linux-kernel - Re: [PATCH v2 2/9] remoteproc: mediatek: Support hanlding scp core 1 wdt timeout

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Date:   Mon, 29 Aug 2022 11:40:21 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Tinghan Shen <tinghan.shen@...iatek.com>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Lee Jones <lee.jones@...aro.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        Daisuke Nojiri <dnojiri@...omium.org>,
        Kees Cook <keescook@...omium.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Prashant Malani <pmalani@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        chrome-platform@...ts.linux.dev,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        weishunc@...gle.com
Subject: Re: [PATCH v2 2/9] remoteproc: mediatek: Support hanlding scp core 1
 wdt timeout

Hi Tinghan,

I have started reviewing this set and I expect comments to be spread out over a few
days.  I will tell you when I am done.

Please see below for comments...

On Wed, Jun 08, 2022 at 04:35:46PM +0800, Tinghan Shen wrote:
> MT8195 SCP is a dual-core processor. The SCP core 1 watchdog timeout
> interrupt uses the same interrupt line of SCP core 0 watchdog timeout
> interrupt.
> 
> Add support for handling SCP core 1 watchdog timeout interrupt in the
> SCP IRQ handler.
> 
> Signed-off-by: Tinghan Shen <tinghan.shen@...iatek.com>
> ---
>  drivers/remoteproc/mtk_common.h |  4 ++++
>  drivers/remoteproc/mtk_scp.c    | 27 ++++++++++++++++++++++++++-
>  2 files changed, 30 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
> index ea6fa1100a00..73e8adf00de3 100644
> --- a/drivers/remoteproc/mtk_common.h
> +++ b/drivers/remoteproc/mtk_common.h
> @@ -54,6 +54,10 @@
>  #define MT8192_CORE0_WDT_IRQ		0x10030
>  #define MT8192_CORE0_WDT_CFG		0x10034
>  
> +#define MT8195_SYS_STATUS		0x4004
> +#define MT8195_CORE0_WDT		BIT(16)
> +#define MT8195_CORE1_WDT		BIT(17)
> +
>  #define MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS		GENMASK(7, 4)
>  
>  #define SCP_FW_VER_LEN			32
> diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> index 47b2a40e1b4a..3510c6d0bbc8 100644
> --- a/drivers/remoteproc/mtk_scp.c
> +++ b/drivers/remoteproc/mtk_scp.c
> @@ -212,6 +212,31 @@ static void mt8192_scp_irq_handler(struct mtk_scp *scp)
>  	}
>  }
>  
> +static void mt8195_scp_irq_handler(struct mtk_scp *scp)
> +{
> +	u32 scp_to_host;
> +
> +	scp_to_host = readl(scp->reg_base + MT8192_SCP2APMCU_IPC_SET);
> +
> +	if (scp_to_host & MT8192_SCP_IPC_INT_BIT) {
> +		scp_ipi_handler(scp);
> +
> +		/*
> +		 * SCP won't send another interrupt until we clear
> +		 * MT8192_SCP2APMCU_IPC.
> +		 */
> +		writel(MT8192_SCP_IPC_INT_BIT,
> +		       scp->reg_base + MT8192_SCP2APMCU_IPC_CLR);
> +	} else {
> +		if (readl(scp->reg_base + MT8195_SYS_STATUS) & MT8195_CORE1_WDT) {
> +			writel(1, scp->reg_base + MT8195_CORE1_WDT_IRQ);
> +		} else {
> +			writel(1, scp->reg_base + MT8192_CORE0_WDT_IRQ);
> +			scp_wdt_handler(scp, scp_to_host);

Why is scp_wdt_handler() not called when CORE1 signals a watchdog failure?  If
this is the intended behaviour there is no way for anyone but you to know that
it is the case.  

> +		}
> +	}
> +}
> +
>  static irqreturn_t scp_irq_handler(int irq, void *priv)
>  {
>  	struct mtk_scp *scp = priv;
> @@ -961,7 +986,7 @@ static const struct mtk_scp_of_data mt8192_of_data = {
>  static const struct mtk_scp_of_data mt8195_of_data = {
>  	.scp_clk_get = mt8195_scp_clk_get,
>  	.scp_before_load = mt8195_scp_before_load,
> -	.scp_irq_handler = mt8192_scp_irq_handler,
> +	.scp_irq_handler = mt8195_scp_irq_handler,
>  	.scp_reset_assert = mt8192_scp_reset_assert,
>  	.scp_reset_deassert = mt8192_scp_reset_deassert,
>  	.scp_stop = mt8195_scp_stop,
> -- 
> 2.18.0
>