISR, data->hwirq);
> +	else
> +		pruss_intc_write_reg(intc, PRU_INTC_SICR, data->hwirq);
> +
> +	return 0;
> +}
> +
>  static struct irq_chip pruss_irqchip = {
>  	.name = "pruss-intc",
>  	.irq_ack = pruss_intc_irq_ack,
> @@ -152,6 +189,8 @@ static struct irq_chip pruss_irqchip = {
>  	.irq_unmask = pruss_intc_irq_unmask,
>  	.irq_request_resources = pruss_intc_irq_reqres,
>  	.irq_release_resources = pruss_intc_irq_relres,
> +	.irq_get_irqchip_state = pruss_intc_irq_get_irqchip_state,
> +	.irq_set_irqchip_state = pruss_intc_irq_set_irqchip_state,
>  };
> 
>  static int pruss_intc_irq_domain_map(struct irq_domain *d, unsigned 
> int virq,

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...