linux-kernel - [PATCH 05/16] habanalabs/gaudi: minimize number of register reads

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Message-Id: <20210818133922.63637-5-ogabbay@kernel.org>
Date:   Wed, 18 Aug 2021 16:39:11 +0300
From:   Oded Gabbay <ogabbay@...nel.org>
To:     linux-kernel@...r.kernel.org
Subject: [PATCH 05/16] habanalabs/gaudi: minimize number of register reads

Because the register reads might be trapped by the hypervisor in
certain deployments, minimize the number of reads during runtime by
moving static initializations to functions that occur during device
initialization instead of context open.

Signed-off-by: Oded Gabbay <ogabbay@...nel.org>
---
 drivers/misc/habanalabs/gaudi/gaudi.c           | 15 +++++++++++----
 drivers/misc/habanalabs/gaudi/gaudi_coresight.c |  5 -----
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/habanalabs/gaudi/gaudi.c b/drivers/misc/habanalabs/gaudi/gaudi.c
index d8d296b66f9d..1b98233ffc4b 100644
--- a/drivers/misc/habanalabs/gaudi/gaudi.c
+++ b/drivers/misc/habanalabs/gaudi/gaudi.c
@@ -1596,6 +1596,11 @@ static int gaudi_late_init(struct hl_device *hdev)
 		goto disable_pci_access;
 	}
 
+	/* We only support a single ASID for the user, so for the sake of optimization, just
+	 * initialize the ASID one time during device initialization with the fixed value of 1
+	 */
+	gaudi_mmu_prepare(hdev, 1);
+
 	return 0;
 
 disable_pci_access:
@@ -6793,6 +6798,9 @@ static void gaudi_mmu_prepare(struct hl_device *hdev, u32 asid)
 				asid);
 	}
 
+	gaudi_mmu_prepare_reg(hdev, mmPSOC_GLOBAL_CONF_TRACE_ARUSER, asid);
+	gaudi_mmu_prepare_reg(hdev, mmPSOC_GLOBAL_CONF_TRACE_AWUSER, asid);
+
 	hdev->asic_funcs->set_clock_gating(hdev);
 
 	mutex_unlock(&gaudi->clk_gate_mutex);
@@ -6842,7 +6850,8 @@ static int gaudi_send_job_on_qman0(struct hl_device *hdev,
 
 	dma_offset = gaudi_dma_assignment[GAUDI_PCI_DMA_1] * DMA_CORE_OFFSET;
 
-	WREG32_OR(mmDMA0_CORE_PROT + dma_offset, BIT(DMA0_CORE_PROT_VAL_SHIFT));
+	WREG32(mmDMA0_CORE_PROT + dma_offset,
+			BIT(DMA0_CORE_PROT_ERR_VAL_SHIFT) | BIT(DMA0_CORE_PROT_VAL_SHIFT));
 
 	rc = hl_hw_queue_send_cb_no_cmpl(hdev, GAUDI_QUEUE_ID_DMA_0_0,
 					job->job_cb_size, cb->bus_address);
@@ -6863,8 +6872,7 @@ static int gaudi_send_job_on_qman0(struct hl_device *hdev,
 	}
 
 free_fence_ptr:
-	WREG32_AND(mmDMA0_CORE_PROT + dma_offset,
-			~BIT(DMA0_CORE_PROT_VAL_SHIFT));
+	WREG32(mmDMA0_CORE_PROT + dma_offset, BIT(DMA0_CORE_PROT_ERR_VAL_SHIFT));
 
 	hdev->asic_funcs->asic_dma_pool_free(hdev, (void *) fence_ptr,
 					fence_dma_addr);
@@ -8653,7 +8661,6 @@ static int gaudi_ctx_init(struct hl_ctx *ctx)
 	if (ctx->asid == HL_KERNEL_ASID_ID)
 		return 0;
 
-	gaudi_mmu_prepare(ctx->hdev, ctx->asid);
 	return gaudi_internal_cb_pool_init(ctx->hdev, ctx);
 }
 
diff --git a/drivers/misc/habanalabs/gaudi/gaudi_coresight.c b/drivers/misc/habanalabs/gaudi/gaudi_coresight.c
index c2a27ed1c4d1..5349c1be13f9 100644
--- a/drivers/misc/habanalabs/gaudi/gaudi_coresight.c
+++ b/drivers/misc/habanalabs/gaudi/gaudi_coresight.c
@@ -622,11 +622,6 @@ static int gaudi_config_etr(struct hl_device *hdev,
 			return -EINVAL;
 		}
 
-		gaudi_mmu_prepare_reg(hdev, mmPSOC_GLOBAL_CONF_TRACE_ARUSER,
-						hdev->compute_ctx->asid);
-		gaudi_mmu_prepare_reg(hdev, mmPSOC_GLOBAL_CONF_TRACE_AWUSER,
-						hdev->compute_ctx->asid);
-
 		msb = upper_32_bits(input->buffer_address) >> 8;
 		msb &= PSOC_GLOBAL_CONF_TRACE_ADDR_MSB_MASK;
 		WREG32(mmPSOC_GLOBAL_CONF_TRACE_ADDR, msb);
-- 
2.17.1