From: Fu Wei fu.wei@linaro.org
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@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- 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@linaro.org + * Hanjun Guo hanjun.guo@linaro.org + * + * 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);