src/kernel/linux/v4.19/drivers/acpi/arm64/gtdt.c - T800 - Gitiles

 /*
  * ARM Specific GTDT table Support
  *
  * Copyright (C) 2016, 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/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>

 #include <clocksource/arm_arch_timer.h>

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

 /**
  * struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
  * @gtdt:	The pointer to the struct acpi_table_gtdt of GTDT table.
  * @gtdt_end:	The pointer to the end of GTDT table.
  * @platform_timer:	The pointer to the start of Platform Timer Structure
  *
  * The struct store the key info of GTDT table, it should be initialized by
  * acpi_gtdt_init.
  */
 struct acpi_gtdt_descriptor {
 	struct acpi_table_gtdt *gtdt;
 	void *gtdt_end;
 	void *platform_timer;
 };

 static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

 static inline void *next_platform_timer(void *platform_timer)
 {
 	struct acpi_gtdt_header *gh = platform_timer;

 	platform_timer += gh->length;
 	if (platform_timer < acpi_gtdt_desc.gtdt_end)
 		return platform_timer;

 	return NULL;
 }

 #define for_each_platform_timer(_g)				\
 	for (_g = acpi_gtdt_desc.platform_timer; _g;	\
 	     _g = next_platform_timer(_g))

 static inline bool is_timer_block(void *platform_timer)
 {
 	struct acpi_gtdt_header *gh = platform_timer;

 	return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;
 }

 static inline bool is_non_secure_watchdog(void *platform_timer)
 {
 	struct acpi_gtdt_header *gh = platform_timer;
 	struct acpi_gtdt_watchdog *wd = platform_timer;

 	if (gh->type != ACPI_GTDT_TYPE_WATCHDOG)
 		return false;

 	return !(wd->timer_flags & ACPI_GTDT_WATCHDOG_SECURE);
 }

 static int __init map_gt_gsi(u32 interrupt, u32 flags)
 {
 	int trigger, polarity;

 	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);
 }

 /**
  * acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
  * @type:	the type of PPI.
  *
  * Note: Secure state is not managed by the kernel on ARM64 systems.
  * So we only handle the non-secure timer PPIs,
  * ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
  *
  * Return: the mapped PPI value, 0 if error.
  */
 int __init acpi_gtdt_map_ppi(int type)
 {
 	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;

 	switch (type) {
 	case ARCH_TIMER_PHYS_NONSECURE_PPI:
 		return map_gt_gsi(gtdt->non_secure_el1_interrupt,
 				  gtdt->non_secure_el1_flags);
 	case ARCH_TIMER_VIRT_PPI:
 		return map_gt_gsi(gtdt->virtual_timer_interrupt,
 				  gtdt->virtual_timer_flags);

 	case ARCH_TIMER_HYP_PPI:
 		return map_gt_gsi(gtdt->non_secure_el2_interrupt,
 				  gtdt->non_secure_el2_flags);
 	default:
 		pr_err("Failed to map timer interrupt: invalid type.\n");
 	}

 	return 0;
 }

 /**
  * acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
  * @type:	the type of PPI.
  *
  * Return: true if the timer HW state is lost when a CPU enters an idle state,
  * false otherwise
  */
 bool __init acpi_gtdt_c3stop(int type)
 {
 	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;

 	switch (type) {
 	case ARCH_TIMER_PHYS_NONSECURE_PPI:
 		return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);

 	case ARCH_TIMER_VIRT_PPI:
 		return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);

 	case ARCH_TIMER_HYP_PPI:
 		return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);

 	default:
 		pr_err("Failed to get c3stop info: invalid type.\n");
 	}

 	return false;
 }

 /**
  * acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
  * @table:			The pointer to GTDT table.
  * @platform_timer_count:	It points to a integer variable which is used
  *				for storing the number of platform timers.
  *				This pointer could be NULL, if the caller
  *				doesn't need this info.
  *
  * Return: 0 if success, -EINVAL if error.
  */
 int __init acpi_gtdt_init(struct acpi_table_header *table,
 			  int *platform_timer_count)
 {
 	void *platform_timer;
 	struct acpi_table_gtdt *gtdt;

 	gtdt = container_of(table, struct acpi_table_gtdt, header);
 	acpi_gtdt_desc.gtdt = gtdt;
 	acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
 	acpi_gtdt_desc.platform_timer = NULL;
 	if (platform_timer_count)
 		*platform_timer_count = 0;

 	if (table->revision < 2) {
 		pr_warn("Revision:%d doesn't support Platform Timers.\n",
 			table->revision);
 		return 0;
 	}

 	if (!gtdt->platform_timer_count) {
 		pr_debug("No Platform Timer.\n");
 		return 0;
 	}

 	platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
 	if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
 		pr_err(FW_BUG "invalid timer data.\n");
 		return -EINVAL;
 	}
 	acpi_gtdt_desc.platform_timer = platform_timer;
 	if (platform_timer_count)
 		*platform_timer_count = gtdt->platform_timer_count;

 	return 0;
 }

 static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,
 					 struct arch_timer_mem *timer_mem)
 {
 	int i;
 	struct arch_timer_mem_frame *frame;
 	struct acpi_gtdt_timer_entry *gtdt_frame;

 	if (!block->timer_count) {
 		pr_err(FW_BUG "GT block present, but frame count is zero.\n");
 		return -ENODEV;
 	}

 	if (block->timer_count > ARCH_TIMER_MEM_MAX_FRAMES) {
 		pr_err(FW_BUG "GT block lists %d frames, ACPI spec only allows 8\n",
 		       block->timer_count);
 		return -EINVAL;
 	}

 	timer_mem->cntctlbase = (phys_addr_t)block->block_address;
 	/*
 	 * The CNTCTLBase frame is 4KB (register offsets 0x000 - 0xFFC).
 	 * See ARM DDI 0487A.k_iss10775, page I1-5129, Table I1-3
 	 * "CNTCTLBase memory map".
 	 */
 	timer_mem->size = SZ_4K;

 	gtdt_frame = (void *)block + block->timer_offset;
 	if (gtdt_frame + block->timer_count != (void *)block + block->header.length)
 		return -EINVAL;

 	/*
 	 * Get the GT timer Frame data for every GT Block Timer
 	 */
 	for (i = 0; i < block->timer_count; i++, gtdt_frame++) {
 		if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER)
 			continue;
 		if (gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES ||
 		    !gtdt_frame->base_address || !gtdt_frame->timer_interrupt)
 			goto error;

 		frame = &timer_mem->frame[gtdt_frame->frame_number];

 		/* duplicate frame */
 		if (frame->valid)
 			goto error;

 		frame->phys_irq = map_gt_gsi(gtdt_frame->timer_interrupt,
 					     gtdt_frame->timer_flags);
 		if (frame->phys_irq <= 0) {
 			pr_warn("failed to map physical timer irq in frame %d.\n",
 				gtdt_frame->frame_number);
 			goto error;
 		}

 		if (gtdt_frame->virtual_timer_interrupt) {
 			frame->virt_irq =
 				map_gt_gsi(gtdt_frame->virtual_timer_interrupt,
 					   gtdt_frame->virtual_timer_flags);
 			if (frame->virt_irq <= 0) {
 				pr_warn("failed to map virtual timer irq in frame %d.\n",
 					gtdt_frame->frame_number);
 				goto error;
 			}
 		} else {
 			pr_debug("virtual timer in frame %d not implemented.\n",
 				 gtdt_frame->frame_number);
 		}

 		frame->cntbase = gtdt_frame->base_address;
 		/*
 		 * The CNTBaseN frame is 4KB (register offsets 0x000 - 0xFFC).
 		 * See ARM DDI 0487A.k_iss10775, page I1-5130, Table I1-4
 		 * "CNTBaseN memory map".
 		 */
 		frame->size = SZ_4K;
 		frame->valid = true;
 	}

 	return 0;

 error:
 	do {
 		if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER ||
 		    gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES)
 			continue;

 		frame = &timer_mem->frame[gtdt_frame->frame_number];

 		if (frame->phys_irq > 0)
 			acpi_unregister_gsi(gtdt_frame->timer_interrupt);
 		frame->phys_irq = 0;

 		if (frame->virt_irq > 0)
 			acpi_unregister_gsi(gtdt_frame->virtual_timer_interrupt);
 		frame->virt_irq = 0;
 	} while (i-- >= 0 && gtdt_frame--);

 	return -EINVAL;
 }

 /**
  * acpi_arch_timer_mem_init() - Get the info of all GT blocks in GTDT table.
  * @timer_mem:	The pointer to the array of struct arch_timer_mem for returning
  *		the result of parsing. The element number of this array should
  *		be platform_timer_count(the total number of platform timers).
  * @timer_count: It points to a integer variable which is used for storing the
  *		number of GT blocks we have parsed.
  *
  * Return: 0 if success, -EINVAL/-ENODEV if error.
  */
 int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,
 				    int *timer_count)
 {
 	int ret;
 	void *platform_timer;

 	*timer_count = 0;
 	for_each_platform_timer(platform_timer) {
 		if (is_timer_block(platform_timer)) {
 			ret = gtdt_parse_timer_block(platform_timer, timer_mem);
 			if (ret)
 				return ret;
 			timer_mem++;
 			(*timer_count)++;
 		}
 	}

 	if (*timer_count)
 		pr_info("found %d memory-mapped timer block(s).\n",
 			*timer_count);

 	return 0;
 }

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

 	/*
 	 * 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),
 	};
 	int nr_res = ARRAY_SIZE(res);

 	pr_debug("found a Watchdog (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 to get the Watchdog base address.\n");
 		acpi_unregister_gsi(wd->timer_interrupt);
 		return -EINVAL;
 	}

 	if (irq <= 0) {
 		pr_warn("failed to map the Watchdog interrupt.\n");
 		nr_res--;
 	}

 	/*
 	 * Add a platform device named "sbsa-gwdt" to match the platform driver.
 	 * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog
 	 * The platform driver can get device info below by matching this name.
 	 */
 	pdev = platform_device_register_simple("sbsa-gwdt", index, res, nr_res);
 	if (IS_ERR(pdev)) {
 		acpi_unregister_gsi(wd->timer_interrupt);
 		return PTR_ERR(pdev);
 	}

 	return 0;
 }

 static int __init gtdt_sbsa_gwdt_init(void)
 {
 	void *platform_timer;
 	struct acpi_table_header *table;
 	int ret, timer_count, gwdt_count = 0;

 	if (acpi_disabled)
 		return 0;

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

 	/*
 	 * Note: Even though the global variable acpi_gtdt_desc has been
 	 * initialized by acpi_gtdt_init() while initializing the arch timers,
 	 * when we call this function to get SBSA watchdogs info from GTDT, the
 	 * pointers stashed in it are stale (since they are early temporary
 	 * mappings carried out before acpi_permanent_mmap is set) and we need
 	 * to re-initialize them with permanent mapped pointer values to let the
 	 * GTDT parsing possible.
 	 */
 	ret = acpi_gtdt_init(table, &timer_count);
 	if (ret || !timer_count)
 		return ret;

 	for_each_platform_timer(platform_timer) {
 		if (is_non_secure_watchdog(platform_timer)) {
 			ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count);
 			if (ret)
 				break;
 			gwdt_count++;
 		}
 	}

 	if (gwdt_count)
 		pr_info("found %d SBSA generic Watchdog(s).\n", gwdt_count);

 	return ret;
 }

 device_initcall(gtdt_sbsa_gwdt_init);
	/*
	* ARM Specific GTDT table Support
	*
	* Copyright (C) 2016, 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/irqdomain.h>
	#include <linux/kernel.h>
	#include <linux/platform_device.h>

	#include <clocksource/arm_arch_timer.h>

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

	/**
	* struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
	* @gtdt: The pointer to the struct acpi_table_gtdt of GTDT table.
	* @gtdt_end: The pointer to the end of GTDT table.
	* @platform_timer: The pointer to the start of Platform Timer Structure
	*
	* The struct store the key info of GTDT table, it should be initialized by
	* acpi_gtdt_init.
	*/
	struct acpi_gtdt_descriptor {
	struct acpi_table_gtdt *gtdt;
	void *gtdt_end;
	void *platform_timer;
	};

	static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

	static inline void next_platform_timer(void platform_timer)
	{
	struct acpi_gtdt_header *gh = platform_timer;

	platform_timer += gh->length;
	if (platform_timer < acpi_gtdt_desc.gtdt_end)
	return platform_timer;

	return NULL;
	}

	#define for_each_platform_timer(_g) \
	for (_g = acpi_gtdt_desc.platform_timer; _g; \
	_g = next_platform_timer(_g))

	static inline bool is_timer_block(void *platform_timer)
	{
	struct acpi_gtdt_header *gh = platform_timer;

	return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;
	}

	static inline bool is_non_secure_watchdog(void *platform_timer)
	{
	struct acpi_gtdt_header *gh = platform_timer;
	struct acpi_gtdt_watchdog *wd = platform_timer;

	if (gh->type != ACPI_GTDT_TYPE_WATCHDOG)
	return false;

	return !(wd->timer_flags & ACPI_GTDT_WATCHDOG_SECURE);
	}

	static int __init map_gt_gsi(u32 interrupt, u32 flags)
	{
	int trigger, polarity;

	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);
	}

	/**
	* acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
	* @type: the type of PPI.
	*
	* Note: Secure state is not managed by the kernel on ARM64 systems.
	* So we only handle the non-secure timer PPIs,
	* ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
	*
	* Return: the mapped PPI value, 0 if error.
	*/
	int __init acpi_gtdt_map_ppi(int type)
	{
	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;

	switch (type) {
	case ARCH_TIMER_PHYS_NONSECURE_PPI:
	return map_gt_gsi(gtdt->non_secure_el1_interrupt,
	gtdt->non_secure_el1_flags);
	case ARCH_TIMER_VIRT_PPI:
	return map_gt_gsi(gtdt->virtual_timer_interrupt,
	gtdt->virtual_timer_flags);

	case ARCH_TIMER_HYP_PPI:
	return map_gt_gsi(gtdt->non_secure_el2_interrupt,
	gtdt->non_secure_el2_flags);
	default:
	pr_err("Failed to map timer interrupt: invalid type.\n");
	}

	return 0;
	}

	/**
	* acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
	* @type: the type of PPI.
	*
	* Return: true if the timer HW state is lost when a CPU enters an idle state,
	* false otherwise
	*/
	bool __init acpi_gtdt_c3stop(int type)
	{
	struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;

	switch (type) {
	case ARCH_TIMER_PHYS_NONSECURE_PPI:
	return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);

	case ARCH_TIMER_VIRT_PPI:
	return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);

	case ARCH_TIMER_HYP_PPI:
	return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);

	default:
	pr_err("Failed to get c3stop info: invalid type.\n");
	}

	return false;
	}

	/**
	* acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
	* @table: The pointer to GTDT table.
	* @platform_timer_count: It points to a integer variable which is used
	* for storing the number of platform timers.
	* This pointer could be NULL, if the caller
	* doesn't need this info.
	*
	* Return: 0 if success, -EINVAL if error.
	*/
	int __init acpi_gtdt_init(struct acpi_table_header *table,
	int *platform_timer_count)
	{
	void *platform_timer;
	struct acpi_table_gtdt *gtdt;

	gtdt = container_of(table, struct acpi_table_gtdt, header);
	acpi_gtdt_desc.gtdt = gtdt;
	acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
	acpi_gtdt_desc.platform_timer = NULL;
	if (platform_timer_count)
	*platform_timer_count = 0;

	if (table->revision < 2) {
	pr_warn("Revision:%d doesn't support Platform Timers.\n",
	table->revision);
	return 0;
	}

	if (!gtdt->platform_timer_count) {
	pr_debug("No Platform Timer.\n");
	return 0;
	}

	platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
	if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
	pr_err(FW_BUG "invalid timer data.\n");
	return -EINVAL;
	}
	acpi_gtdt_desc.platform_timer = platform_timer;
	if (platform_timer_count)
	*platform_timer_count = gtdt->platform_timer_count;

	return 0;
	}

	static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,
	struct arch_timer_mem *timer_mem)
	{
	int i;
	struct arch_timer_mem_frame *frame;
	struct acpi_gtdt_timer_entry *gtdt_frame;

	if (!block->timer_count) {
	pr_err(FW_BUG "GT block present, but frame count is zero.\n");
	return -ENODEV;
	}

	if (block->timer_count > ARCH_TIMER_MEM_MAX_FRAMES) {
	pr_err(FW_BUG "GT block lists %d frames, ACPI spec only allows 8\n",
	block->timer_count);
	return -EINVAL;
	}

	timer_mem->cntctlbase = (phys_addr_t)block->block_address;
	/*
	* The CNTCTLBase frame is 4KB (register offsets 0x000 - 0xFFC).
	* See ARM DDI 0487A.k_iss10775, page I1-5129, Table I1-3
	* "CNTCTLBase memory map".
	*/
	timer_mem->size = SZ_4K;

	gtdt_frame = (void *)block + block->timer_offset;
	if (gtdt_frame + block->timer_count != (void *)block + block->header.length)
	return -EINVAL;

	/*
	* Get the GT timer Frame data for every GT Block Timer
	*/
	for (i = 0; i < block->timer_count; i++, gtdt_frame++) {
	if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER)
	continue;
	if (gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES \|\|
	!gtdt_frame->base_address \|\| !gtdt_frame->timer_interrupt)
	goto error;

	frame = &timer_mem->frame[gtdt_frame->frame_number];

	/* duplicate frame */
	if (frame->valid)
	goto error;

	frame->phys_irq = map_gt_gsi(gtdt_frame->timer_interrupt,
	gtdt_frame->timer_flags);
	if (frame->phys_irq <= 0) {
	pr_warn("failed to map physical timer irq in frame %d.\n",
	gtdt_frame->frame_number);
	goto error;
	}

	if (gtdt_frame->virtual_timer_interrupt) {
	frame->virt_irq =
	map_gt_gsi(gtdt_frame->virtual_timer_interrupt,
	gtdt_frame->virtual_timer_flags);
	if (frame->virt_irq <= 0) {
	pr_warn("failed to map virtual timer irq in frame %d.\n",
	gtdt_frame->frame_number);
	goto error;
	}
	} else {
	pr_debug("virtual timer in frame %d not implemented.\n",
	gtdt_frame->frame_number);
	}

	frame->cntbase = gtdt_frame->base_address;
	/*
	* The CNTBaseN frame is 4KB (register offsets 0x000 - 0xFFC).
	* See ARM DDI 0487A.k_iss10775, page I1-5130, Table I1-4
	* "CNTBaseN memory map".
	*/
	frame->size = SZ_4K;
	frame->valid = true;
	}

	return 0;

	error:
	do {
	if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER \|\|
	gtdt_frame->frame_number >= ARCH_TIMER_MEM_MAX_FRAMES)
	continue;

	frame = &timer_mem->frame[gtdt_frame->frame_number];

	if (frame->phys_irq > 0)
	acpi_unregister_gsi(gtdt_frame->timer_interrupt);
	frame->phys_irq = 0;

	if (frame->virt_irq > 0)
	acpi_unregister_gsi(gtdt_frame->virtual_timer_interrupt);
	frame->virt_irq = 0;
	} while (i-- >= 0 && gtdt_frame--);

	return -EINVAL;
	}

	/**
	* acpi_arch_timer_mem_init() - Get the info of all GT blocks in GTDT table.
	* @timer_mem: The pointer to the array of struct arch_timer_mem for returning
	* the result of parsing. The element number of this array should
	* be platform_timer_count(the total number of platform timers).
	* @timer_count: It points to a integer variable which is used for storing the
	* number of GT blocks we have parsed.
	*
	* Return: 0 if success, -EINVAL/-ENODEV if error.
	*/
	int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,
	int *timer_count)
	{
	int ret;
	void *platform_timer;

	*timer_count = 0;
	for_each_platform_timer(platform_timer) {
	if (is_timer_block(platform_timer)) {
	ret = gtdt_parse_timer_block(platform_timer, timer_mem);
	if (ret)
	return ret;
	timer_mem++;
	(*timer_count)++;
	}
	}

	if (*timer_count)
	pr_info("found %d memory-mapped timer block(s).\n",
	*timer_count);

	return 0;
	}

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

	/*
	* 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),
	};
	int nr_res = ARRAY_SIZE(res);

	pr_debug("found a Watchdog (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 to get the Watchdog base address.\n");
	acpi_unregister_gsi(wd->timer_interrupt);
	return -EINVAL;
	}

	if (irq <= 0) {
	pr_warn("failed to map the Watchdog interrupt.\n");
	nr_res--;
	}

	/*
	* Add a platform device named "sbsa-gwdt" to match the platform driver.
	* "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog
	* The platform driver can get device info below by matching this name.
	*/
	pdev = platform_device_register_simple("sbsa-gwdt", index, res, nr_res);
	if (IS_ERR(pdev)) {
	acpi_unregister_gsi(wd->timer_interrupt);
	return PTR_ERR(pdev);
	}

	return 0;
	}

	static int __init gtdt_sbsa_gwdt_init(void)
	{
	void *platform_timer;
	struct acpi_table_header *table;
	int ret, timer_count, gwdt_count = 0;

	if (acpi_disabled)
	return 0;

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

	/*
	* Note: Even though the global variable acpi_gtdt_desc has been
	* initialized by acpi_gtdt_init() while initializing the arch timers,
	* when we call this function to get SBSA watchdogs info from GTDT, the
	* pointers stashed in it are stale (since they are early temporary
	* mappings carried out before acpi_permanent_mmap is set) and we need
	* to re-initialize them with permanent mapped pointer values to let the
	* GTDT parsing possible.
	*/
	ret = acpi_gtdt_init(table, &timer_count);
	if (ret \|\| !timer_count)
	return ret;

	for_each_platform_timer(platform_timer) {
	if (is_non_secure_watchdog(platform_timer)) {
	ret = gtdt_import_sbsa_gwdt(platform_timer, gwdt_count);
	if (ret)
	break;
	gwdt_count++;
	}
	}

	if (gwdt_count)
	pr_info("found %d SBSA generic Watchdog(s).\n", gwdt_count);

	return ret;
	}

	device_initcall(gtdt_sbsa_gwdt_init);