Re: [PATCH] acpi: implement Generic Event Device

[Andy Shevchenko]

On Mon, Jan 25, 2016 at 11:29 PM, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:

Few comments below.

> Generic Event Device described in ACPI 6.1 allows platforms to handle
> platform interrupts in ACPI ASL statements. It borrows constructs like
> _EVT from GPIO events.

Can it share code with gpiolib-acpi.c ? I see some duplication.

> All interrupts are listed in _CRS and the handler
> is written in _EVT method. Here is an example.


>
> Device (GED0)
> {
>
>         Name (_HID, "ACPI0013")
>         Name (_UID, 0)
>         Name(_CRS, ResourceTemplate ()
>         {
>                 Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
>                  {123}
>         })
>
>         Method (_EVT, 1) {
>                 if (Lequal(123, Arg0))
>                 {
>                 }
>         }
> }
>
> Wake capability has not been implemented yet.
>
> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> ---
>  drivers/acpi/Makefile |   1 +
>  drivers/acpi/evged.c  | 162 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 163 insertions(+)
>  create mode 100644 drivers/acpi/evged.c
>
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index b5e7cd8..4dbb732 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -46,6 +46,7 @@ acpi-y                                += acpi_pnp.o
>  acpi-y                         += int340x_thermal.o
>  acpi-y                         += power.o
>  acpi-y                         += event.o
> +acpi-$(CONFIG_ACPI_REDUCED_HARDWARE_ONLY) += evged.o
>  acpi-y                         += sysfs.o
>  acpi-y                         += property.o
>  acpi-$(CONFIG_X86)             += acpi_cmos_rtc.o
> diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c
> new file mode 100644
> index 0000000..a904676
> --- /dev/null
> +++ b/drivers/acpi/evged.c
> @@ -0,0 +1,162 @@
> +/*
> + * Generic Event Device for ACPI.
> + *
> + * Copyright (c) 2016, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * Generic Event Device allows platforms to handle
> + * interrupts in ACPI ASL statements. It follows very similar
> + * _EVT method approach from GPIO events.
> + * All interrupts are listed in _CRS and the handler
> + * is written in _EVT method. Here is an example.

Can it be wider on screen?

> + *
> + * Device (GED0)
> + * {
> + *
> + *     Name (_HID, "ACPI0013")
> + *     Name (_UID, 0)
> + *     Method (_CRS, 0x0, Serialized)
> + *     {
> + *             Name (RBUF, ResourceTemplate ()
> + *             {
> + *             Interrupt(ResourceConsumer, Edge, ActiveHigh, Shared, , , )
> + *             {123}
> + *             }
> + *     })
> + *
> + *     Method (_EVT, 1) {
> + *             if (Lequal(123, Arg0))
> + *             {
> + *             }
> + *     }
> + * }
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/list.h>
> +#include <linux/platform_device.h>
> +#include <linux/acpi.h>
> +
> +#define MODULE_NAME    "acpi-ged"
> +
> +struct acpi_ged_event {
> +       struct list_head node;
> +       struct device *dev;
> +       unsigned int gsi;
> +       unsigned int irq;
> +       acpi_handle handle;
> +};
> +
> +static irqreturn_t acpi_ged_irq_handler(int irq, void *data)
> +{
> +       struct acpi_ged_event *event = data;
> +       acpi_status acpi_ret;
> +
> +       acpi_ret = acpi_execute_simple_method(event->handle, NULL, event->gsi);
> +       if (ACPI_FAILURE(acpi_ret))
> +               dev_err_once(event->dev, "IRQ method execution failed\n");
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
> +                                             void *context)
> +{
> +       struct acpi_ged_event *event;
> +       unsigned int irq;
> +       unsigned int gsi;
> +       unsigned int irqflags = IRQF_ONESHOT;
> +       struct device *dev = context;
> +       acpi_handle handle = ACPI_HANDLE(dev);
> +       acpi_handle evt_handle;
> +       struct resource r;
> +       struct acpi_resource_irq *p = &ares->data.irq;
> +       struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
> +
> +       if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
> +               return AE_OK;
> +
> +       if (!acpi_dev_resource_interrupt(ares, 0, &r)) {
> +               dev_err(dev, "unable to parse IRQ resource\n");
> +               return AE_ERROR;
> +       }
> +       if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
> +               gsi = p->interrupts[0];
> +       else
> +               gsi = pext->interrupts[0];
> +
> +       irq = r.start;
> +
> +       if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
> +               dev_err(dev, "cannot locate _EVT method\n");
> +               return AE_ERROR;
> +       }
> +
> +       dev_info(dev, "GED listening GSI %u @ IRQ %u\n", gsi, irq);



> +
> +       event = devm_kzalloc(dev, sizeof(*event), GFP_KERNEL);
> +       if (!event)
> +               return AE_ERROR;
> +
> +       event->gsi = gsi;
> +       event->dev = dev;
> +       event->irq = irq;
> +       event->handle = evt_handle;
> +
> +       if (r.flags & IORESOURCE_IRQ_SHAREABLE)
> +               irqflags |= IRQF_SHARED;
> +
> +       if (devm_request_threaded_irq(dev, irq, NULL, acpi_ged_irq_handler,
> +                                     irqflags, "ACPI:Ged", event)) {
> +               dev_err(dev, "failed to setup event handler for irq %u\n", irq);
> +               return AE_ERROR;
> +       }

The above part is clearly belongs to ged_probe().

> +
> +       return AE_OK;
> +}
> +
> +static int ged_probe(struct platform_device *pdev)
> +{
> +       acpi_status acpi_ret;
> +
> +       acpi_ret = acpi_walk_resources(ACPI_HANDLE(&pdev->dev), "_CRS",
> +                                      acpi_ged_request_interrupt, &pdev->dev);
> +       if (ACPI_FAILURE(acpi_ret)) {
> +               dev_err(&pdev->dev, "unable to parse the _CRS record\n");
> +               return -EINVAL;
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct acpi_device_id ged_acpi_ids[] = {
> +       {"ACPI0013"},
> +       {},
> +};
> +
> +static struct platform_driver ged_driver = {
> +       .probe = ged_probe,
> +       .driver = {
> +               .name = MODULE_NAME,

> +               .owner = THIS_MODULE,

Do you need this one?


> +               .acpi_match_table = ACPI_PTR(ged_acpi_ids),
> +       },
> +};
> +
> +static int __init ged_init(void)
> +{
> +       return platform_driver_register(&ged_driver);
> +}
> +

> +subsys_initcall(ged_init);

Any specific reason to have on that level?

-- 
With Best Regards,
Andy Shevchenko