linux-kernel - Re: [PATCH v4 3/4] remoteproc: qcom: q6v5: Add common panic handler

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Date:   Mon, 23 Mar 2020 16:36:24 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Andy Gross <agross@...nel.org>, Ohad Ben-Cohen <ohad@...ery.com>,
        linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/4] remoteproc: qcom: q6v5: Add common panic handler

On Mon, Mar 09, 2020 at 11:38:16PM -0700, Bjorn Andersson wrote:
> Add a common panic handler that invokes a stop request and sleep enough
> to let the remoteproc flush it's caches etc in order to aid post mortem
> debugging. For now a hard coded 200ms is returned to the remoteproc
> core, this value is taken from the downstream kernel.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
> 
> Change since v3:
>  - Change return type to unsigned long
> 
>  drivers/remoteproc/qcom_q6v5.c | 20 ++++++++++++++++++++
>  drivers/remoteproc/qcom_q6v5.h |  1 +
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/remoteproc/qcom_q6v5.c b/drivers/remoteproc/qcom_q6v5.c
> index cb0f4a0be032..111a442c993c 100644
> --- a/drivers/remoteproc/qcom_q6v5.c
> +++ b/drivers/remoteproc/qcom_q6v5.c
> @@ -15,6 +15,8 @@
>  #include <linux/remoteproc.h>
>  #include "qcom_q6v5.h"
>  
> +#define Q6V5_PANIC_DELAY_MS	200
> +
>  /**
>   * qcom_q6v5_prepare() - reinitialize the qcom_q6v5 context before start
>   * @q6v5:	reference to qcom_q6v5 context to be reinitialized
> @@ -162,6 +164,24 @@ int qcom_q6v5_request_stop(struct qcom_q6v5 *q6v5)
>  }
>  EXPORT_SYMBOL_GPL(qcom_q6v5_request_stop);
>  
> +/**
> + * qcom_q6v5_panic() - panic handler to invoke a stop on the remote
> + * @q6v5:	reference to qcom_q6v5 context
> + *
> + * Set the stop bit and sleep in order to allow the remote processor to flush
> + * its caches etc for post mortem debugging.
> + *
> + * Return: 200ms
> + */
> +unsigned long qcom_q6v5_panic(struct qcom_q6v5 *q6v5)
> +{
> +	qcom_smem_state_update_bits(q6v5->state,
> +				    BIT(q6v5->stop_bit), BIT(q6v5->stop_bit));
> +
> +	return Q6V5_PANIC_DELAY_MS;
> +}
> +EXPORT_SYMBOL_GPL(qcom_q6v5_panic);
> +
>  /**
>   * qcom_q6v5_init() - initializer of the q6v5 common struct
>   * @q6v5:	handle to be initialized
> diff --git a/drivers/remoteproc/qcom_q6v5.h b/drivers/remoteproc/qcom_q6v5.h
> index 7ac92c1e0f49..c4ed887c1499 100644
> --- a/drivers/remoteproc/qcom_q6v5.h
> +++ b/drivers/remoteproc/qcom_q6v5.h
> @@ -42,5 +42,6 @@ int qcom_q6v5_prepare(struct qcom_q6v5 *q6v5);
>  int qcom_q6v5_unprepare(struct qcom_q6v5 *q6v5);
>  int qcom_q6v5_request_stop(struct qcom_q6v5 *q6v5);
>  int qcom_q6v5_wait_for_start(struct qcom_q6v5 *q6v5, int timeout);
> +unsigned long qcom_q6v5_panic(struct qcom_q6v5 *q6v5);

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

>  
>  #endif
> -- 
> 2.24.0
>