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-rw-r--r--drivers/clocksource/timer-mediatek-cpux.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-mediatek-cpux.c b/drivers/clocksource/timer-mediatek-cpux.c
new file mode 100644
index 0000000000..a8e3df4c09
--- /dev/null
+++ b/drivers/clocksource/timer-mediatek-cpux.c
@@ -0,0 +1,140 @@
+// 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);