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SubjectRe: [PATCH v4 4/5] irqchip/gic-v3-its: add ability to resend MAPC on resume
On Tue, Feb 6, 2018 at 8:40 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> On 03/02/18 01:24, Derek Basehore wrote:
>> This adds functionality to resend the MAPC command to an ITS node on
>> 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.
>>
>> This feature is enabled via Kconfig and a device tree entry.
>>
>> Signed-off-by: Derek Basehore <dbasehore@chromium.org>
>> ---
>> arch/arm64/Kconfig | 10 ++++
>> drivers/irqchip/irq-gic-v3-its.c | 101 ++++++++++++++++++++++++---------------
>> 2 files changed, 73 insertions(+), 38 deletions(-)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 53612879fe56..f38f1a7b4266 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -571,6 +571,16 @@ config HISILICON_ERRATUM_161600802
>>
>> If unsure, say Y.
>>
>> +config ARM_GIC500_COLLECTIONS_RESET
>> + bool "GIC-500 Collections: Workaround for GIC-500 Collections on suspend reset"
>> + default y
>> + help
>> + The GIC-500 can store Collections state internally for the ITS. If
>> + the ITS is reset on suspend (ie from power getting disabled), the
>> + collections need to be reconfigured on resume.
>> +
>> + If unsure, say Y.
>> +
>> config QCOM_FALKOR_ERRATUM_E1041
>> bool "Falkor E1041: Speculative instruction fetches might cause errant memory access"
>> default y
>> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
>> index e13515cdb68f..63764efa4dcc 100644
>> --- a/drivers/irqchip/irq-gic-v3-its.c
>> +++ b/drivers/irqchip/irq-gic-v3-its.c
>> @@ -48,6 +48,7 @@
>> #define ITS_FLAGS_WORKAROUND_CAVIUM_22375 (1ULL << 1)
>> #define ITS_FLAGS_WORKAROUND_CAVIUM_23144 (1ULL << 2)
>> #define ITS_FLAGS_SAVE_SUSPEND_STATE (1ULL << 3)
>> +#define ITS_FLAGS_WORKAROUND_GIC500_MAPC (1ULL << 4)
>>
>> #define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING (1 << 0)
>>
>> @@ -1950,52 +1951,53 @@ 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);
>> }
>> @@ -2997,6 +2999,18 @@ static bool __maybe_unused its_enable_quirk_hip07_161600802(void *data)
>> return true;
>> }
>>
>> +static bool __maybe_unused its_enable_quirk_gic500_collections(void *data)
>> +{
>> + struct its_node *its = data;
>> +
>> + if (fwnode_property_present(its->fwnode_handle,
>> + "collections-reset-on-suspend")) {
>> + its->flags |= ITS_FLAGS_WORKAROUND_GIC500_MAPC;
>> + return true;
>> + }
>> + return false;
>> +}
>> +
>> static const struct gic_quirk its_quirks[] = {
>> #ifdef CONFIG_CAVIUM_ERRATUM_22375
>> {
>> @@ -3042,6 +3056,14 @@ static const struct gic_quirk its_quirks[] = {
>> .mask = 0xffffffff,
>> .init = its_enable_quirk_hip07_161600802,
>> },
>> +#endif
>> +#ifdef CONFIG_ARM_GIC500_COLLECTIONS_RESET
>> + {
>> + .desc = "ITS: GIC-500 Collections Reset on Resume",
>> + .iidr = 0x00000000,
>> + .mask = 0xff000000,
>> + .init = its_enable_quirk_gic500_collections,
>> + },
>> #endif
>> {
>> }
>> @@ -3129,6 +3151,9 @@ static void its_restore_enable(void)
>> }
>> writel_relaxed(ctx->ctlr, base + GITS_CTLR);
>> }
>> +
>> + if (its->flags & ITS_FLAGS_WORKAROUND_GIC500_MAPC)
>> + its_cpu_init_collection(its);
>> }
>> spin_unlock(&its_lock);
>> }
>> @@ -3395,7 +3420,7 @@ int its_cpu_init(void)
>> return -ENXIO;
>> }
>> its_cpu_init_lpis();
>> - its_cpu_init_collection();
>> + its_cpu_init_collections();
>> }
>>
>> return 0;
>>
>
> I wonder if a better way to implement this is simply to bite the bullet
> and implement the letter of the architecture:
>
> If GITS_TYPER.HCC != 0, then collections 0...HCC-1 are held in HW, and
> the rest in a SW-managed table. That would allow us to deal with this
> without a quirk (which I asked for initially, apologies for changing my
> mind).
>
> We still the same DT flag to tell us we're going to be reset on suspend.

So this would just be under the generic reset-on-suspend flag that I
added in patch 2/5?

>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...

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