diff options
Diffstat (limited to 'lib_blackfin/clocks.c')
-rw-r--r-- | lib_blackfin/clocks.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/lib_blackfin/clocks.c b/lib_blackfin/clocks.c new file mode 100644 index 00000000000..0be395bb30f --- /dev/null +++ b/lib_blackfin/clocks.c @@ -0,0 +1,77 @@ +/* + * clocks.c - figure out sclk/cclk/vco and such + * + * Copyright (c) 2005-2008 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <common.h> +#include <asm/blackfin.h> + +/* Get the voltage input multiplier */ +static u_long cached_vco_pll_ctl, cached_vco; +u_long get_vco(void) +{ + u_long msel; + + u_long pll_ctl = bfin_read_PLL_CTL(); + if (pll_ctl == cached_vco_pll_ctl) + return cached_vco; + else + cached_vco_pll_ctl = pll_ctl; + + msel = (pll_ctl >> 9) & 0x3F; + if (0 == msel) + msel = 64; + + cached_vco = CONFIG_CLKIN_HZ; + cached_vco >>= (1 & pll_ctl); /* DF bit */ + cached_vco *= msel; + return cached_vco; +} + +/* Get the Core clock */ +static u_long cached_cclk_pll_div, cached_cclk; +u_long get_cclk(void) +{ + u_long csel, ssel; + + if (bfin_read_PLL_STAT() & 0x1) + return CONFIG_CLKIN_HZ; + + ssel = bfin_read_PLL_DIV(); + if (ssel == cached_cclk_pll_div) + return cached_cclk; + else + cached_cclk_pll_div = ssel; + + csel = ((ssel >> 4) & 0x03); + ssel &= 0xf; + if (ssel && ssel < (1 << csel)) /* SCLK > CCLK */ + cached_cclk = get_vco() / ssel; + else + cached_cclk = get_vco() >> csel; + return cached_cclk; +} + +/* Get the System clock */ +static u_long cached_sclk_pll_div, cached_sclk; +u_long get_sclk(void) +{ + u_long ssel; + + if (bfin_read_PLL_STAT() & 0x1) + return CONFIG_CLKIN_HZ; + + ssel = bfin_read_PLL_DIV(); + if (ssel == cached_sclk_pll_div) + return cached_sclk; + else + cached_sclk_pll_div = ssel; + + ssel &= 0xf; + + cached_sclk = get_vco() / ssel; + return cached_sclk; +} |