diff options
| author | Damien Zammit <damien@zamaudio.com> | 2016-06-18 23:57:43 +1000 |
|---|---|---|
| committer | Kyösti Mälkki <kyosti.malkki@gmail.com> | 2016-07-09 13:49:00 +0200 |
| commit | 9ae0985328d53b0a2b1a6673853367061dd695cd (patch) | |
| tree | 26fc0e1af0fd6527c0dea9ed58862049e39769d0 | |
| parent | dc542702108fc80997f074978ac404c83ee0e9bf (diff) | |
nb/intel/x4x: Fix underclocking of 800MHz DDR2 RAM
Previously, any 800MHz DIMMs were being slowed to 667MHz
for no reason other than there was a bug in the maximum
frequency detection code for the MCH.
Change-Id: Id6c6c88c4a40631f6caf52f536a939a43cb3faf1
Signed-off-by: Damien Zammit <damien@zamaudio.com>
Reviewed-on: https://review.coreboot.org/15257
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
| -rw-r--r-- | src/northbridge/intel/x4x/raminit.c | 33 |
1 files changed, 20 insertions, 13 deletions
diff --git a/src/northbridge/intel/x4x/raminit.c b/src/northbridge/intel/x4x/raminit.c index 4f5575ceae..5d341dbd1e 100644 --- a/src/northbridge/intel/x4x/raminit.c +++ b/src/northbridge/intel/x4x/raminit.c @@ -264,11 +264,13 @@ static u8 msbpos(u8 val) //Reverse static void mchinfo_ddr2(struct sysinfo *s) { + u8 capablefreq, maxfreq; + const u32 eax = cpuid_ext(0x04, 0).eax; s->cores = ((eax >> 26) & 0x3f) + 1; printk(BIOS_WARNING, "%d CPU cores\n", s->cores); - u32 capid = pci_read_config16(PCI_DEV(0,0,0), 0xe8); + u32 capid = pci_read_config16(PCI_DEV(0, 0, 0), 0xe8); if (!(capid & (1<<(79-64)))) { printk(BIOS_WARNING, "iTPM enabled\n"); } @@ -282,7 +284,19 @@ static void mchinfo_ddr2(struct sysinfo *s) printk(BIOS_WARNING, "AMT enabled\n"); } - s->max_ddr2_mhz = (capid & (1<<(53-32)))?667:800; + maxfreq = MEM_CLOCK_800MHz; + capablefreq = (u8)((pci_read_config16(PCI_DEV(0, 0, 0), 0xea) >> 4) & 0x3f); + capablefreq &= 0x7; + if (capablefreq) + maxfreq = capablefreq + 1; + + if (maxfreq > MEM_CLOCK_800MHz) + maxfreq = MEM_CLOCK_800MHz; + + if (maxfreq < MEM_CLOCK_667MHz) + maxfreq = MEM_CLOCK_667MHz; + + s->max_ddr2_mhz = (maxfreq == MEM_CLOCK_800MHz) ? 800 : 667; printk(BIOS_WARNING, "Capable of DDR2 of %d MHz or lower\n", s->max_ddr2_mhz); if (!(capid & (1<<(48-32)))) { @@ -317,19 +331,11 @@ static void sdram_detect_ram_speed(struct sysinfo *s) break; } - // Find RAM speed - maxfreq = (u8) ((pci_read_config16(PCI_DEV(0,0,0), 0xea) >> 4) & 0x3f); + // Max RAM speed if (s->spd_type == DDR2) { - // Limit frequency for MCH - maxfreq &= 0x7; - freq = MEM_CLOCK_800MHz; - if (maxfreq) { - freq = maxfreq; - } - if (freq > MEM_CLOCK_800MHz) { - freq = MEM_CLOCK_800MHz; - } + // Choose max memory frequency for MCH as previously detected + freq = (s->max_ddr2_mhz == 800) ? MEM_CLOCK_800MHz : MEM_CLOCK_667MHz; // Detect a common CAS latency commoncas = 0xff; @@ -411,6 +417,7 @@ static void sdram_detect_ram_speed(struct sysinfo *s) } else { // DDR3 // Limit frequency for MCH + maxfreq = (s->max_ddr2_mhz == 800) ? MEM_CLOCK_800MHz : MEM_CLOCK_667MHz; maxfreq >>= 3; freq = MEM_CLOCK_1333MHz; if (maxfreq) { |