diff options
| -rw-r--r-- | drivers/irqchip/irq-bcm2836.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-bcm2836.c b/drivers/irqchip/irq-bcm2836.c index f68708281fcf..6ec125ef3607 100644 --- a/drivers/irqchip/irq-bcm2836.c +++ b/drivers/irqchip/irq-bcm2836.c @@ -21,6 +21,9 @@ #include <linux/irqdomain.h> #include <asm/exception.h> +#define LOCAL_CONTROL 0x000 +#define LOCAL_PRESCALER 0x008 + /* * The low 2 bits identify the CPU that the GPU IRQ goes to, and the * next 2 bits identify the CPU that the GPU FIQ goes to. @@ -237,6 +240,27 @@ bcm2836_arm_irqchip_smp_init(void) #endif } +/* + * The LOCAL_IRQ_CNT* timer firings are based off of the external + * oscillator with some scaling. The firmware sets up CNTFRQ to + * report 19.2Mhz, but doesn't set up the scaling registers. + */ +static void bcm2835_init_local_timer_frequency(void) +{ + /* + * Set the timer to source from the 19.2Mhz crystal clock (bit + * 8 unset), and only increment by 1 instead of 2 (bit 9 + * unset). + */ + writel(0, intc.base + LOCAL_CONTROL); + + /* + * Set the timer prescaler to 1:1 (timer freq = input freq * + * 2**31 / prescaler) + */ + writel(0x80000000, intc.base + LOCAL_PRESCALER); +} + static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node, struct device_node *parent) { @@ -246,6 +270,8 @@ static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node, node->full_name); } + bcm2835_init_local_timer_frequency(); + intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1, &bcm2836_arm_irqchip_intc_ops, NULL); |