platform/x86: intel_scu_wdt: Move driver from arch/x86

The ACPI-enabled Intel MID platforms neither have WDAT table nor proper IDs
to instantiate watchdog device. In order to keep them working move the board
code from arch/x86 to drivers/platform/x86.

Note, the complete SFI support is going to be removed, that's why PDx86
has been chosen as a new home for it. This is the only device which needs
additional code so far.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 91 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 4a5798a0ce0c..0bb85eabace1 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1424,6 +1424,14 @@ config INTEL_SCU_PLATFORM
 	  and SCU (sometimes called PMC as well). The driver currently
 	  supports Intel Elkhart Lake and compatible platforms.
 
+config INTEL_SCU_WDT
+	bool
+	default INTEL_SCU_PCI
+	depends on INTEL_MID_WATCHDOG
+	help
+	  This is a specific platform code to instantiate watchdog device
+	  on ACPI-based Intel MID platforms.
+
 config INTEL_SCU_IPC_UTIL
 	tristate "Intel SCU IPC utility driver"
 	depends on INTEL_SCU
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 728ccc226a29..19306450d791 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -146,6 +146,7 @@ obj-$(CONFIG_INTEL_PUNIT_IPC)		+= intel_punit_ipc.o
 obj-$(CONFIG_INTEL_SCU_IPC)		+= intel_scu_ipc.o
 obj-$(CONFIG_INTEL_SCU_PCI)		+= intel_scu_pcidrv.o
 obj-$(CONFIG_INTEL_SCU_PLATFORM)	+= intel_scu_pltdrv.o
+obj-$(CONFIG_INTEL_SCU_WDT)		+= intel_scu_wdt.o
 obj-$(CONFIG_INTEL_SCU_IPC_UTIL)	+= intel_scu_ipcutil.o
 obj-$(CONFIG_INTEL_TELEMETRY)		+= intel_telemetry_core.o \
 					   intel_telemetry_pltdrv.o \
diff --git a/drivers/platform/x86/intel_scu_wdt.c b/drivers/platform/x86/intel_scu_wdt.c
new file mode 100644
index 000000000000..227218a8f98e
--- /dev/null
+++ b/drivers/platform/x86/intel_scu_wdt.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Merrifield watchdog platform device library file
+ *
+ * (C) Copyright 2014 Intel Corporation
+ * Author: David Cohen <david.a.cohen@linux.intel.com>
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/intel-mid_wdt.h>
+
+#include <asm/intel-mid.h>
+#include <asm/intel_scu_ipc.h>
+#include <asm/io_apic.h>
+#include <asm/hw_irq.h>
+
+#define TANGIER_EXT_TIMER0_MSI 12
+
+static struct platform_device wdt_dev = {
+	.name = "intel_mid_wdt",
+	.id = -1,
+};
+
+static int tangier_probe(struct platform_device *pdev)
+{
+	struct irq_alloc_info info;
+	struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
+	int gsi = TANGIER_EXT_TIMER0_MSI;
+	int irq;
+
+	if (!pdata)
+		return -EINVAL;
+
+	/* IOAPIC builds identity mapping between GSI and IRQ on MID */
+	ioapic_set_alloc_attr(&info, cpu_to_node(0), 1, 0);
+	irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info);
+	if (irq < 0) {
+		dev_warn(&pdev->dev, "cannot find interrupt %d in ioapic\n", gsi);
+		return irq;
+	}
+
+	pdata->irq = irq;
+	return 0;
+}
+
+static struct intel_mid_wdt_pdata tangier_pdata = {
+	.probe = tangier_probe,
+};
+
+static int wdt_scu_status_change(struct notifier_block *nb,
+				 unsigned long code, void *data)
+{
+	if (code == SCU_DOWN) {
+		platform_device_unregister(&wdt_dev);
+		return 0;
+	}
+
+	return platform_device_register(&wdt_dev);
+}
+
+static struct notifier_block wdt_scu_notifier = {
+	.notifier_call	= wdt_scu_status_change,
+};
+
+static int __init register_mid_wdt(void)
+{
+	if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
+		return -ENODEV;
+
+	wdt_dev.dev.platform_data = &tangier_pdata;
+
+	/*
+	 * We need to be sure that the SCU IPC is ready before watchdog device
+	 * can be registered:
+	 */
+	intel_scu_notifier_add(&wdt_scu_notifier);
+
+	return 0;
+}
+arch_initcall(register_mid_wdt);