diff options
Diffstat (limited to 'configs/platform-rpi/patches/linux-4.4/0001-irq-bcm2836-Fix-initialization-of-the-LOCAL_IRQ_CNT-.patch')
| -rw-r--r-- | configs/platform-rpi/patches/linux-4.4/0001-irq-bcm2836-Fix-initialization-of-the-LOCAL_IRQ_CNT-.patch | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/configs/platform-rpi/patches/linux-4.4/0001-irq-bcm2836-Fix-initialization-of-the-LOCAL_IRQ_CNT-.patch b/configs/platform-rpi/patches/linux-4.4/0001-irq-bcm2836-Fix-initialization-of-the-LOCAL_IRQ_CNT-.patch new file mode 100644 index 0000000..ac782ab --- /dev/null +++ b/configs/platform-rpi/patches/linux-4.4/0001-irq-bcm2836-Fix-initialization-of-the-LOCAL_IRQ_CNT-.patch @@ -0,0 +1,66 @@ +From: Eric Anholt <eric@anholt.net> +Date: Wed, 16 Dec 2015 12:25:00 -0800 +Subject: [PATCH] irq: bcm2836: Fix initialization of the LOCAL_IRQ_CNT*IRQ + 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: Eric Anholt <eric@anholt.net> +Signed-off-by: Alexander Aring <alex.aring@gmail.com> +--- + drivers/irqchip/irq-bcm2836.c | 26 ++++++++++++++++++++++++++ + 1 file changed, 26 insertions(+) + +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); |