[U-Boot] [PATCH V2 2/2] Exynos: Fix ARM Clock frequency calculation
Chander Kashyap
chander.kashyap at linaro.org
Mon Dec 19 09:56:44 CET 2011
Earliar ARM clock frequency was calculated by:
MOUTAPLL/(DIVAPLL + 1) which is actually returning SCLKAPLL.
It is fixed by calculating it as follows:
ARMCLK=MOUTCORE / (DIVCORE + 1) / (DIVCORE2 + 1)
Signed-off-by: Chander Kashyap <chander.kashyap at linaro.org>
---
Changes for V2:
- Fixed commit comment
- Fixed comment in clock.c "exynos4_get_arm_clk ()"
- Renamed dout_apll to armclk in clock.c "exynos4_get_arm_clk ()"
arch/arm/cpu/armv7/exynos/clock.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/arch/arm/cpu/armv7/exynos/clock.c b/arch/arm/cpu/armv7/exynos/clock.c
index 64de262..0c199cd 100644
--- a/arch/arm/cpu/armv7/exynos/clock.c
+++ b/arch/arm/cpu/armv7/exynos/clock.c
@@ -102,17 +102,20 @@ static unsigned long exynos4_get_arm_clk(void)
struct exynos4_clock *clk =
(struct exynos4_clock *)samsung_get_base_clock();
unsigned long div;
- unsigned long dout_apll;
- unsigned int apll_ratio;
+ unsigned long armclk;
+ unsigned int core_ratio;
+ unsigned int core2_ratio;
div = readl(&clk->div_cpu0);
- /* APLL_RATIO: [26:24] */
- apll_ratio = (div >> 24) & 0x7;
+ /* CORE_RATIO: [2:0], CORE2_RATIO: [30:28] */
+ core_ratio = (div >> 0) & 0x7;
+ core2_ratio = (div >> 28) & 0x7;
- dout_apll = get_pll_clk(APLL) / (apll_ratio + 1);
+ armclk = get_pll_clk(APLL) / (core_ratio + 1);
+ armclk /= (core2_ratio + 1);
- return dout_apll;
+ return armclk;
}
/* exynos4: return pwm clock frequency */
--
1.7.5.4
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