diff options
Diffstat (limited to 'arch/arm/mach-shmobile/timer.c')
| -rw-r--r-- | arch/arm/mach-shmobile/timer.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/arm/mach-shmobile/timer.c b/arch/arm/mach-shmobile/timer.c index 62d7052d6f21..942efdc82a62 100644 --- a/arch/arm/mach-shmobile/timer.c +++ b/arch/arm/mach-shmobile/timer.c @@ -21,6 +21,24 @@ #include <linux/platform_device.h> #include <linux/clocksource.h> #include <linux/delay.h> +#include <linux/of_address.h> + +void __init shmobile_setup_delay_hz(unsigned int max_cpu_core_hz, + unsigned int mult, unsigned int div) +{ + /* calculate a worst-case loops-per-jiffy value + * based on maximum cpu core hz setting and the + * __delay() implementation in arch/arm/lib/delay.S + * + * this will result in a longer delay than expected + * when the cpu core runs on lower frequencies. + */ + + unsigned int value = HZ * div / mult; + + if (!preset_lpj) + preset_lpj = max_cpu_core_hz / value; +} void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz, unsigned int mult, unsigned int div) @@ -39,6 +57,41 @@ void __init shmobile_setup_delay(unsigned int max_cpu_core_mhz, preset_lpj = max_cpu_core_mhz * value; } +void __init shmobile_init_delay(void) +{ + struct device_node *np, *cpus; + bool is_a8_a9 = false; + bool is_a15 = false; + u32 max_freq = 0; + + cpus = of_find_node_by_path("/cpus"); + if (!cpus) + return; + + for_each_child_of_node(cpus, np) { + u32 freq; + + if (!of_property_read_u32(np, "clock-frequency", &freq)) + max_freq = max(max_freq, freq); + + if (of_device_is_compatible(np, "arm,cortex-a8") || + of_device_is_compatible(np, "arm,cortex-a9")) + is_a8_a9 = true; + else if (of_device_is_compatible(np, "arm,cortex-a15")) + is_a15 = true; + } + + of_node_put(cpus); + + if (!max_freq) + return; + + if (is_a8_a9) + shmobile_setup_delay_hz(max_freq, 1, 3); + else if (is_a15 && !IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) + shmobile_setup_delay_hz(max_freq, 2, 4); +} + static void __init shmobile_late_time_init(void) { /* |
