Re: [PATCH V5 7/7] acpi, gicv3, its: Use MADT ITS subtable to do PCI/MSI domain initialization.

[Tomasz Nowicki <tn@semihalf.com>]

On 04.06.2016 14:07, Marc Zyngier wrote:
> On Tue, 31 May 2016 13:19:44 +0200
> Tomasz Nowicki <tn@semihalf.com> wrote:
>
>> Let ACPI build ITS PCI MSI domain. ACPI is responsible for retrieving
>> inner domain token and passing it on to its_pci_msi_init_one generic
>> init call.
>>
>> We have now full PCI MSI domain stack, thus we can enable ITS initialization
>> from GICv3 core driver for ACPI scenario.
>>
>> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
>> ---
>>   drivers/irqchip/irq-gic-v3-its-pci-msi.c | 42 +++++++++++++++++++++++++++++++-
>>   drivers/irqchip/irq-gic-v3.c             |  3 +--
>>   2 files changed, 42 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
>> index 23679ae..985f5d9 100644
>> --- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
>> +++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
>> @@ -15,6 +15,7 @@
>>    * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>>    */
>>
>> +#include <linux/iort.h>
>>   #include <linux/msi.h>
>>   #include <linux/of.h>
>>   #include <linux/of_irq.h>
>> @@ -144,10 +145,49 @@ static int __init its_pci_of_msi_init(void)
>>   	return 0;
>>   }
>>
>> +#ifdef CONFIG_ACPI
>> +
>> +static int __init
>> +its_pci_msi_parse_madt(struct acpi_subtable_header *header,
>> +		       const unsigned long end)
>> +{
>> +	struct acpi_madt_generic_translator *its_entry;
>> +	struct fwnode_handle *dom_handle;
>> +	char node_name[6 + 16 + 1]; // ITS identification name
>
> Jeezus... Where is that coming from? Is that the size of "ITS@0x"+16
> hex digits and a final NUL? For the sake of keeping things
> maintainable/readable, please use kasprintf/kfree.

kasprintf/kfree will be used here.

>
>> +
>> +	its_entry = (struct acpi_madt_generic_translator *)header;
>> +	snprintf(node_name, 23, "ITS@0x%lx", (long)its_entry->base_address);
>> +	dom_handle = iort_its_find_domain_token(its_entry->translation_id);
>> +	if (!dom_handle) {
>> +		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
>> +		return 0;
>
> return 0? not even a slap on the wrist? Hum...
>
>> +	}
>> +
>> +	if (its_pci_msi_init_one(dom_handle, node_name))
>> +		return 0;
>
> Same here.

Yeah, decent error code are needed here.

>
>> +
>> +	pr_info("PCI/MSI: %s domain created\n", node_name);
>> +	return 0;
>> +}
>> +
>> +static int __init its_pci_acpi_msi_init(void)
>> +{
>> +	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
>> +			      its_pci_msi_parse_madt, 0);
>> +	return 0;
>> +}
>> +#else
>> +inline static int __init its_pci_acpi_msi_init(void)
>
> static only.

OK

>
>> +{
>> +	return 0;
>> +}
>> +#endif
>> +
>>   static int __init its_pci_msi_init(void)
>>   {
>>   	its_pci_of_msi_init();
>> +	its_pci_acpi_msi_init();
>> +
>>   	return 0;
>>   }
>> -
>>   early_initcall(its_pci_msi_init);
>> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
>> index cee8296..41c1cda 100644
>> --- a/drivers/irqchip/irq-gic-v3.c
>> +++ b/drivers/irqchip/irq-gic-v3.c
>> @@ -951,8 +951,7 @@ static int __init gic_init_bases(void __iomem *dist_base,
>>
>>   	set_handle_irq(gic_handle_irq);
>>
>> -	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis() &&
>> -	    to_of_node(handle)) /* Temp hack to prevent ITS init for ACPI */
>> +	if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
>>   		its_init(handle, &gic_data.rdists, gic_data.domain);
>>
>>   	gic_smp_init();
>

Thanks for review.

Tomasz