Subject: [PATCH v8 15/21] ARM64 / ACPI: Introduce ACPI_IRQ_MODEL_GIC and register device's gsi

From: [email-masked] (Hanjun Guo)
Date: Mon, 09 Feb 2015 14:53:31 +0800

On 2015?02?09? 14:34, Will Deacon wrote:
> On Mon, Feb 02, 2015 at 12:45:43PM +0000, Hanjun Guo wrote:
>> Introduce ACPI_IRQ_MODEL_GIC which is needed for ARM64 as GIC is
>> used, and then register device's gsi with the core IRQ subsystem.
>>
>> acpi_register_gsi() is similar to DT based irq_of_parse_and_map(),
>> since gsi is unique in the system, so use hwirq number directly
>> for the mapping.
>>
>> We are going to implement stacked domains when GICv2m, GICv3, ITS
>> support are added.
>>
>> CC: Marc Zyngier <[email-masked]>
>> Originally-by: Amit Daniel Kachhap <[email-masked]>
>> Tested-by: Suravee Suthikulpanit <[email-masked]>
>> Tested-by: Yijing Wang <[email-masked]>
>> Tested-by: Mark Langsdorf <[email-masked]>
>> Tested-by: Jon Masters <[email-masked]>
>> Tested-by: Timur Tabi <[email-masked]>
>> Signed-off-by: Hanjun Guo <[email-masked]>
>> ---
>>   arch/arm64/kernel/acpi.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   drivers/acpi/bus.c       |  3 ++
>>   include/linux/acpi.h     |  1 +
>>   3 files changed, 77 insertions(+)
>>
>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>> index f80caef..f86a982 100644
>> --- a/arch/arm64/kernel/acpi.c
>> +++ b/arch/arm64/kernel/acpi.c
>> @@ -38,6 +38,12 @@ EXPORT_SYMBOL(acpi_pci_disabled);
>>   static int enabled_cpus;	/* Processors (GICC) with enabled flag in MADT */
>>
>>   /*
>> + * Since we're on ARM, the default interrupt routing model
>> + * clearly has to be GIC.
>> + */
>> +enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_GIC;
>> +
>> +/*
>>    * __acpi_map_table() will be called before page_init(), so early_ioremap()
>>    * or early_memremap() should be called here to for ACPI table mapping.
>>    */
>> @@ -185,6 +191,73 @@ void __init acpi_init_cpus(void)
>>   	pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
>>   }
>>
>> +int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
>> +{
>> +	*irq = irq_find_mapping(NULL, gsi);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>> +
>> +/*
>> + * success: return IRQ number (>0)
>> + * failure: return =< 0
>> + */
>> +int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
>> +{
>> +	unsigned int irq;
>> +	unsigned int irq_type;
>> +
>> +	/*
>> +	 * ACPI have no bindings to indicate SPI or PPI, so we
>> +	 * use different mappings from DT in ACPI.
>> +	 *
>> +	 * For FDT
>> +	 * PPI interrupt: in the range [0, 15];
>> +	 * SPI interrupt: in the range [0, 987];
>> +	 *
>> +	 * For ACPI, GSI should be unique so using
>> +	 * the hwirq directly for the mapping:
>> +	 * PPI interrupt: in the range [16, 31];
>> +	 * SPI interrupt: in the range [32, 1019];
>> +	 */
>> +
>> +	if (trigger == ACPI_EDGE_SENSITIVE &&
>> +				polarity == ACPI_ACTIVE_LOW)
>> +		irq_type = IRQ_TYPE_EDGE_FALLING;
>> +	else if (trigger == ACPI_EDGE_SENSITIVE &&
>> +				polarity == ACPI_ACTIVE_HIGH)
>> +		irq_type = IRQ_TYPE_EDGE_RISING;
>> +	else if (trigger == ACPI_LEVEL_SENSITIVE &&
>> +				polarity == ACPI_ACTIVE_LOW)
>> +		irq_type = IRQ_TYPE_LEVEL_LOW;
>> +	else if (trigger == ACPI_LEVEL_SENSITIVE &&
>> +				polarity == ACPI_ACTIVE_HIGH)
>> +		irq_type = IRQ_TYPE_LEVEL_HIGH;
>> +	else
>> +		irq_type = IRQ_TYPE_NONE;
>> +
>> +	/*
>> +	 * Since only one GIC is supported in ACPI 5.0, we can
>> +	 * create mapping refer to the default domain
>> +	 */
>> +	irq = irq_create_mapping(NULL, gsi);
>> +	if (!irq)
>> +		return irq;
>> +
>> +	/* Set irq type if specified and different than the current one */
>> +	if (irq_type != IRQ_TYPE_NONE &&
>> +		irq_type != irq_get_trigger_type(irq))
>> +		irq_set_irq_type(irq, irq_type);
>> +	return irq;
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_register_gsi);
>> +
>> +void acpi_unregister_gsi(u32 gsi)
>> +{
>> +}
>> +EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
>> +
>>   static int __init acpi_parse_fadt(struct acpi_table_header *table)
>>   {
>>   	struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
>
> Does this code *have* to sit under arch/arm64? I can't see anything
> architecture-specific about it and the bulk of the functions map directly
> onto irq domain callbacks. I know that the answer is probably "we can fix
> that in the future", but it doesn't seem like a huge amount of effort to
> get the right abstractions in place from the beginning so that we don't
> have to churn this stuff later on.

Do you mean move acpi_register_gsi()/acpi_unregister_gsi() to irqdomain
related file?

Since x86 and IA64 have their arch specific acpi_register_gsi()
/acpi_unregister_gsi(), we will got compile errors on x86 and IA64
platforms.

Thanks
Hanjun