diff options
Diffstat (limited to 'c/src/lib/libcpu/arm/at91rm9200/pmc/pmc.c')
-rw-r--r-- | c/src/lib/libcpu/arm/at91rm9200/pmc/pmc.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/arm/at91rm9200/pmc/pmc.c b/c/src/lib/libcpu/arm/at91rm9200/pmc/pmc.c new file mode 100644 index 0000000000..b2877f866c --- /dev/null +++ b/c/src/lib/libcpu/arm/at91rm9200/pmc/pmc.c @@ -0,0 +1,99 @@ +/* + * Atmel AT91RM9200 PMC functions + * + * Copyright (c) 2004 by Jay Monkman <jtm@lopingdog.com> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * + * http://www.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include <rtems.h> +#include <bsp.h> +#include <at91rm9200.h> +#include <at91rm9200_pmc.h> + +int at91rm9200_get_mainclk(void) +{ + return BSP_MAIN_FREQ; +} + +int at91rm9200_get_slck(void) +{ + return BSP_SLCK_FREQ; +} + +int at91rm9200_get_mck(void) +{ + uint32_t mck_reg; + uint32_t mck_freq; + uint32_t pll_reg; + int prescaler; + + mck_reg = PMC_REG(PMC_MCKR); + + switch(mck_reg & PMC_MCKR_PRES_MASK) { + case PMC_MCKR_PRES_1: + prescaler = 1; + break; + case PMC_MCKR_PRES_2: + prescaler = 2; + break; + case PMC_MCKR_PRES_4: + prescaler = 4; + break; + case PMC_MCKR_PRES_8: + prescaler = 8; + break; + case PMC_MCKR_PRES_16: + prescaler = 16; + break; + case PMC_MCKR_PRES_32: + prescaler = 32; + break; + case PMC_MCKR_PRES_64: + prescaler = 64; + break; + } + + /* Let's find out what MCK's source is */ + switch (mck_reg & PMC_MCKR_CSS_MASK) { + case PMC_MCKR_CSS_SLOW: + /* I'm assuming the slow clock is 32.768 MHz */ + mck_freq = at91rm9200_get_slck() / prescaler; + break; + + case PMC_MCKR_CSS_MAIN: + mck_freq = at91rm9200_get_mainclk() / prescaler; + break; + + case PMC_MCKR_CSS_PLLA: + pll_reg = PMC_REG(PMC_PLLAR); + mck_freq = at91rm9200_get_mainclk() / prescaler; + mck_freq = mck_freq / (pll_reg & PMC_PLLAR_DIV_MASK); + mck_freq = mck_freq * (((pll_reg & PMC_PLLAR_MUL_MASK) >> 16) + 1); + break; + + case PMC_MCKR_CSS_PLLB: + pll_reg = PMC_REG(PMC_PLLBR); + mck_freq = at91rm9200_get_mainclk() / prescaler; + mck_freq = mck_freq / (pll_reg & PMC_PLLBR_DIV_MASK); + mck_freq = mck_freq * (((pll_reg & PMC_PLLBR_MUL_MASK) >> 16) + 1); + break; + } + + if ((mck_reg & PMC_MCKR_MDIV_MASK) == PMC_MCKR_MDIV_2) { + mck_freq = mck_freq / 2; + } else if ((mck_reg & PMC_MCKR_MDIV_MASK) == PMC_MCKR_MDIV_3) { + mck_freq = mck_freq / 3; + } else if ((mck_reg & PMC_MCKR_MDIV_MASK) == PMC_MCKR_MDIV_4) { + mck_freq = mck_freq / 4; + } + + + return mck_freq; +} + |