RE: [PATCH] crypto: caam/jr - fix shared IRQ line handling

[Gaurav Jain]

Reviewed-by: Gaurav Jain <gaurav.jain@xxxxxxx>

> -----Original Message-----
> From: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>
> Sent: Tuesday, August 8, 2023 4:25 PM
> To: Horia Geanta <horia.geanta@xxxxxxx>; Varun Sethi <V.Sethi@xxxxxxx>;
> Pankaj Gupta <pankaj.gupta@xxxxxxx>; Gaurav Jain <gaurav.jain@xxxxxxx>;
> herbert@xxxxxxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; linux-
> crypto@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>
> Subject: [PATCH] crypto: caam/jr - fix shared IRQ line handling
> 
> From: Horia Geantă <horia.geanta@xxxxxxx>
> 
> There are cases when the interrupt status register (JRINTR) is non-zero, even
> though:
> 1. An interrupt was generated, but it was masked OR 2. There was no interrupt
> generated at all for the corresponding job ring.
> 
> 1. The case when interrupt is masked (JRCFGR_LS[IMSK]=1b'1) while other
> events have happened and are being accounted for, e.g.
> -JRINTR[HALT]=2b'10 - input job ring underwent a flush of all on-going jobs and
> processing of still-existing jobs (sitting in the ring) has been halted
> -JRINTR[HALT]=2b'01 - input job ring is currently undergoing a flush
> -JRINTR[ENTER_FAIL]=1b'1 - SecMon / SNVS transitioned to FAIL MODE It
> doesn't matter whether these events would assert the interrupt signal or not,
> interrupt is anyhow masked.
> 
> 2. The case when interrupt is not masked (JRCFGR_LS[IMSK]=1b'0), however the
> events accounted for in JRINTR do not generate interrupts, e.g.:
> -JRINTR[HALT]=2b'01
> -JRINTR[ENTER_FAIL]=1b'1 and JRCFGR_MS[FAIL_MODE]=1b'0
> 
> Currently in these cases, when the JR interrupt handler is invoked (as a
> consequence of JR sharing the interrupt line with other devices - e.g.
> the two JRs on i.MX7ULP) it continues execution instead of returning IRQ_NONE.
> This could lead to situations like interrupt handler clearing JRINTR (and thus also
> the JRINTR[HALT] field) while corresponding job ring is suspended and then that
> job ring failing on resume path, due to expecting
> JRINTR[HALT]=b'10 and reading instead JRINTR[HALT]=b'00.
> 
> Fix this by checking status of JRINTR[JRI] in the JR interrupt handler.
> If JRINTR[JRI]=1b'0, there was no interrupt generated for this JR and handler
> must return IRQ_NONE.
> 
> Signed-off-by: Horia Geantă <horia.geanta@xxxxxxx>
> Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>
> ---
>  drivers/crypto/caam/jr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c index
> 5507d5d34a4c..07ec2f27cc68 100644
> --- a/drivers/crypto/caam/jr.c
> +++ b/drivers/crypto/caam/jr.c
> @@ -232,7 +232,7 @@ static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
>  	 * tasklet if jobs done.
>  	 */
>  	irqstate = rd_reg32(&jrp->rregs->jrintstatus);
> -	if (!irqstate)
> +	if (!(irqstate & JRINT_JR_INT))
>  		return IRQ_NONE;
> 
>  	/*
> --
> 2.25.1