[coreboot-gerrit] Patch set updated for coreboot: nb/intel/sandybridge/raminit: support calling dram_freq multiple times
Patrick Rudolph (siro@das-labor.org)
gerrit at coreboot.org
Wed Apr 6 16:04:43 CEST 2016
Patrick Rudolph (siro at das-labor.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14174
-gerrit
commit e6858d07550d7d13e6829c23f0cc2377b9e24cb8
Author: Patrick Rudolph <siro at das-labor.org>
Date: Sat Mar 26 17:20:02 2016 +0100
nb/intel/sandybridge/raminit: support calling dram_freq multiple times
The PLL will never lock if the requested frequency is already set.
As the fallback may request the same frequency again exit early
to prevent a hang.
Test system:
* Gigabyte GA-B75M-D3H
* Intel Pentium CPU G2130
Change-Id: I625b2956346d8c50cca84def6190c076bf99dbec
Signed-off-by: Patrick Rudolph <siro at das-labor.org>
---
src/northbridge/intel/sandybridge/raminit.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/src/northbridge/intel/sandybridge/raminit.c b/src/northbridge/intel/sandybridge/raminit.c
index b71f2ad..c812a24 100644
--- a/src/northbridge/intel/sandybridge/raminit.c
+++ b/src/northbridge/intel/sandybridge/raminit.c
@@ -810,6 +810,17 @@ static void dram_freq(ramctr_timing * ctrl)
/* Frequency mulitplier. */
u32 FRQ = get_FRQ(ctrl->tCK);
+ /* The PLL will never lock if the required frequency is
+ * already set. Exit early to prevent a system hang.
+ */
+ reg1 = MCHBAR32(0x5e04);
+ val2 = (u8) reg1;
+ if (val2 == FRQ) {
+ printk(BIOS_DEBUG, "MCU frequency is set at : %d MHz\n",
+ (1000 << 8) / ctrl->tCK);
+ return;
+ }
+
/* Step 2 - Select frequency in the MCU */
reg1 = FRQ;
reg1 |= 0x80000000; // set running bit
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