diff options
| author | Patrick Rudolph <siro@das-labor.org> | 2016-03-26 17:20:02 +0100 |
|---|---|---|
| committer | Martin Roth <martinroth@google.com> | 2016-05-04 19:59:02 +0200 |
| commit | 9c9bde3aa35922cf680c91f9260dd7905cc8cb6b (patch) | |
| tree | e7906cdb35066496285b751c1dc2d4e26615ef79 | |
| parent | 2ccb74b6e97381ce2b2f8520076204f7737ade4c (diff) | |
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@das-labor.org>
Reviewed-on: https://review.coreboot.org/14174
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
| -rw-r--r-- | src/northbridge/intel/sandybridge/raminit.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/northbridge/intel/sandybridge/raminit.c b/src/northbridge/intel/sandybridge/raminit.c index 0c191b2abd..1ed77ebd44 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 |