From: Fu Wei <fu.wei@xxxxxxxxxx>
This driver adds support for parsing SBSA Generic Watchdog
Structure in GTDT, and creating a platform device with that
information. This allows the operating system to obtain device
data from the resource of platform device.
The platform device named "sbsa-gwdt" can be used by the
ARM SBSA Generic Watchdog driver.
Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
drivers/acpi/Kconfig | 9 ++++
drivers/acpi/Makefile | 1 +
drivers/acpi/gtdt.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 147 insertions(+)
create mode 100644 drivers/acpi/gtdt.c
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 1bbaa3d..e125698 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -433,4 +433,13 @@ config XPOWER_PMIC_OPREGION
endif
+config ACPI_GTDT
+ bool "ACPI GTDT Support"
+ depends on ARM64
+ help
+ GTDT (Generic Timer Description Table) provides information
+ for per-processor timers and Platform (memory-mapped) timers
+ for ARM platforms. Select this option to provide information
+ needed for the timers init.
+
endif # ACPI
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 431e587..2c5a194 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -96,3 +96,4 @@ obj-$(CONFIG_ACPI_EXTLOG) += acpi_extlog.o
obj-$(CONFIG_PMIC_OPREGION) += pmic/intel_pmic.o
obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+obj-$(CONFIG_ACPI_GTDT) += gtdt.o
diff --git a/drivers/acpi/gtdt.c b/drivers/acpi/gtdt.c
new file mode 100644
index 0000000..a92abf2
--- /dev/null
+++ b/drivers/acpi/gtdt.c
@@ -0,0 +1,137 @@
+/*
+ * ARM Specific GTDT table Support
+ *
+ * Copyright (C) 2015, Linaro Ltd.
+ * Author: Fu Wei <fu.wei@xxxxxxxxxx>
+ * Hanjun Guo <hanjun.guo@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
+{
+ int trigger, polarity;
+
+ if (!interrupt)
+ return 0;
+
+ trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+ : ACPI_LEVEL_SENSITIVE;
+
+ polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+ : ACPI_ACTIVE_HIGH;
+
+ return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/*
+ * Initialize a SBSA generic Watchdog platform device info from GTDT
+ * According to SBSA specification the size of refresh and control
+ * frames of SBSA Generic Watchdog is SZ_4K(Offset 0x000 – 0xFFF).
+ */
+static int __init gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,
+ int index)
+{
+ struct platform_device *pdev;
+ int irq = map_generic_timer_interrupt(wd->timer_interrupt,
+ wd->timer_flags);
+ struct resource res[] = {
+ DEFINE_RES_IRQ_NAMED(irq, "ws0"),
+ DEFINE_RES_MEM_NAMED(wd->refresh_frame_address, SZ_4K,
+ "refresh"),
+ DEFINE_RES_MEM_NAMED(wd->control_frame_address, SZ_4K,
+ "control"),
+ };
+
+ pr_debug("GTDT: a Watchdog GT(0x%llx/0x%llx gsi:%u flags:0x%x)\n",
+ wd->refresh_frame_address, wd->control_frame_address,
+ wd->timer_interrupt, wd->timer_flags);
+
+ if (!(wd->refresh_frame_address &&
+ wd->control_frame_address &&
+ wd->timer_interrupt)) {
+ pr_err("GTDT: failed geting the device info.\n");
+ return -EINVAL;
+ }
+
+ if (irq < 0) {
+ pr_err("GTDT: failed to register GSI of the Watchdog GT.\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Add a platform device named "sbsa-gwdt" to match the platform driver.
+ * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog
+ * The platform driver (like drivers/watchdog/sbsa_gwdt.c)can get device
+ * info below by matching this name.
+ */
+ pdev = platform_device_register_simple("sbsa-gwdt", index, res,
+ ARRAY_SIZE(res));
+ if (IS_ERR(pdev)) {
+ acpi_unregister_gsi(wd->timer_interrupt);
+ return PTR_ERR(pdev);
+ }
+
+ return 0;
+}
+
+static int __init gtdt_platform_timer_parse(struct acpi_table_header *table)
+{
+ struct acpi_gtdt_header *header;
+ struct acpi_table_gtdt *gtdt;
+ void *gtdt_subtable;
+ int i, gwdt_index;
+ int ret = 0;
+
+ if (table->revision < 2) {
+ pr_warn("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 = 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;
+}
+
+static int __init gtdt_platform_timer_init(void)
+{
+ if (acpi_disabled)
+ return 0;
+
+ return acpi_table_parse(ACPI_SIG_GTDT, gtdt_platform_timer_parse);
+}
+
+device_initcall(gtdt_platform_timer_init);
--
1.9.1
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