As David suggested, this patch warns the user if the RTC frequency is
altered by Linux (at least a little time will have been lost during
firmware boot).
Please apply to _2_4_devel.
-Hollis
--
PowerPC Linux
IBM Linux Technology Center
-------------- next part --------------
# This is a BitKeeper generated patch for the following project:
# Project Name: Linux 2.4 for PowerPC development tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.1179 -> 1.1180
# arch/ppc/platforms/ibm405lp.c 1.5 -> 1.6
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/12/19 hollis at granite.austin.ibm.com 1.1180
# print a warning message if RTC frequency is altered
# --------------------------------------------
#
diff -Nru a/arch/ppc/platforms/ibm405lp.c b/arch/ppc/platforms/ibm405lp.c
--- a/arch/ppc/platforms/ibm405lp.c Thu Dec 19 11:27:45 2002
+++ b/arch/ppc/platforms/ibm405lp.c Thu Dec 19 11:27:45 2002
@@ -288,7 +288,14 @@
mtdcr(DCRN_RTC0_CR1, 0x80); /* Disable update
cycles/interrupts*/
mtdcr(DCRN_RTC0_WRAP, 0); /* toggle NRST & NMR */
mtdcr(DCRN_RTC0_WRAP, 3);
- mtdcr(DCRN_RTC0_CR0, (RTC_DVBITS & 0x7) << 4); /*
input clock */
+
+ /* if necessary, set the input clock frequency */
+ if ((mfdcr(DCRN_RTC0_CR0) >> 4) != RTC_DVBITS) {
+ printk(KERN_WARNING "Warning: RTC frequency was
incorrect\n");
+ mtdcr(DCRN_RTC0_CR0,
+ ((RTC_DVBITS & 0x7) << 4) |
(mfdcr(DCRN_RTC0_CR0) & 0xf));
+ }
+
mtdcr(DCRN_RTC0_CR1, mfdcr(DCRN_RTC0_CR1) & 0x7f); /*
allow updates */
not_initialized = 0;
