linux-kernel - Re: [Patch v2 1/5] firmware: qcom_scm: Introduce SCM calls to access LMh

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Message-ID: <YNTFdCPU2saMCT/y@google.com>
Date:   Thu, 24 Jun 2021 10:48:36 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Thara Gopinath <thara.gopinath@...aro.org>
Cc:     agross@...nel.org, bjorn.andersson@...aro.org, rui.zhang@...el.com,
        daniel.lezcano@...aro.org, viresh.kumar@...aro.org,
        rjw@...ysocki.net, robh+dt@...nel.org,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [Patch v2 1/5] firmware: qcom_scm: Introduce SCM calls to access
 LMh

On Thu, Jun 24, 2021 at 07:58:09AM -0400, Thara Gopinath wrote:
> Introduce SCM calls to access/configure limits management hardware(LMH).
> 
> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
> ---
> 
> v1->v2:
> 	Changed the input parameters in qcom_scm_lmh_dcvsh from payload_buf and
> 	payload_size to payload_fn, payload_reg, payload_val as per Bjorn's review
> 	comments.
> 
>  drivers/firmware/qcom_scm.c | 54 +++++++++++++++++++++++++++++++++++++
>  drivers/firmware/qcom_scm.h |  4 +++
>  include/linux/qcom_scm.h    | 14 ++++++++++
>  3 files changed, 72 insertions(+)
> 
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index ee9cb545e73b..19e9fb91d084 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -1147,6 +1147,60 @@ int qcom_scm_qsmmu500_wait_safe_toggle(bool en)
>  }
>  EXPORT_SYMBOL(qcom_scm_qsmmu500_wait_safe_toggle);
>  
> +bool qcom_scm_lmh_dcvsh_available(void)
> +{
> +	return __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_LMH, QCOM_SCM_LMH_LIMIT_DCVSH);
> +}
> +EXPORT_SYMBOL(qcom_scm_lmh_dcvsh_available);
> +
> +int qcom_scm_lmh_profile_change(u32 profile_id)
> +{
> +	struct qcom_scm_desc desc = {
> +		.svc = QCOM_SCM_SVC_LMH,
> +		.cmd = QCOM_SCM_LMH_LIMIT_PROFILE_CHANGE,
> +		.arginfo = QCOM_SCM_ARGS(1, QCOM_SCM_VAL),
> +		.args[0] = profile_id,
> +		.owner = ARM_SMCCC_OWNER_SIP,
> +	};
> +
> +	return qcom_scm_call(__scm->dev, &desc, NULL);
> +}
> +EXPORT_SYMBOL(qcom_scm_lmh_profile_change);
> +
> +int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
> +		       u64 limit_node, u32 node_id, u64 version)
> +{
> +	dma_addr_t payload_phys;
> +	u32 *payload_buf;
> +	int payload_size = 5 * sizeof(u32);
> +
> +	struct qcom_scm_desc desc = {
> +		.svc = QCOM_SCM_SVC_LMH,
> +		.cmd = QCOM_SCM_LMH_LIMIT_DCVSH,
> +		.arginfo = QCOM_SCM_ARGS(5, QCOM_SCM_RO, QCOM_SCM_VAL, QCOM_SCM_VAL,
> +					QCOM_SCM_VAL, QCOM_SCM_VAL),
> +		.args[1] = payload_size,
> +		.args[2] = limit_node,
> +		.args[3] = node_id,
> +		.args[4] = version,
> +		.owner = ARM_SMCCC_OWNER_SIP,
> +	};
> +
> +	payload_buf = dma_alloc_coherent(__scm->dev, payload_size, &payload_phys, GFP_KERNEL);
> +	if (!payload_buf)
> +		return -ENOMEM;
> +
> +	payload_buf[0] = payload_fn;
> +	payload_buf[1] = 0;
> +	payload_buf[2] = payload_reg;
> +	payload_buf[3] = 1;
> +	payload_buf[4] = payload_val;
> +
> +	desc.args[0] = payload_phys;
> +	return qcom_scm_call(__scm->dev, &desc, NULL);

dma_free_coherent()?