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
--- a/cpu/mpc85xx/speed.c
+++ b/cpu/mpc85xx/speed.c
@@ -37,49 +37,21 @@
{
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;