Re: [PATCH v1 3/7] net: ipa: gsi: Avoid some writes during irq setup for older IPA

[Alex Elder]

On 2/11/21 11:50 AM, AngeloGioacchino Del Regno wrote:
> On some IPA versions (v3.1 and older), writing to registers
> GSI_INTER_EE_SRC_CH_IRQ_OFFSET and GSI_INTER_EE_SRC_EV_CH_IRQ_OFFSET
> will generate a fault and the SoC will lockup.
>
> Avoid clearing CH and EV_CH interrupts on GSI probe to fix this bad
> behavior: we are anyway not going to get spurious interrupts.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>

Looking at this more closely, I see that you have found
a *bug* that I will fix.  The bug is that these registers
are the IRQ status registers, not the IRQ mask registers.

I have posted a fix for this bug, and once fixed, and I would
like to know whether this fix makes the fault you were
observing go away.
  https://lore.kernel.org/netdev/20210505223636.232527-1-elder@xxxxxxxxxx

					-Alex

> ---
>   drivers/net/ipa/gsi.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
> index 6315336b3ca8..b5460cbb085c 100644
> --- a/drivers/net/ipa/gsi.c
> +++ b/drivers/net/ipa/gsi.c
> @@ -207,11 +207,14 @@ static void gsi_irq_setup(struct gsi *gsi)
>   	iowrite32(0, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_MSK_OFFSET);
>   
>   	/* Reverse the offset adjustment for inter-EE register offsets */
> -	adjust = gsi->version < IPA_VERSION_4_5 ? 0 : GSI_EE_REG_ADJUST;
> -	iowrite32(0, gsi->virt + adjust + GSI_INTER_EE_SRC_CH_IRQ_OFFSET);
> -	iowrite32(0, gsi->virt + adjust + GSI_INTER_EE_SRC_EV_CH_IRQ_OFFSET);
> +	if (gsi->version > IPA_VERSION_3_1) {
> +		adjust = gsi->version < IPA_VERSION_4_5 ? 0 : GSI_EE_REG_ADJUST;
> +		iowrite32(0, gsi->virt + adjust + GSI_INTER_EE_SRC_CH_IRQ_OFFSET);
> +		iowrite32(0, gsi->virt + adjust + GSI_INTER_EE_SRC_EV_CH_IRQ_OFFSET);
> +	}
>   
>   	iowrite32(0, gsi->virt + GSI_CNTXT_GSI_IRQ_EN_OFFSET);
> +
>   }
>   
>   /* Turn off all GSI interrupts when we're all done */