linux-kernel - Re: [PATCH v1] clk: qcom: clk-rpmh: Add IPA clock support

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Message-ID: <154775097646.169631.4497796001681545243@swboyd.mtv.corp.google.com>
Date:   Thu, 17 Jan 2019 10:49:36 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     David Dai <daidavid1@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     georgi.djakov@...aro.org, bjorn.andersson@...aro.org,
        evgreen@...gle.com, tdas@...eaurora.org, elder@...aro.org
Subject: Re: [PATCH v1] clk: qcom: clk-rpmh: Add IPA clock support

Quoting David Dai (2019-01-16 16:54:39)
> 
> On 1/14/2019 8:47 AM, Stephen Boyd wrote:
> > Quoting David Dai (2019-01-11 16:56:14)
> >> On 1/9/2019 11:28 AM, Stephen Boyd wrote:
> >>> Quoting David Dai (2018-12-13 18:35:04)
> >>>> +
> >>>> +#define BCM_TCS_CMD(valid, vote)                               \
> >>>> +       (BCM_TCS_CMD_COMMIT_MASK |                              \
> >>>> +       ((valid) << BCM_TCS_CMD_VALID_SHIFT) |                  \
> >>>> +       ((cpu_to_le32(vote) &                                   \
> >>> Why?
> >> Sorry, could you clarify this question? If you're referring to the
> >> cpu_to_le32, shouldn't we be explicit about converting endianness even
> >> if it might be redundant for this particular qcom platform?
> > Is only the vote part of the message in little endian format and the
> > rest is native CPU endianess? It's very odd to see that jammed in the
> > middle of a bit packing statement like that. Typically the whole u32
> > would be in one or the other endianness. Also, sparse right complains
> > about this macro and it's usage, so something is wrong.
> Point taken, I'll leave it out of the macro for now.
> > I think one other problem is that rpmh API doesn't really talk about
> > endianness here and that's busted. So if you want to fix endianness
> > issues that needs to be fixed first.
> 
> Since a similar macro is being used as part of the interconnect provider 
> driver, I was thinking a better place for this macro might be in the 
> tcs.h as part of the rpmh driver? I could submit a different patch for 
> rpmh that mentions endianness along with this change.

Sure that's fine. But be warned that making a dependency across kernel
trees is best avoided. I would do that sort of cleanup and consolidation
after the two drivers are merged upstream so that it can go via either
tree.