linux-kernel - Re: [GIT pull] irq updates for 4.13

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Date:   Tue, 11 Jul 2017 06:51:32 -0700
From:   Tony Lindgren <tony@...mide.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Sebastian Reichel <sebastian.reichel@...labora.co.uk>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, Pavel Machek <pavel@....cz>,
        Linus Walleij <linus.walleij@...aro.org>,
        Grygorii Strashko <grygorii.strashko@...com>
Subject: Re: [GIT pull] irq updates for 4.13

* Thomas Gleixner <tglx@...utronix.de> [170711 02:48]:
> On Tue, 11 Jul 2017, Thomas Gleixner wrote:
> 
> So Tony actually provided the part of dmesg which shows the initial
> failure, which subsequently leads to the splat Sebastian reported.
> 
> Unhandled fault: external abort on non-linefetch (0x1028) at 0xfb050034
> pgd = c0004000 [fb050034] *pgd=49011452(bad)
> Internal error: : 1028 [#1] SMP ARM
> Workqueue: events deferred_probe_work_func
> task: ce1d41c0 task.stack: ce1fc000
> PC is at omap_gpio_get_direction+0x2c/0x44
> LR is at _raw_spin_lock_irqsave+0x40/0x4c
> pc : [<c0509258>]    lr : [<c08263c4>]    psr: 60000093
> sp : ce1fdb78  ip : c0dce42c  fp : ce22d810
> r10: ce22d800  r9 : 00000000  r8 : ce22d900
> r7 : 00000016  r6 : ce223864  r5 : fb050034  r4 : 00000020
> r3 : ce1d41c0  r2 : 00000000  r1 : a0000013  r0 : a0000013
> Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
> Control: 10c5387d  Table: 80004019  DAC: 00000051
> Process kworker/0:1 (pid: 14, stack limit = 0xce1fc218)
> 
> The callstack is:
> 
> omap_gpio_get_direction
> gpiochip_lock_as_irq
> gpiochip_irq_reqres
> __setup_irq
> request_threaded_irq
> smc_probe
> smc_drv_probe
> platform_drv_probe
> ....
> 
> So the SMC91X network driver request an IRQ, which ends up calling into the
> GPIO interrupt setup and that fails. I have no idea why that would not fail
> with the patch reverted. Dusting off a Beaglebone board....

And "external abort on non-linefetch" means something is not clocked
in this case. The following alone makes things boot for me again, but I don't
quite follow what has now changed with the ordering.. Thomas, any ideas?

Anyways, adding Linus W and Grygorii to Cc since things now point to
gpio-omap.

Regards,

Tony

8< ---------------------
diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -919,13 +919,24 @@ static int omap_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
 	struct gpio_bank *bank;
 	unsigned long flags;
 	void __iomem *reg;
-	int dir;
+	int error, dir;
 
 	bank = gpiochip_get_data(chip);
 	reg = bank->base + bank->regs->direction;
+	error = pm_runtime_get_sync(bank->chip.parent);
+	if (error < 0) {
+		dev_err(bank->chip.parent,
+			"Could not enable gpio bank %p: %d\n",
+			bank, error);
+		pm_runtime_put_noidle(bank->chip.parent);
+
+		return error;
+	}
 	raw_spin_lock_irqsave(&bank->lock, flags);
 	dir = !!(readl_relaxed(reg) & BIT(offset));
 	raw_spin_unlock_irqrestore(&bank->lock, flags);
+	pm_runtime_put_sync(bank->chip.parent);
+
 	return dir;
 }
 
-- 
2.13.2