Thermal: Intel SoC DTS: Translate IO-APIC GSI number to linux irq number

The Intel SoC DTS uses a hardcoded GSI number, before this commit
it was passing it to request_irq as if it were a linux irq number,
but there is no 1:1 mapping so in essence it was requesting a
random interrupt.

Besides this causing the DTS driver to not actually get an interrupt
if the thermal thresholds are exceeded this also is causing an
interrupt conflict on some devices since the linux irq 86 which is
being requested is already in use, leading to oopses like this:

genirq: Flags mismatch irq 86. 00002001 (soc_dts) vs. 00000083 (volume_down)
CPU: 0 PID: 601 Comm: systemd-udevd Tainted: G         C OE     4.17.0-rc6+ #45
Hardware name: Insyde i86/Type2 - Board Product Name, BIOS CHUWI.D86JLBNR03 01/14/2015
Call Trace:
  dump_stack+0x5c/0x80
  __setup_irq.cold.50+0x4e/0xac
  ? request_threaded_irq+0xad/0x160
  request_threaded_irq+0xf5/0x160
  ? 0xffffffffc0a93000
  intel_soc_thermal_init+0x74/0x1000 [intel_soc_dts_thermal]

This commit makes the intel_soc_dts_thermal.c code call
acpi_register_gsi() to translate the hardcoded IO-APIC GSI number (86)
to a linux irq, so that the dts code uses the right interrupt and we
no longer get an oops about an irq conflict.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/Kconfig

@@ -360,7 +360,7 @@ config INTEL_SOC_DTS_IOSF_CORE
 
 config INTEL_SOC_DTS_THERMAL
 	tristate "Intel SoCs DTS thermal driver"
-	depends on X86 && PCI
+	depends on X86 && PCI && ACPI
 	select INTEL_SOC_DTS_IOSF_CORE
 	select THERMAL_WRITABLE_TRIPS
 	help

drivers/thermal/intel_soc_dts_thermal.c

@@ -15,6 +15,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <asm/cpu_device_id.h>
@@ -31,6 +32,7 @@ MODULE_PARM_DESC(crit_offset,
 /* IRQ 86 is a fixed APIC interrupt for BYT DTS Aux threshold notifications */
 #define BYT_SOC_DTS_APIC_IRQ	86
 
+static int soc_dts_thres_gsi;
 static int soc_dts_thres_irq;
 static struct intel_soc_dts_sensors *soc_dts;
 
@@ -65,7 +67,21 @@ static int __init intel_soc_thermal_init(void)
 		return err;
 	}
 
-	soc_dts_thres_irq = (int)match_cpu->driver_data;
+	soc_dts_thres_gsi = (int)match_cpu->driver_data;
+	if (soc_dts_thres_gsi) {
+		/*
+		 * Note the flags here MUST match the firmware defaults, rather
+		 * then the request_irq flags, otherwise we get an EBUSY error.
+		 */
+		soc_dts_thres_irq = acpi_register_gsi(NULL, soc_dts_thres_gsi,
+						      ACPI_LEVEL_SENSITIVE,
+						      ACPI_ACTIVE_LOW);
+		if (soc_dts_thres_irq < 0) {
+			pr_warn("intel_soc_dts: Could not get IRQ for GSI %d, err %d\n",
+				soc_dts_thres_gsi, soc_dts_thres_irq);
+			soc_dts_thres_irq = 0;
+		}
+	}
 
 	if (soc_dts_thres_irq) {
 		err = request_threaded_irq(soc_dts_thres_irq, NULL,
@@ -90,8 +106,10 @@ static int __init intel_soc_thermal_init(void)
 	return 0;
 
 error_trips:
-	if (soc_dts_thres_irq)
+	if (soc_dts_thres_irq) {
 		free_irq(soc_dts_thres_irq, soc_dts);
+		acpi_unregister_gsi(soc_dts_thres_gsi);
+	}
 	intel_soc_dts_iosf_exit(soc_dts);
 
 	return err;
@@ -99,8 +117,10 @@ static int __init intel_soc_thermal_init(void)
 
 static void __exit intel_soc_thermal_exit(void)
 {
-	if (soc_dts_thres_irq)
+	if (soc_dts_thres_irq) {
 		free_irq(soc_dts_thres_irq, soc_dts);
+		acpi_unregister_gsi(soc_dts_thres_gsi);
+	}
 	intel_soc_dts_iosf_exit(soc_dts);
 }