Re: [PATCH 3/3] hw/misc: Implement mailbox properties for customer OTP and device specific private keys

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 10/5/24 16:10, Rayhan Faizel wrote:
> Four mailbox properties are implemented as follows:
> 1. Customer OTP: GET_CUSTOMER_OTP and SET_CUSTOMER_OTP
> 2. Device-specific private key: GET_PRIVATE_KEY and
> SET_PRIVATE_KEY.
> 
> The customer OTP is located in the rows 36-43. The device-specific private key
> is located in the rows 56-63.

Better to define these instead of using magic values in the code,
i.e.:

   #define OTP_PRIVATE_KEY_OFFSET 56
   #define OTP_PRIVATE_KEY_LENGTH 8

> The customer OTP can be locked with the magic numbers 0xffffffff 0xaffe0000
> when running the SET_CUSTOMER_OTP mailbox command.
> 
> P.S I am not sure if the magic lock combo applies to the private key as well.
> 
> Signed-off-by: Rayhan Faizel <rayhan.faizel@gmail.com>
> ---
>   hw/arm/bcm2835_peripherals.c         |  2 +
>   hw/misc/bcm2835_property.c           | 71 ++++++++++++++++++++++++++++
>   include/hw/arm/raspberrypi-fw-defs.h |  2 +
>   include/hw/misc/bcm2835_property.h   |  2 +
>   4 files changed, 77 insertions(+)


> +        /* Device-specific private key */
> +
> +        case RPI_FWREQ_GET_PRIVATE_KEY:
> +            start_num = ldl_le_phys(&s->dma_as, value + 12);
> +            number = ldl_le_phys(&s->dma_as, value + 16);
> +
> +            resplen = 8 + 4 * number;
> +
> +            for (n = start_num; n < start_num + number && n < 8; n++) {
> +                stl_le_phys(&s->dma_as,
> +                            value + 20 + ((n - start_num) << 2),
> +                            bcm2835_otp_read_row(s->otp, 56 + n));
> +            }
> +            break;
> +        case RPI_FWREQ_SET_PRIVATE_KEY:
> +            start_num = ldl_le_phys(&s->dma_as, value + 12);
> +            number = ldl_le_phys(&s->dma_as, value + 16);
> +
> +            resplen = 4;
> +
> +            for (n = start_num; n < start_num + number && n < 8; n++) {
> +                otp_row = ldl_le_phys(&s->dma_as,
> +                                      value + 20 + ((n - start_num) << 2));
> +                bcm2835_otp_write_row(s->otp, 56 + n, otp_row);
> +            }
> +            break;