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irqchip/bcm2836: Fix initialization of the LOCAL_IRQ_CNT timers

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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: Eric 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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Eric Anholt 2015-12-26 13:47:21 -08:00 committed by Thomas Gleixner
parent 5c4acd97e8
commit 401667bb8a
1 changed files with 26 additions and 0 deletions
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26
drivers/irqchip/irq-bcm2836.c
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@ -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);