Re: [RFC part2 PATCH 9/9] ACPI / GIC: Initialize GIC using the information in MADT

Rob Herring
2013-12-03T17:09:47Z

On Tue, Dec 3, 2013 at 10:39 AM, Hanjun Guo <hanjun.guo@linaro.org> wrote:
> In MADT table, there are GIC cpu interface base address and
> GIC distributor base address, use them to convert GIC to ACPI.
>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
> arch/arm64/kernel/irq.c | 5 ++++
> drivers/acpi/plat/arm-core.c | 66 ++++++++++++++++++++++++++++++++++++------
> include/linux/acpi.h | 6 ++++
> 3 files changed, 68 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/irq.c b/arch/arm64/kernel/irq.c
> index 473e5db..a9e68bf 100644
> --- a/arch/arm64/kernel/irq.c
> +++ b/arch/arm64/kernel/irq.c
> @@ -25,6 +25,7 @@
> #include <linux/irq.h>
> #include <linux/smp.h>
> #include <linux/init.h>
> +#include <linux/acpi.h>
> #include <linux/irqchip.h>
> #include <linux/seq_file.h>
> #include <linux/ratelimit.h>
> @@ -78,6 +79,10 @@ void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
> void __init init_IRQ(void)
> {
> irqchip_init();
> +
> + if (!handle_arch_irq)
> + acpi_gic_init();
> +
> if (!handle_arch_irq)
> panic("No interrupt controller found.");
> }
> diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c
> index 17c99e1..509b847 100644
> --- a/drivers/acpi/plat/arm-core.c
> +++ b/drivers/acpi/plat/arm-core.c
> @@ -29,6 +29,7 @@
> #include <linux/module.h>
> #include <linux/irq.h>
> #include <linux/irqdomain.h>
> +#include <linux/irqchip/arm-gic.h>
> #include <linux/slab.h>
> #include <linux/bootmem.h>
> #include <linux/ioport.h>
> @@ -211,11 +212,21 @@ acpi_parse_gic(struct acpi_subtable_header *header, const unsigned long end)
> return 0;
> }
>
> +#ifdef CONFIG_ARM_GIC

Perhaps this should go in the GIC code? This is more of a general
question of where init/probing code goes. For DT, this as been with
the driver code.

> +/*
> + * Hard code here, we can not get memory size from MADT (but FDT does),
> + * this size is described in ARMv8 foudation model's User Guide
> + */
> +#define GIC_DISTRIBUTOR_MEMORY_SIZE (SZ_8K)
> +#define GIC_CPU_INTERFACE_MEMORY_SIZE (SZ_4K)

You have the sizes swapped. The cpu interface has the DIR register at 0x1000.

> +
> static int __init
> acpi_parse_gic_distributor(struct acpi_subtable_header *header,
> const unsigned long end)
> {
> struct acpi_madt_generic_distributor *distributor = NULL;
> + void __iomem *dist_base = NULL;
> + void __iomem *cpu_base = NULL;

Initialization here is unnecessary.

>
> distributor = (struct acpi_madt_generic_distributor *)header;
>
> @@ -224,8 +235,43 @@ acpi_parse_gic_distributor(struct acpi_subtable_header *header,
>
> acpi_table_print_madt_entry(header);
>
> + /* GIC is initialised after page_init(), no need for early_ioremap */
> + dist_base = ioremap(distributor->base_address,
> + GIC_CPU_INTERFACE_MEMORY_SIZE);

Should be GIC_DISTRIBUTOR_MEMORY_SIZE.

> + if (!dist_base) {
> + pr_warn(PREFIX "unable to map gic dist registers\n");
> + return -ENOMEM;
> + }
> +
> + /*
> + * acpi_lapic_addr is stored in acpi_parse_madt(),
> + * so we can use it here for GIC init
> + */
> + if (acpi_lapic_addr) {

Checking this first would be cleaner.

> + iounmap(dist_base);
> + pr_warn(PREFIX "Invalid GIC cpu interface base address\n");
> + return -EINVAL;
> + }
> +
> + cpu_base = ioremap(acpi_lapic_addr, GIC_CPU_INTERFACE_MEMORY_SIZE);

How are gic's with different cpu address per core going to be handled?

> + if (!cpu_base) {
> + iounmap(dist_base);
> + pr_warn(PREFIX "unable to map gic cpu registers\n");

All the printks are a bit verbose for my tastes. I think a single
error print would suffice.

> + return -ENOMEM;
> + }
> +
> + gic_init(distributor->gic_id, -1, dist_base, cpu_base);
> +
> return 0;
> }
> +#else
> +static int __init
> +acpi_parse_gic_distributor(struct acpi_subtable_header *header,
> + const unsigned long end)
> +{
> + return -ENODEV;
> +}
> +#endif /* CONFIG_ARM_GIC */

A "if (!IS_ENABLED(CONFIG_ARM_GIC)) return;" in the above function
would eliminate this ifdef.

>
> /*
> * Parse GIC cpu interface related entries in MADT
> @@ -234,7 +280,7 @@ acpi_parse_gic_distributor(struct acpi_subtable_header *header,
> static int __init acpi_parse_madt_gic_entries(void)
> {
> int count;
> -
> +

Unnecessary whitespace change.

> /*
> * do a partial walk of MADT to determine how many CPUs
> * we have including disabled CPUs
> @@ -468,19 +514,21 @@ static void __init acpi_process_madt(void)
> * Parse MADT GIC cpu interface entries
> */
> error = acpi_parse_madt_gic_entries();
> - if (!error) {
> - /*
> - * Parse MADT GIC distributor entries
> - */
> - acpi_parse_madt_gic_distributor_entries();
> - }
> + if (!error)
> + pr_info("Using ACPI for processor (GIC) configuration information\n");
> }
>
> - pr_info("Using ACPI for processor (GIC) configuration information\n");
> -
> return;
> }
>
> +int __init acpi_gic_init(void)
> +{
> + /*
> + * Parse MADT GIC distributor entries
> + */
> + return acpi_parse_madt_gic_distributor_entries();
> +}
> +
> /*
> * acpi_boot_table_init() and acpi_boot_init()
> * called from setup_arch(), always.
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index edd5806..58a4bf4 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -112,6 +112,7 @@ char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
> void __acpi_unmap_table(char *map, unsigned long size);
> int early_acpi_boot_init(void);
> int acpi_boot_init (void);
> +int acpi_gic_init(void);
> void acpi_boot_table_init (void);
> int acpi_mps_check (void);
> int acpi_numa_init (void);
> @@ -444,6 +445,11 @@ static inline int acpi_boot_init(void)
> return 0;
> }
>
> +static inline int acpi_gic_init(void)
> +{
> + return -ENODEV;
> +}
> +
> static inline void acpi_boot_table_init(void)
> {
> return;
> --
> 1.7.9.5
>
>
> _______________________________________________
> linaro-kernel mailing list
> linaro-kernel@lists.linaro.org
> http://lists.linaro.org/mailman/listinfo/linaro-kernel