Re: [PATCH v3 1/3] hw/i2c: add smbus pec utility function

[Philippe Mathieu-Daudé]

On 31/5/23 13:47, Klaus Jensen wrote:
> From: Klaus Jensen <k.jensen@samsung.com>
>
> Add i2c_smbus_pec() to calculate the SMBus Packet Error Code for a
> message.
>
> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> ---
>   hw/i2c/smbus_master.c         | 28 ++++++++++++++++++++++++++++
>   include/hw/i2c/smbus_master.h |  2 ++
>   2 files changed, 30 insertions(+)
>
> diff --git a/hw/i2c/smbus_master.c b/hw/i2c/smbus_master.c
> index 6a53c34e70b7..47f9eb24e033 100644
> --- a/hw/i2c/smbus_master.c
> +++ b/hw/i2c/smbus_master.c
> @@ -15,6 +15,34 @@
>   #include "hw/i2c/i2c.h"
>   #include "hw/i2c/smbus_master.h"
>   
> +static uint8_t crc8(uint16_t data)
> +{
> +#define POLY (0x1070U << 3)

static const unsigned crc8_poly = ..., but why not inline the single use?
  data ^= 0x1070U << 3;
and
  data <<= 1;

> +    int i;
> +
> +    for (i = 0; i < 8; i++) {
> +        if (data & 0x8000) {
> +            data = data ^ POLY;
> +        }
> +
> +        data = data << 1;
> +    }
> +
> +    return (uint8_t)(data >> 8);
> +#undef POLY
> +}

We have "qemu/crc32c.h", maybe we could have a similar crc8.h. Just 
wondering...