On Tue, 02 Aug 2022, Matt Roper <matthew.d.roper@xxxxxxxxx> wrote:
> On Wed, Jul 27, 2022 at 06:34:10PM -0700, Radhakrishna Sripada wrote:
>> Since Xe LPD+, Memory latency data are in LATENCY_LPX_LPY registers
>> instead of GT driver mailbox.
>>
>> Bspec: 64608
>>
>> Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
>> Original Author: Caz Yokoyama
>> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/i915_reg.h | 7 +++
>> drivers/gpu/drm/i915/intel_pm.c | 105 +++++++++++++++++++-------------
>> 2 files changed, 71 insertions(+), 41 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>> index 6087d40eed70..23b50d671550 100644
>> --- a/drivers/gpu/drm/i915/i915_reg.h
>> +++ b/drivers/gpu/drm/i915/i915_reg.h
>> @@ -8754,4 +8754,11 @@ enum skl_power_gate {
>> #define GEN12_STATE_ACK_DEBUG _MMIO(0x20BC)
>>
>> #define MTL_MEDIA_GSI_BASE 0x380000
>> +
>> +#define MTL_LATENCY_LP0_LP1 _MMIO(0x45780)
>> +#define MTL_LATENCY_LP2_LP3 _MMIO(0x45784)
>> +#define MTL_LATENCY_LP4_LP5 _MMIO(0x45788)
>> +#define MTL_LATENCY_LEVEL0_2_4_MASK REG_GENMASK(12, 0)
>> +#define MTL_LATENCY_LEVEL1_3_5_MASK REG_GENMASK(28, 16)
>> +
>> #endif /* _I915_REG_H_ */
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index ef7553b494ea..fac565d23d57 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -2861,16 +2861,75 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
>> result->enable = true;
>> }
>>
>> +static void
>> +adjust_wm_latency(u16 wm[], int max_level, int read_latency,
>> + bool wm_lv_0_adjust_needed)
>
> The refactoring to separate the adjustment from the readout should
> probably be a separate patch before you add the MTL-specific changes on
> top.
Agreed.
>
>
> Matt
>
>> +{
>> + int i, level;
>> +
>> + /*
>> + * If a level n (n > 1) has a 0us latency, all levels m (m >= n)
>> + * need to be disabled. We make sure to sanitize the values out
>> + * of the punit to satisfy this requirement.
>> + */
>> + for (level = 1; level <= max_level; level++) {
>> + if (wm[level] == 0) {
>> + for (i = level + 1; i <= max_level; i++)
>> + wm[i] = 0;
>> +
>> + max_level = level - 1;
>> + break;
>> + }
>> + }
>> +
>> + /*
>> + * WaWmMemoryReadLatency
>> + *
>> + * punit doesn't take into account the read latency so we need
>> + * to add proper adjustement to each valid level we retrieve
>> + * from the punit when level 0 response data is 0us.
>> + */
>> + if (wm[0] == 0) {
>> + for (level = 0; level <= max_level; level++)
>> + wm[level] += read_latency;
>> + }
>> +
>> + /*
>> + * WA Level-0 adjustment for 16GB DIMMs: SKL+
>> + * If we could not get dimm info enable this WA to prevent from
>> + * any underrun. If not able to get Dimm info assume 16GB dimm
>> + * to avoid any underrun.
>> + */
>> + if (wm_lv_0_adjust_needed)
>> + wm[0] += 1;
>> +}
>> +
>> static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
>> u16 wm[])
>> {
>> struct intel_uncore *uncore = &dev_priv->uncore;
>> + int max_level = ilk_wm_max_level(dev_priv);
>>
>> - if (DISPLAY_VER(dev_priv) >= 9) {
>> + if (DISPLAY_VER(dev_priv) >= 14) {
>> u32 val;
>> - int ret, i;
>> - int level, max_level = ilk_wm_max_level(dev_priv);
>> +
>> + val = intel_uncore_read(uncore, MTL_LATENCY_LP0_LP1);
>> + wm[0] = REG_FIELD_GET(MTL_LATENCY_LEVEL0_2_4_MASK, val);
>> + wm[1] = REG_FIELD_GET(MTL_LATENCY_LEVEL1_3_5_MASK, val);
>> + val = intel_uncore_read(uncore, MTL_LATENCY_LP2_LP3);
>> + wm[2] = REG_FIELD_GET(MTL_LATENCY_LEVEL0_2_4_MASK, val);
>> + wm[3] = REG_FIELD_GET(MTL_LATENCY_LEVEL1_3_5_MASK, val);
>> + val = intel_uncore_read(uncore, MTL_LATENCY_LP4_LP5);
>> + wm[4] = REG_FIELD_GET(MTL_LATENCY_LEVEL0_2_4_MASK, val);
>> + wm[5] = REG_FIELD_GET(MTL_LATENCY_LEVEL1_3_5_MASK, val);
>> +
>> + adjust_wm_latency(wm, max_level, 6,
>> + dev_priv->dram_info.wm_lv_0_adjust_needed);
>> + } else if (DISPLAY_VER(dev_priv) >= 9) {
>> + int read_latency = DISPLAY_VER(dev_priv) >= 12 ? 3 : 2;
>> int mult = IS_DG2(dev_priv) ? 2 : 1;
>> + u32 val;
>> + int ret;
>>
>> /* read the first set of memory latencies[0:3] */
>> val = 0; /* data0 to be programmed to 0 for first set */
>> @@ -2909,44 +2968,8 @@ static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
>> wm[7] = ((val >> GEN9_MEM_LATENCY_LEVEL_3_7_SHIFT) &
>> GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
>>
>> - /*
>> - * If a level n (n > 1) has a 0us latency, all levels m (m >= n)
>> - * need to be disabled. We make sure to sanitize the values out
>> - * of the punit to satisfy this requirement.
>> - */
>> - for (level = 1; level <= max_level; level++) {
>> - if (wm[level] == 0) {
>> - for (i = level + 1; i <= max_level; i++)
>> - wm[i] = 0;
>> -
>> - max_level = level - 1;
>> -
>> - break;
>> - }
>> - }
>> -
>> - /*
>> - * WaWmMemoryReadLatency
>> - *
>> - * punit doesn't take into account the read latency so we need
>> - * to add proper adjustement to each valid level we retrieve
>> - * from the punit when level 0 response data is 0us.
>> - */
>> - if (wm[0] == 0) {
>> - u8 adjust = DISPLAY_VER(dev_priv) >= 12 ? 3 : 2;
>> -
>> - for (level = 0; level <= max_level; level++)
>> - wm[level] += adjust;
>> - }
>> -
>> - /*
>> - * WA Level-0 adjustment for 16GB DIMMs: SKL+
>> - * If we could not get dimm info enable this WA to prevent from
>> - * any underrun. If not able to get Dimm info assume 16GB dimm
>> - * to avoid any underrun.
>> - */
>> - if (dev_priv->dram_info.wm_lv_0_adjust_needed)
>> - wm[0] += 1;
>> + adjust_wm_latency(wm, max_level, read_latency,
>> + dev_priv->dram_info.wm_lv_0_adjust_needed);
>> } else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) {
>> u64 sskpd = intel_uncore_read64(uncore, MCH_SSKPD);
>>
>> --
>> 2.25.1
>>
--
Jani Nikula, Intel Open Source Graphics Center
