Hi Günter, On Wed, Apr 7, 2021 at 10:58 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On 4/7/21 3:17 AM, Andy Shevchenko wrote: > > With platform_get_irq() and its optional variant it's possible to get > > a deferred probe error code. Since the commit ed7027fdf4ec ("driver core: > > platform: Make platform_get_irq_optional() optional") the error code > > can be distinguished from no IRQ case. With this, rewrite IRQ resource > > handling in sh-sci driver to follow above and allow to respect deferred > > probe. > > > > Fixes: ed7027fdf4ec ("driver core: platform: Make platform_get_irq_optional() optional") > > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > This patch alone causes a hard hang early during boot. It works if applied > together with ed7027fdf4ec. Ultimately that means that ed7027fdf4ec introduces > a functional change, and will need to be applied very carefully. A cursory > glance through callers of platform_get_irq_optional() shows that many > do not handle this correctly: various drivers handle a return value of 0 > as valid interrupt, and others treat errors other than -ENXIO as fatal. > > Also, each patch on its own causes failures on sh, which is problematic > when applying them even as series. See below for an idea how to > address that. > > > --- > > v2: fixed a typo: i -> 0 > > drivers/tty/serial/sh-sci.c | 18 ++++++++---------- > > 1 file changed, 8 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c > > index ad2c189e8fc8..574f68ba50ff 100644 > > --- a/drivers/tty/serial/sh-sci.c > > +++ b/drivers/tty/serial/sh-sci.c > > @@ -2899,13 +2899,6 @@ static int sci_init_single(struct platform_device *dev, > > port->mapbase = res->start; > > sci_port->reg_size = resource_size(res); > > > > - for (i = 0; i < ARRAY_SIZE(sci_port->irqs); ++i) { > > - if (i) > > - sci_port->irqs[i] = platform_get_irq_optional(dev, i); > > - else > > - sci_port->irqs[i] = platform_get_irq(dev, i); > > - } > > - > > /* The SCI generates several interrupts. They can be muxed together or > > * connected to different interrupt lines. In the muxed case only one > > * interrupt resource is specified as there is only one interrupt ID. > > @@ -2913,12 +2906,17 @@ static int sci_init_single(struct platform_device *dev, > > * from the SCI, however those signals might have their own individual > > * interrupt ID numbers, or muxed together with another interrupt. > > */ > > + sci_port->irqs[0] = platform_get_irq(dev, 0); > > if (sci_port->irqs[0] < 0) > > - return -ENXIO; > > + return sci_port->irqs[0]; > > > > - if (sci_port->irqs[1] < 0) > > - for (i = 1; i < ARRAY_SIZE(sci_port->irqs); i++) > > + for (i = 1; i < ARRAY_SIZE(sci_port->irqs); ++i) { > > + sci_port->irqs[i] = platform_get_irq_optional(dev, i); > > + if (sci_port->irqs[i] < 0) > > + return sci_port->irqs[i]; > > + if (sci_port->irqs[i] == 0) > > sci_port->irqs[i] = sci_port->irqs[0]; > > Since sh never gets -EPROBE_DEFER, the following code can be applied > on its own and does not depend on ed7027fdf4ec. Note that the sh-sci driver is also used on ARM32/64 and H8/300. On ARM, I don't expect GIC interrupts causing -EPROBE_DEFER, though. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds