Messages in this thread | | | Subject | Re: [PATCH] soc: qcom-geni-se: Don't use relaxed writes when writing commands | From | "Mukesh, Savaliya" <> | Date | Thu, 23 Jul 2020 14:27:20 +0530 |
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On 7/23/2020 3:31 AM, Douglas Anderson wrote: > Writing the command is the final step in kicking off a transfer. > Let's use writel() to ensure that any other memory accesses are done > before the command kicks off. It's expected that this is mostly > relevant if we're in DMA mode but since it doesn't appear to regress > performance in a measurable way [1] even in PIO mode and it's easier > to reason about then let's just always use it. > > NOTE: this patch came about due to code inspection. No actual > problems were observed that this patch fixes. > > [1] Tested by timing "flashrom -p ec" on a Chromebook which stresses > GENI SPI a lot. > > Suggested-by: Stephen Boyd <swboyd@chromium.org> > Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Mukesh Kumar Savaliya <msavaliy@codeaurora.org> > --- > > include/linux/qcom-geni-se.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h > index dd464943f717..f50c73be1428 100644 > --- a/include/linux/qcom-geni-se.h > +++ b/include/linux/qcom-geni-se.h > @@ -262,7 +262,7 @@ static inline void geni_se_setup_m_cmd(struct geni_se *se, u32 cmd, u32 params) > u32 m_cmd; > > m_cmd = (cmd << M_OPCODE_SHFT) | (params & M_PARAMS_MSK); > - writel_relaxed(m_cmd, se->base + SE_GENI_M_CMD0); > + writel(m_cmd, se->base + SE_GENI_M_CMD0); > } > > /** > @@ -282,7 +282,7 @@ static inline void geni_se_setup_s_cmd(struct geni_se *se, u32 cmd, u32 params) > s_cmd &= ~(S_OPCODE_MSK | S_PARAMS_MSK); > s_cmd |= (cmd << S_OPCODE_SHFT); > s_cmd |= (params & S_PARAMS_MSK); > - writel_relaxed(s_cmd, se->base + SE_GENI_S_CMD0); > + writel(s_cmd, se->base + SE_GENI_S_CMD0); > } > > /**
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