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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* MediaTek SoCs CPUX General Purpose Timer handling
*
* Based on timer-mediatek.c:
* Copyright (C) 2014 Matthias Brugger <matthias.bgg@gmail.com>
*
* Copyright (C) 2022 Collabora Ltd.
* AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.h>
#include <linux/sched_clock.h>
#include <linux/slab.h>
#include "timer-of.h"
#define TIMER_SYNC_TICKS 3
/* cpux mcusys wrapper */
#define CPUX_CON_REG 0x0
#define CPUX_IDX_REG 0x4
/* cpux */
#define CPUX_IDX_GLOBAL_CTRL 0x0
#define CPUX_ENABLE BIT(0)
#define CPUX_CLK_DIV_MASK GENMASK(10, 8)
#define CPUX_CLK_DIV1 BIT(8)
#define CPUX_CLK_DIV2 BIT(9)
#define CPUX_CLK_DIV4 BIT(10)
#define CPUX_IDX_GLOBAL_IRQ 0x30
static u32 mtk_cpux_readl(u32 reg_idx, struct timer_of *to)
{
writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
return readl(timer_of_base(to) + CPUX_CON_REG);
}
static void mtk_cpux_writel(u32 val, u32 reg_idx, struct timer_of *to)
{
writel(reg_idx, timer_of_base(to) + CPUX_IDX_REG);
writel(val, timer_of_base(to) + CPUX_CON_REG);
}
static void mtk_cpux_set_irq(struct timer_of *to, bool enable)
{
const unsigned long *irq_mask = cpumask_bits(cpu_possible_mask);
u32 val;
val = mtk_cpux_readl(CPUX_IDX_GLOBAL_IRQ, to);
if (enable)
val |= *irq_mask;
else
val &= ~(*irq_mask);
mtk_cpux_writel(val, CPUX_IDX_GLOBAL_IRQ, to);
}
static int mtk_cpux_clkevt_shutdown(struct clock_event_device *clkevt)
{
/* Clear any irq */
mtk_cpux_set_irq(to_timer_of(clkevt), false);
/*
* Disabling CPUXGPT timer will crash the platform, especially
* if Trusted Firmware is using it (usually, for sleep states),
* so we only mask the IRQ and call it a day.
*/
return 0;
}
static int mtk_cpux_clkevt_resume(struct clock_event_device *clkevt)
{
mtk_cpux_set_irq(to_timer_of(clkevt), true);
return 0;
}
static struct timer_of to = {
/*
* There are per-cpu interrupts for the CPUX General Purpose Timer
* but since this timer feeds the AArch64 System Timer we can rely
* on the CPU timer PPIs as well, so we don't declare TIMER_OF_IRQ.
*/
.flags = TIMER_OF_BASE | TIMER_OF_CLOCK,
.clkevt = {
.name = "mtk-cpuxgpt",
.cpumask = cpu_possible_mask,
.rating = 10,
.set_state_shutdown = mtk_cpux_clkevt_shutdown,
.tick_resume = mtk_cpux_clkevt_resume,
},
};
static int __init mtk_cpux_init(struct device_node *node)
{
u32 freq, val;
int ret;
/* If this fails, bad things are about to happen... */
ret = timer_of_init(node, &to);
if (ret) {
WARN(1, "Cannot start CPUX timers.\n");
return ret;
}
/*
* Check if we're given a clock with the right frequency for this
* timer, otherwise warn but keep going with the setup anyway, as
* that makes it possible to still boot the kernel, even though
* it may not work correctly (random lockups, etc).
* The reason behind this is that having an early UART may not be
* possible for everyone and this gives a chance to retrieve kmsg
* for eventual debugging even on consumer devices.
*/
freq = timer_of_rate(&to);
if (freq > 13000000)
WARN(1, "Requested unsupported timer frequency %u\n", freq);
/* Clock input is 26MHz, set DIV2 to achieve 13MHz clock */
val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to);
val &= ~CPUX_CLK_DIV_MASK;
val |= CPUX_CLK_DIV2;
mtk_cpux_writel(val, CPUX_IDX_GLOBAL_CTRL, &to);
/* Enable all CPUXGPT timers */
val = mtk_cpux_readl(CPUX_IDX_GLOBAL_CTRL, &to);
mtk_cpux_writel(val | CPUX_ENABLE, CPUX_IDX_GLOBAL_CTRL, &to);
clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
TIMER_SYNC_TICKS, 0xffffffff);
return 0;
}
TIMER_OF_DECLARE(mtk_mt6795, "mediatek,mt6795-systimer", mtk_cpux_init);
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