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northbridge/amd/amdht: Allow mainboards to set HT frequency limit

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This is useful when the PCB layout of a mainboard does not allow
stable operation at the increased HyperTransport speeds of newer
processors.

Change-Id: Idc93a1294608178ddf38ca72d40e6bad7deb9004
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/8464
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
This commit is contained in:
Timothy Pearson
2015-02-16 14:57:06 -06:00
committed by Marc Jones
parent 668828d3b3
commit 586d6e2a88
4 changed files with 49 additions and 4 deletions
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40
src/northbridge/amd/amdht/h3finit.c
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@@ -75,6 +75,41 @@ static const uint16_t ht_speed_limit[16] =
0x00FF, 0x007F, 0x003F, 0x001F,
0x000F, 0x0007, 0x0003, 0x0001};
static const struct ht_speed_limit_map_t {
uint16_t mhz;
uint8_t config;
} ht_speed_limit_map[] = {
{0, NVRAM_LIMIT_HT_SPEED_AUTO},
{200, NVRAM_LIMIT_HT_SPEED_200},
{300, NVRAM_LIMIT_HT_SPEED_300},
{400, NVRAM_LIMIT_HT_SPEED_400},
{500, NVRAM_LIMIT_HT_SPEED_500},
{600, NVRAM_LIMIT_HT_SPEED_600},
{800, NVRAM_LIMIT_HT_SPEED_800},
{1000, NVRAM_LIMIT_HT_SPEED_1000},
{1200, NVRAM_LIMIT_HT_SPEED_1200},
{1400, NVRAM_LIMIT_HT_SPEED_1400},
{1600, NVRAM_LIMIT_HT_SPEED_1600},
{1800, NVRAM_LIMIT_HT_SPEED_1800},
{2000, NVRAM_LIMIT_HT_SPEED_2000},
{2200, NVRAM_LIMIT_HT_SPEED_2200},
{2400, NVRAM_LIMIT_HT_SPEED_2400},
{2600, NVRAM_LIMIT_HT_SPEED_2600},
};
static const uint16_t ht_speed_mhz_to_hw(uint16_t mhz)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(ht_speed_limit_map); i++)
if (ht_speed_limit_map[i].mhz == mhz)
return ht_speed_limit_map[i].config;
printk(BIOS_WARNING,
"WARNING: Invalid HT link limit frequency %d specified, ignoring...\n",
mhz);
return ht_speed_limit[NVRAM_LIMIT_HT_SPEED_AUTO];
}
/*----------------------------------------------------------------------------
* TYPEDEFS AND STRUCTURES
*
@@ -1359,10 +1394,9 @@ static void selectOptimalWidthAndFrequency(sMainData *pDat)
for (i = 0; i < pDat->TotalLinks*2; i += 2)
{
/* FIXME
* Mainboards need to be able to set cbPCBFreqLimit
*/
cbPCBFreqLimit = 0xFFFF; // Maximum allowed by autoconfiguration
if (pDat->HtBlock->ht_link_configuration)
cbPCBFreqLimit = ht_speed_mhz_to_hw(pDat->HtBlock->ht_link_configuration->ht_speed_limit);
cbPCBFreqLimit = min(cbPCBFreqLimit, cbPCBFreqLimit_NVRAM);
#if CONFIG_EXPERT && CONFIG_LIMIT_HT_DOWN_WIDTH_8