[PATCH 6/6] ACPI: import watchdog info of GTDT into platform device

[fu.wei@linaro.org]

From: Fu Wei <fu.wei@linaro.org>

Parse SBSA Generic Watchdog Structure in GTDT table of ACPI,
and create a platform device with that information
This platform device can be used by the ARM SBSA Generic Watchdog driver

Signed-off-by: Fu Wei <fu.wei@linaro.org>
---
 arch/arm64/kernel/acpi.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 8b83955..1ed11fd 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -23,6 +23,7 @@
 #include <linux/irqdomain.h>
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
+#include <linux/platform_device.h>
 #include <linux/smp.h>
 
 #include <asm/cputype.h>
@@ -343,3 +344,138 @@ void __init acpi_gic_init(void)
 
 	early_acpi_os_unmap_memory((char *)table, tbl_size);
 }
+
+static int __init acpi_gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,
+					     int index)
+{
+	struct platform_device *pdev;
+	struct resource *res;
+	u32 gsi, flags;
+	int irq, trigger, polarity;
+	resource_size_t rf_base_phy, cf_base_phy;
+	int err = -ENOMEM;
+
+	/*
+	 * Get SBSA Generic Watchdog info
+	 * from a Watchdog GT type structure in GTDT
+	 */
+	rf_base_phy = (resource_size_t)wd->refresh_frame_address;
+	cf_base_phy = (resource_size_t)wd->control_frame_address;
+	gsi = wd->timer_interrupt;
+	flags = wd->timer_flags;
+
+	pr_info("GTDT: a Watchdog GT structure(0x%llx/0x%llx gsi:%u flags:0x%x)\n",
+		rf_base_phy, cf_base_phy, gsi, flags);
+
+	if (!(rf_base_phy && cf_base_phy && gsi)) {
+		pr_err("GTDT: failed geting the device info.\n");
+		return -EINVAL;
+	}
+
+	trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+			: ACPI_LEVEL_SENSITIVE;
+	polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+			: ACPI_ACTIVE_HIGH;
+	irq = acpi_register_gsi(NULL, gsi, trigger, polarity);
+	if (irq < 0) {
+		pr_err("GTDT: failed to register GSI of the Watchdog GT.\n");
+		return -EINVAL;
+	}
+
+	pdev = platform_device_alloc("sbsa-gwdt", index);
+	if (!pdev)
+		goto err_unregister_gsi;
+
+	res = kcalloc(3, sizeof(*res), GFP_KERNEL);
+	if (!res)
+		goto err_device_put;
+
+	res[0].start = rf_base_phy;
+	res[0].end = rf_base_phy + SZ_4K - 1;
+	res[0].name = "refresh";
+	res[0].flags = IORESOURCE_MEM;
+
+	res[1].start = cf_base_phy;
+	res[1].end = cf_base_phy + SZ_4K - 1;
+	res[1].name = "control";
+	res[1].flags = IORESOURCE_MEM;
+
+	res[2].start = irq;
+	res[2].end = res[2].start;
+	res[2].name = "ws0";
+	res[2].flags = IORESOURCE_IRQ;
+
+	err = platform_device_add_resources(pdev, res, 3);
+	if (err)
+		goto err_free_res;
+
+	err = platform_device_add(pdev);
+	if (err)
+		goto err_free_res;
+
+	return 0;
+
+err_free_res:
+	kfree(res);
+err_device_put:
+	platform_device_put(pdev);
+err_unregister_gsi:
+	acpi_unregister_gsi(gsi);
+
+	return err;
+}
+
+/* Initialize SBSA generic Watchdog platform device info from GTDT */
+static int __init acpi_gtdt_sbsa_gwdt_init(struct acpi_table_header *table)
+{
+	struct acpi_table_gtdt *gtdt;
+	struct acpi_gtdt_header *header;
+	void *gtdt_subtable;
+	int i, gwdt_index;
+	int ret = 0;
+
+	if (table->revision < 2) {
+		pr_info("GTDT: Revision:%d doesn't support Platform Timers.\n",
+			table->revision);
+		return 0;
+	}
+
+	gtdt = container_of(table, struct acpi_table_gtdt, header);
+	if (!gtdt->platform_timer_count) {
+		pr_info("GTDT: No Platform Timer structures.\n");
+		return 0;
+	}
+
+	gtdt_subtable = (void *)gtdt + gtdt->platform_timer_offset;
+
+	for (i = 0, gwdt_index = 0; i < gtdt->platform_timer_count; i++) {
+		if (gtdt_subtable > (void *)table + table->length) {
+			pr_err("GTDT: subtable pointer overflows, bad table\n");
+			return -EINVAL;
+		}
+		header = (struct acpi_gtdt_header *)gtdt_subtable;
+		if (header->type == ACPI_GTDT_TYPE_WATCHDOG) {
+			ret = acpi_gtdt_import_sbsa_gwdt(gtdt_subtable,
+							 gwdt_index);
+			if (ret)
+				pr_err("GTDT: failed to import subtable %d\n",
+				       i);
+			else
+				gwdt_index++;
+		}
+		gtdt_subtable += header->length;
+	}
+
+	return ret;
+}
+
+/* Initialize the SBSA Generic Watchdog presented in GTDT */
+static int __init acpi_gtdt_init(void)
+{
+	if (acpi_disabled)
+		return 0;
+
+	return acpi_table_parse(ACPI_SIG_GTDT, acpi_gtdt_sbsa_gwdt_init);
+}
+
+arch_initcall(acpi_gtdt_init);
-- 
1.9.1