Re: [PATCH v11 2/4] hw/arm/boot: arm_load_kernel implemented as a machine init done notifier

["Alex Bennée" <alex.bennee@linaro.org>]

Eric Auger <eric.auger@linaro.org> writes:

> Device tree nodes for the platform bus and its children dynamic sysbus
> devices are added in a machine init done notifier. To load the dtb once,
> after those latter nodes are built and before ROM freeze, the actual
> arm_load_kernel existing code is moved into a notifier notify function,
> arm_load_kernel_notify. arm_load_kernel now only registers the
> corresponding notifier.
>
> Machine files that do not support platform bus stay unchanged. Machine
> files willing to support dynamic sysbus devices must call arm_load_kernel
> before sysbus-fdt arm_register_platform_bus_fdt_creator to make sure
> dynamic sysbus device nodes are integrated in the dtb.
>
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> Reviewed-by: Shannon Zhao <zhaoshenglong@huawei.com>
> Reviewed-by: Alexander Graf <agraf@suse.de>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

>
> ---
>
> v8 -> v9:
> - fix compilation with arm-linux-user
> - reorder fields in ArmLoadKernelNotifier and use DO_UPCAST
>
> v7 -> v8:
> - Add Reviewed-by from Alex & Shannon
> - rebase on 2.2.0
>
> v6: creation of this patch file
> ---
>  hw/arm/boot.c        | 14 +++++++++++++-
>  include/hw/arm/arm.h | 28 ++++++++++++++++++++++++++++
>  2 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> index a48d1b2..5ac5479 100644
> --- a/hw/arm/boot.c
> +++ b/hw/arm/boot.c
> @@ -555,7 +555,7 @@ static void load_image_to_fw_cfg(FWCfgState *fw_cfg, uint16_t size_key,
>      fw_cfg_add_bytes(fw_cfg, data_key, data, size);
>  }
>  
> -void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
> +static void arm_load_kernel_notify(Notifier *notifier, void *data)
>  {
>      CPUState *cs;
>      int kernel_size;
> @@ -566,6 +566,11 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
>      hwaddr entry, kernel_load_offset;
>      int big_endian;
>      static const ARMInsnFixup *primary_loader;
> +    ArmLoadKernelNotifier *n = DO_UPCAST(ArmLoadKernelNotifier,
> +                                         notifier, notifier);
> +    ARMCPU *cpu = n->cpu;
> +    struct arm_boot_info *info =
> +        container_of(n, struct arm_boot_info, load_kernel_notifier);
>  
>      /* CPU objects (unlike devices) are not automatically reset on system
>       * reset, so we must always register a handler to do so. If we're
> @@ -773,3 +778,10 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
>          ARM_CPU(cs)->env.boot_info = info;
>      }
>  }
> +
> +void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
> +{
> +    info->load_kernel_notifier.cpu = cpu;
> +    info->load_kernel_notifier.notifier.notify = arm_load_kernel_notify;
> +    qemu_add_machine_init_done_notifier(&info->load_kernel_notifier.notifier);
> +}
> diff --git a/include/hw/arm/arm.h b/include/hw/arm/arm.h
> index 5c940eb..760804c 100644
> --- a/include/hw/arm/arm.h
> +++ b/include/hw/arm/arm.h
> @@ -13,11 +13,21 @@
>  
>  #include "exec/memory.h"
>  #include "hw/irq.h"
> +#include "qemu/notify.h"
>  
>  /* armv7m.c */
>  qemu_irq *armv7m_init(MemoryRegion *system_memory, int mem_size, int num_irq,
>                        const char *kernel_filename, const char *cpu_model);
>  
> +/*
> + * struct used as a parameter of the arm_load_kernel machine init
> + * done notifier
> + */
> +typedef struct {
> +    Notifier notifier; /* actual notifier */
> +    ARMCPU *cpu; /* handle to the first cpu object */
> +} ArmLoadKernelNotifier;
> +
>  /* arm_boot.c */
>  struct arm_boot_info {
>      uint64_t ram_size;
> @@ -64,6 +74,8 @@ struct arm_boot_info {
>       * the user it should implement this hook.
>       */
>      void (*modify_dtb)(const struct arm_boot_info *info, void *fdt);
> +    /* machine init done notifier executing arm_load_dtb */
> +    ArmLoadKernelNotifier load_kernel_notifier;
>      /* Used internally by arm_boot.c */
>      int is_linux;
>      hwaddr initrd_start;
> @@ -75,6 +87,22 @@ struct arm_boot_info {
>       */
>      bool firmware_loaded;
>  };
> +
> +/**
> + * arm_load_kernel - Loads memory with everything needed to boot
> + *
> + * @cpu: handle to the first CPU object
> + * @info: handle to the boot info struct
> + * Registers a machine init done notifier that copies to memory
> + * everything needed to boot, depending on machine and user options:
> + * kernel image, boot loaders, initrd, dtb. Also registers the CPU
> + * reset handler.
> + *
> + * In case the machine file supports the platform bus device and its
> + * dynamically instantiable sysbus devices, this function must be called
> + * before sysbus-fdt arm_register_platform_bus_fdt_creator. Indeed the
> + * machine init done notifiers are called in registration reverse order.
> + */
>  void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info);
>  
>  /* Multiplication factor to convert from system clock ticks to qemu timer

-- 
Alex Bennée
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