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IB/hfi1: Add special setting for low power AOC 

Low power QSFP AOC cables require a different SerDes
Tx PLL bandwidth setting than the default.  The
8051 firmware does not know the details, so the driver
needs to tell the firmware through a special setting.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Dean Luick 2016-12-07 19:33:13 -08:00 committed by Doug Ledford
parent 6e40b59cfa
commit 5213006ade
1 changed files with 43 additions and 1 deletions
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44
drivers/infiniband/hw/hfi1/platform.c
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@ -637,6 +637,38 @@ static void apply_tx_lanes(struct hfi1_pportdata *ppd, u8 field_id,
}
}
/*
* Return a special SerDes setting for low power AOC cables. The power class
* threshold and setting being used were all found by empirical testing.
*
* Summary of the logic:
*
* if (QSFP and QSFP_TYPE == AOC and QSFP_POWER_CLASS < 4)
* return 0xe
* return 0; // leave at default
*/
static u8 aoc_low_power_setting(struct hfi1_pportdata *ppd)
{
u8 *cache = ppd->qsfp_info.cache;
int power_class;
/* QSFP only */
if (ppd->port_type != PORT_TYPE_QSFP)
return 0; /* leave at default */
/* active optical cables only */
switch ((cache[QSFP_MOD_TECH_OFFS] & 0xF0) >> 4) {
case 0x0 ... 0x9: /* fallthrough */
case 0xC: /* fallthrough */
case 0xE:
/* active AOC */
power_class = get_qsfp_power_class(cache[QSFP_MOD_PWR_OFFS]);
if (power_class < QSFP_POWER_CLASS_4)
return 0xe;
}
return 0; /* leave at default */
}
static void apply_tunings(
struct hfi1_pportdata *ppd, u32 tx_preset_index,
u8 tuning_method, u32 total_atten, u8 limiting_active)
@ -705,7 +737,17 @@ static void apply_tunings(
tx_preset_index, TX_PRESET_TABLE_POSTCUR, &tx_preset, 4);
postcur = tx_preset;
config_data = precur | (attn << 8) | (postcur << 16);
/*
* NOTES:
* o The aoc_low_power_setting is applied to all lanes even
* though only lane 0's value is examined by the firmware.
* o A lingering low power setting after a cable swap does
* not occur. On cable unplug the 8051 is reset and
* restarted on cable insert. This resets all settings to
* their default, erasing any previous low power setting.
*/
config_data = precur | (attn << 8) | (postcur << 16) |
(aoc_low_power_setting(ppd) << 24);
apply_tx_lanes(ppd, TX_EQ_SETTINGS, config_data,
"Applying TX settings");