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Commit 401667bb authored by Eric Anholt's avatar Eric Anholt Committed by Thomas Gleixner
Browse files

irqchip/bcm2836: Fix initialization of the LOCAL_IRQ_CNT timers 



The irqchip's register area includes the the setup for the timer's
scaling factors, and for the platform we want a fixed configuration of
these registers.

Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Lee Jones <lee@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-rpi-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1451166444-11044-2-git-send-email-eric@anholt.net


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 5c4acd97

drivers/irqchip/irq-bcm2836.c

+26 −0
Original line number Diff line number Diff line
@@ -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);