Re: [PATCH RESEND v2 4/4] i3c: master: svc: Fix npcm845 invalid slvstart event

[Frank Li]

On Thu, Feb 20, 2025 at 02:11:07PM +0800, Stanley Chu wrote:
> From: Stanley Chu <yschu@xxxxxxxxxxx>
>
> 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
					      ^^^ is? "should be"
				 	      look like unconfirmed.

> the MSTATUS state to ignore the false event.
>
> Signed-off-by: Stanley Chu <yschu@xxxxxxxxxxx>

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

> ---
>  drivers/i3c/master/svc-i3c-master.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 2140da3f5187..5861358eb9e5 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -58,6 +58,7 @@
>  #define SVC_I3C_MSTATUS      0x088
>  #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_SLVREQ(x) (SVC_I3C_MSTATUS_STATE(x) == 1)
>  #define   SVC_I3C_MSTATUS_STATE_IDLE(x) (SVC_I3C_MSTATUS_STATE(x) == 0)
>  #define   SVC_I3C_MSTATUS_BETWEEN(x) FIELD_GET(BIT(4), (x))
>  #define   SVC_I3C_MSTATUS_NACKED(x) FIELD_GET(BIT(5), (x))
> @@ -589,6 +590,11 @@ 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_FALSE_SLVSTART) &&
> +	    !SVC_I3C_MSTATUS_STATE_SLVREQ(active))
> +		return IRQ_HANDLED;
> +
>  	svc_i3c_master_disable_interrupts(master);
>
>  	/* Handle the interrupt in a non atomic context */
> --
> 2.34.1
>