From 9c9bde3aa35922cf680c91f9260dd7905cc8cb6b Mon Sep 17 00:00:00 2001 From: Patrick Rudolph Date: Sat, 26 Mar 2016 17:20:02 +0100 Subject: [PATCH] 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 Reviewed-on: https://review.coreboot.org/14174 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel Reviewed-by: Martin Roth --- 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 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