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

[pandora-u-boot.git] / README

diff --git a/README b/README
index 58267f1..61d55d4 100644 (file)
--- a/README
+++ b/README
@@ -415,12 +415,28 @@ The following options need to be configured:
                Define exactly one of
                CONFIG_MPC8240, CONFIG_MPC8245
 
-- 8xx CPU Options: (if using an 8xx cpu)
+- 8xx CPU Options: (if using an MPC8xx cpu)
                Define one or more of
                CONFIG_8xx_GCLK_FREQ    - if get_gclk_freq() cannot work
                                          e.g. if there is no 32KHz
                                          reference PIT/RTC clock
 
+- 859/866 CPU options: (if using a MPC859 or MPC866 CPU):
+               CFG_866_OSCCLK
+               CFG_866_CPUCLK_MIN
+               CFG_866_CPUCLK_MAX
+               CFG_866_CPUCLK_DEFAULT
+                       See doc/README.MPC866
+
+               CFG_MEASURE_CPUCLK
+
+                Define this to measure the actual CPU clock instead
+                of relying on the correctness of the configured
+                values. Mostly useful for board bringup to make sure
+                the PLL is locked at the intended frequency. Note
+                that this requires a (stable) reference clock (32 kHz
+                RTC clock),
+
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ