linux-kernel - Re: [PATCH v2 04/14] irqchip: pruss: Add a PRUSS irqchip driver for PRUSS interrupts

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Date:   Tue, 5 Feb 2019 10:51:14 +0200
From:   Roger Quadros <rogerq@...com>
To:     "Andrew F. Davis" <afd@...com>, <tony@...mide.com>,
        <ohad@...ery.com>, <bjorn.andersson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>
CC:     <s-anna@...com>, <david@...hnology.com>, <nsekhar@...com>,
        <t-kristo@...com>, <nsaulnier@...com>, <jreeder@...com>,
        <m-karicheri2@...com>, <woods.technical@...il.com>,
        <linux-omap@...r.kernel.org>, <linux-remoteproc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>
Subject: Re: [PATCH v2 04/14] irqchip: pruss: Add a PRUSS irqchip driver for
 PRUSS interrupts

+Rob

Andrew,

On 04/02/19 17:33, Roger Quadros wrote:
> On 04/02/19 17:11, Andrew F. Davis wrote:
>> On 2/4/19 8:22 AM, Roger Quadros wrote:
>>> From: "Andrew F. Davis" <afd@...com>
>>>
>>
>> [...]
>>
>>> +static const struct pruss_intc_match_data am437x_pruss_intc_data = {
>>> +	.no_host7_intr = true,
>>
>> Like done for the PRUSS driver with 'has_no_sharedram' becoming a DT
>> flag the same could be done here, then all this match data stuff could
>> be dropped.
> 
> Agreed.
> 

Going back and looking at code here is a different perspective.

The has_no_sharedram case was a an odd duck because the 2 ICSSG instances
within the same SoC (AM437x) had differences. So we couldn't use
the compatible to differentiate there. The DT flag makes sense there.

In the no_host7_intr case, it SoC specific so we can use the compatible to
differentiate. And AM6 SoC has different number of system_events and host_interrupts
so that could come in macth_data as well. See below.

static const struct pruss_intc_match_data am335x_am57xx_pruss_intc_data = {
        .num_system_events = 64,
        .num_host_intrs = 10,
        .no_host7_intr = false,
};

static const struct pruss_intc_match_data am437x_k2g_pruss_intc_data = {
        .num_system_events = 64,
        .num_host_intrs = 10,
        .no_host7_intr = true,
};

static const struct pruss_intc_match_data am6x_icssg_intc_data = {
        .num_system_events = 160,
        .num_host_intrs = 20,
        .no_host7_intr = false,
};

Alternatively, we add a DT property each for all 3 of them and get rid
of match_data entirely.

Which is a better approach?

cheers,
-roger


>>
>>> +};
>>> +
>>> +static const struct of_device_id pruss_intc_of_match[] = {
>>> +	{
>>> +		.compatible = "ti,am3356-pruss-intc",
>>> +		.data = NULL,
>>> +	},
>>> +	{
>>> +		.compatible = "ti,am4376-pruss-intc",
>>> +		.data = &am437x_pruss_intc_data,
>>> +	},
>>> +	{
>>> +		.compatible = "ti,am5728-pruss-intc",
>>> +		.data = NULL,
>>> +	},
>>> +	{ /* sentinel */ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, pruss_intc_of_match);
>>> +
>>> +static struct platform_driver pruss_intc_driver = {
>>> +	.driver = {
>>> +		.name = "pruss-intc",
>>> +		.of_match_table = pruss_intc_of_match,
>>> +	},
>>> +	.probe  = pruss_intc_probe,
>>> +	.remove = pruss_intc_remove,
>>> +};
>>> +module_platform_driver(pruss_intc_driver);
>>> +
>>> +MODULE_AUTHOR("Andrew F. Davis <afd@...com>");
>>> +MODULE_AUTHOR("Suman Anna <s-anna@...com>");
>>> +MODULE_DESCRIPTION("PRU-ICSS INTC Driver");
>>> +MODULE_LICENSE("GPL v2");
>>> diff --git a/include/linux/irqchip/irq-pruss-intc.h b/include/linux/irqchip/irq-pruss-intc.h
>>> new file mode 100644
>>> index 0000000..4538a0b
>>> --- /dev/null
>>> +++ b/include/linux/irqchip/irq-pruss-intc.h
>>> @@ -0,0 +1,94 @@
>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>> +/**
>>> + * irq-pruss-intc.h - PRU-ICSS INTC management
>>
>> Filename not needed.
> 
> OK.
> 
> cheers,
> -roger
> 
>>
>> Andrew
>>
>>> + *
>>> + * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com
>>> + */
>>> +
>>> +#ifndef __INCLUDE_LINUX_IRQCHIP_IRQ_PRUSS_INTC_H
>>> +#define __INCLUDE_LINUX_IRQCHIP_IRQ_PRUSS_INTC_H
>>> +
>>> +/* maximum number of system events */
>>> +#define MAX_PRU_SYS_EVENTS	64
>>> +
>>> +/* maximum number of interrupt channels */
>>> +#define MAX_PRU_CHANNELS	10
>>> +
>>> +/**
>>> + * struct pruss_intc_config - INTC configuration info
>>> + * @sysev_to_ch: system events to channel mapping information
>>> + * @ch_to_host: interrupt channel to host interrupt information
>>> + */
>>> +struct pruss_intc_config {
>>> +	s8 sysev_to_ch[MAX_PRU_SYS_EVENTS];
>>> +	s8 ch_to_host[MAX_PRU_CHANNELS];
>>> +};
>>> +
>>> +#if IS_ENABLED(CONFIG_TI_PRUSS)
>>> +
>>> +/**
>>> + * pruss_intc_configure() - configure the PRUSS INTC
>>> + * @dev: device
>>> + * @intc_config: PRU core-specific INTC configuration
>>> + *
>>> + * Configures the PRUSS INTC with the provided configuration from
>>> + * a PRU core. Any existing event to channel mappings or channel to
>>> + * host interrupt mappings are checked to make sure there are no
>>> + * conflicting configuration between both the PRU cores. The function
>>> + * is intended to be used only by the PRU remoteproc driver.
>>> + *
>>> + * Returns 0 on success, or a suitable error code otherwise
>>> + */
>>> +int pruss_intc_configure(struct device *dev,
>>> +			 struct pruss_intc_config *intc_config);
>>> +
>>> +/**
>>> + * pruss_intc_unconfigure() - unconfigure the PRUSS INTC
>>> + * @dev: device
>>> + * @intc_config: PRU core specific INTC configuration
>>> + *
>>> + * Undo whatever was done in pruss_intc_configure() for a PRU core.
>>> + * It should be sufficient to just mark the resources free in the
>>> + * global map and disable the host interrupts and sysevents.
>>> + */
>>> +int pruss_intc_unconfigure(struct device *dev,
>>> +			   struct pruss_intc_config *intc_config);
>>> +/**
>>> + * pruss_intc_trigger() - trigger a PRU system event
>>> + * @irq: linux IRQ number associated with a PRU system event
>>> + *
>>> + * Trigger an interrupt by signalling 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);
>>> +
>>> +#else
>>> +
>>> +static inline int pruss_intc_configure(struct device *dev,
>>> +				       struct pruss_intc_config *intc_config)
>>> +{
>>> +	return -ENOTSUPP;
>>> +}
>>> +
>>> +static inline int pruss_intc_unconfigure(struct device *dev,
>>> +					 struct pruss_intc_config *intc_config)
>>> +{
>>> +	return -ENOTSUPP;
>>> +}
>>> +
>>> +static inline int pruss_intc_trigger(unsigned int irq)
>>> +{
>>> +	return -ENOTSUPP;
>>> +}
>>> +
>>> +#endif	/* CONFIG_TI_PRUSS */
>>> +
>>> +#endif /* __INCLUDE_LINUX_IRQCHIP_IRQ_OMAP_INTC_H */
>>> +
>>>
> 

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