linux-kernel - Re: [PATCH 1/5] hwtracing: hisi_ptt: Disable interrupt after trace end

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Date:   Fri, 25 Aug 2023 12:23:10 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Yicong Yang <yangyicong@...wei.com>
CC:     <suzuki.poulose@....com>, <mathieu.poirier@...aro.org>,
        <linux-kernel@...r.kernel.org>,
        <alexander.shishkin@...ux.intel.com>, <helgaas@...nel.org>,
        <linux-pci@...r.kernel.org>, <prime.zeng@...ilicon.com>,
        <linuxarm@...wei.com>, <yangyicong@...ilicon.com>,
        <hejunhao3@...wei.com>
Subject: Re: [PATCH 1/5] hwtracing: hisi_ptt: Disable interrupt after trace
 end

On Wed, 9 Aug 2023 16:18:21 +0800
Yicong Yang <yangyicong@...wei.com> wrote:

> From: Yicong Yang <yangyicong@...ilicon.com>
> 
> On trace end we disable the hardware but leave the interrupt
> unmasked. Mask the interrupt to make the process reverse to
> the start. No actual issue since hardware should send no
> interrupt after disabled.
> 
> Signed-off-by: Yicong Yang <yangyicong@...ilicon.com>

Acked-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> ---
>  drivers/hwtracing/ptt/hisi_ptt.c | 4 ++++
>  drivers/hwtracing/ptt/hisi_ptt.h | 1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
> index ba081b6d2435..5f0a8e653ae8 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.c
> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
> @@ -183,6 +183,10 @@ static void hisi_ptt_wait_dma_reset_done(struct hisi_ptt *hisi_ptt)
>  static void hisi_ptt_trace_end(struct hisi_ptt *hisi_ptt)
>  {
>  	writel(0, hisi_ptt->iobase + HISI_PTT_TRACE_CTRL);
> +
> +	/* Mask the interrupt on the end */
> +	writel(HISI_PTT_TRACE_INT_MASK_ALL, hisi_ptt->iobase + HISI_PTT_TRACE_INT_MASK);
> +
>  	hisi_ptt->trace_ctrl.started = false;
>  }
>  
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.h b/drivers/hwtracing/ptt/hisi_ptt.h
> index e17f045d7e72..46030aa88081 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.h
> +++ b/drivers/hwtracing/ptt/hisi_ptt.h
> @@ -47,6 +47,7 @@
>  #define HISI_PTT_TRACE_INT_STAT		0x0890
>  #define   HISI_PTT_TRACE_INT_STAT_MASK	GENMASK(3, 0)
>  #define HISI_PTT_TRACE_INT_MASK		0x0894
> +#define   HISI_PTT_TRACE_INT_MASK_ALL	GENMASK(3, 0)
>  #define HISI_PTT_TUNING_INT_STAT	0x0898
>  #define   HISI_PTT_TUNING_INT_STAT_MASK	BIT(0)
>  #define HISI_PTT_TRACE_WR_STS		0x08a0