habanalabs: add MMU DRAM default page mapping

This patch provides a workaround for a H/W bug in Goya, where access to
RAZWI from TPC can cause PCI completion timeout.

The WA is to use the device MMU to map any unmapped DRAM memory to a
default page in the DRAM. That way, the TPC will never reach RAZWI upon
accessing a bad address in the DRAM.

When a DRAM page is mapped by the user, its default mapping is
overwritten. Once that page is unmapped, the MMU driver will map that page
to the default page.

To help debugging, the driver will set the default page area to 0x99 on
device initialization.

Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 75 insertions, 115 deletions

diff --git a/drivers/misc/habanalabs/goya/goya.c b/drivers/misc/habanalabs/goya/goya.c
index 447d907bddf3..7c2edabe20bd 100644
--- a/drivers/misc/habanalabs/goya/goya.c
+++ b/drivers/misc/habanalabs/goya/goya.c
@@ -304,6 +304,7 @@ static u32 goya_non_fatal_events[GOYA_ASYC_EVENT_GROUP_NON_FATAL_SIZE] = {
 static int goya_armcp_info_get(struct hl_device *hdev);
 static void goya_mmu_prepare(struct hl_device *hdev, u32 asid);
 static int goya_mmu_clear_pgt_range(struct hl_device *hdev);
+static int goya_mmu_set_dram_default_page(struct hl_device *hdev);
 static int goya_mmu_update_asid_hop0_addr(struct hl_device *hdev, u32 asid,
 					u64 phys_addr);
 
@@ -345,6 +346,7 @@ static void goya_get_fixed_properties(struct hl_device *hdev)
 						SRAM_USER_BASE_OFFSET;
 
 	prop->mmu_pgt_addr = MMU_PAGE_TABLES_ADDR;
+	prop->mmu_dram_default_page_addr = MMU_DRAM_DEFAULT_PAGE_ADDR;
 	if (hdev->pldm)
 		prop->mmu_pgt_size = 0x800000; /* 8MB */
 	else
@@ -359,6 +361,8 @@ static void goya_get_fixed_properties(struct hl_device *hdev)
 	prop->va_space_host_end_address = VA_HOST_SPACE_END;
 	prop->va_space_dram_start_address = VA_DDR_SPACE_START;
 	prop->va_space_dram_end_address = VA_DDR_SPACE_END;
+	prop->dram_size_for_default_page_mapping =
+			prop->va_space_dram_end_address;
 	prop->cfg_size = CFG_SIZE;
 	prop->max_asid = MAX_ASID;
 	prop->num_of_events = GOYA_ASYNC_EVENT_ID_SIZE;
@@ -816,6 +820,12 @@ static int goya_late_init(struct hl_device *hdev)
 		goto disable_pci_access;
 	}
 
+	rc = goya_mmu_set_dram_default_page(hdev);
+	if (rc) {
+		dev_err(hdev->dev, "Failed to set DRAM default page\n");
+		goto disable_pci_access;
+	}
+
 	return 0;
 
 disable_pci_access:
@@ -2648,6 +2658,7 @@ static int goya_mmu_init(struct hl_device *hdev)
 		return 0;
 
 	hdev->dram_supports_virtual_memory = true;
+	hdev->dram_default_page_mapping = true;
 
 	for (i = 0 ; i < prop->max_asid ; i++) {
 		hop0_addr = prop->mmu_pgt_addr +
@@ -4303,98 +4314,6 @@ static void goya_update_eq_ci(struct hl_device *hdev, u32 val)
 	WREG32(mmPSOC_GLOBAL_CONF_SCRATCHPAD_6, val);
 }
 
-static int goya_context_switch(struct hl_device *hdev, u32 asid)
-{
-	struct asic_fixed_properties *prop = &hdev->asic_prop;
-	struct packet_lin_dma *clear_sram_pkt;
-	struct hl_cs_parser parser;
-	struct hl_cs_job *job;
-	u32 cb_size;
-	struct hl_cb *cb;
-	int rc;
-
-	cb = hl_cb_kernel_create(hdev, PAGE_SIZE);
-	if (!cb)
-		return -EFAULT;
-
-	clear_sram_pkt = (struct packet_lin_dma *)
-					(uintptr_t) cb->kernel_address;
-
-	memset(clear_sram_pkt, 0, sizeof(*clear_sram_pkt));
-	cb_size = sizeof(*clear_sram_pkt);
-
-	clear_sram_pkt->ctl = ((PACKET_LIN_DMA << GOYA_PKT_CTL_OPCODE_SHIFT) |
-		(DMA_HOST_TO_SRAM << GOYA_PKT_LIN_DMA_CTL_DMA_DIR_SHIFT) |
-		(1 << GOYA_PKT_LIN_DMA_CTL_MEMSET_SHIFT) |
-		(1 << GOYA_PKT_LIN_DMA_CTL_WO_SHIFT) |
-		(1 << GOYA_PKT_CTL_RB_SHIFT) |
-		(1 << GOYA_PKT_CTL_MB_SHIFT));
-
-	clear_sram_pkt->src_addr = 0x7777777777777777ull;
-	clear_sram_pkt->dst_addr = prop->sram_base_address;
-	if (hdev->pldm)
-		clear_sram_pkt->tsize = 0x10000;
-	else
-		clear_sram_pkt->tsize = prop->sram_size;
-
-	job = hl_cs_allocate_job(hdev, true);
-	if (!job) {
-		dev_err(hdev->dev, "Failed to allocate a new job\n");
-		rc = -ENOMEM;
-		goto release_cb;
-	}
-
-	job->id = 0;
-	job->user_cb = cb;
-	job->user_cb->cs_cnt++;
-	job->user_cb_size = cb_size;
-	job->hw_queue_id = GOYA_QUEUE_ID_DMA_0;
-
-	hl_debugfs_add_job(hdev, job);
-
-	parser.ctx_id = HL_KERNEL_ASID_ID;
-	parser.cs_sequence = 0;
-	parser.job_id = job->id;
-	parser.hw_queue_id = job->hw_queue_id;
-	parser.job_userptr_list = &job->userptr_list;
-	parser.user_cb = job->user_cb;
-	parser.user_cb_size = job->user_cb_size;
-	parser.ext_queue = job->ext_queue;
-	parser.use_virt_addr = hdev->mmu_enable;
-
-	rc = hdev->asic_funcs->cs_parser(hdev, &parser);
-	if (rc) {
-		dev_err(hdev->dev,
-			"Failed to parse kernel CB during context switch\n");
-		goto free_job;
-	}
-
-	job->patched_cb = parser.patched_cb;
-	job->job_cb_size = parser.patched_cb_size;
-	job->patched_cb->cs_cnt++;
-
-	rc = goya_send_job_on_qman0(hdev, job);
-
-	/* no point in setting the asid in case of failure */
-	if (!rc)
-		goya_mmu_prepare(hdev, asid);
-
-	job->patched_cb->cs_cnt--;
-	hl_cb_put(job->patched_cb);
-
-free_job:
-	hl_userptr_delete_list(hdev, &job->userptr_list);
-	hl_debugfs_remove_job(hdev, job);
-	kfree(job);
-	cb->cs_cnt--;
-
-release_cb:
-	hl_cb_put(cb);
-	hl_cb_destroy(hdev, &hdev->kernel_cb_mgr, cb->id << PAGE_SHIFT);
-
-	return rc;
-}
-
 static void goya_restore_phase_topology(struct hl_device *hdev)
 {
 	int i, num_of_sob_in_longs, num_of_mon_in_longs;
@@ -4864,41 +4783,37 @@ void *goya_get_events_stat(struct hl_device *hdev, u32 *size)
 	return goya->events_stat;
 }
 
-static int goya_mmu_clear_pgt_range(struct hl_device *hdev)
+static int goya_memset_device_memory(struct hl_device *hdev, u64 addr, u32 size,
+				u64 val, bool is_dram)
 {
-	struct asic_fixed_properties *prop = &hdev->asic_prop;
-	struct goya_device *goya = hdev->asic_specific;
-	struct packet_lin_dma *clear_pgt_range_pkt;
+	struct packet_lin_dma *lin_dma_pkt;
 	struct hl_cs_parser parser;
 	struct hl_cs_job *job;
 	u32 cb_size;
 	struct hl_cb *cb;
 	int rc;
 
-	if (!(goya->hw_cap_initialized & HW_CAP_MMU))
-		return 0;
-
 	cb = hl_cb_kernel_create(hdev, PAGE_SIZE);
 	if (!cb)
 		return -EFAULT;
 
-	clear_pgt_range_pkt = (struct packet_lin_dma *)
-					(uintptr_t) cb->kernel_address;
+	lin_dma_pkt = (struct packet_lin_dma *) (uintptr_t) cb->kernel_address;
+
+	memset(lin_dma_pkt, 0, sizeof(*lin_dma_pkt));
+	cb_size = sizeof(*lin_dma_pkt);
 
-	memset(clear_pgt_range_pkt, 0, sizeof(*clear_pgt_range_pkt));
-	cb_size = sizeof(*clear_pgt_range_pkt);
+	lin_dma_pkt->ctl = ((PACKET_LIN_DMA << GOYA_PKT_CTL_OPCODE_SHIFT) |
+				(1 << GOYA_PKT_LIN_DMA_CTL_MEMSET_SHIFT) |
+				(1 << GOYA_PKT_LIN_DMA_CTL_WO_SHIFT) |
+				(1 << GOYA_PKT_CTL_RB_SHIFT) |
+				(1 << GOYA_PKT_CTL_MB_SHIFT));
 
-	clear_pgt_range_pkt->ctl =
-		((PACKET_LIN_DMA << GOYA_PKT_CTL_OPCODE_SHIFT) |
-		(DMA_HOST_TO_DRAM << GOYA_PKT_LIN_DMA_CTL_DMA_DIR_SHIFT) |
-		(1 << GOYA_PKT_LIN_DMA_CTL_MEMSET_SHIFT) |
-		(1 << GOYA_PKT_LIN_DMA_CTL_WO_SHIFT) |
-		(1 << GOYA_PKT_CTL_RB_SHIFT) |
-		(1 << GOYA_PKT_CTL_MB_SHIFT));
+	lin_dma_pkt->ctl |= (is_dram ? DMA_HOST_TO_DRAM : DMA_HOST_TO_SRAM) <<
+				GOYA_PKT_LIN_DMA_CTL_DMA_DIR_SHIFT;
 
-	clear_pgt_range_pkt->src_addr = 0;
-	clear_pgt_range_pkt->dst_addr = prop->mmu_pgt_addr;
-	clear_pgt_range_pkt->tsize = prop->mmu_pgt_size + MMU_CACHE_MNG_SIZE;
+	lin_dma_pkt->src_addr = val;
+	lin_dma_pkt->dst_addr = addr;
+	lin_dma_pkt->tsize = size;
 
 	job = hl_cs_allocate_job(hdev, true);
 	if (!job) {
@@ -4927,8 +4842,7 @@ static int goya_mmu_clear_pgt_range(struct hl_device *hdev)
 
 	rc = hdev->asic_funcs->cs_parser(hdev, &parser);
 	if (rc) {
-		dev_err(hdev->dev,
-			"Failed to parse kernel CB when clearing pgt\n");
+		dev_err(hdev->dev, "Failed to parse kernel CB\n");
 		goto free_job;
 	}
 
@@ -4954,6 +4868,52 @@ release_cb:
 	return rc;
 }
 
+static int goya_context_switch(struct hl_device *hdev, u32 asid)
+{
+	struct asic_fixed_properties *prop = &hdev->asic_prop;
+	u64 addr = prop->sram_base_address;
+	u32 size = hdev->pldm ? 0x10000 : prop->sram_size;
+	u64 val = 0x7777777777777777ull;
+	int rc;
+
+	rc = goya_memset_device_memory(hdev, addr, size, val, false);
+	if (rc) {
+		dev_err(hdev->dev, "Failed to clear SRAM in context switch\n");
+		return rc;
+	}
+
+	goya_mmu_prepare(hdev, asid);
+
+	return 0;
+}
+
+static int goya_mmu_clear_pgt_range(struct hl_device *hdev)
+{
+	struct asic_fixed_properties *prop = &hdev->asic_prop;
+	struct goya_device *goya = hdev->asic_specific;
+	u64 addr = prop->mmu_pgt_addr;
+	u32 size = prop->mmu_pgt_size + MMU_DRAM_DEFAULT_PAGE_SIZE +
+			MMU_CACHE_MNG_SIZE;
+
+	if (!(goya->hw_cap_initialized & HW_CAP_MMU))
+		return 0;
+
+	return goya_memset_device_memory(hdev, addr, size, 0, true);
+}
+
+static int goya_mmu_set_dram_default_page(struct hl_device *hdev)
+{
+	struct goya_device *goya = hdev->asic_specific;
+	u64 addr = hdev->asic_prop.mmu_dram_default_page_addr;
+	u32 size = MMU_DRAM_DEFAULT_PAGE_SIZE;
+	u64 val = 0x9999999999999999ull;
+
+	if (!(goya->hw_cap_initialized & HW_CAP_MMU))
+		return 0;
+
+	return goya_memset_device_memory(hdev, addr, size, val, true);
+}
+
 static void goya_mmu_prepare(struct hl_device *hdev, u32 asid)
 {
 	struct goya_device *goya = hdev->asic_specific;