Re: [PATCH] net: ipa: fix some resource limit max values

[Caleb Connolly <caleb.connolly@xxxxxxxxxx>]

On 24/10/2022 20:15, Alex Elder wrote:
> On 10/24/22 11:56 AM, Caleb Connolly wrote:
> > Some resource limits on IPA v3.1 and v3.5.1 have their max values set to
> > 255, this causes a few splats in ipa_reg_encode and prevents it from booting.
> > The limits are all 6 bits wide so adjust the max values to 63.
>
> Thank you for sending this Caleb.
>
> On IPA v3.5.1 (SDM845) I confirm that these resource limit fields are
> 6 bits wide, while the values we assign are in some cases 255, which
> cannot be represented in 6 bits.  Your fix in this case is proper,
> changing the maximum limit from 255 to be 63.  (Just in case, I've
> sent a note to Qualcomm to ask them to confirm this, but I think this
> is fine.)

Great, thanks

> I re-checked the definitions of the MIN_LIMIT and MAX_LIMIT fields
> for IPA v3.1, and it turns out in that case the *register field*
> definitions were wrong.  They should, in fact, be 8 bits wide rather
> than just 6.  So in that case, 255 would be a reasonable limit value.

Heh, well that's fun... Thanks for checking

> Did you observe these splats when doing actual testing on an msm8998
> (which has IPA v3.1)?  Or did you just double-check the code?  I
> looked at the other currently-supported platforms and didn't see
> this sort of problem elsewhere (IPA v4.2, 4.5, 4.9, 4.11).

I found these just by 'grep'ing for "max = 255", none of the other versions had 
that and I didn't see anything obvious at a glance so I expect only these two 
platforms are affected. The same issue has been confirmed on MSM8998: 
https://gitlab.com/msm8998-mainline/linux/-/issues/39

Jami (CC'd) has offered to test the next revision of the fix there so we can be 
sure it works on v3.1 and v3.5.1.
> Could you please send a new version of your patch, which fixes the
> register definition in "ipa_reg-v3.1.c" instead?
>
> It might be best to fix the two issues in separate patches, since
> they will parts pf the code with different development histories.

That makes sense, will do.
> Thanks!
>
>                      -Alex
>
> > Fixes: 1c418c4a929c ("net: ipa: define resource group/type IPA register fields")
> > Signed-off-by: Caleb Connolly <caleb.connolly@xxxxxxxxxx>
> > ---
> >   drivers/net/ipa/data/ipa_data-v3.1.c   | 62 +++++++++++++-------------
> >   drivers/net/ipa/data/ipa_data-v3.5.1.c |  4 +-
> >   2 files changed, 33 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/net/ipa/data/ipa_data-v3.1.c 
> > b/drivers/net/ipa/data/ipa_data-v3.1.c
> > index e0d71f609272..7ff093f982ad 100644
> > --- a/drivers/net/ipa/data/ipa_data-v3.1.c
> > +++ b/drivers/net/ipa/data/ipa_data-v3.1.c
> > @@ -187,53 +187,53 @@ static const struct ipa_gsi_endpoint_data 
> > ipa_gsi_endpoint_data[] = {
> >   static const struct ipa_resource ipa_resource_src[] = {
> >       [IPA_RESOURCE_TYPE_SRC_PKT_CONTEXTS] = {
> >           .limits[IPA_RSRC_GROUP_SRC_UL] = {
> > -            .min = 3,    .max = 255,
> > +            .min = 3,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DL] = {
> > -            .min = 3,    .max = 255,
> > +            .min = 3,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DIAG] = {
> > -            .min = 1,    .max = 255,
> > +            .min = 1,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DMA] = {
> > -            .min = 1,    .max = 255,
> > +            .min = 1,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> > -            .min = 2,    .max = 255,
> > +            .min = 2,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_HDR_SECTORS] = {
> >           .limits[IPA_RSRC_GROUP_SRC_UL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DIAG] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DMA] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_HDRI1_BUFFER] = {
> >           .limits[IPA_RSRC_GROUP_SRC_UL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DIAG] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DMA] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_DESCRIPTOR_LISTS] = {
> > @@ -272,36 +272,36 @@ static const struct ipa_resource ipa_resource_src[] = {
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_HDRI2_BUFFERS] = {
> >           .limits[IPA_RSRC_GROUP_SRC_UL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DIAG] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DMA] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_HPS_DMARS] = {
> >           .limits[IPA_RSRC_GROUP_SRC_UL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DIAG] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_DMA] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_SRC_ACK_ENTRIES] = {
> > @@ -345,22 +345,22 @@ static const struct ipa_resource ipa_resource_dst[] = {
> >       },
> >       [IPA_RESOURCE_TYPE_DST_DATA_SECTOR_LISTS] = {
> >           .limits[IPA_RSRC_GROUP_DST_UL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_DST_DL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_DST_DIAG_DPL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_DST_DMA] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_DST_Q6ZIP_GENERAL] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_DST_Q6ZIP_ENGINE] = {
> > -            .min = 0,    .max = 255,
> > +            .min = 0,    .max = 63,
> >           },
> >       },
> >       [IPA_RESOURCE_TYPE_DST_DPS_DMARS] = {
> > diff --git a/drivers/net/ipa/data/ipa_data-v3.5.1.c 
> > b/drivers/net/ipa/data/ipa_data-v3.5.1.c
> > index 383ef1890065..42f2c88a92d4 100644
> > --- a/drivers/net/ipa/data/ipa_data-v3.5.1.c
> > +++ b/drivers/net/ipa/data/ipa_data-v3.5.1.c
> > @@ -179,10 +179,10 @@ static const struct ipa_gsi_endpoint_data 
> > ipa_gsi_endpoint_data[] = {
> >   static const struct ipa_resource ipa_resource_src[] = {
> >       [IPA_RESOURCE_TYPE_SRC_PKT_CONTEXTS] = {
> >           .limits[IPA_RSRC_GROUP_SRC_LWA_DL] = {
> > -            .min = 1,    .max = 255,
> > +            .min = 1,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UL_DL] = {
> > -            .min = 1,    .max = 255,
> > +            .min = 1,    .max = 63,
> >           },
> >           .limits[IPA_RSRC_GROUP_SRC_UC_RX_Q] = {
> >               .min = 1,    .max = 63,

--
Kind Regards,
Caleb (they/them)