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Message-ID: <5e6124390b9e3e7f4d6f6decbdb669ca@kernel.org>
Date: Thu, 06 Aug 2020 09:49:39 +0100
From: Marc Zyngier <maz@...nel.org>
To: John Stultz <john.stultz@...aro.org>
Cc: Saravana Kannan <saravanak@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Matthias Brugger <matthias.bgg@...il.com>,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Android Kernel Team <kernel-team@...roid.com>,
lkml <linux-kernel@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@...ts.infradead.org>,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
Hanks Chen <hanks.chen@...iatek.com>,
CC Hwang <cc.hwang@...iatek.com>,
Loda Chou <loda.chou@...iatek.com>, steev@...i.org
Subject: Re: [PATCH v3 2/4] irqchip/qcom-pdc: Switch to using
IRQCHIP_PLATFORM_DRIVER helper macros
On 2020-08-06 02:24, John Stultz wrote:
> On Wed, Aug 5, 2020 at 1:19 PM Saravana Kannan <saravanak@...gle.com>
> wrote:
>> On Wed, Aug 5, 2020 at 12:44 AM John Stultz <john.stultz@...aro.org>
>> wrote:
>> > On Fri, Jul 17, 2020 at 5:06 PM Saravana Kannan <saravanak@...gle.com> wrote:
>> > >
>> > > Switch the driver to use the helper macros. In addition to reducing the
>> > > number of lines, this also adds module unload protection (if the driver
>> > > is compiled as a module) by switching from module_platform_driver to
>> > > builtin_platform_driver.
>> > >
>> > > Signed-off-by: Saravana Kannan <saravanak@...gle.com>
>> > > ---
>> > > drivers/irqchip/qcom-pdc.c | 26 +++-----------------------
>> > > 1 file changed, 3 insertions(+), 23 deletions(-)
>> > >
>> > > diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c
>> > > index 5b624e3295e4..c1c5dfad57cc 100644
>> > > --- a/drivers/irqchip/qcom-pdc.c
>> > > +++ b/drivers/irqchip/qcom-pdc.c
>> > > @@ -432,28 +432,8 @@ static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
>> > > return ret;
>> > > }
>> > >
>> > > -static int qcom_pdc_probe(struct platform_device *pdev)
>> > > -{
>> > > - struct device_node *np = pdev->dev.of_node;
>> > > - struct device_node *parent = of_irq_find_parent(np);
>> > > -
>> > > - return qcom_pdc_init(np, parent);
>> > > -}
>> > > -
>> > > -static const struct of_device_id qcom_pdc_match_table[] = {
>> > > - { .compatible = "qcom,pdc" },
>> > > - {}
>> > > -};
>> > > -MODULE_DEVICE_TABLE(of, qcom_pdc_match_table);
>> > > -
>> > > -static struct platform_driver qcom_pdc_driver = {
>> > > - .probe = qcom_pdc_probe,
>> > > - .driver = {
>> > > - .name = "qcom-pdc",
>> > > - .of_match_table = qcom_pdc_match_table,
>> > > - .suppress_bind_attrs = true,
>> > > - },
>> > > -};
>> > > -module_platform_driver(qcom_pdc_driver);
>> > > +IRQCHIP_PLATFORM_DRIVER_BEGIN(qcom_pdc)
>> > > +IRQCHIP_MATCH("qcom,pdc", qcom_pdc_init)
>> > > +IRQCHIP_PLATFORM_DRIVER_END(qcom_pdc)
>> > > MODULE_DESCRIPTION("Qualcomm Technologies, Inc. Power Domain Controller");
>> > > MODULE_LICENSE("GPL v2");
>> >
>> > <sigh>
>> > So this is where I bashfully admit I didn't get a chance to try this
>> > patch series out, as I had success with a much older version of
>> > Saravana's macro magic.
>> >
>> > But unfortunately, now that this has landed in mainline, I'm seeing
>> > boot regressions on db845c. :( This is in the non-modular case,
>> > building the driver in.
>>
>> Does that mean the modular version is working? Or you haven't tried
>> that yet? I'll wait for your reply before I try to fix it. I don't
>> have the hardware, but it should be easy to guess this issue looking
>> at the code delta.
>
> I've not yet tested with modules with your patch.
>
>> The only significant change from what your probe function is doing is
>> this snippet. But it'd be surprising if this only affects the builtin
>> case.
>>
>> + if (par_np == np)
>> + par_np = NULL;
>> +
>> + /*
>> + * If there's a parent interrupt controller and none of the parent
>> irq
>> + * domains have been registered, that means the parent interrupt
>> + * controller has not been initialized yet. it's not time for this
>> + * interrupt controller to initialize. So, defer probe of this
>> + * interrupt controller. The actual initialization callback of this
>> + * interrupt controller can check for specific domains as necessary.
>> + */
>> + if (par_np && !irq_find_matching_host(np, DOMAIN_BUS_ANY))
>> + return -EPROBE_DEFER;
>
> Yep. We're getting caught on the irq_find_matching_host() check. I'm a
> little lost as when I look at the qcom,pdc node in the dtsi its not
> under a parent controller (instead the soc node).
> Not sure if that's an issue in the dtsi or if par_np check needs to
> ignore the soc node and pass null?
I think you have nailed it. This checks for a domain attached to
the driver we are about to probe, and this domain cannot possibly
exist. Instead, it is the *parent* this should check for, as we
depend on it for successful probing.
Can you please give this a go?
Thanks,
M.
diff --git a/drivers/irqchip/irqchip.c b/drivers/irqchip/irqchip.c
index 1bb0e36c2bf3..d2341153e181 100644
--- a/drivers/irqchip/irqchip.c
+++ b/drivers/irqchip/irqchip.c
@@ -52,7 +52,7 @@ int platform_irqchip_probe(struct platform_device
*pdev)
* interrupt controller. The actual initialization callback of this
* interrupt controller can check for specific domains as necessary.
*/
- if (par_np && !irq_find_matching_host(np, DOMAIN_BUS_ANY))
+ if (par_np && !irq_find_matching_host(par_np, DOMAIN_BUS_ANY))
return -EPROBE_DEFER;
return irq_init_cb(np, par_np);
--
Jazz is not dead. It just smells funny...
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