Reworked 85xx speed detection code

Changed the code to read the registers and calculate the clock
rates, rather than using a "switch" statement.

Idea from Andrew Klossner <andrew@cesa.opbu.xerox.com>

Signed-off-by: Andy Fleming <afleming@freescale.com>

diff --git a/cpu/mpc85xx/speed.c b/cpu/mpc85xx/speed.c
index ca81ee7..12359a2 100644 (file)
--- a/cpu/mpc85xx/speed.c
+++ b/cpu/mpc85xx/speed.c
@@ -37,49 +37,21 @@ void get_sys_info (sys_info_t * sysInfo)
 {
        volatile immap_t    *immap = (immap_t *)CFG_IMMR;
        volatile ccsr_gur_t *gur = &immap->im_gur;
-       uint plat_ratio,e500_ratio;
+       uint plat_ratio,e500_ratio,half_freqSystemBus;
 
        plat_ratio = (gur->porpllsr) & 0x0000003e;
        plat_ratio >>= 1;
-       switch(plat_ratio) {
-       case 0x02:
-       case 0x03:
-       case 0x04:
-       case 0x05:
-       case 0x06:
-       case 0x08:
-       case 0x09:
-       case 0x0a:
-       case 0x0c:
-       case 0x10:
-               sysInfo->freqSystemBus = plat_ratio * CONFIG_SYS_CLK_FREQ;
-               break;
-       default:
-               sysInfo->freqSystemBus = 0;
-               break;
-       }
-
+       sysInfo->freqSystemBus = plat_ratio * CONFIG_SYS_CLK_FREQ;
        e500_ratio = (gur->porpllsr) & 0x003f0000;
        e500_ratio >>= 16;
-       switch(e500_ratio) {
-       case 0x04:
-               sysInfo->freqProcessor = 2*sysInfo->freqSystemBus;
-               break;
-       case 0x05:
-               sysInfo->freqProcessor = 5*sysInfo->freqSystemBus/2;
-               break;
-       case 0x06:
-               sysInfo->freqProcessor = 3*sysInfo->freqSystemBus;
-               break;
-       case 0x07:
-               sysInfo->freqProcessor = 7*sysInfo->freqSystemBus/2;
-               break;
-       default:
-               sysInfo->freqProcessor = 0;
-               break;
-       }
+
+       /* Divide before multiply to avoid integer
+        * overflow for processor speeds above 2GHz */
+       half_freqSystemBus = sysInfo->freqSystemBus/2;
+       sysInfo->freqProcessor = e500_ratio*half_freqSystemBus;
 }
 
+
 int get_clocks (void)
 {
        sys_info_t sys_info;