Re: [PATCH v3 1/3] drivers: mailbox: zynqmp: handle multiple child nodes

[Michal Simek]

On 2/22/23 18:34, Mathieu Poirier wrote:
> On Mon, Feb 13, 2023 at 01:18:24PM -0800, Tanmay Shah wrote:
> > As of now only one child node is handled by zynqmp-ipi
> > mailbox driver. Upon introducing remoteproc r5 core mailbox
> > nodes, found few enhancements in Xilinx zynqmp mailbox driver
> > as following:
> >
> > - fix mailbox child node counts
> >    If child mailbox node status is disabled it causes
> >    crash in interrupt handler. Fix this by assigning
> >    only available child node during driver probe.
> >
> > - fix typo in IPI documentation %s/12/32/
> >    Xilinx IPI message buffers allows 32-byte data transfer.
> >    Fix documentation that says 12 bytes
> >
> > - fix bug in zynqmp-ipi isr handling
> >    Multiple IPI channels are mapped to same interrupt handler.
> >    Current isr implementation handles only one channel per isr.
> >    Fix this behavior by checking isr status bit of all child
> >    mailbox nodes.
> >
> > Fixes: 4981b82ba2ff ("mailbox: ZynqMP IPI mailbox controller")
> > Signed-off-by: Tanmay Shah <tanmay.shah@xxxxxxx>
> > ---
> >
> > Changelog:
> >    - This is first version of this change, however posting as part of the series
> >      that has version v3.
> >
> > v2: https://lore.kernel.org/all/20230126213154.1707300-1-tanmay.shah@xxxxxxx/
> >
> >   drivers/mailbox/zynqmp-ipi-mailbox.c       | 8 ++++----
> >   include/linux/mailbox/zynqmp-ipi-message.h | 2 +-
> >   2 files changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c
> > index 12e004ff1a14..b1498f6f06e1 100644
> > --- a/drivers/mailbox/zynqmp-ipi-mailbox.c
> > +++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
> > @@ -152,7 +152,7 @@ static irqreturn_t zynqmp_ipi_interrupt(int irq, void *data)
> >   	struct zynqmp_ipi_message *msg;
> >   	u64 arg0, arg3;
> >   	struct arm_smccc_res res;
> > -	int ret, i;
> > +	int ret, i, status = IRQ_NONE;
> >   
> >   	(void)irq;
> >   	arg0 = SMC_IPI_MAILBOX_STATUS_ENQUIRY;
> > @@ -170,11 +170,11 @@ static irqreturn_t zynqmp_ipi_interrupt(int irq, void *data)
> >   				memcpy_fromio(msg->data, mchan->req_buf,
> >   					      msg->len);
> >   				mbox_chan_received_data(chan, (void *)msg);
> > -				return IRQ_HANDLED;
> > +				status = IRQ_HANDLED;
> >   			}
> >   		}
> >   	}
> > -	return IRQ_NONE;
> > +	return status;
> >   }
> >   
> >   /**
> > @@ -634,7 +634,7 @@ static int zynqmp_ipi_probe(struct platform_device *pdev)
> >   	struct zynqmp_ipi_mbox *mbox;
> >   	int num_mboxes, ret = -EINVAL;
> >   
> > -	num_mboxes = of_get_child_count(np);
> > +	num_mboxes = of_get_available_child_count(np);
> >   	pdata = devm_kzalloc(dev, sizeof(*pdata) + (num_mboxes * sizeof(*mbox)),
> >   			     GFP_KERNEL);
> >   	if (!pdata)
> > diff --git a/include/linux/mailbox/zynqmp-ipi-message.h b/include/linux/mailbox/zynqmp-ipi-message.h
> > index 35ce84c8ca02..31d8046d945e 100644
> > --- a/include/linux/mailbox/zynqmp-ipi-message.h
> > +++ b/include/linux/mailbox/zynqmp-ipi-message.h
> > @@ -9,7 +9,7 @@
> >    * @data: message payload
> >    *
> >    * This is the structure for data used in mbox_send_message
> > - * the maximum length of data buffer is fixed to 12 bytes.
> > + * the maximum length of data buffer is fixed to 32 bytes.
> >    * Client is supposed to be aware of this.
>
> I agree that this should be split in 3 patches but the fixes are so small that
> it is hardly required.  I'll leave it up to Michal to decide.

Generic guidance is saying that you should split that patches. I personally 
prefer to have one patch per change. It is useful for bisecting and faster for 
reviewing.
I would expect that this patch should go via mailbox tree and the rest via 
remoteproc tree. That's why maintainer should say what it is preferred way.

In connection mailbox. I recently had some time to look at this driver and I 
didn't really get why there are registers listed. Because all that addresses can 
be calculated based on soc compatible string and by xlnx,ipi-id for both sides.

Thanks,
Michal