[PATCH 2/8] drm/i915: Decode system memory bandwidth

Mahesh Kumar mahesh1.kumar at intel.com
Thu Feb 9 08:40:22 UTC 2017


This patch adds support to decode system memory bandwidth
which will be used for arbitrated display memory percentage
calculation in GEN9 based system.

Changes from v1:
 - Address comments from Paulo
 - implement decode function for SKL/KBL also
Changes from v2:
 - Rewrite the code as per HW team inputs
 - Addresses review comments
Changes from v3:
 - Fix compilation warning
Changes from v4:
 - Address review comments
 - Round-off the frequency & bandwidth results

Signed-off-by: Mahesh Kumar <mahesh1.kumar at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 179 ++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_drv.h |  12 +++
 drivers/gpu/drm/i915/i915_reg.h |  37 +++++++++
 3 files changed, 228 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 1612498ccf21..17abadaf27b5 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -996,6 +996,179 @@ static void intel_sanitize_options(struct drm_i915_private *dev_priv)
 	DRM_DEBUG_DRIVER("use GPU sempahores? %s\n", yesno(i915.semaphores));
 }
 
+static enum rank
+skl_memdev_get_channel_rank(uint32_t val)
+{
+	uint8_t l_rank, s_rank;
+	uint8_t l_size, s_size;
+
+	if (!val)
+		return I915_DRAM_RANK_INVALID;
+
+	l_size = (val >> SKL_DRAM_SIZE_L_SHIFT) & SKL_DRAM_SIZE_MASK;
+	s_size = (val >> SKL_DRAM_SIZE_S_SHIFT) & SKL_DRAM_SIZE_MASK;
+	l_rank = (val >> SKL_DRAM_RANK_L_SHIFT) & SKL_DRAM_RANK_MASK;
+	s_rank = (val >> SKL_DRAM_RANK_S_SHIFT) & SKL_DRAM_RANK_MASK;
+
+	if ((l_size == 0) && (s_size == 0))
+		return I915_DRAM_RANK_INVALID;
+
+	if (l_rank == SKL_DRAM_RANK_DUAL || s_rank == SKL_DRAM_RANK_DUAL)
+		return I915_DRAM_RANK_DUAL;
+
+	if ((l_size && l_rank == SKL_DRAM_RANK_SINGLE) &&
+		(s_size && s_rank == SKL_DRAM_RANK_SINGLE))
+		return I915_DRAM_RANK_DUAL;
+	return I915_DRAM_RANK_SINGLE;
+}
+
+static int
+skl_get_memdev_info(struct drm_i915_private *dev_priv)
+{
+	struct memdev_info *memdev_info = &dev_priv->memdev_info;
+	uint32_t mem_freq_khz;
+	uint32_t val;
+	enum rank ch0_rank, ch1_rank;
+
+	val = I915_READ(SKL_MC_BIOS_DATA_0_0_0_MCHBAR_PCU);
+	mem_freq_khz = DIV_ROUND_UP((val & SKL_REQ_DATA_MASK) *
+				SKL_MEMORY_FREQ_MULTIPLIER_HZ, 1000);
+
+	val = I915_READ(SKL_MAD_DIMM_CH0_0_0_0_MCHBAR_MCMAIN);
+	ch0_rank = skl_memdev_get_channel_rank(val);
+	if (ch0_rank != I915_DRAM_RANK_INVALID)
+		memdev_info->num_channels++;
+
+	val = I915_READ(SKL_MAD_DIMM_CH1_0_0_0_MCHBAR_MCMAIN);
+	ch1_rank = skl_memdev_get_channel_rank(val);
+	if (ch1_rank != I915_DRAM_RANK_INVALID)
+		memdev_info->num_channels++;
+
+	if (memdev_info->num_channels == 0) {
+		DRM_ERROR("Number of mem channels are zero\n");
+		return -EINVAL;
+	}
+
+	memdev_info->bandwidth_kbps = memdev_info->num_channels *
+							mem_freq_khz * 8;
+
+	if (memdev_info->bandwidth_kbps == 0) {
+		DRM_ERROR("Couldn't get system memory bandwidth\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * If any of channel is single rank channel, worst case output will be
+	 * same as if single rank memory, so consider single rank memory.
+	 */
+	if (ch0_rank == I915_DRAM_RANK_SINGLE
+				|| ch1_rank == I915_DRAM_RANK_SINGLE)
+		memdev_info->rank = I915_DRAM_RANK_SINGLE;
+	else
+		memdev_info->rank = max(ch0_rank, ch1_rank);
+
+	if (memdev_info->rank == I915_DRAM_RANK_INVALID) {
+		DRM_ERROR("couldn't get memory rank information\n");
+		return -EINVAL;
+	}
+
+	memdev_info->valid = true;
+	return 0;
+}
+
+static int
+bxt_get_memdev_info(struct drm_i915_private *dev_priv)
+{
+	struct memdev_info *memdev_info = &dev_priv->memdev_info;
+	uint32_t dram_channels;
+	uint32_t mem_freq_khz, val;
+	uint8_t 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_SHIFT) &
+					BXT_DRAM_CHANNEL_ACTIVE_MASK;
+	num_active_channels = hweight32(dram_channels);
+
+	/* each active bit represents 4-byte channel */
+	memdev_info->bandwidth_kbps = (mem_freq_khz * num_active_channels * 4);
+
+	if (memdev_info->bandwidth_kbps == 0) {
+		DRM_ERROR("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 = 0; i < BXT_D_CR_DRP0_DUNIT_MAX; i++) {
+		val = I915_READ(BXT_D_CR_DRP0_DUNIT(i));
+		if (val != 0xFFFFFFFF) {
+			uint8_t rank;
+			enum rank ch_rank;
+
+			memdev_info->num_channels++;
+			rank = val & BXT_DRAM_RANK_MASK;
+			if (rank == BXT_DRAM_RANK_SINGLE)
+				ch_rank = I915_DRAM_RANK_SINGLE;
+			else if (rank == BXT_DRAM_RANK_DUAL)
+				ch_rank = I915_DRAM_RANK_DUAL;
+			else
+				ch_rank = I915_DRAM_RANK_INVALID;
+
+			/*
+			 * If any of channel is single rank channel,
+			 * worst case output will be same as if single rank
+			 * memory, so consider single rank memory.
+			 */
+			if (memdev_info->rank == I915_DRAM_RANK_INVALID)
+				memdev_info->rank = ch_rank;
+			else if (ch_rank == I915_DRAM_RANK_SINGLE)
+				memdev_info->rank = I915_DRAM_RANK_SINGLE;
+		}
+	}
+
+	if (memdev_info->rank == I915_DRAM_RANK_INVALID) {
+		DRM_ERROR("couldn't get memory rank information\n");
+		return -EINVAL;
+	}
+
+	memdev_info->valid = true;
+	return 0;
+}
+
+static void
+intel_get_memdev_info(struct drm_i915_private *dev_priv)
+{
+	struct memdev_info *memdev_info = &dev_priv->memdev_info;
+	int ret;
+
+	memdev_info->valid = false;
+	memdev_info->rank = I915_DRAM_RANK_INVALID;
+	memdev_info->num_channels = 0;
+
+	if (!IS_GEN9(dev_priv))
+		return;
+
+	if (IS_BROXTON(dev_priv))
+		ret = bxt_get_memdev_info(dev_priv);
+	else
+		ret = skl_get_memdev_info(dev_priv);
+	if (ret)
+		return;
+
+	DRM_DEBUG_DRIVER("DRAM bandwidth: %u KBps total-channels: %u\n",
+				memdev_info->bandwidth_kbps,
+				memdev_info->num_channels);
+	DRM_DEBUG_DRIVER("DRAM rank: %s rank\n",
+				(memdev_info->rank == I915_DRAM_RANK_DUAL) ?
+						"dual" : "single");
+}
+
+
 /**
  * i915_driver_init_hw - setup state requiring device access
  * @dev_priv: device private
@@ -1102,6 +1275,12 @@ static int i915_driver_init_hw(struct drm_i915_private *dev_priv)
 	if (ret)
 		goto out_ggtt;
 
+	/*
+	 * Fill the memdev structure to get the system raw bandwidth
+	 * This will be used by WM algorithm, to implement GEN9 based WA
+	 */
+	intel_get_memdev_info(dev_priv);
+
 	return 0;
 
 out_ggtt:
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 58bb5ca0e8e3..3f4535d190b4 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2384,6 +2384,18 @@ struct drm_i915_private {
 		bool distrust_bios_wm;
 	} wm;
 
+	struct memdev_info {
+		bool valid;
+		uint32_t bandwidth_kbps;
+		uint8_t num_channels;
+		enum rank {
+			I915_DRAM_RANK_INVALID = 0,
+			I915_DRAM_RANK_SINGLE,
+			I915_DRAM_RANK_DUAL
+		} rank;
+	} memdev_info;
+
+
 	struct i915_runtime_pm pm;
 
 	struct {
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 208605d9837c..8e6ffe8845bc 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8113,6 +8113,43 @@ enum {
 #define  DC_STATE_DEBUG_MASK_CORES	(1<<0)
 #define  DC_STATE_DEBUG_MASK_MEMORY_UP	(1<<1)
 
+#define BXT_P_CR_MC_BIOS_REQ_0_0_0	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x7114)
+#define BXT_REQ_DATA_MASK			0x3F
+#define BXT_DRAM_ACTIVE_CHANNEL_SHIFT		12
+#define BXT_DRAM_ACTIVE_CHANNEL_MASK		0xF
+/*
+ * BIOS programs this field of REQ_DATA [5:0] in integer
+ * multiple of 133333 KHz (133.33MHz)
+ */
+#define BXT_MEMORY_FREQ_MULTIPLIER_HZ		133333333
+#define BXT_D_CR_DRP0_DUNIT8			0x1000
+#define BXT_D_CR_DRP0_DUNIT9			0x1200
+#define BXT_D_CR_DRP0_DUNIT_MAX			4
+#define _MMIO_MCHBAR_DUNIT(x, a, b) _MMIO(MCHBAR_MIRROR_BASE_SNB + (a) + (x)*((b)-(a)))
+#define BXT_D_CR_DRP0_DUNIT(x)	_MMIO_MCHBAR_DUNIT(x, BXT_D_CR_DRP0_DUNIT8, BXT_D_CR_DRP0_DUNIT9)
+#define BXT_DRAM_CHANNEL_ACTIVE_SHIFT		12
+#define BXT_DRAM_CHANNEL_ACTIVE_MASK		0xF
+#define BXT_DRAM_RANK_MASK			0x3
+#define BXT_DRAM_RANK_SINGLE			0x1
+#define BXT_DRAM_RANK_DUAL			0x3
+
+/*
+ * SKL memory frequeny multiplier is 266667 KHz (266.67 MHz)
+ */
+#define SKL_MEMORY_FREQ_MULTIPLIER_HZ		266666666
+#define SKL_MC_BIOS_DATA_0_0_0_MCHBAR_PCU	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5E04)
+#define SKL_REQ_DATA_MASK			(0xF << 0)
+#define SKL_MAD_DIMM_CH0_0_0_0_MCHBAR_MCMAIN	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x500C)
+#define SKL_MAD_DIMM_CH1_0_0_0_MCHBAR_MCMAIN	_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5010)
+#define SKL_DRAM_SIZE_MASK			0x1F
+#define SKL_DRAM_SIZE_L_SHIFT			0
+#define SKL_DRAM_SIZE_S_SHIFT			16
+#define SKL_DRAM_RANK_MASK			0x1
+#define SKL_DRAM_RANK_L_SHIFT			10
+#define SKL_DRAM_RANK_S_SHIFT			26
+#define SKL_DRAM_RANK_SINGLE			0x0
+#define SKL_DRAM_RANK_DUAL			0x1
+
 /* Please see hsw_read_dcomp() and hsw_write_dcomp() before using this register,
  * since on HSW we can't write to it using I915_WRITE. */
 #define D_COMP_HSW			_MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5F0C)
-- 
2.11.0



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