From: Fu Wei fu.wei@linaro.org
Signed-off-by: Fu Wei fu.wei@linaro.org --- drivers/acpi/acpi_gtdt.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+)
diff --git a/drivers/acpi/acpi_gtdt.c b/drivers/acpi/acpi_gtdt.c new file mode 100644 index 0000000..54d7644e --- /dev/null +++ b/drivers/acpi/acpi_gtdt.c @@ -0,0 +1,85 @@ +/* + * ARM Specific GTDT table Support + * + * Copyright (C) 2015, Linaro Ltd. + * Author: Daniel Lezcano daniel.lezcano@linaro.org + * 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/init.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#undef pr_fmt +#define pr_fmt(fmt) "GTDT: " fmt + +typedef struct { + struct acpi_table_gtdt *gtdt; + void *platform_timer_start; + void *gtdt_end; +} acpi_gtdt_desc_t; + +static acpi_gtdt_desc_t acpi_gtdt_desc __initdata; + +static inline void *gtdt_next(void *platform_timer, void *end, int type) +{ + struct acpi_gtdt_header *gh = platform_timer; + + while ((void *)(gh += gh->length) < end) + if (gh->type == type) + return (void *)gh; + return NULL; +} + +#define for_each_gtdt_type(_g, _t) \ + for (_g = acpi_gtdt_desc.platform_timer_start; _g; \ + _g = gtdt_next(_g, acpi_gtdt_desc.gtdt_end, _t)) + +#define for_each_gtdt_timer(_g) \ + for_each_gtdt_type(_g, ACPI_GTDT_TYPE_TIMER_BLOCK) + +#define for_each_gtdt_watchdog(_g) \ + for_each_gtdt_type(_g, ACPI_GTDT_TYPE_WATCHDOG) + +/* + * Get some basic info from GTDT table, and init the global variables above + * for all timers initialization of Generic Timer. + * This function does some validation on GTDT table. + */ +static int __init acpi_gtdt_desc_init(struct acpi_table_header *table) +{ + struct acpi_table_gtdt *gtdt = container_of(table, + struct acpi_table_gtdt, + header); + + acpi_gtdt_desc.gtdt = gtdt; + acpi_gtdt_desc.gtdt_end = (void *)table + table->length; + + if (table->revision < 2) { + pr_info("Revision:%d doesn't support Platform Timers.\n", + table->revision); + return 0; + } + + if (!gtdt->platform_timer_count) { + pr_info("No Platform Timer.\n"); + return 0; + } + + acpi_gtdt_desc.platform_timer_start = (void *)gtdt + + gtdt->platform_timer_offset; + if (acpi_gtdt_desc.platform_timer_start < + (void *)table + sizeof(struct acpi_table_gtdt)) { + pr_err(FW_BUG "Platform Timer pointer error.\n"); + acpi_gtdt_desc.platform_timer_start = NULL; + return -EINVAL; + } + + return gtdt->platform_timer_count; +}