- always-on : a boolean property. If present, the timer is powered through an
always-on power domain, therefore it never loses context.
+** Optional properties:
+
+- arm,cpu-registers-not-fw-configured : Firmware does not initialize
+ any of the generic timer CPU registers, which contain their
+ architecturally-defined reset values. Only supported for 32-bit
+ systems which follow the ARMv7 architected reset values.
+
+
Example:
timer {
return val;
}
+static inline u64 arch_counter_get_cntpct(void)
+{
+ u64 cval;
+
+ isb();
+ asm volatile("mrrc p15, 0, %Q0, %R0, c14" : "=r" (cval));
+ return cval;
+}
+
static inline u64 arch_counter_get_cntvct(void)
{
u64 cval;
asm volatile("msr cntkctl_el1, %0" : : "r" (cntkctl));
}
+static inline u64 arch_counter_get_cntpct(void)
+{
+ /*
+ * AArch64 kernel and user space mandate the use of CNTVCT.
+ */
+ BUG();
+ return 0;
+}
+
static inline u64 arch_counter_get_cntvct(void)
{
u64 cval;
/* Register the CP15 based counter if we have one */
if (type & ARCH_CP15_TIMER) {
- arch_timer_read_counter = arch_counter_get_cntvct;
+ if (arch_timer_use_virtual)
+ arch_timer_read_counter = arch_counter_get_cntvct;
+ else
+ arch_timer_read_counter = arch_counter_get_cntpct;
} else {
arch_timer_read_counter = arch_counter_get_cntvct_mem;
arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
arch_timer_detect_rate(NULL, np);
+ /*
+ * If we cannot rely on firmware initializing the timer registers then
+ * we should use the physical timers instead.
+ */
+ if (IS_ENABLED(CONFIG_ARM) &&
+ of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+ arch_timer_use_virtual = false;
+
/*
* If HYP mode is available, we know that the physical timer
* has been configured to be accessible from PL1. Use it, so