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authorDamien Zammit <damien@zamaudio.com>2016-06-18 23:57:43 +1000
committerKyösti Mälkki <kyosti.malkki@gmail.com>2016-07-09 13:49:00 +0200
commit9ae0985328d53b0a2b1a6673853367061dd695cd (patch)
tree26fc0e1af0fd6527c0dea9ed58862049e39769d0 /src/northbridge/intel/x4x
parentdc542702108fc80997f074978ac404c83ee0e9bf (diff)
downloadcoreboot-9ae0985328d53b0a2b1a6673853367061dd695cd.tar.xz
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>
Diffstat (limited to 'src/northbridge/intel/x4x')
-rw-r--r--src/northbridge/intel/x4x/raminit.c33
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) {