Re: [PATCH] net: wan: fsl_ucc_hdlc: allocate enough MURAM for HDLC PRAM

[Matevz Langus]

Yes, this patch is for all devices with QE / QuiccEngine.
In reality also for CPM based devices like MPC8260 even MPC860 on all cases 256 Bytes should be reserved for PRAM.


> On 3 Aug 2026, at 16:18, Christophe Leroy (CS GROUP) <chleroy@xxxxxxxxxx> wrote:
> 
> 
> 
> Le 03/08/2026 à 14:58, Matevz Langus a écrit :
>> [Vous ne recevez pas souvent de courriers de matevz.langus@xxxxxxxx. D?couvrez pourquoi ceci est important ? https://aka.ms/LearnAboutSenderIdentification ]
>> More MURAM needs to be allocated than just sizeof(struct ucc_hdlc_param).
>> We have noticed MURAM corruption outside of struct ucc_hdlc_param. It was
>> caused by QE UCC HDLC microcode. NXP QEIWRM.pdf Rev.9 05/2018 chapter
>> 14.2.2.1 HDLC Parameter RAM says 0x6c-0x100 Reserved.
>> Even looking into QE UCC HDLC microcode source code reveals it actually
>> stores data beyond 0x6c.
>> Tested on LS1043A, T1040 and MPC8569 boards running UCC in HDLC mode on kernel 6.12.
>> Signed-off-by: Matevz Langus <matevz.langus@xxxxxxxx>
> 
> Same in MPC8323 reference manual, it is marked "reserved" until offset 0x100
> 
> Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@xxxxxxxxxx>
> 
> 
> 
>> ---
>>  drivers/net/wan/fsl_ucc_hdlc.h | 1 +
>>  1 file changed, 1 insertion(+)
>> diff --git a/drivers/net/wan/fsl_ucc_hdlc.h b/drivers/net/wan/fsl_ucc_hdlc.h
>> index 71d5ad0a7b98..e170d3ac9116 100644
>> --- a/drivers/net/wan/fsl_ucc_hdlc.h
>> +++ b/drivers/net/wan/fsl_ucc_hdlc.h
>> @@ -60,6 +60,7 @@ struct ucc_hdlc_param {
>>   __be16 haddr4;
>>   __be16 ts_tmp;
>>   __be16 tmp_mb;
>> + __u8 reserved[148];
>>  };
>>    struct ucc_hdlc_private {
>> --  2.34.1
>