On Mon, Jun 23, 2025 at 06:01:16PM +0200, Jacek Kowalski wrote:
> As described by Vitaly Lifshits:
>
> > Starting from Tiger Lake, LAN NVM is locked for writes by SW, so the
> > driver cannot perform checksum validation and correction. This means
> > that all NVM images must leave the factory with correct checksum and
> > checksum valid bit set.
>
> Unfortunately some systems have left the factory with an empty checksum.
> NVM is not modifiable on this platform, hence ignore checksum 0xFFFF on
> Tiger Lake systems to work around this.
>
> Signed-off-by: Jacek Kowalski <[email protected]>
> Fixes: 4051f68318ca9 ("e1000e: Do not take care about recovery NVM checksum")
> Cc: [email protected]
> ---
> v2: new check to fix yet another checksum issue
> drivers/net/ethernet/intel/e1000e/defines.h | 1 +
> drivers/net/ethernet/intel/e1000e/nvm.c | 5 +++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/defines.h
> b/drivers/net/ethernet/intel/e1000e/defines.h
> index 8294a7c4f122..01696eb8dace 100644
> --- a/drivers/net/ethernet/intel/e1000e/defines.h
> +++ b/drivers/net/ethernet/intel/e1000e/defines.h
> @@ -637,6 +637,7 @@
>
> /* For checksumming, the sum of all words in the NVM should equal 0xBABA. */
> #define NVM_SUM 0xBABA
> +#define NVM_SUM_FACTORY_DEFAULT 0xFFFF
>
> /* PBA (printed board assembly) number words */
> #define NVM_PBA_OFFSET_0 8
> diff --git a/drivers/net/ethernet/intel/e1000e/nvm.c
> b/drivers/net/ethernet/intel/e1000e/nvm.c
> index e609f4df86f4..37cbf9236d84 100644
> --- a/drivers/net/ethernet/intel/e1000e/nvm.c
> +++ b/drivers/net/ethernet/intel/e1000e/nvm.c
> @@ -558,6 +558,11 @@ s32 e1000e_validate_nvm_checksum_generic(struct e1000_hw
> *hw)
> checksum += nvm_data;
> }
>
> + if (hw->mac.type == e1000_pch_tgp && checksum ==
> (u16)NVM_SUM_FACTORY_DEFAULT) {
I see that a similar cast is applied to NVM_SUM. But why?
If it's not necessary then I would advocate dropping it.
> + e_dbg("Factory-default NVM Checksum on TGP platform -
> ignoring\n");
> + return 0;
> + }
> +
> if (checksum != (u16)NVM_SUM) {
> e_dbg("NVM Checksum Invalid\n");
> return -E1000_ERR_NVM;
> --
> 2.47.2
>
>
