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path: root/drivers/acpi/acpi_gtdt.c
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/*
 * 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>

#include <clocksource/arm_arch_timer.h>

#undef pr_fmt
#define pr_fmt(fmt) "GTDT: " fmt

typedef int (*platform_timer_handler)(void *platform_timer, int index,
				      void *data);

static void *platform_timer_struct __initdata;
static u32 platform_timer_count __initdata;
static void *gtdt_end __initdata;

static int __init for_platform_timer(enum acpi_gtdt_type type,
				     platform_timer_handler handler, void *data)
{
	struct acpi_gtdt_header *header;
	int i, index, ret;
	void *platform_timer = platform_timer_struct;

	for (i = 0, index = 0; i < platform_timer_count; i++) {
		if (platform_timer > gtdt_end) {
			pr_err(FW_BUG "subtable pointer overflows.\n");
			platform_timer_count = i;
			break;
		}
		header = (struct acpi_gtdt_header *)platform_timer;
		if (header->type == type) {
			ret = handler(platform_timer, index, data);
			if (ret)
				pr_err("failed to handler subtable %d.\n", i);
			else
				index++;
		}
		platform_timer += header->length;
	}

	return index;
}

/*
 * 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, and will be run only once.
 */
static void __init platform_timer_init(struct acpi_table_header *table,
				       struct acpi_table_gtdt *gtdt)
{
	gtdt_end = (void *)table + table->length;

	if (table->revision < 2) {
		pr_info("Revision:%d doesn't support Platform Timers.\n",
			table->revision);
		return;
	}

	platform_timer_count = gtdt->platform_timer_count;
	if (!platform_timer_count) {
		pr_info("No Platform Timer structures.\n");
		return;
	}

	platform_timer_struct = (void *)gtdt + gtdt->platform_timer_offset;
	if (platform_timer_struct < (void *)table +
				    sizeof(struct acpi_table_gtdt)) {
		pr_err(FW_BUG "Platform Timer pointer error.\n");
		platform_timer_struct = NULL;
		platform_timer_count = 0;
	}
}

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);
}

/*
 * Get the necessary info of arch_timer from GTDT table.
 */
int __init gtdt_arch_timer_init(struct acpi_table_header *table, int *ppi,
				bool *c3stop, u32 *timer_count)
{
	struct acpi_table_gtdt *gtdt;

	if (acpi_disabled || !table || !ppi || !c3stop)
		return -EINVAL;

	gtdt = container_of(table, struct acpi_table_gtdt, header);
	if (!gtdt) {
		pr_err("table pointer error.\n");
		return -EINVAL;
	}

	ppi[PHYS_SECURE_PPI] =
		map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
					    gtdt->secure_el1_flags);

	ppi[PHYS_NONSECURE_PPI] =
		map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
					    gtdt->non_secure_el1_flags);

	ppi[VIRT_PPI] =
		map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
					    gtdt->virtual_timer_flags);

	ppi[HYP_PPI] =
		map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
					    gtdt->non_secure_el2_flags);

	*c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);

	platform_timer_init(table, gtdt);
	if (timer_count)
		*timer_count = platform_timer_count;

	return 0;
}

/*
 * Helper function for getting the pointer of a timer frame in GT block.
 */
static void __init *gtdt_gt_timer_frame(struct acpi_gtdt_timer_block *gt_block,
					int index)
{
	void *timer_frame = (void *)gt_block + gt_block->timer_offset +
			    sizeof(struct acpi_gtdt_timer_entry) * index;

	if (timer_frame <= (void *)gt_block + gt_block->header.length -
			   sizeof(struct acpi_gtdt_timer_entry))
		return timer_frame;

	return NULL;
}

static int __init gtdt_parse_gt_block(void *platform_timer, int index,
				      void *data)
{
	struct acpi_gtdt_timer_block *block;
	struct acpi_gtdt_timer_entry *frame;
	struct gt_block_data *block_data;
	int i, j;

	if (!platform_timer || !data)
		return -EINVAL;

	block = platform_timer;
	block_data = data + sizeof(struct gt_block_data) * index;

	if (!block->block_address || !block->timer_count) {
		pr_err(FW_BUG "invalid GT Block data.\n");
		return -EINVAL;
	}
	block_data->cntctlbase_phy = (phys_addr_t)block->block_address;
	block_data->timer_count = block->timer_count;

	/*
	 * Get the GT timer Frame data for every GT Block Timer
	 */
	for (i = 0, j = 0; i < block->timer_count; i++) {
		frame = gtdt_gt_timer_frame(block, i);
		if (!frame || !frame->base_address || !frame->timer_interrupt) {
			pr_err(FW_BUG "invalid GT Block Timer data, skip.\n");
			continue;
		}
		block_data->timer[j].frame_nr = frame->frame_number;
		block_data->timer[j].cntbase_phy = frame->base_address;
		block_data->timer[j].irq = map_generic_timer_interrupt(
						   frame->timer_interrupt,
						   frame->timer_flags);
		if (frame->virtual_timer_interrupt)
			block_data->timer[j].virt_irq =
				map_generic_timer_interrupt(
					frame->virtual_timer_interrupt,
					frame->virtual_timer_flags);
		j++;
	}

	if (j)
		return 0;

	block_data->cntctlbase_phy = (phys_addr_t)NULL;
	block_data->timer_count = 0;

	return -EINVAL;
}

/*
 * Get the GT block info for memory-mapped timer from GTDT table.
 * Please make sure we have called gtdt_arch_timer_init, because it helps to
 * init the global variables.
 */
int __init gtdt_arch_timer_mem_init(struct gt_block_data *data)
{
	int ret = for_platform_timer(ACPI_GTDT_TYPE_TIMER_BLOCK,
				     gtdt_parse_gt_block, (void *)data);

	pr_info("found %d memory-mapped timer block.\n", ret);

	return ret;
}

/*
 * Initialize a SBSA generic Watchdog platform device info from GTDT
 */
static int __init gtdt_import_sbsa_gwdt(void *platform_timer,
					int index, void *data)
{
	struct platform_device *pdev;
	struct acpi_gtdt_watchdog *wd = platform_timer;
	int irq = map_generic_timer_interrupt(wd->timer_interrupt,
					      wd->timer_flags);
	int no_irq = 1;

	/*
	 * According to SBSA specification the size of refresh and control
	 * frames of SBSA Generic Watchdog is SZ_4K(Offset 0x000 – 0xFFF).
	 */
	struct resource res[] = {
		DEFINE_RES_MEM(wd->control_frame_address, SZ_4K),
		DEFINE_RES_MEM(wd->refresh_frame_address, SZ_4K),
		DEFINE_RES_IRQ(irq),
	};

	pr_debug("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)) {
		pr_err(FW_BUG "failed getting the Watchdog GT frame addr.\n");
		return -EINVAL;
	}

	if (!wd->timer_interrupt)
		pr_warn(FW_BUG "failed getting the Watchdog GT GSIV.\n");
	else if (irq <= 0)
		pr_warn("failed to map the Watchdog GT GSIV.\n");
	else
		no_irq = 0;

	/*
	 * 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) - no_irq);
	if (IS_ERR(pdev)) {
		acpi_unregister_gsi(wd->timer_interrupt);
		return PTR_ERR(pdev);
	}

	return 0;
}

static int __init gtdt_sbsa_gwdt_init(void)
{
	struct acpi_table_header *table;
	struct acpi_table_gtdt *gtdt;
	int ret;

	if (acpi_disabled)
		return 0;

	if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table)))
		return -EINVAL;

	/* global variables initialization */
	gtdt_end = (void *)table + table->length;
	gtdt = container_of(table, struct acpi_table_gtdt, header);
	platform_timer_struct = (void *)gtdt + gtdt->platform_timer_offset;

	ret = for_platform_timer(ACPI_GTDT_TYPE_WATCHDOG,
				 gtdt_import_sbsa_gwdt, NULL);
	pr_info("found %d SBSA generic Watchdog.\n", ret);

	return 0;
}

device_initcall(gtdt_sbsa_gwdt_init);