habanalabs/gaudi: skip iATU if F/W security is enabled

As part of the securing GAUDI, the F/W will configure the PCI iATU
regions. If the driver identifies a secured PCI ID, it will know to
skip iATU configuration in a very early stage.
Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

drivers/misc/habanalabs/common/habanalabs.h

@@ -445,6 +445,7 @@ struct hl_mmu_properties {
  * @dram_supports_virtual_memory: is there an MMU towards the DRAM
  * @hard_reset_done_by_fw: true if firmware is handling hard reset flow
  * @num_functional_hbms: number of functional HBMs in each DCORE.
+ * @iatu_done_by_fw: true if iATU configuration is being done by FW.
  */
 struct asic_fixed_properties {
 	struct hw_queue_properties	*hw_queues_props;
@@ -508,6 +509,7 @@ struct asic_fixed_properties {
 	u8				dram_supports_virtual_memory;
 	u8				hard_reset_done_by_fw;
 	u8				num_functional_hbms;
+	u8				iatu_done_by_fw;
 };
 
 /**
@@ -2400,6 +2402,7 @@ int hl_fw_read_preboot_status(struct hl_device *hdev, u32 cpu_boot_status_reg,
 
 int hl_pci_bars_map(struct hl_device *hdev, const char * const name[3],
 			bool is_wc[3]);
+int hl_pci_elbi_read(struct hl_device *hdev, u64 addr, u32 *data);
 int hl_pci_iatu_write(struct hl_device *hdev, u32 addr, u32 data);
 int hl_pci_set_inbound_region(struct hl_device *hdev, u8 region,
 		struct hl_inbound_pci_region *pci_region);

drivers/misc/habanalabs/common/pci/pci.c

@@ -85,6 +85,58 @@ static void hl_pci_bars_unmap(struct hl_device *hdev)
 	pci_release_regions(pdev);
 }
 
+int hl_pci_elbi_read(struct hl_device *hdev, u64 addr, u32 *data)
+{
+	struct pci_dev *pdev = hdev->pdev;
+	ktime_t timeout;
+	u64 msec;
+	u32 val;
+
+	if (hdev->pldm)
+		msec = HL_PLDM_PCI_ELBI_TIMEOUT_MSEC;
+	else
+		msec = HL_PCI_ELBI_TIMEOUT_MSEC;
+
+	/* Clear previous status */
+	pci_write_config_dword(pdev, mmPCI_CONFIG_ELBI_STS, 0);
+
+	pci_write_config_dword(pdev, mmPCI_CONFIG_ELBI_ADDR, (u32) addr);
+	pci_write_config_dword(pdev, mmPCI_CONFIG_ELBI_CTRL, 0);
+
+	timeout = ktime_add_ms(ktime_get(), msec);
+	for (;;) {
+		pci_read_config_dword(pdev, mmPCI_CONFIG_ELBI_STS, &val);
+		if (val & PCI_CONFIG_ELBI_STS_MASK)
+			break;
+		if (ktime_compare(ktime_get(), timeout) > 0) {
+			pci_read_config_dword(pdev, mmPCI_CONFIG_ELBI_STS,
+						&val);
+			break;
+		}
+
+		usleep_range(300, 500);
+	}
+
+	if ((val & PCI_CONFIG_ELBI_STS_MASK) == PCI_CONFIG_ELBI_STS_DONE) {
+		pci_read_config_dword(pdev, mmPCI_CONFIG_ELBI_DATA, data);
+
+		return 0;
+	}
+
+	if (val & PCI_CONFIG_ELBI_STS_ERR) {
+		dev_err(hdev->dev, "Error reading from ELBI\n");
+		return -EIO;
+	}
+
+	if (!(val & PCI_CONFIG_ELBI_STS_MASK)) {
+		dev_err(hdev->dev, "ELBI read didn't finish in time\n");
+		return -EIO;
+	}
+
+	dev_err(hdev->dev, "ELBI read has undefined bits in status\n");
+	return -EIO;
+}
+
 /**
  * hl_pci_elbi_write() - Write through the ELBI interface.
  * @hdev: Pointer to hl_device structure.

drivers/misc/habanalabs/gaudi/gaudi.c

@@ -629,6 +629,11 @@ static int gaudi_init_iatu(struct hl_device *hdev)
 	struct hl_outbound_pci_region outbound_region;
 	int rc;
 
+	if (hdev->asic_prop.iatu_done_by_fw) {
+		hdev->asic_funcs->set_dma_mask_from_fw(hdev);
+		return 0;
+	}
+
 	/* Inbound Region 0 - Bar 0 - Point to SRAM + CFG */
 	inbound_region.mode = PCI_BAR_MATCH_MODE;
 	inbound_region.bar = SRAM_BAR_ID;
@@ -673,6 +678,7 @@ static int gaudi_early_init(struct hl_device *hdev)
 {
 	struct asic_fixed_properties *prop = &hdev->asic_prop;
 	struct pci_dev *pdev = hdev->pdev;
+	u32 fw_boot_status;
 	int rc;
 
 	rc = gaudi_get_fixed_properties(hdev);
@@ -706,6 +712,23 @@ static int gaudi_early_init(struct hl_device *hdev)
 
 	prop->dram_pci_bar_size = pci_resource_len(pdev, HBM_BAR_ID);
 
+	/* If FW security is enabled at this point it means no access to ELBI */
+	if (!hdev->asic_prop.fw_security_disabled) {
+		hdev->asic_prop.iatu_done_by_fw = true;
+		goto pci_init;
+	}
+
+	rc = hl_pci_elbi_read(hdev, CFG_BASE + mmCPU_BOOT_DEV_STS0,
+				&fw_boot_status);
+	if (rc)
+		goto free_queue_props;
+
+	/* Check whether FW is configuring iATU */
+	if ((fw_boot_status & CPU_BOOT_DEV_STS0_ENABLED) &&
+			(fw_boot_status & CPU_BOOT_DEV_STS0_FW_IATU_CONF_EN))
+		hdev->asic_prop.iatu_done_by_fw = true;
+
+pci_init:
 	rc = hl_pci_init(hdev);
 	if (rc)
 		goto free_queue_props;

drivers/misc/habanalabs/goya/goya.c

@@ -555,6 +555,11 @@ static int goya_init_iatu(struct hl_device *hdev)
 	struct hl_outbound_pci_region outbound_region;
 	int rc;
 
+	if (hdev->asic_prop.iatu_done_by_fw) {
+		hdev->asic_funcs->set_dma_mask_from_fw(hdev);
+		return 0;
+	}
+
 	/* Inbound Region 0 - Bar 0 - Point to SRAM and CFG */
 	inbound_region.mode = PCI_BAR_MATCH_MODE;
 	inbound_region.bar = SRAM_CFG_BAR_ID;
@@ -602,7 +607,7 @@ static int goya_early_init(struct hl_device *hdev)
 {
 	struct asic_fixed_properties *prop = &hdev->asic_prop;
 	struct pci_dev *pdev = hdev->pdev;
-	u32 val;
+	u32 fw_boot_status, val;
 	int rc;
 
 	rc = goya_get_fixed_properties(hdev);
@@ -636,6 +641,23 @@ static int goya_early_init(struct hl_device *hdev)
 
 	prop->dram_pci_bar_size = pci_resource_len(pdev, DDR_BAR_ID);
 
+	/* If FW security is enabled at this point it means no access to ELBI */
+	if (!hdev->asic_prop.fw_security_disabled) {
+		hdev->asic_prop.iatu_done_by_fw = true;
+		goto pci_init;
+	}
+
+	rc = hl_pci_elbi_read(hdev, CFG_BASE + mmCPU_BOOT_DEV_STS0,
+				&fw_boot_status);
+	if (rc)
+		goto free_queue_props;
+
+	/* Check whether FW is configuring iATU */
+	if ((fw_boot_status & CPU_BOOT_DEV_STS0_ENABLED) &&
+			(fw_boot_status & CPU_BOOT_DEV_STS0_FW_IATU_CONF_EN))
+		hdev->asic_prop.iatu_done_by_fw = true;
+
+pci_init:
 	rc = hl_pci_init(hdev);
 	if (rc)
 		goto free_queue_props;