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Subject: Re: [PATCH] soc: qcom: smem: introduce qcom_smem_virt_to_phys()
To:     Alex Elder <elder@linaro.org>, andy.gross@linaro.org
Cc:     aneela@codeaurora.org, david.brown@linaro.org,
        linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20180425151820.25595-1-elder@linaro.org>
From:   Chris Lew <clew@codeaurora.org>
Message-ID: <4a127dda-576c-4eae-80d3-a928e578a1b9@codeaurora.org>
Date:   Wed, 25 Apr 2018 16:29:26 -0700
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Hi Alex,

Minor comment.

On 4/25/2018 8:18 AM, Alex Elder wrote:
> Create function qcom_smem_virt_to_phys(), which returns the physical
> address corresponding to a given SMEM item's virtual address.  This
> feature is required for a driver that will soon be out for review.
> 
> Signed-off-by: Alex Elder <elder@linaro.org>
> ---
>   drivers/soc/qcom/smem.c       | 27 +++++++++++++++++++++++++++
>   include/linux/soc/qcom/smem.h |  2 ++
>   2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
> index 7d9a43da5084..70b2ee80d6bd 100644
> --- a/drivers/soc/qcom/smem.c
> +++ b/drivers/soc/qcom/smem.c
> @@ -655,6 +655,33 @@ int qcom_smem_get_free_space(unsigned host)
>   }
>   EXPORT_SYMBOL(qcom_smem_get_free_space);
>   
> +/**
> + * qcom_smem_virt_to_phys() - return the physical address associated
> + * with an smem item pointer (previously returned by qcom_smem_get()
> + * @p:	the virtual address to convert
> + *
> + * Returns 0 if the pointer provided is not within any smem region.
> + */
> +phys_addr_t qcom_smem_virt_to_phys(void *p)
> +{
> +	unsigned i;
> +

We have a null pointer check for __smem here since it is called by 
external clients. This case should probably never happen though.

> +	for (i = 0; i < __smem->num_regions; i++) {
> +		struct smem_region *region = &__smem->regions[i];
> +
> +		if (p < region->virt_base)
> +			continue;
> +		if (p < region->virt_base + region->size) {
> +			u64 offset = p - region->virt_base;
> +
> +			return (phys_addr_t)region->aux_base + offset;
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(qcom_smem_virt_to_phys);

Thanks,
Chris

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