iwlwifi: change monitor DMA to be coherent

Allow access to the memory by the host and the device simultaneously.
This will be needed in some future patches.
Signed-off-by: Shahar S Matityahu <shahar.s.matityahu@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/pcie/internal.h

@@ -464,7 +464,7 @@ struct iwl_self_init_dram {
  * @mutex: to protect stop_device / start_fw / start_hw
  * @cmd_in_flight: true when we have a host command in flight
  * @fw_mon_phys: physical address of the buffer for the firmware monitor
- * @fw_mon_page: points to the first page of the buffer for the firmware monitor
+ * @fw_mon_cpu_addr: address of the buffer for the firmware monitor
  * @fw_mon_size: size of the buffer for the firmware monitor
  * @msix_entries: array of MSI-X entries
  * @msix_enabled: true if managed to enable MSI-X
@@ -554,7 +554,7 @@ struct iwl_trans_pcie {
 	bool ref_cmd_in_flight;
 
 	dma_addr_t fw_mon_phys;
-	struct page *fw_mon_page;
+	void *fw_mon_cpu_addr;
 	u32 fw_mon_size;
 
 	struct msix_entry msix_entries[IWL_MAX_RX_HW_QUEUES];

drivers/net/wireless/intel/iwlwifi/pcie/trans.c

@@ -187,14 +187,13 @@ static void iwl_pcie_free_fw_monitor(struct iwl_trans *trans)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 
-	if (!trans_pcie->fw_mon_page)
+	if (!trans_pcie->fw_mon_cpu_addr)
 		return;
 
-	dma_unmap_page(trans->dev, trans_pcie->fw_mon_phys,
-		       trans_pcie->fw_mon_size, DMA_FROM_DEVICE);
-	__free_pages(trans_pcie->fw_mon_page,
-		     get_order(trans_pcie->fw_mon_size));
-	trans_pcie->fw_mon_page = NULL;
+	dma_free_coherent(trans->dev, trans_pcie->fw_mon_size,
+			  trans_pcie->fw_mon_cpu_addr,
+			  trans_pcie->fw_mon_phys);
+	trans_pcie->fw_mon_cpu_addr = NULL;
 	trans_pcie->fw_mon_phys = 0;
 	trans_pcie->fw_mon_size = 0;
 }
@@ -202,7 +201,7 @@ static void iwl_pcie_free_fw_monitor(struct iwl_trans *trans)
 void iwl_pcie_alloc_fw_monitor(struct iwl_trans *trans, u8 max_power)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
-	struct page *page = NULL;
+	void *cpu_addr = NULL;
 	dma_addr_t phys;
 	u32 size = 0;
 	u8 power;
@@ -219,38 +218,25 @@ void iwl_pcie_alloc_fw_monitor(struct iwl_trans *trans, u8 max_power)
 		 max_power))
 		return;
 
-	if (trans_pcie->fw_mon_page) {
-		dma_sync_single_for_device(trans->dev, trans_pcie->fw_mon_phys,
-					   trans_pcie->fw_mon_size,
-					   DMA_FROM_DEVICE);
+	if (trans_pcie->fw_mon_cpu_addr)
 		return;
-	}
 
 	phys = 0;
 	for (power = max_power; power >= 11; power--) {
-		int order;
-
 		size = BIT(power);
-		order = get_order(size);
-		page = alloc_pages(__GFP_COMP | __GFP_NOWARN | __GFP_ZERO,
-				   order);
-		if (!page)
+		cpu_addr = dma_alloc_coherent(trans->dev, size, &phys,
+					      GFP_KERNEL | __GFP_NOWARN |
+					      __GFP_ZERO | __GFP_COMP);
+		if (!cpu_addr)
 			continue;
 
-		phys = dma_map_page(trans->dev, page, 0, PAGE_SIZE << order,
-				    DMA_FROM_DEVICE);
-		if (dma_mapping_error(trans->dev, phys)) {
-			__free_pages(page, order);
-			page = NULL;
-			continue;
-		}
 		IWL_INFO(trans,
-			 "Allocated 0x%08x bytes (order %d) for firmware monitor.\n",
-			 size, order);
+			 "Allocated 0x%08x bytes for firmware monitor.\n",
+			 size);
 		break;
 	}
 
-	if (WARN_ON_ONCE(!page))
+	if (WARN_ON_ONCE(!cpu_addr))
 		return;
 
 	if (power != max_power)
@@ -259,7 +245,7 @@ void iwl_pcie_alloc_fw_monitor(struct iwl_trans *trans, u8 max_power)
 			(unsigned long)BIT(power - 10),
 			(unsigned long)BIT(max_power - 10));
 
-	trans_pcie->fw_mon_page = page;
+	trans_pcie->fw_mon_cpu_addr = cpu_addr;
 	trans_pcie->fw_mon_phys = phys;
 	trans_pcie->fw_mon_size = size;
 }
@@ -2863,7 +2849,7 @@ iwl_trans_pcie_dump_monitor(struct iwl_trans *trans,
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	u32 len = 0;
 
-	if ((trans_pcie->fw_mon_page &&
+	if ((trans_pcie->fw_mon_cpu_addr &&
 	     trans->cfg->device_family == IWL_DEVICE_FAMILY_7000) ||
 	    trans->dbg_dest_tlv) {
 		struct iwl_fw_error_dump_fw_mon *fw_mon_data;
@@ -2891,19 +2877,9 @@ iwl_trans_pcie_dump_monitor(struct iwl_trans *trans,
 			cpu_to_le32(iwl_read_prph(trans, base));
 
 		len += sizeof(**data) + sizeof(*fw_mon_data);
-		if (trans_pcie->fw_mon_page) {
-			/*
-			 * The firmware is now asserted, it won't write anything
-			 * to the buffer. CPU can take ownership to fetch the
-			 * data. The buffer will be handed back to the device
-			 * before the firmware will be restarted.
-			 */
-			dma_sync_single_for_cpu(trans->dev,
-						trans_pcie->fw_mon_phys,
-						trans_pcie->fw_mon_size,
-						DMA_FROM_DEVICE);
+		if (trans_pcie->fw_mon_cpu_addr) {
 			memcpy(fw_mon_data->data,
-			       page_address(trans_pcie->fw_mon_page),
+			       trans_pcie->fw_mon_cpu_addr,
 			       trans_pcie->fw_mon_size);
 
 			monitor_len = trans_pcie->fw_mon_size;
@@ -2966,7 +2942,7 @@ static struct iwl_trans_dump_data
 		cmdq->n_window * (sizeof(*txcmd) + TFD_MAX_PAYLOAD_SIZE);
 
 	/* FW monitor */
-	if (trans_pcie->fw_mon_page) {
+	if (trans_pcie->fw_mon_cpu_addr) {
 		len += sizeof(*data) + sizeof(struct iwl_fw_error_dump_fw_mon) +
 		       trans_pcie->fw_mon_size;
 		monitor_len = trans_pcie->fw_mon_size;