From 9ef62592b80c7ffb8cd987d889f659c1dc4f9f16 Mon Sep 17 00:00:00 2001 From: Alastair D'Silva Date: Wed, 16 Sep 2026 14:29:10 +1000 Subject: [PATCH] clk: sunxi-ng: ccu_common: Use readl_relaxed_poll_timeout_atomic for PLL lock The Allwinner sunxi-ng CCU driver currently uses readl_relaxed_poll_timeout() in ccu_helper_wait_for_lock() to wait for PLLs to lock. This non-atomic poll macro relies on ktime_get() and the kernel timekeeping infrastructure. During early boot or sensitive clock transitions (such as CPUfreq DVFS scaling) where timer interrupts or timekeeping may be suspended or unstable, ktime_get() fails to advance. This turns the timeout calculation into an infinite busy-wait loop, causing RCU stalls and system freezes if the PLL lock bit does not assert immediately. Switch to readl_relaxed_poll_timeout_atomic(). This atomic variant relies on udelay() rather than timekeeping, making it safe to execute even when timekeeping is suspended or uninitialized. Assisted-by: LLM Signed-off-by: Alastair D'Silva Link: https://patch.msgid.link/20260916042910.382744-1-alastair@d-silva.org Signed-off-by: Chen-Yu Tsai --- drivers/clk/sunxi-ng/ccu_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c index 43d8eca6abee..248e58c9562d 100644 --- a/drivers/clk/sunxi-ng/ccu_common.c +++ b/drivers/clk/sunxi-ng/ccu_common.c @@ -35,7 +35,7 @@ void ccu_helper_wait_for_lock(struct ccu_common *common, u32 lock) else addr = common->base + common->reg; - WARN_ON(readl_relaxed_poll_timeout(addr, reg, reg & lock, 100, 70000)); + WARN_ON(readl_relaxed_poll_timeout_atomic(addr, reg, reg & lock, 100, 70000)); } EXPORT_SYMBOL_NS_GPL(ccu_helper_wait_for_lock, "SUNXI_CCU");