diff mbox series

[v6,4/7] drm/msm: adreno: find bandwidth index of OPP and set it along freq index

Message ID 20241217-topic-sm8x50-gpu-bw-vote-v6-4-1adaf97e7310@linaro.org
State New
Headers show
Series drm/msm: adreno: add support for DDR bandwidth scaling via GMU | expand

Commit Message

Neil Armstrong Dec. 17, 2024, 2:51 p.m. UTC 
The Adreno GPU Management Unit (GMU) can also scale the DDR Bandwidth
along the Frequency and Power Domain level, until now we left the OPP
core scale the OPP bandwidth via the interconnect path.

In order to enable bandwidth voting via the GPU Management
Unit (GMU), when an opp is set by devfreq we also look for
the corresponding bandwidth index in the previously generated
bw_table and pass this value along the frequency index to the GMU.

The GMU also takes another vote called AB which is a 16bit quantized
value of the floor bandwidth against the maximum supported bandwidth.

The AB is calculated with a default 25% of the bandwidth like the
downstream implementation too inform the GMU firmware the minimal
quantity of bandwidth we require for this OPP. Only pass the AB
vote starting from A750 GPUs.

Since we now vote for all resources via the GMU, setting the OPP
is no more needed, so we can completely skip calling
dev_pm_opp_set_opp() in this situation.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c   | 39 +++++++++++++++++++++++++++++++--
 drivers/gpu/drm/msm/adreno/a6xx_gmu.h   |  2 +-
 drivers/gpu/drm/msm/adreno/a6xx_hfi.c   |  6 ++---
 drivers/gpu/drm/msm/adreno/a6xx_hfi.h   |  5 +++++
 drivers/gpu/drm/msm/adreno/adreno_gpu.h |  5 +++++
 5 files changed, 51 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index b1dadafc35e95d6173019bda1105008dec1ac03a..9520fbcc89d85ee6dd4bdb17cef5f38dbf5afe6d 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -110,9 +110,11 @@  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
 		       bool suspended)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	const struct a6xx_info *info = adreno_gpu->info->a6xx;
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 	u32 perf_index;
+	u32 bw_index = 0;
 	unsigned long gpu_freq;
 	int ret = 0;
 
@@ -125,6 +127,37 @@  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
 		if (gpu_freq == gmu->gpu_freqs[perf_index])
 			break;
 
+	/* If enabled, find the corresponding DDR bandwidth index */
+	if (info->bcms && gmu->nr_gpu_bws > 1) {
+		unsigned int bw = dev_pm_opp_get_bw(opp, true, 0);
+
+		for (bw_index = 0; bw_index < gmu->nr_gpu_bws - 1; bw_index++) {
+			if (bw == gmu->gpu_bw_table[bw_index])
+				break;
+		}
+
+		/* Vote AB as a fraction of the max bandwidth, starting from A750 */
+		if (bw && adreno_is_a750_family(adreno_gpu)) {
+			u64 tmp;
+
+			/* For now, vote for 25% of the bandwidth */
+			tmp = bw * 25;
+			do_div(tmp, 100);
+
+			/*
+			 * The AB vote consists of a 16 bit wide quantized level
+			 * against the maximum supported bandwidth.
+			 * Quantization can be calculated as below:
+			 * vote = (bandwidth * 2^16) / max bandwidth
+			 */
+			tmp *= MAX_AB_VOTE;
+			do_div(tmp, gmu->gpu_bw_table[gmu->nr_gpu_bws - 1]);
+
+			bw_index |= AB_VOTE(clamp(tmp, 1, MAX_AB_VOTE));
+			bw_index |= AB_VOTE_ENABLE;
+		}
+	}
+
 	gmu->current_perf_index = perf_index;
 	gmu->freq = gmu->gpu_freqs[perf_index];
 
@@ -140,8 +173,10 @@  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
 		return;
 
 	if (!gmu->legacy) {
-		a6xx_hfi_set_freq(gmu, perf_index);
-		dev_pm_opp_set_opp(&gpu->pdev->dev, opp);
+		a6xx_hfi_set_freq(gmu, perf_index, bw_index);
+		/* With Bandwidth voting, we now vote for all resources, so skip OPP set */
+		if (!bw_index)
+			dev_pm_opp_set_opp(&gpu->pdev->dev, opp);
 		return;
 	}
 
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index 2062a2be224768c1937d7768f7b8439920e9e127..0c888b326cfb485400118f3601fa5f1949b03374 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -209,7 +209,7 @@  void a6xx_hfi_init(struct a6xx_gmu *gmu);
 int a6xx_hfi_start(struct a6xx_gmu *gmu, int boot_state);
 void a6xx_hfi_stop(struct a6xx_gmu *gmu);
 int a6xx_hfi_send_prep_slumber(struct a6xx_gmu *gmu);
-int a6xx_hfi_set_freq(struct a6xx_gmu *gmu, int index);
+int a6xx_hfi_set_freq(struct a6xx_gmu *gmu, u32 perf_index, u32 bw_index);
 
 bool a6xx_gmu_gx_is_on(struct a6xx_gmu *gmu);
 bool a6xx_gmu_sptprac_is_on(struct a6xx_gmu *gmu);
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_hfi.c b/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
index 995526620d678cd05020315f771213e4a6943bec..0989aee3dd2cf9bc3405c3b25a595c22e6f06387 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_hfi.c
@@ -772,13 +772,13 @@  static int a6xx_hfi_send_core_fw_start(struct a6xx_gmu *gmu)
 		sizeof(msg), NULL, 0);
 }
 
-int a6xx_hfi_set_freq(struct a6xx_gmu *gmu, int index)
+int a6xx_hfi_set_freq(struct a6xx_gmu *gmu, u32 freq_index, u32 bw_index)
 {
 	struct a6xx_hfi_gx_bw_perf_vote_cmd msg = { 0 };
 
 	msg.ack_type = 1; /* blocking */
-	msg.freq = index;
-	msg.bw = 0; /* TODO: bus scaling */
+	msg.freq = freq_index;
+	msg.bw = bw_index;
 
 	return a6xx_hfi_send_msg(gmu, HFI_H2F_MSG_GX_BW_PERF_VOTE, &msg,
 		sizeof(msg), NULL, 0);
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_hfi.h b/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
index 528110169398f69f16443a29a1594d19c36fb595..52ba4a07d7b9a709289acd244a751ace9bdaab5d 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
@@ -173,6 +173,11 @@  struct a6xx_hfi_gx_bw_perf_vote_cmd {
 	u32 bw;
 };
 
+#define AB_VOTE_MASK		GENMASK(31, 16)
+#define MAX_AB_VOTE		(FIELD_MAX(AB_VOTE_MASK) - 1)
+#define AB_VOTE(vote)		FIELD_PREP(AB_VOTE_MASK, (vote))
+#define AB_VOTE_ENABLE		BIT(8)
+
 #define HFI_H2F_MSG_PREPARE_SLUMBER 33
 
 struct a6xx_hfi_prep_slumber_cmd {
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
index e71f420f8b3a8e6cfc52dd1c4d5a63ef3704a07f..f5d6087376f52c93648e136449cfd4f703ecfb7f 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
@@ -559,6 +559,11 @@  static inline int adreno_is_a740_family(struct adreno_gpu *gpu)
 	       gpu->info->family == ADRENO_7XX_GEN3;
 }
 
+static inline int adreno_is_a750_family(struct adreno_gpu *gpu)
+{
+	return gpu->info->family == ADRENO_7XX_GEN3;
+}
+
 static inline int adreno_is_a7xx(struct adreno_gpu *gpu)
 {
 	/* Update with non-fake (i.e. non-A702) Gen 7 GPUs */