Fix variable CPU clock for MPC859/866 systems for low CPU clocks

3 files changed, 41 insertions, 10 deletions

diff --git a/cpu/mpc8xx/cpu.c b/cpu/mpc8xx/cpu.c
index 3fb97b07ca7..81d2047c9cc 100644
--- a/cpu/mpc8xx/cpu.c
+++ b/cpu/mpc8xx/cpu.c
@@ -123,10 +123,22 @@ static int check_CPU (long clock, uint pvr, uint immr)
 	else
 		printf ("unknown M%s (0x%08x)", id_str, k);
 
-	printf (" at %s MHz:", strmhz (buf, clock));
 
-	printf (" %u kB I-Cache", checkicache () >> 10);
-	printf (" %u kB D-Cache", checkdcache () >> 10);
+#if defined(CFG_866_CPUCLK_MIN) && defined(CFG_866_CPUCLK_MAX)
+	printf (" at %s MHz [%d.%d...%d.%d MHz]\n       ",
+		strmhz (buf, clock),
+		CFG_866_CPUCLK_MIN / 1000000,
+		((CFG_866_CPUCLK_MIN % 1000000) + 50000) / 100000,
+		CFG_866_CPUCLK_MAX / 1000000,
+		((CFG_866_CPUCLK_MAX % 1000000) + 50000) / 100000
+	);
+#else
+	printf (" at %s MHz: ", strmhz (buf, clock));
+#endif
+	printf ("%u kB I-Cache %u kB D-Cache",
+		checkicache () >> 10,
+		checkdcache () >> 10
+	);
 
 	/* do we have a FEC (860T/P or 852/859/866)? */
 
diff --git a/cpu/mpc8xx/serial.c b/cpu/mpc8xx/serial.c
index a875963df36..71f3ae1f458 100644
--- a/cpu/mpc8xx/serial.c
+++ b/cpu/mpc8xx/serial.c
@@ -71,11 +71,11 @@
 static void serial_setdivisor(volatile cpm8xx_t *cp)
 {
 	DECLARE_GLOBAL_DATA_PTR;
-	int divisor=gd->cpu_clk/16/gd->baudrate;
+	int divisor=(gd->cpu_clk + 8*gd->baudrate)/16/gd->baudrate;
 
 	if(divisor/16>0x1000) {
 		/* bad divisor, assume 50Mhz clock and 9600 baud */
-		divisor=(50*1000*1000)/16/9600;
+		divisor=(50*1000*1000 + 8*9600)/16/9600;
 	}
 
 #ifdef CFG_BRGCLK_PRESCALE
diff --git a/cpu/mpc8xx/speed.c b/cpu/mpc8xx/speed.c
index 8583eef63c7..8f8efce5052 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)