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/*
* 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/kernel.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 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;
}
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