Re: [PATCH v4 07/10] irqchip / GICv3 / ACPI: Add GICR support via GICC structures

[Marc Zyngier <marc.zyngier@arm.com>]

On 29/07/15 11:08, Hanjun Guo wrote:
> On systems supporting GICv3 and above, in MADT GICC structures, the
> field of GICR Base Address holds the 64-bit physical address of the
> associated Redistributor if the GIC Redistributors are not in the
> always-on power domain, so instead of init GICR regions via GIC
> redistributor structure(s), init it with GICR base address in GICC
> structures in that case.
> 
> As GICR base in MADT GICC is another way to indicate the GIC version
> is 3 or 4, add its support to find out the GIC versions.
> 
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
>  drivers/irqchip/irq-gic-acpi.c       |  35 ++++++-
>  drivers/irqchip/irq-gic-v3.c         | 197 +++++++++++++++++++++++++++++++----
>  include/linux/irqchip/arm-gic-acpi.h |   2 +
>  3 files changed, 215 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-acpi.c b/drivers/irqchip/irq-gic-acpi.c
> index 95454e3..3e5c8f4 100644
> --- a/drivers/irqchip/irq-gic-acpi.c
> +++ b/drivers/irqchip/irq-gic-acpi.c
> @@ -21,6 +21,11 @@ static u8 gic_version __initdata = ACPI_MADT_GIC_VERSION_NONE;
> 
>  static phys_addr_t dist_phy_base __initdata;
> 
> +u8 __init acpi_gic_version(void)
> +{
> +       return gic_version;
> +}
> +
>  static int __init
>  acpi_gic_parse_distributor(struct acpi_subtable_header *header,
>                            const unsigned long end)
> @@ -38,6 +43,27 @@ acpi_gic_parse_distributor(struct acpi_subtable_header *header,
>  }
> 
>  static int __init
> +gic_acpi_parse_madt_gicc(struct acpi_subtable_header *header,
> +                        const unsigned long end)
> +{
> +       struct acpi_madt_generic_interrupt *gicc;
> +
> +       gicc = (struct acpi_madt_generic_interrupt *)header;
> +
> +       if (BAD_MADT_GICC_ENTRY(gicc, end))
> +               return -EINVAL;
> +
> +       /*
> +        * If GICC is enabled but has no valid gicr base address, then it
> +        * means GICR base is not presented via GICC
> +        */
> +       if ((gicc->flags & ACPI_MADT_ENABLED) && !gicc->gicr_base_address)
> +               return -ENODEV;
> +
> +       return 0;
> +}
> +
> +static int __init
>  match_gic_redist(struct acpi_subtable_header *header, const unsigned long end)
>  {
>         return 0;
> @@ -51,7 +77,14 @@ static bool __init acpi_gic_redist_is_present(void)
>         count  =  acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR,
>                                         match_gic_redist, 0);
> 
> -       /* that's true if we have at least one GIC redistributor entry */
> +       /* has at least one GIC redistributor entry */
> +       if (count > 0)
> +               return true;
> +
> +       /* else try to find GICR base in GICC entries */
> +       count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
> +                                     gic_acpi_parse_madt_gicc, 0);
> +
>         return count > 0;
>  }
> 
> diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> index ebc5604..b72ccbb 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -389,9 +389,8 @@ static void __init gic_dist_init(void)
>                 writeq_relaxed(affinity, base + GICD_IROUTER + i * 8);
>  }
> 
> -static int gic_populate_rdist(void)
> +static int gic_populate_rdist_with_regions(u64 mpidr)
>  {
> -       u64 mpidr = cpu_logical_map(smp_processor_id());
>         u64 typer;
>         u32 aff;
>         int i;
> @@ -439,6 +438,34 @@ static int gic_populate_rdist(void)
>                 } while (!(typer & GICR_TYPER_LAST));
>         }
> 
> +       return -ENODEV;
> +}
> +
> +#ifdef CONFIG_ACPI
> +/*
> + * Populate redist when GIC redistributor address is presented in ACPI
> + * MADT GICC entries
> + */
> +static int gic_populate_rdist_with_gicr_base(u64 mpidr);
> +#else
> +static inline int gic_populate_rdist_with_gicr_base(u64 mpidr)
> +{
> +       return -ENODEV;
> +}
> +#endif
> +
> +static int gic_populate_rdist(void)
> +{
> +       u64 mpidr = cpu_logical_map(smp_processor_id());
> +
> +       if (gic_data.nr_redist_regions) {
> +               if (!gic_populate_rdist_with_regions(mpidr))
> +                       return 0;
> +       } else {
> +               if (!gic_populate_rdist_with_gicr_base(mpidr))
> +                       return 0;
> +       }
> +
>         /* We couldn't even deal with ourselves... */
>         WARN(true, "CPU%d: mpidr %llx has no re-distributor!\n",
>              smp_processor_id(), (unsigned long long)mpidr);
> @@ -900,6 +927,16 @@ IRQCHIP_DECLARE(gic_v3, "arm,gic-v3", gic_of_init);
>  #endif
> 
>  #ifdef CONFIG_ACPI
> +
> +struct acpi_gicc_redist {
> +       struct list_head list;
> +       u64 mpidr;
> +       phys_addr_t phys_base;
> +       void __iomem *redist_base;
> +};
> +
> +static LIST_HEAD(redist_list);
> +
>  static struct redist_region *redist_regs __initdata;
>  static u32 nr_redist_regions __initdata;
>  static phys_addr_t dist_phys_base __initdata;
> @@ -932,6 +969,17 @@ gic_acpi_register_redist(u64 phys_base, u64 size)
>         return 0;
>  }
> 
> +static void __init
> +gic_acpi_release_redist_regions(void)
> +{
> +       int i;
> +
> +       for (i = 0; i < nr_redist_regions; i++)
> +               if (redist_regs[i].redist_base)
> +                       iounmap(redist_regs[i].redist_base);
> +       kfree(redist_regs);
> +}
> +
>  static int __init
>  gic_acpi_parse_madt_redist(struct acpi_subtable_header *header,
>                         const unsigned long end)
> @@ -989,9 +1037,130 @@ static int gic_acpi_gsi_desc_populate(struct acpi_gsi_descriptor *data,
>  }
> 
>  static int __init
> +gic_acpi_add_gicc_redist(phys_addr_t phys_base, u64 mpidr)
> +{
> +       struct acpi_gicc_redist *redist;
> +
> +       redist = kzalloc(sizeof(*redist), GFP_KERNEL);
> +       if (!redist)
> +               return -ENOMEM;
> +
> +       redist->mpidr = mpidr;
> +       redist->phys_base = phys_base;
> +
> +       if (acpi_gic_version() == ACPI_MADT_GIC_VERSION_V3)
> +               /* RD_base + SGI_base */
> +               redist->redist_base = ioremap(phys_base, 2 * SZ_64K);
> +       else
> +               /*
> +                * RD_base + SGI_base + VLPI_base,
> +                * we don't map reserved page as it's buggy to access it
> +                */
> +               redist->redist_base = ioremap(phys_base, 3 * SZ_64K);
> +
> +       if (!redist->redist_base) {
> +               kfree(redist);
> +               return -ENOMEM;
> +       }
> +
> +       list_add(&redist->list, &redist_list);
> +       return 0;
> +}
> +
> +static void __init
> +gic_acpi_release_gicc_redist(void)
> +{
> +       struct acpi_gicc_redist *redist, *t;
> +
> +       list_for_each_entry_safe(redist, t, &redist_list, list) {
> +               list_del(&redist->list);
> +               iounmap(redist->redist_base);
> +               kfree(redist);
> +       }
> +}
> +
> +static int __init
> +gic_acpi_parse_madt_gicc(struct acpi_subtable_header *header,
> +                        const unsigned long end)
> +{
> +       struct acpi_madt_generic_interrupt *gicc;
> +
> +       gicc = (struct acpi_madt_generic_interrupt *)header;
> +
> +       if (BAD_MADT_GICC_ENTRY(gicc, end))
> +               return -EINVAL;
> +
> +       /*
> +        * just quietly ingore the disabled CPU(s) and continue
> +        * to find the enabled one(s), if we return error here,
> +        * the scanning will be stopped.
> +        */
> +       if (!(gicc->flags & ACPI_MADT_ENABLED))
> +               return 0;
> +
> +       return gic_acpi_add_gicc_redist(gicc->gicr_base_address,
> +                                       gicc->arm_mpidr);
> +}
> +
> +static int gic_populate_rdist_with_gicr_base(u64 mpidr)
> +{
> +       struct acpi_gicc_redist *redist;
> +       void __iomem *ptr;
> +       u32 reg;
> +
> +       list_for_each_entry(redist, &redist_list, list) {
> +               if (redist->mpidr != mpidr)
> +                       continue;
> +
> +               ptr = redist->redist_base;
> +               reg = readl_relaxed(ptr + GICR_PIDR2) & GIC_PIDR2_ARCH_MASK;
> +               if (reg != GIC_PIDR2_ARCH_GICv3 && reg != GIC_PIDR2_ARCH_GICv4) {
> +                       pr_warn("No redistributor present @%p\n", ptr);
> +                       return -ENODEV;
> +               }
> +
> +               gic_data_rdist_rd_base() = ptr;
> +               gic_data_rdist()->phys_base = redist->phys_base;
> +               pr_info("CPU%d: found redistributor %llx phys base:%pa\n",
> +                       smp_processor_id(),
> +                       (unsigned long long)mpidr,
> +                       &gic_data_rdist()->phys_base);
> +               return 0;
> +       }
> +
> +       return -ENODEV;
> +}
> +
> +static int __init collect_gicr_base(struct acpi_table_header *table)
> +{
> +       int count;
> +
> +       /* Collect redistributor base addresses in GICR entries */
> +       count = acpi_parse_entries(ACPI_SIG_MADT,
> +                       sizeof(struct acpi_table_madt),
> +                       gic_acpi_parse_madt_redist, table,
> +                       ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR, 0);
> +       if (count > 0)
> +               return 0;
> +
> +       pr_info("No valid GICR entries exist, try GICC entries\n");
> +
> +       /* Collect redistributor base addresses in GICC entries */
> +       count = acpi_parse_entries(ACPI_SIG_MADT,
> +                       sizeof(struct acpi_table_madt),
> +                       gic_acpi_parse_madt_gicc, table,
> +                       ACPI_MADT_TYPE_GENERIC_INTERRUPT, 0);
> +       if (count > 0 && !list_empty(&redist_list))
> +               return 0;
> +
> +       pr_info("No valid GICC entries exist for GICR base\n");
> +       return -ENODEV;
> +}
> +
> +static int __init
>  gic_acpi_init(struct acpi_table_header *table)
>  {
> -       int count, i, err = 0;
> +       int count, err = 0;
>         void __iomem *dist_base;
> 
>         /* Get distributor base address */
> @@ -1020,30 +1189,22 @@ gic_acpi_init(struct acpi_table_header *table)
>         }
> 
>         /* Collect redistributor base addresses */
> -       count = acpi_parse_entries(ACPI_SIG_MADT,
> -                       sizeof(struct acpi_table_madt),
> -                       gic_acpi_parse_madt_redist, table,
> -                       ACPI_MADT_TYPE_GENERIC_REDISTRIBUTOR, 0);
> -       if (count <= 0) {
> -               pr_info("No valid GICR entries exist\n");
> -               err = -EINVAL;
> -               goto out_redist_unmap;
> -       }
> +       if (collect_gicr_base(table))
> +               goto out_release_redist;
> 
>         err = gic_init_bases(dist_base, redist_regs, nr_redist_regions, 0,
>                              (void *)ACPI_IRQ_MODEL_GIC);
>         if (err)
> -               goto out_redist_unmap;
> +               goto out_release_redist;
> 
>         acpi_set_irq_model(ACPI_IRQ_MODEL_GIC, ACPI_IRQ_MODEL_GIC,
>                            gic_acpi_gsi_desc_populate);
>         return 0;
> 
> -out_redist_unmap:
> -       for (i = 0; i < nr_redist_regions; i++)
> -               if (redist_regs[i].redist_base)
> -                       iounmap(redist_regs[i].redist_base);
> -       kfree(redist_regs);
> +out_release_redist:
> +       gic_acpi_release_redist_regions();
> +       if (!list_empty(&redist_list))
> +               gic_acpi_release_gicc_redist();
>  out_dist_unmap:
>         iounmap(dist_base);
>         return err;
> diff --git a/include/linux/irqchip/arm-gic-acpi.h b/include/linux/irqchip/arm-gic-acpi.h
> index 56cd82c..0d43f515 100644
> --- a/include/linux/irqchip/arm-gic-acpi.h
> +++ b/include/linux/irqchip/arm-gic-acpi.h
> @@ -21,5 +21,7 @@
>  #define ACPI_GIC_CPU_IF_MEM_SIZE       (SZ_8K)
>  #define ACPI_GICV3_DIST_MEM_SIZE       (SZ_64K)
> 
> +u8 acpi_gic_version(void);
> +
>  #endif /* CONFIG_ACPI */
>  #endif /* ARM_GIC_ACPI_H_ */
> --
> 1.9.1
> 

This looks absolutely horrid. Why don't you simply populate one region
per redistributor, add a flag to struct redist_region so we know not to
check for GICR_TYPER_LAST but to move on to the next region instead?

We already have all the flexibility you require, please don't invent
stuff that is already there.

Thanks,

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