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Subject: Re: [PATCH 5/6] irqchip/irq-pruss-intc: Add API to trigger a PRU
 sysevent
To:     Suman Anna <s-anna@ti.com>, Marc Zyngier <marc.zyngier@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>
Cc:     Tony Lindgren <tony@atomide.com>, "Andrew F. Davis" <afd@ti.com>,
        Roger Quadros <rogerq@ti.com>,
        Lokesh Vutla <lokeshvutla@ti.com>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Sekhar Nori <nsekhar@ti.com>,
        Murali Karicheri <m-karicheri2@ti.com>,
        devicetree@vger.kernel.org, linux-omap@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20190708035243.12170-1-s-anna@ti.com>
 <20190708035243.12170-6-s-anna@ti.com>
From:   David Lechner <david@lechnology.com>
Message-ID: <49628f74-1081-894a-14a2-adc58b2051e8@lechnology.com>
Date:   Thu, 11 Jul 2019 15:40:20 -0500
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On 7/7/19 10:52 PM, Suman Anna wrote:
> From: "Andrew F. Davis" <afd@ti.com>
> 
> The PRUSS INTC can generate an interrupt to various processor
> subsystems on the SoC through a set of 64 possible PRU system
> events. These system events can be used by PRU client drivers
> or applications for event notifications/signalling between PRUs
> and MPU or other processors. A new API, pruss_intc_trigger() is
> provided to MPU-side PRU client drivers/applications to be able
> to trigger an event/interrupt using IRQ numbers provided by the
> PRUSS-INTC irqdomain chip.
> 
> Signed-off-by: Andrew F. Davis <afd@ti.com>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>   drivers/irqchip/irq-pruss-intc.c | 31 +++++++++++++++++++++++++++++++
>   include/linux/pruss_intc.h       | 26 ++++++++++++++++++++++++++
>   2 files changed, 57 insertions(+)
>   create mode 100644 include/linux/pruss_intc.h
> 
> diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
> index 8118c2a2ac43..a0ad50b95cd5 100644
> --- a/drivers/irqchip/irq-pruss-intc.c
> +++ b/drivers/irqchip/irq-pruss-intc.c
> @@ -421,6 +421,37 @@ static void pruss_intc_irq_relres(struct irq_data *data)
>   	module_put(THIS_MODULE);
>   }
>   
> +/**
> + * pruss_intc_trigger() - trigger a PRU system event
> + * @irq: linux IRQ number associated with a PRU system event
> + *
> + * Trigger an interrupt by signaling a specific PRU system event.
> + * This can be used by PRUSS client users to raise/send an event to
> + * a PRU or any other core that is listening on the host interrupt
> + * mapped to that specific PRU system event. The @irq variable is the
> + * Linux IRQ number associated with a specific PRU system event that
> + * a client user/application uses. The interrupt mappings for this is
> + * provided by the PRUSS INTC irqchip instance.
> + *
> + * Returns 0 on success, or an error value upon failure.
> + */
> +int pruss_intc_trigger(unsigned int irq)
> +{
> +	struct irq_desc *desc;
> +
> +	if (irq <= 0)
> +		return -EINVAL;
> +
> +	desc = irq_to_desc(irq);
> +	if (!desc)
> +		return -EINVAL;
> +
> +	pruss_intc_irq_retrigger(&desc->irq_data);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(pruss_intc_trigger);

Although it is not quite as obvious, we can do the same thing with:

irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true);

So I don't think a new API is needed. We just need to implement the
irq_set_irqchip_state callback as in the following patch.

---
 From c5991a11a19858d74e2a184b76c3ef5823f09ef6 Mon Sep 17 00:00:00 2001
From: David Lechner <david@lechnology.com>
Date: Thu, 11 Jul 2019 15:33:29 -0500
Subject: [PATCH] irqchip/irq-pruss-intc: implement irq_{get,set}_irqchip_state

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.

Example:

     irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true);

Signed-off-by: David Lechner <david@lechnology.com>
---
  drivers/irqchip/irq-pruss-intc.c | 41 ++++++++++++++++++++++++++++++--
  1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-pruss-intc.c b/drivers/irqchip/irq-pruss-intc.c
index dd14addfd0b4..129dfd52248b 100644
--- a/drivers/irqchip/irq-pruss-intc.c
+++ b/drivers/irqchip/irq-pruss-intc.c
@@ -7,6 +7,7 @@
   *	Suman Anna <s-anna@ti.com>
   */
  
+#include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/irqchip/chained_irq.h>
  #include <linux/irqdomain.h>
@@ -46,8 +47,7 @@
  #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
@@ -386,6 +386,41 @@ 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);
+	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)
+		return pruss_intc_check_write(intc, PRU_INTC_SISR, data->hwirq);
+
+	return pruss_intc_check_write(intc, PRU_INTC_SICR, data->hwirq);
+}
+
  static int
  pruss_intc_irq_domain_xlate(struct irq_domain *d, struct device_node *node,
  			    const u32 *intspec, unsigned int intsize,
@@ -583,6 +618,8 @@ static int pruss_intc_probe(struct platform_device *pdev)
  	irqchip->irq_retrigger = pruss_intc_irq_retrigger;
  	irqchip->irq_request_resources = pruss_intc_irq_reqres;
  	irqchip->irq_release_resources = pruss_intc_irq_relres;
+	irqchip->irq_get_irqchip_state = pruss_intc_irq_get_irqchip_state;
+	irqchip->irq_set_irqchip_state = pruss_intc_irq_set_irqchip_state;
  	irqchip->parent_device = dev;
  	irqchip->name = dev_name(dev);
  	intc->irqchip = irqchip;
-- 
2.17.1