[PATCH v2 28/31] arm64: Generic timers support

On 08/14/2012 01:52 PM, Catalin Marinas wrote:

From: Marc Zyngier <redacted>

This patch adds support for the ARM generic timers with A64 instructions
for accessing the timer registers. It uses the physical counter as the
clock source and the virtual counter as sched_clock.

The timer frequency can be specified via DT or read from the CNTFRQ_EL0
register. The physical counter is also accessible from user space
allowing fast gettimeofday() implementation.

[...]

[...]

+static void arch_timer_reg_write(int reg, u32 val)
+{
+	switch (reg) {
+	case ARCH_TIMER_REG_CTRL:
+		asm volatile("msr cntp_ctl_el0,  %0" : : "r" (val));
+		break;
+	case ARCH_TIMER_REG_TVAL:
+		asm volatile("msr cntp_tval_el0, %0" : : "r" (val));
+		break;
+	default:
+		BUG();
+	}
+
+	isb();
+}

Doesn't architecture-specific assembly need to go in the arch directory rather
than the drivers directory?

Christopher

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