netdev - Re: [PATCH net-next 02/15] ice: cache NVM module bank information

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Date:   Fri, 29 Jan 2021 16:01:01 -0500
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Tony Nguyen <anthony.l.nguyen@...el.com>
Cc:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Jacob Keller <jacob.e.keller@...el.com>,
        Network Development <netdev@...r.kernel.org>,
        sassmann@...hat.com, Tony Brelinski <tonyx.brelinski@...el.com>
Subject: Re: [PATCH net-next 02/15] ice: cache NVM module bank information

On Thu, Jan 28, 2021 at 7:46 PM Tony Nguyen <anthony.l.nguyen@...el.com> wrote:
>
> From: Jacob Keller <jacob.e.keller@...el.com>
>
> The ice flash contains two copies of each of the NVM, Option ROM, and
> Netlist modules. Each bank has a pointer word and a size word. In order
> to correctly read from the active flash bank, the driver must calculate
> the offset manually.
>
> During NVM initialization, read the Shadow RAM control word and
> determine which bank is active for each NVM module. Additionally, cache
> the size and pointer values for use in calculating the correct offset.
>
> Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
> Tested-by: Tony Brelinski <tonyx.brelinski@...el.com>
> Signed-off-by: Tony Nguyen <anthony.l.nguyen@...el.com>
> ---
>  drivers/net/ethernet/intel/ice/ice_nvm.c  | 151 ++++++++++++++++++++++
>  drivers/net/ethernet/intel/ice/ice_type.h |  37 ++++++
>  2 files changed, 188 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_nvm.c b/drivers/net/ethernet/intel/ice/ice_nvm.c
> index b0f0b4fc266b..308344045397 100644
> --- a/drivers/net/ethernet/intel/ice/ice_nvm.c
> +++ b/drivers/net/ethernet/intel/ice/ice_nvm.c
> @@ -603,6 +603,151 @@ static enum ice_status ice_discover_flash_size(struct ice_hw *hw)
>         return status;
>  }
>
> +/**
> + * ice_read_sr_pointer - Read the value of a Shadow RAM pointer word
> + * @hw: pointer to the HW structure
> + * @offset: the word offset of the Shadow RAM word to read
> + * @pointer: pointer value read from Shadow RAM
> + *
> + * Read the given Shadow RAM word, and convert it to a pointer value specified
> + * in bytes. This function assumes the specified offset is a valid pointer
> + * word.
> + *
> + * Each pointer word specifies whether it is stored in word size or 4KB
> + * sector size by using the highest bit. The reported pointer value will be in
> + * bytes, intended for flat NVM reads.
> + */
> +static enum ice_status
> +ice_read_sr_pointer(struct ice_hw *hw, u16 offset, u32 *pointer)
> +{
> +       enum ice_status status;
> +       u16 value;
> +
> +       status = ice_read_sr_word(hw, offset, &value);
> +       if (status)
> +               return status;
> +
> +       /* Determine if the pointer is in 4KB or word units */
> +       if (value & ICE_SR_NVM_PTR_4KB_UNITS)
> +               *pointer = (value & ~ICE_SR_NVM_PTR_4KB_UNITS) * 4 * 1024;
> +       else
> +               *pointer = value * 2;

Should this be << 2, for 4B words?