drm/i915/bxt: Decode memory bandwidth and parameters
This patch adds support to decode system memory bandwidth and other
parameters for broxton platform, which will be used for arbitrated
display memory bandwidth calculation in GEN9 based platforms and
WM latency level-0 Work-around calculation on GEN9+ platforms.
Changes since V1:
- s/memdev_info/dram_info
Changes since V2:
- Adhere to i915 coding style (Rodrigo)
Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180824093225.12598-2-mahesh1.kumar@intel.com
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 5dd7fc5..52befc1 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1063,6 +1063,117 @@ static void intel_sanitize_options(struct drm_i915_private *dev_priv)
intel_gvt_sanitize_options(dev_priv);
}
+static int
+bxt_get_dram_info(struct drm_i915_private *dev_priv)
+{
+ struct dram_info *dram_info = &dev_priv->dram_info;
+ u32 dram_channels;
+ u32 mem_freq_khz, val;
+ u8 num_active_channels;
+ int i;
+
+ val = I915_READ(BXT_P_CR_MC_BIOS_REQ_0_0_0);
+ mem_freq_khz = DIV_ROUND_UP((val & BXT_REQ_DATA_MASK) *
+ BXT_MEMORY_FREQ_MULTIPLIER_HZ, 1000);
+
+ dram_channels = val & BXT_DRAM_CHANNEL_ACTIVE_MASK;
+ num_active_channels = hweight32(dram_channels);
+
+ /* Each active bit represents 4-byte channel */
+ dram_info->bandwidth_kbps = (mem_freq_khz * num_active_channels * 4);
+
+ if (dram_info->bandwidth_kbps == 0) {
+ DRM_INFO("Couldn't get system memory bandwidth\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Now read each DUNIT8/9/10/11 to check the rank of each dimms.
+ */
+ for (i = BXT_D_CR_DRP0_DUNIT_START; i <= BXT_D_CR_DRP0_DUNIT_END; i++) {
+ u8 size, width;
+ enum dram_rank rank;
+ u32 tmp;
+
+ val = I915_READ(BXT_D_CR_DRP0_DUNIT(i));
+ if (val == 0xFFFFFFFF)
+ continue;
+
+ dram_info->num_channels++;
+ tmp = val & BXT_DRAM_RANK_MASK;
+
+ if (tmp == BXT_DRAM_RANK_SINGLE)
+ rank = I915_DRAM_RANK_SINGLE;
+ else if (tmp == BXT_DRAM_RANK_DUAL)
+ rank = I915_DRAM_RANK_DUAL;
+ else
+ rank = I915_DRAM_RANK_INVALID;
+
+ tmp = val & BXT_DRAM_SIZE_MASK;
+ if (tmp == BXT_DRAM_SIZE_4GB)
+ size = 4;
+ else if (tmp == BXT_DRAM_SIZE_6GB)
+ size = 6;
+ else if (tmp == BXT_DRAM_SIZE_8GB)
+ size = 8;
+ else if (tmp == BXT_DRAM_SIZE_12GB)
+ size = 12;
+ else if (tmp == BXT_DRAM_SIZE_16GB)
+ size = 16;
+ else
+ size = 0;
+
+ tmp = (val & BXT_DRAM_WIDTH_MASK) >> BXT_DRAM_WIDTH_SHIFT;
+ width = (1 << tmp) * 8;
+ DRM_DEBUG_KMS("dram size:%dGB width:X%d rank:%s\n", size,
+ width, rank == I915_DRAM_RANK_SINGLE ? "single" :
+ rank == I915_DRAM_RANK_DUAL ? "dual" : "unknown");
+
+ /*
+ * If any of the channel is single rank channel,
+ * worst case output will be same as if single rank
+ * memory, so consider single rank memory.
+ */
+ if (dram_info->rank == I915_DRAM_RANK_INVALID)
+ dram_info->rank = rank;
+ else if (rank == I915_DRAM_RANK_SINGLE)
+ dram_info->rank = I915_DRAM_RANK_SINGLE;
+ }
+
+ if (dram_info->rank == I915_DRAM_RANK_INVALID) {
+ DRM_INFO("couldn't get memory rank information\n");
+ return -EINVAL;
+ }
+
+ dram_info->valid = true;
+ return 0;
+}
+
+static void
+intel_get_dram_info(struct drm_i915_private *dev_priv)
+{
+ struct dram_info *dram_info = &dev_priv->dram_info;
+ int ret;
+
+ dram_info->valid = false;
+ dram_info->rank = I915_DRAM_RANK_INVALID;
+ dram_info->bandwidth_kbps = 0;
+ dram_info->num_channels = 0;
+
+ if (!IS_BROXTON(dev_priv))
+ return;
+
+ ret = bxt_get_dram_info(dev_priv);
+ if (ret)
+ return;
+
+ DRM_DEBUG_KMS("DRAM bandwidth:%d KBps, total-channels: %u\n",
+ dram_info->bandwidth_kbps, dram_info->num_channels);
+ DRM_DEBUG_KMS("DRAM rank: %s rank\n",
+ (dram_info->rank == I915_DRAM_RANK_DUAL) ?
+ "dual" : "single");
+}
+
/**
* i915_driver_init_hw - setup state requiring device access
* @dev_priv: device private
@@ -1180,6 +1291,12 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
goto err_msi;
intel_opregion_setup(dev_priv);
+ /*
+ * Fill the dram structure to get the system raw bandwidth and
+ * dram info. This will be used for memory latency calculation.
+ */
+ intel_get_dram_info(dev_priv);
+
return 0;