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added support for flexible PLL in MPC866 and friends

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This commit is contained in:
Thomas Doerfler
2008-09-08 09:54:22 +00:00
parent 95c274ecf3
commit 663e52939c
1 changed files with 38 additions and 4 deletions
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42
c/src/lib/libcpu/powerpc/mpc8xx/clock/clock.c
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@@ -72,18 +72,52 @@ void clockOn(void* unused)
{
unsigned desiredLevel;
uint32_t pit_value;
uint32_t mf_value;
uint32_t extclk;
bool force_prescaler = false;
extern uint32_t bsp_clicks_per_usec;
extern uint32_t bsp_clock_speed;
uint32_t immr_val;
if (bsp_clicks_per_usec == 0) {
/*
* oscclk is too low for PIT, compute extclk and derive PIT from there
*/
mf_value = m8xx.plprcr >> 20;
pit_value = (bsp_clock_speed
/ (mf_value+1)
/*
* determine external input clock by examining the PLL settings
* this must be done differently depending on type of PLL
*/
_mfspr(immr_val,M8xx_IMMR);
if (8 == ((immr_val & 0x0000FF00) >> 8)) {
/*
* for MPC866: complex PLL
*/
uint32_t plprcr_val;
uint32_t mfn_value;
uint32_t mfd_value;
uint32_t mfi_value;
uint32_t pdf_value;
uint32_t s_value;
plprcr_val = m8xx.plprcr;
mfn_value = (plprcr_val & (0xf8000000)) >> (31- 4);
mfd_value = (plprcr_val & (0x07c00000)) >> (31- 9);
s_value = (plprcr_val & (0x00300000)) >> (31-11);
mfi_value = (plprcr_val & (0x000f0000)) >> (31-15);
pdf_value = (plprcr_val & (0x00000006)) >> (31-30);
extclk = (((uint64_t)bsp_clock_speed)
* ((pdf_value + 1) * (mfd_value + 1))
/ (mfi_value * (mfd_value + 1) + mfn_value)
* (1 << s_value));
}
else {
/*
* for MPC860/850 etc: simple PLL
*/
uint32_t mf_value;
mf_value = m8xx.plprcr >> 20;
extclk = bsp_clock_speed / (mf_value+1);
}
pit_value = (extclk
/ 1000
/ 4
* rtems_configuration_get_microseconds_per_tick()