linux-kernel - Re: [PATCH v2 1/1] x86/rtc: Allocate interrupt for platform device

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Date:   Wed, 18 Jan 2017 11:24:50 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
cc:     "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
        x86@...nel.org
Subject: Re: [PATCH v2 1/1] x86/rtc: Allocate interrupt for platform device

On Tue, 17 Jan 2017, Andy Shevchenko wrote:

> On Mon, 2017-01-16 at 22:00 +0100, Thomas Gleixner wrote:
> 
> > The early callback does not work, but we have one which is invoked
> > later
> > on: x86_init.wallclock_init(). That's invoked after the (IO/APIC)
> > setup has
> > been completed. See patch below.
> 
> Unfortunately it is till too early. Looks like descriptors are not
> available yet and we still can't get an allocation:
> 
> [    0.000000] intel_mid: Failed to allocate RTC interrupt. Disabling
> RTC
> 
> ...
> 
> [    0.000000] NR_IRQS:4352 nr_irqs:512 0

Indeed. Did not think about that we need the irq subsystem up not only the
primary IOAPIC init done.

Looking deeper it's actually simple. MID already overloads the timer_init()
setup function. So we can just do it there.

Thanks,

	tglx

--- a/arch/x86/platform/intel-mid/intel-mid.c
+++ b/arch/x86/platform/intel-mid/intel-mid.c
@@ -93,6 +93,17 @@ static void __init intel_mid_setup_bp_ti
 	setup_boot_APIC_clock();
 }
 
+static void __init intel_mid_legacy_rtc_init(void)
+{
+	struct irq_alloc_info info;
+
+	ioapic_set_alloc_attr(&info, NUMA_NO_NODE, 1, 0);
+	if (mp_map_gsi_to_irq(RTC_IRQ, IOAPIC_MAP_ALLOC, &info) < 0) {
+		pr_info("Failed to allocate RTC interrupt. Disabling RTC\n");
+		x86_platform.legacy.rtc = 0;
+	}
+}
+
 static void __init intel_mid_time_init(void)
 {
 	sfi_table_parse(SFI_SIG_MTMR, NULL, NULL, sfi_parse_mtmr);
@@ -115,6 +126,10 @@ static void __init intel_mid_time_init(v
 	}
 
 	x86_init.timers.setup_percpu_clockev = apbt_time_init;
+
+	/* If the platform has an RTC make sure the APIC entry is allocated */
+	if (x86_platform.legacy.rtc)
+		intel_mid_legacy_rtc_init();
 }
 
 static void intel_mid_arch_setup(void)
--- a/arch/x86/platform/intel-mid/sfi.c
+++ b/arch/x86/platform/intel-mid/sfi.c
@@ -540,21 +540,8 @@ static int __init sfi_parse_devs(struct
 	return 0;
 }
 
-static int __init intel_mid_legacy_rtc_init(void)
-{
-	struct irq_alloc_info info;
-
-	if (!x86_platform.legacy.rtc)
-		return -ENODEV;
-
-	ioapic_set_alloc_attr(&info, NUMA_NO_NODE, 1, 0);
-	return mp_map_gsi_to_irq(RTC_IRQ, IOAPIC_MAP_ALLOC, &info);
-}
-
 static int __init intel_mid_platform_init(void)
 {
-	intel_mid_legacy_rtc_init();
-
 	sfi_table_parse(SFI_SIG_GPIO, NULL, NULL, sfi_parse_gpio);
 	sfi_table_parse(SFI_SIG_DEVS, NULL, NULL, sfi_parse_devs);
 	return 0;