Re: [PATCH v4 10/20] hw/arm/allwinner-h3: add Boot ROM support - Philippe Mathieu-Daudé

From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: Niek Linnenbank <nieklinnenbank@gmail.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, jasowang@redhat.com,
	b.galvani@gmail.com, qemu-arm@nongnu.org, imammedo@redhat.com,
	alex.bennee@linaro.org
Subject: Re: [PATCH v4 10/20] hw/arm/allwinner-h3: add Boot ROM support
Date: Sun, 19 Jan 2020 20:14:18 +0100	[thread overview]
Message-ID: <1179d8a3-e61d-ad1f-bde9-3a73fde766a8@redhat.com> (raw)
In-Reply-To: <20200119005102.3847-11-nieklinnenbank@gmail.com>

On 1/19/20 1:50 AM, Niek Linnenbank wrote:
> A real Allwinner H3 SoC contains a Boot ROM which is the
> first code that runs right after the SoC is powered on.
> The Boot ROM is responsible for loading user code (e.g. a bootloader)
> from any of the supported external devices and writing the downloaded
> code to internal SRAM. After loading the SoC begins executing the code
> written to SRAM.
> 
> This commits adds emulation of the Boot ROM firmware setup functionality
> by loading user code from SD card in the A1 SRAM. While the A1 SRAM is
> 64KiB, we limit the size to 32KiB because the real H3 Boot ROM also rejects
> sizes larger than 32KiB. For reference, this behaviour is documented
> by the Linux Sunxi project wiki at:
> 
>    https://linux-sunxi.org/BROM#U-Boot_SPL_limitations
> 
> Signed-off-by: Niek Linnenbank <nieklinnenbank@gmail.com>
> ---
>   include/hw/arm/allwinner-h3.h | 23 +++++++++++++++++++++++
>   hw/arm/allwinner-h3.c         | 28 ++++++++++++++++++++++++++++
>   hw/arm/orangepi.c             |  5 +++++
>   3 files changed, 56 insertions(+)
> 
> diff --git a/include/hw/arm/allwinner-h3.h b/include/hw/arm/allwinner-h3.h
> index f9b9a02373..f5e16266cd 100644
> --- a/include/hw/arm/allwinner-h3.h
> +++ b/include/hw/arm/allwinner-h3.h
> @@ -46,6 +46,7 @@
>   #include "hw/sd/allwinner-sdhost.h"
>   #include "hw/net/allwinner-sun8i-emac.h"
>   #include "target/arm/cpu.h"
> +#include "sysemu/block-backend.h"
>   
>   /**
>    * Allwinner H3 device list
> @@ -129,4 +130,26 @@ typedef struct AwH3State {
>       MemoryRegion sram_c;
>   } AwH3State;
>   
> +/**
> + * Emulate Boot ROM firmware setup functionality.
> + *
> + * A real Allwinner H3 SoC contains a Boot ROM
> + * which is the first code that runs right after
> + * the SoC is powered on. The Boot ROM is responsible
> + * for loading user code (e.g. a bootloader) from any
> + * of the supported external devices and writing the
> + * downloaded code to internal SRAM. After loading the SoC
> + * begins executing the code written to SRAM.
> + *
> + * This function emulates the Boot ROM by copying 32 KiB
> + * of data from the given block device and writes it to
> + * the start of the first internal SRAM memory.
> + *
> + * @s: Allwinner H3 state object pointer
> + * @blk: Block backend device object pointer
> + * @errp: Error object pointer for raising errors
> + */
> +void allwinner_h3_bootrom_setup(AwH3State *s, BlockBackend *blk,
> +                                Error **errp);
> +
>   #endif /* HW_ARM_ALLWINNER_H3_H */
> diff --git a/hw/arm/allwinner-h3.c b/hw/arm/allwinner-h3.c
> index 1085223812..3d0470825a 100644
> --- a/hw/arm/allwinner-h3.c
> +++ b/hw/arm/allwinner-h3.c
> @@ -29,6 +29,7 @@
>   #include "hw/char/serial.h"
>   #include "hw/misc/unimp.h"
>   #include "hw/usb/hcd-ehci.h"
> +#include "hw/loader.h"
>   #include "sysemu/sysemu.h"
>   #include "hw/arm/allwinner-h3.h"
>   
> @@ -170,6 +171,33 @@ enum {
>       AW_H3_GIC_NUM_SPI       = 128
>   };
>   
> +void allwinner_h3_bootrom_setup(AwH3State *s, BlockBackend *blk, Error **errp)
> +{
> +    uint8_t *buffer;
> +    int64_t rom_size = 32 * KiB;
> +
> +    int64_t blk_size = blk_getlength(blk);
> +    if (blk_size <= 0) {
> +        error_setg(errp, "%s: failed to get BlockBackend size", __func__);
> +        return;
> +    }
> +
> +    if (rom_size > blk_size) {
> +        rom_size = blk_size;

This doesn't seem correct, have you tried to use a 1MB file?

This can't be bigger than the SRAM size, 64KB.

> +    }
> +
> +    buffer = g_new0(uint8_t, rom_size);
> +    if (blk_pread(blk, 8 * KiB, buffer, rom_size) < 0) {
> +        error_setg(errp, "%s: failed to read BlockBackend data", __func__);
> +        return;
> +    }
> +
> +    rom_add_blob("allwinner-h3.bootrom", buffer, rom_size,
> +                  rom_size, s->memmap[AW_H3_SRAM_A1],
> +                  NULL, NULL, NULL, NULL, false);
> +    g_free(buffer);
> +}
> +
>   static void allwinner_h3_init(Object *obj)
>   {
>       AwH3State *s = AW_H3(obj);
> diff --git a/hw/arm/orangepi.c b/hw/arm/orangepi.c
> index 25bf85f8fc..9d4c79885e 100644
> --- a/hw/arm/orangepi.c
> +++ b/hw/arm/orangepi.c
> @@ -95,6 +95,11 @@ static void orangepi_init(MachineState *machine)
>       memory_region_add_subregion(get_system_memory(), s->h3->memmap[AW_H3_SDRAM],
>                                   &s->sdram);
>   
> +    /* Load target kernel or start using BootROM */
> +    if (!machine->kernel_filename && blk_is_available(blk)) {
> +        /* Use Boot ROM to copy data from SD card to SRAM */
> +        allwinner_h3_bootrom_setup(s->h3, blk, &error_fatal);
allwinner_h3_bootrom_setup() doesn't need the errp argument, you can use 
error_fatal directly there.

> +    }
>       orangepi_binfo.loader_start = s->h3->memmap[AW_H3_SDRAM];
>       orangepi_binfo.ram_size = machine->ram_size;
>       arm_load_kernel(ARM_CPU(first_cpu), machine, &orangepi_binfo);
> 