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Date:   Wed, 24 May 2023 19:54:45 -0700
From:   Bjorn Andersson <andersson@kernel.org>
To:     Konrad Dybcio <konrad.dybcio@linaro.org>
Cc:     Trilok Soni <quic_tsoni@quicinc.com>,
        Robert Marko <robimarko@gmail.com>, agross@kernel.org,
        ilia.lin@kernel.org, rafael@kernel.org, viresh.kumar@linaro.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-pm@vger.kernel.org, ansuelsmth@gmail.com
Subject: Re: [PATCH v2 2/4] soc: qcom: smem: introduce qcom_smem_get_msm_id()
Message-ID: <20230525025445.lxfvmnlm2ezzi45g@ripper>
References: <20230524162329.819770-1-robimarko@gmail.com>
 <20230524162329.819770-2-robimarko@gmail.com>
 <47c0faf0-f855-d3c4-6825-e51a1a1a7c83@quicinc.com>
 <d9406953-6452-2394-ab3f-4ce1d8986fce@linaro.org>
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On Wed, May 24, 2023 at 08:27:03PM +0200, Konrad Dybcio wrote:
> 
> 
> On 24.05.2023 20:16, Trilok Soni wrote:
> > On 5/24/2023 9:23 AM, Robert Marko wrote:
> >> Introduce a helper to return the SoC SMEM ID, which is used to identify the
> >> exact SoC model as there may be differences in the same SoC family.
> >>
> >> Currently, cpufreq-nvmem does this completely in the driver and there has
> >> been more interest expresed for other drivers to use this information so
> >> lets expose a common helper to prevent redoing it in individual drivers
> >> since this field is present on every SMEM table version.
> >>
> >> Signed-off-by: Robert Marko <robimarko@gmail.com>
> >> ---
> >> ? drivers/soc/qcom/smem.c?????? | 19 +++++++++++++++++++
> >> ? include/linux/soc/qcom/smem.h |? 2 ++
> >> ? 2 files changed, 21 insertions(+)
> >>
> >> diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
> >> index 6be7ea93c78c..0d6ba9bce8cb 100644
> >> --- a/drivers/soc/qcom/smem.c
> >> +++ b/drivers/soc/qcom/smem.c
> >> @@ -14,6 +14,7 @@
> >> ? #include <linux/sizes.h>
> >> ? #include <linux/slab.h>
> >> ? #include <linux/soc/qcom/smem.h>
> >> +#include <linux/soc/qcom/socinfo.h>
> >> ? ? /*
> >> ?? * The Qualcomm shared memory system is a allocate only heap structure that
> >> @@ -772,6 +773,24 @@ phys_addr_t qcom_smem_virt_to_phys(void *p)
> >> ? }
> >> ? EXPORT_SYMBOL(qcom_smem_virt_to_phys);
> >> ? +/**
> >> + * qcom_smem_get_msm_id() - return the SoC ID
> >> + *
> >> + * Look up SoC ID from HW/SW build ID and return it.
> >> + */
> >> +int qcom_smem_get_msm_id(void)
> On top of Trilok's point, this should return le32, or at least unsigned int.
> 

Returning the value in CPU-native endian sounds very reasonable, so we
don't need __le32_to_cpu() on the calling side.

If we want to worry about this value going beyond 31 bits the
appropriate way would be to take, and assign, a unsigned int* argument
and return 0/-errno to indicate success/failure.

Regards,
Bjorn

> Konrad
> >> +{
> >> +??? size_t len;
> >> +??? struct socinfo *info;
> >> +
> >> +??? info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_HW_SW_BUILD_ID, &len);
> >> +??? if (IS_ERR(info))
> >> +??????? return PTR_ERR(info);
> >> +
> >> +??? return __le32_to_cpu(info->id);
> >> +}
> >> +EXPORT_SYMBOL(qcom_smem_get_msm_id);
> > 
> > EXPORT_SYMBOL_GPL please?
> > 
> > Please change it for other symbols in the driver as well w/ separate patch.
> > 
> > ---Trilok Soni
> > 
> >