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authorwdenk <wdenk>2004-01-31 20:06:54 +0000
committerwdenk <wdenk>2004-01-31 20:06:54 +0000
commit75d1ea7f6aa00c280c495a1ff6502f091c4244fe (patch)
treebb1ee058f8886ae42cb85a6b2c82f3d6b18661bf /cpu/mpc8xx/speed.c
parent6876609446980c3055bbd32c195a63330e21d8e6 (diff)
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Fix variable CPU clock for MPC859/866 systems for low CPU clocks
Diffstat (limited to 'cpu/mpc8xx/speed.c')
-rw-r--r--cpu/mpc8xx/speed.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/cpu/mpc8xx/speed.c b/cpu/mpc8xx/speed.c
index 8583eef..8f8efce 100644
--- a/cpu/mpc8xx/speed.c
+++ b/cpu/mpc8xx/speed.c
@@ -25,7 +25,7 @@
#include <mpc8xx.h>
#include <asm/processor.h>
-#ifndef CONFIG_TQM866M
+#if !defined(CONFIG_TQM866M) || defined(CFG_MEASURE_CPUCLK)
#define PITC_SHIFT 16
#define PITR_SHIFT 16
@@ -170,6 +170,10 @@ unsigned long measure_gclk(void)
#endif
}
+#endif
+
+#if !defined(CONFIG_TQM866M)
+
/*
* get_clocks() fills in gd->cpu_clock depending on CONFIG_8xx_GCLK_FREQ
* or (if it is not defined) measure_gclk() (which uses the ref clock)
@@ -230,6 +234,9 @@ int get_clocks_866 (void)
cpuclk = CFG_866_CPUCLK_DEFAULT;
gd->cpu_clk = init_pll_866 (cpuclk);
+#if defined(CFG_MEASURE_CPUCLK)
+ gd->cpu_clk = measure_gclk ();
+#endif
if ((immr->im_clkrst.car_sccr & SCCR_EBDF11) == 0)
gd->bus_clk = gd->cpu_clk;
@@ -269,8 +276,19 @@ static long init_pll_866 (long clk)
char mfi, mfn, mfd, s, pdf;
long step_mfi, step_mfn;
- pdf = 0;
- if (clk < 80000000) {
+ if (clk < 20000000) {
+ clk *= 2;
+ pdf = 1;
+ } else {
+ pdf = 0;
+ }
+
+ if (clk < 40000000) {
+ s = 2;
+ step_mfi = CFG_866_OSCCLK / 4;
+ mfd = 7;
+ step_mfn = CFG_866_OSCCLK / 30;
+ } else if (clk < 80000000) {
s = 1;
step_mfi = CFG_866_OSCCLK / 2;
mfd = 14;
@@ -294,13 +312,14 @@ static long init_pll_866 (long clk)
/* Calculate effective clk
*/
- n = (mfi * step_mfi) + (mfn * step_mfn);
+ n = ((mfi * step_mfi) + (mfn * step_mfn)) / (pdf + 1);
immr->im_clkrstk.cark_plprcrk = KAPWR_KEY;
plprcr = (immr->im_clkrst.car_plprcr & ~(PLPRCR_MFN_MSK
| PLPRCR_MFD_MSK | PLPRCR_S_MSK
- | PLPRCR_MFI_MSK | PLPRCR_DBRMO))
+ | PLPRCR_MFI_MSK | PLPRCR_DBRMO
+ | PLPRCR_PDF_MSK))
| (mfn << PLPRCR_MFN_SHIFT)
| (mfd << PLPRCR_MFD_SHIFT)
| (s << PLPRCR_S_SHIFT)