Re: [PATCH V5 5/7] irqchip, gicv3, its: Probe ITS in the ACPI way.

[Marc Zyngier]

On Tue, 31 May 2016 13:19:42 +0200
Tomasz Nowicki <tn@xxxxxxxxxxxx> wrote:

> ITS is prepared for being initialized different than DT,
> therefore we can initialize it in ACPI way. We collect register base
> address from MADT table and pass mandatory info to firmware-agnostic
> ITS init call.
> 
> Note that we are using here IORT lib to register ITS domain which
> then can be found and used on to build another PCI MSI domain
> in hierarchical stack domain.
> 
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> ---
>  drivers/irqchip/Kconfig          |  1 +
>  drivers/irqchip/irq-gic-v3-its.c | 60 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 61 insertions(+)
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index fa33c50..c6e652f 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -32,6 +32,7 @@ config ARM_GIC_V3
>  config ARM_GIC_V3_ITS
>  	bool
>  	select PCI_MSI_IRQ_DOMAIN
> +	select IORT_TABLE if ACPI
>  
>  config ARM_NVIC
>  	bool
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 6a97ee5..c8f36a5 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -15,10 +15,13 @@
>   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/acpi.h>
>  #include <linux/bitmap.h>
>  #include <linux/cpu.h>
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>
> +#include <linux/irqdomain.h>
> +#include <linux/iort.h>
>  #include <linux/log2.h>
>  #include <linux/mm.h>
>  #include <linux/msi.h>
> @@ -1312,6 +1315,11 @@ static int its_irq_gic_domain_alloc(struct irq_domain *domain,
>  		fwspec.param[0] = GIC_IRQ_TYPE_LPI;
>  		fwspec.param[1] = hwirq;
>  		fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
> +	} else if (is_fwnode_irqchip(domain->parent->fwnode)) {
> +		fwspec.fwnode = domain->parent->fwnode;
> +		fwspec.param_count = 2;
> +		fwspec.param[0] = hwirq;
> +		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
>  	} else {
>  		return -EINVAL;
>  	}
> @@ -1645,6 +1653,56 @@ static int __init its_of_probe(struct device_node *node)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_ACPI
> +
> +#define ACPI_GICV3_ITS_MEM_SIZE (2 * SZ_64K)

SZ_128k?

> +
> +static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
> +					  const unsigned long end)
> +{
> +	struct acpi_madt_generic_translator *its_entry;
> +	struct fwnode_handle *dom_handle;
> +	struct resource res;
> +	int err;
> +
> +	its_entry = (struct acpi_madt_generic_translator *)header;
> +	res.start = its_entry->base_address;
> +	res.end = its_entry->base_address + ACPI_GICV3_ITS_MEM_SIZE - 1;
> +
> +	dom_handle = irq_domain_alloc_fwnode((void *)its_entry->base_address);
> +	if (!dom_handle) {
> +		pr_err("ITS@%pa: Unable to allocate GICv3 ITS domain token\n",
> +		       &res.start);
> +		return -ENOMEM;
> +	}
> +
> +	err = iort_register_domain_token(its_entry->translation_id, dom_handle);
> +	if (err) {
> +		pr_err("ITS@%pa: Unable to register GICv3 ITS domain token (ITS ID %d) to IORT\n",
> +		       &res.start, its_entry->translation_id);
> +		goto dom_err;
> +	}
> +
> +	err = its_probe_one(&res, dom_handle);
> +	if (!err)
> +		return 0;
> +
> +	iort_deregister_domain_token(its_entry->translation_id);
> +dom_err:
> +	irq_domain_free_fwnode(dom_handle);
> +	return err;
> +}
> +
> +void __init its_acpi_probe(void)

Should be static.

> +{
> +	if (acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
> +				  gic_acpi_parse_madt_its, 0) <= 0)
> +		pr_info("No valid GIC ITS entries exist\n");

We already have a message further down, no need to shout twice.

> +}
> +#else
> +static inline void __init its_acpi_probe(struct irq_domain *parent_domain) { }

Drop the inline, the compiler can figure out that by itself.

> +#endif
> +
>  int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
>  		    struct irq_domain *parent_domain)
>  {
> @@ -1654,6 +1712,8 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
>  	of_node = to_of_node(handle);
>  	if (of_node)
>  		its_of_probe(of_node);
> +	else
> +		its_acpi_probe();
>  
>  	if (list_empty(&its_nodes)) {
>  		pr_warn("ITS: No ITS available, not enabling LPIs\n");


Thanks,

	M.
-- 
Jazz is not dead. It just smells funny.