Message-ID: <23223841dd58cda0d7fb6fc4e3580b50@codeaurora.org>
Date:   Thu, 20 Oct 2016 17:21:04 -0400
From:   agustinv@...eaurora.org
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Cc:     linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, rjw@...ysocki.net,
        lenb@...nel.org, tglx@...utronix.de, jason@...edaemon.net,
        marc.zyngier@....com, timur@...eaurora.org, cov@...eaurora.org,
        agross@...eaurora.org, harba@...eaurora.org, jcm@...hat.com,
        msalter@...hat.com, mlangsdo@...hat.com, ahs3@...hat.com,
        astone@...hat.com, graeme.gregory@...aro.org, guohanjun@...wei.com,
        charles.garcia-tobin@....com
Subject: Re: [PATCH V5 1/2] ACPI: Add support for ResourceSource/IRQ domain
 mapping

Hey Lorenzo,

On 2016-10-20 12:48, Lorenzo Pieralisi wrote:
> Hi Agustin,
> 
> On Tue, Oct 18, 2016 at 01:41:48PM -0400, Agustin Vega-Frias wrote:
>> This allows irqchip drivers to associate an ACPI DSDT device to
>> an IRQ domain and provides support for using the ResourceSource
>> in Extended IRQ Resources to find the domain and map the IRQs
>> specified on that domain.
>> 
>> Signed-off-by: Agustin Vega-Frias <agustinv@...eaurora.org>
>> ---
>>  drivers/acpi/Makefile             |   1 +
>>  drivers/acpi/irqdomain.c          | 141 
>> ++++++++++++++++++++++++++++++++++++++
>>  drivers/acpi/resource.c           |  21 +++---
>>  include/asm-generic/vmlinux.lds.h |   1 +
>>  include/linux/acpi.h              |  71 +++++++++++++++++++
>>  include/linux/irqchip.h           |  17 ++++-
>>  6 files changed, 240 insertions(+), 12 deletions(-)
>>  create mode 100644 drivers/acpi/irqdomain.c
>> 
>> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
>> index 9ed0878..880401b 100644
>> --- a/drivers/acpi/Makefile
>> +++ b/drivers/acpi/Makefile
>> @@ -57,6 +57,7 @@ acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
>>  acpi-y				+= acpi_lpat.o
>>  acpi-$(CONFIG_ACPI_GENERIC_GSI) += gsi.o
>>  acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
>> +acpi-$(CONFIG_IRQ_DOMAIN)	+= irqdomain.o
>> 
>>  # These are (potentially) separate modules
>> 
>> diff --git a/drivers/acpi/irqdomain.c b/drivers/acpi/irqdomain.c
>> new file mode 100644
>> index 0000000..c53b9f4
>> --- /dev/null
>> +++ b/drivers/acpi/irqdomain.c
>> @@ -0,0 +1,141 @@
>> +/*
>> + * ACPI ResourceSource/IRQ domain mapping support
>> + *
>> + * 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.
>> + */
>> +#include <linux/acpi.h>
>> +#include <linux/irq.h>
>> +#include <linux/irqdomain.h>
>> +
>> +/**
>> + * acpi_irq_domain_ensure_probed() - Check if the device has 
>> registered
>> + *                                   an IRQ domain and probe as 
>> necessary
>> + *
>> + * @device: Device to check and probe
>> + *
>> + * Returns: 0 on success, -ENODEV otherwise
> 
> This is not correct (ie it depends on what
> 
> struct acpi_dsdt_probe_entry.probe
> 
> returns) and I would like to take this nit as an opportunity
> to take a step back and ask you a question below.
> 

Will fix this as necessary if this approach is pursued.

>> + */
>> +static int acpi_irq_domain_ensure_probed(struct acpi_device *device)
>> +{
>> +	struct acpi_dsdt_probe_entry *entry;
>> +
>> +	if (irq_find_matching_fwnode(&device->fwnode, DOMAIN_BUS_ANY) != 0)
>> +		return 0;
>> +
>> +	for (entry = &__dsdt_acpi_probe_table;
>> +	     entry < &__dsdt_acpi_probe_table_end; entry++)
>> +		if (strcmp(entry->_hid, acpi_device_hid(device)) == 0)
>> +			return entry->probe(device);
> 
> Through this approch we are forcing an irqchip (that by the way it
> has a physical node ACPI companion by being a DSDT device object so it
> could be managed by a platform driver) to be probed. The question is: 
> is
> there a reason (apart from the current ACPI resource parsing API) why
> this can't be implemented through deferred probing and the device
> dependencies framework Rafael is working on:
> 
> http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1246897.html
> 
> The DT layer, through the of_irq_get() API, supports probe deferral
> and what I am asking you is if there is any blocking point (again,
> apart from the current ACPI API) to implement the same mechanism.
> 
> I have not reviewed the previous versions so I am certainly missing
> some of the bits and pieces already discussed, apologies for that.
> 

I need to review the latest version of Rafael's patchset to see if the 
issues
around ACPI IRQ resource conversion are addressed.

The problem we found before was that probe deferral didn't work because
the ACPI core converts all ACPI IRQ resources to Linux resources for 
devices
at the same init level at the same time and that causes the conversion
to fail unless the supplier driver is promoted to an earlier init level.

Thanks,
Agustin

> Thanks,
> Lorenzo
> 
>> +
>> +	return -ENODEV;
>> +}
>> +
>> +/**
>> + * acpi_irq_domain_register_irq() - Register the mapping for an IRQ 
>> produced
>> + *                                  by the given acpi_resource_source 
>> to a
>> + *                                  Linux IRQ number
>> + * @source: IRQ source
>> + * @hwirq: Hardware IRQ number
>> + * @trigger: trigger type of the IRQ number to be mapped
>> + * @polarity: polarity of the IRQ to be mapped
>> + *
>> + * Returns: a valid linux IRQ number on success
>> + *          -ENODEV if the given acpi_resource_source cannot be found
>> + *          -EPROBE_DEFER if the IRQ domain has not been registered
>> + *          -EINVAL for all other errors
>> + */
>> +int acpi_irq_domain_register_irq(const struct acpi_resource_source 
>> *source,
>> +				 u32 hwirq, int trigger, int polarity)
>> +{
>> +	struct irq_fwspec fwspec;
>> +	struct acpi_device *device;
>> +	acpi_handle handle;
>> +	acpi_status status;
>> +	int ret;
>> +
>> +	/* An empty acpi_resource_source means it is a GSI */
>> +	if (!source->string_length)
>> +		return acpi_register_gsi(NULL, hwirq, trigger, polarity);
>> +
>> +	status = acpi_get_handle(NULL, source->string_ptr, &handle);
>> +	if (ACPI_FAILURE(status))
>> +		return -ENODEV;
>> +
>> +	device = acpi_bus_get_acpi_device(handle);
>> +	if (!device)
>> +		return -ENODEV;
>> +
>> +	ret = acpi_irq_domain_ensure_probed(device);
>> +	if (ret)
>> +		goto out_put_device;
>> +
>> +	fwspec.fwnode = &device->fwnode;
>> +	fwspec.param[0] = hwirq;
>> +	fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
>> +	fwspec.param_count = 2;
>> +
>> +	ret = irq_create_fwspec_mapping(&fwspec);
>> +
>> +out_put_device:
>> +	acpi_bus_put_acpi_device(device);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_irq_domain_register_irq);
>> +
>> +/**
>> + * acpi_irq_domain_unregister_irq() - Delete the mapping for an IRQ 
>> produced
>> + *                                    by the given 
>> acpi_resource_source to a
>> + *                                    Linux IRQ number
>> + * @source: IRQ source
>> + * @hwirq: Hardware IRQ number
>> + *
>> + * Returns: 0 on success
>> + *          -ENODEV if the given acpi_resource_source cannot be found
>> + *          -EINVAL for all other errors
>> + */
>> +int acpi_irq_domain_unregister_irq(const struct acpi_resource_source 
>> *source,
>> +				   u32 hwirq)
>> +{
>> +	struct irq_domain *domain;
>> +	struct acpi_device *device;
>> +	acpi_handle handle;
>> +	acpi_status status;
>> +	int ret = 0;
>> +
>> +	if (!source->string_length) {
>> +		acpi_unregister_gsi(hwirq);
>> +		return 0;
>> +	}
>> +
>> +	status = acpi_get_handle(NULL, source->string_ptr, &handle);
>> +	if (ACPI_FAILURE(status))
>> +		return -ENODEV;
>> +
>> +	device = acpi_bus_get_acpi_device(handle);
>> +	if (!device)
>> +		return -ENODEV;
>> +
>> +	domain = irq_find_matching_fwnode(&device->fwnode, DOMAIN_BUS_ANY);
>> +	if (!domain) {
>> +		ret = -EINVAL;
>> +		goto out_put_device;
>> +	}
>> +
>> +	irq_dispose_mapping(irq_find_mapping(domain, hwirq));
>> +
>> +out_put_device:
>> +	acpi_bus_put_acpi_device(device);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_irq_domain_unregister_irq);
>> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
>> index 56241eb..3fb7abf 100644
>> --- a/drivers/acpi/resource.c
>> +++ b/drivers/acpi/resource.c
>> @@ -381,14 +381,15 @@ static void acpi_dev_irqresource_disabled(struct 
>> resource *res, u32 gsi)
>>  	res->flags = IORESOURCE_IRQ | IORESOURCE_DISABLED | 
>> IORESOURCE_UNSET;
>>  }
>> 
>> -static void acpi_dev_get_irqresource(struct resource *res, u32 gsi,
>> +static void acpi_dev_get_irqresource(struct resource *res, u32 hwirq,
>> +				     const struct acpi_resource_source *source,
>>  				     u8 triggering, u8 polarity, u8 shareable,
>>  				     bool legacy)
>>  {
>>  	int irq, p, t;
>> 
>> -	if (!valid_IRQ(gsi)) {
>> -		acpi_dev_irqresource_disabled(res, gsi);
>> +	if ((source->string_length == 0) && !valid_IRQ(hwirq)) {
>> +		acpi_dev_irqresource_disabled(res, hwirq);
>>  		return;
>>  	}
>> 
>> @@ -402,25 +403,25 @@ static void acpi_dev_get_irqresource(struct 
>> resource *res, u32 gsi,
>>  	 * using extended IRQ descriptors we take the IRQ configuration
>>  	 * from _CRS directly.
>>  	 */
>> -	if (legacy && !acpi_get_override_irq(gsi, &t, &p)) {
>> +	if (legacy && !acpi_get_override_irq(hwirq, &t, &p)) {
>>  		u8 trig = t ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
>>  		u8 pol = p ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
>> 
>>  		if (triggering != trig || polarity != pol) {
>> -			pr_warning("ACPI: IRQ %d override to %s, %s\n", gsi,
>> -				   t ? "level" : "edge", p ? "low" : "high");
>> +			pr_warn("ACPI: IRQ %d override to %s, %s\n", hwirq,
>> +				t ? "level" : "edge", p ? "low" : "high");
>>  			triggering = trig;
>>  			polarity = pol;
>>  		}
>>  	}
>> 
>>  	res->flags = acpi_dev_irq_flags(triggering, polarity, shareable);
>> -	irq = acpi_register_gsi(NULL, gsi, triggering, polarity);
>> +	irq = acpi_irq_domain_register_irq(source, hwirq, triggering, 
>> polarity);
>>  	if (irq >= 0) {
>>  		res->start = irq;
>>  		res->end = irq;
>>  	} else {
>> -		acpi_dev_irqresource_disabled(res, gsi);
>> +		acpi_dev_irqresource_disabled(res, hwirq);
>>  	}
>>  }
>> 
>> @@ -446,6 +447,7 @@ static void acpi_dev_get_irqresource(struct 
>> resource *res, u32 gsi,
>>  bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int 
>> index,
>>  				 struct resource *res)
>>  {
>> +	const struct acpi_resource_source dummy = { 0, 0, NULL };
>>  	struct acpi_resource_irq *irq;
>>  	struct acpi_resource_extended_irq *ext_irq;
>> 
>> @@ -460,7 +462,7 @@ bool acpi_dev_resource_interrupt(struct 
>> acpi_resource *ares, int index,
>>  			acpi_dev_irqresource_disabled(res, 0);
>>  			return false;
>>  		}
>> -		acpi_dev_get_irqresource(res, irq->interrupts[index],
>> +		acpi_dev_get_irqresource(res, irq->interrupts[index], &dummy,
>>  					 irq->triggering, irq->polarity,
>>  					 irq->sharable, true);
>>  		break;
>> @@ -471,6 +473,7 @@ bool acpi_dev_resource_interrupt(struct 
>> acpi_resource *ares, int index,
>>  			return false;
>>  		}
>>  		acpi_dev_get_irqresource(res, ext_irq->interrupts[index],
>> +					 &ext_irq->resource_source,
>>  					 ext_irq->triggering, ext_irq->polarity,
>>  					 ext_irq->sharable, false);
>>  		break;
>> diff --git a/include/asm-generic/vmlinux.lds.h 
>> b/include/asm-generic/vmlinux.lds.h
>> index 3074796..f808afdc 100644
>> --- a/include/asm-generic/vmlinux.lds.h
>> +++ b/include/asm-generic/vmlinux.lds.h
>> @@ -563,6 +563,7 @@
>>  	IRQCHIP_OF_MATCH_TABLE()					\
>>  	ACPI_PROBE_TABLE(irqchip)					\
>>  	ACPI_PROBE_TABLE(clksrc)					\
>> +	ACPI_PROBE_TABLE(dsdt)						\
>>  	EARLYCON_TABLE()
>> 
>>  #define INIT_TEXT							\
>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>> index ddbeda6..bb1a838 100644
>> --- a/include/linux/acpi.h
>> +++ b/include/linux/acpi.h
>> @@ -26,6 +26,7 @@
>>  #include <linux/resource_ext.h>
>>  #include <linux/device.h>
>>  #include <linux/property.h>
>> +#include <linux/irqdomain.h>
>> 
>>  #ifndef _LINUX
>>  #define _LINUX
>> @@ -321,6 +322,31 @@ void acpi_set_irq_model(enum acpi_irq_model_id 
>> model,
>>   */
>>  void acpi_unregister_gsi (u32 gsi);
>> 
>> +#ifdef CONFIG_IRQ_DOMAIN
>> +
>> +int acpi_irq_domain_register_irq(const struct acpi_resource_source 
>> *source,
>> +				 u32 hwirq, int trigger, int polarity);
>> +int acpi_irq_domain_unregister_irq(const struct acpi_resource_source 
>> *source,
>> +				   u32 hwirq);
>> +
>> +#else
>> +
>> +static inline int acpi_irq_domain_register_irq(
>> +	const struct acpi_resource_source *source, u32 hwirq, int trigger,
>> +	int polarity)
>> +{
>> +	return acpi_register_gsi(NULL, hwirq, trigger, polarity);
>> +}
>> +
>> +static inline int acpi_irq_domain_unregister_irq(
>> +	const struct acpi_resource_source *source,  u32 hwirq)
>> +{
>> +	acpi_unregister_gsi(hwirq);
>> +	return 0;
>> +}
>> +
>> +#endif /* CONFIG_IRQ_DOMAIN */
>> +
>>  struct pci_dev;
>> 
>>  int acpi_pci_irq_enable (struct pci_dev *dev);
>> @@ -1024,6 +1050,34 @@ struct acpi_probe_entry {
>>  					  (&ACPI_PROBE_TABLE_END(t) -	\
>>  					   &ACPI_PROBE_TABLE(t)));	\
>>  	})
>> +
>> +/* Length of Hardware ID field in DSDT entries as per ACPI spec */
>> +#define ACPI_HID_LEN 9
>> +
>> +typedef int (*acpi_dsdt_handler)(struct acpi_device *);
>> +
>> +/**
>> + * struct acpi_probe_dsdt_entry - boot-time probing entry for DSDT 
>> devices
>> + * @hid:		_HID of the device
>> + * @fn:		Callback to the driver being probed
>> + * @driver_data:	Sideband data provided back to the driver
>> + */
>> +struct acpi_dsdt_probe_entry {
>> +	__u8 _hid[ACPI_HID_LEN];
>> +	acpi_dsdt_handler probe;
>> +};
>> +
>> +#define ACPI_DECLARE_DSDT_PROBE_ENTRY(name, hid, fn)			\
>> +	static const struct acpi_dsdt_probe_entry __acpi_probe_##name	\
>> +		__used __section(__dsdt_acpi_probe_table) =		\
>> +		{							\
>> +			._hid = hid,					\
>> +			.probe = fn,					\
>> +		}
>> +
>> +extern struct acpi_dsdt_probe_entry __dsdt_acpi_probe_table;
>> +extern struct acpi_dsdt_probe_entry __dsdt_acpi_probe_table_end;
>> +
>>  #else
>>  static inline int acpi_dev_get_property(struct acpi_device *adev,
>>  					const char *name, acpi_object_type type,
>> @@ -1101,8 +1155,25 @@ static inline struct fwnode_handle 
>> *acpi_get_next_subnode(struct device *dev,
>>  		     (void *) data }
>> 
>>  #define acpi_probe_device_table(t)	({ int __r = 0; __r;})
>> +
>> +#define ACPI_DECLARE_DSDT_PROBE_ENTRY(name, hid, fn)			\
>> +	static const void *__acpi_probe_##name[]			\
>> +		__attribute__((unused))				\
>> +		 = { (void *) hid,					\
>> +		     (void *) fn }
>> +
>>  #endif
>> 
>> +#define MADT_IRQCHIP_ACPI_DECLARE(name, subtable, validate, data, 
>> fn)	\
>> +	ACPI_DECLARE_PROBE_ENTRY(irqchip, name, ACPI_SIG_MADT,		\
>> +				 subtable, validate, data, fn)
>> +
>> +#define DSDT_IRQCHIP_ACPI_DECLARE(name, hid, fn)	\
>> +	ACPI_DECLARE_DSDT_PROBE_ENTRY(name, hid, fn)
>> +
>> +#define __IRQCHIP_ACPI_DECLARE(_a1, _a2, _a3, _a4, _a5, type, ...)	\
>> +	type##_IRQCHIP_ACPI_DECLARE
>> +
>>  #ifdef CONFIG_ACPI_TABLE_UPGRADE
>>  void acpi_table_upgrade(void);
>>  #else
>> diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
>> index 89c34b2..c2d0c12 100644
>> --- a/include/linux/irqchip.h
>> +++ b/include/linux/irqchip.h
>> @@ -29,6 +29,10 @@
>>  /*
>>   * This macro must be used by the different irqchip drivers to 
>> declare
>>   * the association between their version and their initialization 
>> function.
>> + * Two syntaxes are supported depending on the table where the 
>> irqchip device
>> + * is declared:
>> + *
>> + * - MADT irqchip syntax, which requires the following five 
>> arguments:
>>   *
>>   * @name: name that must be unique accross all IRQCHIP_ACPI_DECLARE 
>> of the
>>   * same file.
>> @@ -37,10 +41,17 @@
>>   *            Can be NULL.
>>   * @data: data to be checked by the validate function.
>>   * @fn: initialization function
>> + *
>> + * - DSDT irqchip syntax, which requires the following three 
>> arguments:
>> + *
>> + * @name: name that must be unique across all IRQCHIP_ACPI_DECLARE of 
>> the
>> + * same file.
>> + * @hid: _HID of the DSDT device
>> + * @fn: initialization function
>>   */
>> -#define IRQCHIP_ACPI_DECLARE(name, subtable, validate, data, fn)	\
>> -	ACPI_DECLARE_PROBE_ENTRY(irqchip, name, ACPI_SIG_MADT, 		\
>> -				 subtable, validate, data, fn)
>> +
>> +#define IRQCHIP_ACPI_DECLARE(...)					\
>> +	__IRQCHIP_ACPI_DECLARE(__VA_ARGS__, MADT, _unused, 
>> DSDT)(__VA_ARGS__)
>> 
>>  #ifdef CONFIG_IRQCHIP
>>  void irqchip_init(void);
>> --
>> Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm 
>> Technologies, Inc.
>> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a 
>> Linux Foundation Collaborative Project.
>> 
>> --
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>> 

-- 
Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a 
Linux Foundation Collaborative Project.

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