linux-kernel - Re: [PATCH v1 3/3] i3c: master: svc: fix npcm845 invalid slvstart event

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Message-ID: <Z7ZI+9//uliW58+j@lizhi-Precision-Tower-5810>
Date: Wed, 19 Feb 2025 16:11:23 -0500
From: Frank Li <Frank.li@....com>
To: Stanley Chu <stanley.chuys@...il.com>
Cc: miquel.raynal@...tlin.com, alexandre.belloni@...tlin.com,
	linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org,
	tomer.maimon@...oton.com, kwliu@...oton.com, yschu@...oton.com
Subject: Re: [PATCH v1 3/3] i3c: master: svc: fix npcm845 invalid slvstart
 event

On Wed, Feb 19, 2025 at 09:10:19AM +0800, Stanley Chu wrote:
> I3C HW may generate an invalid SlvStart event when emitting a STOP.
> If it is a true SlvStart, the MSTATUS state should be SLVREQ.
> Check the MSTATUS state to ignore the false event.
>
> Signed-off-by: Stanley Chu <yschu@...oton.com>
> ---
>  drivers/i3c/master/svc-i3c-master.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 22cb1f1c1fdc..14cedcb81c52 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -59,6 +59,7 @@
>  #define   SVC_I3C_MSTATUS_STATE(x) FIELD_GET(GENMASK(2, 0), (x))
>  #define   SVC_I3C_MSTATUS_STATE_DAA(x) (SVC_I3C_MSTATUS_STATE(x) == 5)
>  #define   SVC_I3C_MSTATUS_STATE_IDLE(x) (SVC_I3C_MSTATUS_STATE(x) == 0)
> +#define   SVC_I3C_MSTATUS_STATE_SLVREQ(x) (SVC_I3C_MSTATUS_STATE(x) == 1)
>  #define   SVC_I3C_MSTATUS_BETWEEN(x) FIELD_GET(BIT(4), (x))
>  #define   SVC_I3C_MSTATUS_NACKED(x) FIELD_GET(BIT(5), (x))
>  #define   SVC_I3C_MSTATUS_IBITYPE(x) FIELD_GET(GENMASK(7, 6), (x))
> @@ -143,6 +144,12 @@
>   * Fill the FIFO in advance to prevent FIFO from becoming empty.
>   */
>  #define SVC_I3C_QUIRK_FIFO_EMPTY	BIT(0)
> +/*
> + * SVC_I3C_QUIRK_FLASE_SLVSTART:
> + * I3C HW may generate an invalid SlvStart event when emitting a STOP.
> + * If it is a true SlvStart, the MSTATUS state should be SLVREQ.
> + */
> +#define SVC_I3C_QUIRK_FALSE_SLVSTART	BIT(1)
>
>  struct svc_i3c_cmd {
>  	u8 addr;
> @@ -576,6 +583,11 @@ static irqreturn_t svc_i3c_master_irq_handler(int irq, void *dev_id)
>  	/* Clear the interrupt status */
>  	writel(SVC_I3C_MINT_SLVSTART, master->regs + SVC_I3C_MSTATUS);
>
> +	/* Ignore the false event */
> +	if ((master->quirks & SVC_I3C_QUIRK_FIFO_EMPTY) &&

You should check SVC_I3C_QUIRK_FALSE_SLVSTART, not SVC_I3C_QUIRK_FIFO_EMPTY

Frank
> +	    !SVC_I3C_MSTATUS_STATE_SLVREQ(active))
> +		return IRQ_HANDLED;
> +
>  	svc_i3c_master_disable_interrupts(master);
>
>  	/* Handle the interrupt in a non atomic context */
> @@ -1915,7 +1927,8 @@ static int svc_i3c_master_probe(struct platform_device *pdev)
>  	svc_i3c_master_reset(master);
>
>  	if (device_is_compatible(master->dev, "nuvoton,npcm845-i3c"))
> -		master->quirks = SVC_I3C_QUIRK_FIFO_EMPTY;
> +		master->quirks = SVC_I3C_QUIRK_FIFO_EMPTY |
> +				 SVC_I3C_QUIRK_FALSE_SLVSTART;
>
>  	/* Register the master */
>  	ret = i3c_master_register(&master->base, &pdev->dev,
> --
> 2.34.1
>