Re: [PATCH 6/8] irqchip/gic-v3-its: add ability to resend MAPC on resume

[dbasehore .]

On Sun, Jan 14, 2018 at 2:56 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
> On Fri, 12 Jan 2018 21:24:20 +0000,
> Derek Basehore wrote:
>>
>> This adds a DT-binding to resend the MAPC command to an ITS node on
>
> This isn't a DT binding. That's the driver implementation. The binding
> is what you put in Documentation/device-tree...
>
>> resume. If the ITS is powered down during suspend and the collections
>> are not backed by memory, the ITS will lose that state. This just sets
>> up the known state for the collections after the ITS is restored.
>>
>> Change-Id: I4fe7f3f16500e1d3b14368262f03a43509c0049b
>> Signed-off-by: Derek Basehore <dbasehore@xxxxxxxxxxxx>
>> ---
>>  drivers/irqchip/irq-gic-v3-its.c | 85 ++++++++++++++++++++++------------------
>>  1 file changed, 47 insertions(+), 38 deletions(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
>> index 5cb808e3d0bf..6d2688a2ee67 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -46,6 +46,7 @@
>>  #define ITS_FLAGS_CMDQ_NEEDS_FLUSHING                (1ULL << 0)
>>  #define ITS_FLAGS_WORKAROUND_CAVIUM_22375    (1ULL << 1)
>>  #define ITS_FLAGS_WORKAROUND_CAVIUM_23144    (1ULL << 2)
>> +#define ITS_FLAGS_RESEND_MAPC_ON_RESUME              (1ULL << 3)
>>
>>  #define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING  (1 << 0)
>>
>> @@ -1949,52 +1950,53 @@ static void its_cpu_init_lpis(void)
>>       dsb(sy);
>>  }
>>
>> -static void its_cpu_init_collection(void)
>> +static void its_cpu_init_collection(struct its_node *its)
>>  {
>> -     struct its_node *its;
>> -     int cpu;
>> -
>> -     spin_lock(&its_lock);
>> -     cpu = smp_processor_id();
>> -
>> -     list_for_each_entry(its, &its_nodes, entry) {
>> -             u64 target;
>> +     int cpu = smp_processor_id();
>> +     u64 target;
>>
>> -             /* avoid cross node collections and its mapping */
>> -             if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) {
>> -                     struct device_node *cpu_node;
>> +     /* avoid cross node collections and its mapping */
>> +     if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) {
>> +             struct device_node *cpu_node;
>>
>> -                     cpu_node = of_get_cpu_node(cpu, NULL);
>> -                     if (its->numa_node != NUMA_NO_NODE &&
>> -                             its->numa_node != of_node_to_nid(cpu_node))
>> -                             continue;
>> -             }
>> +             cpu_node = of_get_cpu_node(cpu, NULL);
>> +             if (its->numa_node != NUMA_NO_NODE &&
>> +                     its->numa_node != of_node_to_nid(cpu_node))
>> +                     return;
>> +     }
>>
>> +     /*
>> +      * We now have to bind each collection to its target
>> +      * redistributor.
>> +      */
>> +     if (gic_read_typer(its->base + GITS_TYPER) & GITS_TYPER_PTA) {
>>               /*
>> -              * We now have to bind each collection to its target
>> +              * This ITS wants the physical address of the
>>                * redistributor.
>>                */
>> -             if (gic_read_typer(its->base + GITS_TYPER) & GITS_TYPER_PTA) {
>> -                     /*
>> -                      * This ITS wants the physical address of the
>> -                      * redistributor.
>> -                      */
>> -                     target = gic_data_rdist()->phys_base;
>> -             } else {
>> -                     /*
>> -                      * This ITS wants a linear CPU number.
>> -                      */
>> -                     target = gic_read_typer(gic_data_rdist_rd_base() + GICR_TYPER);
>> -                     target = GICR_TYPER_CPU_NUMBER(target) << 16;
>> -             }
>> +             target = gic_data_rdist()->phys_base;
>> +     } else {
>> +             /* This ITS wants a linear CPU number. */
>> +             target = gic_read_typer(gic_data_rdist_rd_base() + GICR_TYPER);
>> +             target = GICR_TYPER_CPU_NUMBER(target) << 16;
>> +     }
>>
>> -             /* Perform collection mapping */
>> -             its->collections[cpu].target_address = target;
>> -             its->collections[cpu].col_id = cpu;
>> +     /* Perform collection mapping */
>> +     its->collections[cpu].target_address = target;
>> +     its->collections[cpu].col_id = cpu;
>>
>> -             its_send_mapc(its, &its->collections[cpu], 1);
>> -             its_send_invall(its, &its->collections[cpu]);
>> -     }
>> +     its_send_mapc(its, &its->collections[cpu], 1);
>> +     its_send_invall(its, &its->collections[cpu]);
>> +}
>> +
>> +static void its_cpu_init_collections(void)
>> +{
>> +     struct its_node *its;
>> +
>> +     spin_lock(&its_lock);
>> +
>> +     list_for_each_entry(its, &its_nodes, entry)
>> +             its_cpu_init_collection(its);
>>
>>       spin_unlock(&its_lock);
>>  }
>> @@ -3089,6 +3091,9 @@ void its_restore_enable(void)
>>                       its_write_baser(its, &its->tables[i],
>>                                       its->tables[i].val);
>>               writel_relaxed(ctx->ctlr, base + GITS_CTLR);
>> +
>> +             if (its->flags & ITS_FLAGS_RESEND_MAPC_ON_RESUME)
>> +                     its_cpu_init_collection(its);
>>       }
>>       spin_unlock(&its_lock);
>>  }
>> @@ -3312,6 +3317,10 @@ static int __init its_probe_one(struct resource *res,
>>               ctlr |= GITS_CTLR_ImDe;
>>       writel_relaxed(ctlr, its->base + GITS_CTLR);
>>
>> +     if (fwnode_property_present(its->fwnode_handle,
>> +                                 "resend-mapc-on-resume"))
>> +             its->flags |= ITS_FLAGS_RESEND_MAPC_ON_RESUME;
>
> This function is firmware agnostic, and I really don't want to make
> this thing a general purpose property.
>
> Please set this as a quirk when you detect some particular combination
> of HW and firmware (in your case, GIC500 + this property). And again,
> the property name is totally backward. IT should be something like
> "collection-state-lost-on-suspend".

So name it ITS_FLAGS_WORKAROUND_GIC500_MAPC or should there be a quirk
number for it?

>
>> +
>>       err = its_init_domain(handle, its);
>>       if (err)
>>               goto out_free_tables;
>> @@ -3347,7 +3356,7 @@ int its_cpu_init(void)
>>                       return -ENXIO;
>>               }
>>               its_cpu_init_lpis();
>> -             its_cpu_init_collection();
>> +             its_cpu_init_collections();
>>       }
>>
>>       return 0;
>> --
>> 2.16.0.rc1.238.g530d649a79-goog
>>
>
> Thanks,
>
>         M.