x86/platform/intel-mid: Allocate RTC interrupt for Merrifield

Legacy RTC requires interrupt line 8 to be dedicated for it. On
Intel MID platforms the legacy PIC is absent and in order to make RTC
work we need to allocate interrupt separately.

Current solution brought by commit de1c2540aa4f does it in a wrong place,
and since it's done unconditionally for all x86 devices, some of them,
e.g. PNP based, might get it wrong because they execute the MID specific
code due to x86_platform.legacy.rtc flag being set.

Move intel_mid_legacy_rtc_init() to its own module and call it before x86 RTC
CMOS initialization.

Fixes: de1c2540aa4f ("x86/platform/intel-mid: Enable RTC on Intel Merrifield")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Link: http://lkml.kernel.org/r/20170119192425.189899-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/platform/intel-mid/device_libs/Makefile

@@ -26,4 +26,5 @@ obj-$(subst m,y,$(CONFIG_GPIO_PCA953X)) += platform_pcal9555a.o
 obj-$(subst m,y,$(CONFIG_GPIO_PCA953X)) += platform_tca6416.o
 # MISC Devices
 obj-$(subst m,y,$(CONFIG_KEYBOARD_GPIO)) += platform_gpio_keys.o
+obj-$(subst m,y,$(CONFIG_RTC_DRV_CMOS)) += platform_mrfld_rtc.o
 obj-$(subst m,y,$(CONFIG_INTEL_MID_WATCHDOG)) += platform_mrfld_wdt.o

arch/x86/platform/intel-mid/device_libs/platform_mrfld_rtc.c

@@ -0,0 +1,48 @@
+/*
+ * Intel Merrifield legacy RTC initialization file
+ *
+ * (C) Copyright 2017 Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/init.h>
+
+#include <asm/hw_irq.h>
+#include <asm/intel-mid.h>
+#include <asm/io_apic.h>
+#include <asm/time.h>
+#include <asm/x86_init.h>
+
+static int __init mrfld_legacy_rtc_alloc_irq(void)
+{
+	struct irq_alloc_info info;
+	int ret;
+
+	if (!x86_platform.legacy.rtc)
+		return -ENODEV;
+
+	ioapic_set_alloc_attr(&info, NUMA_NO_NODE, 1, 0);
+	ret = mp_map_gsi_to_irq(RTC_IRQ, IOAPIC_MAP_ALLOC, &info);
+	if (ret < 0) {
+		pr_info("Failed to allocate RTC interrupt. Disabling RTC\n");
+		x86_platform.legacy.rtc = 0;
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __init mrfld_legacy_rtc_init(void)
+{
+	if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
+		return -ENODEV;
+
+	return mrfld_legacy_rtc_alloc_irq();
+}
+arch_initcall(mrfld_legacy_rtc_init);

arch/x86/platform/intel-mid/sfi.c

@@ -41,7 +41,6 @@
 #include <asm/intel_scu_ipc.h>
 #include <asm/apb_timer.h>
 #include <asm/reboot.h>
-#include <asm/time.h>
 
 #define	SFI_SIG_OEM0	"OEM0"
 #define MAX_IPCDEVS	24
@@ -540,21 +539,8 @@ static int __init sfi_parse_devs(struct sfi_table_header *table)
 	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;