From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752869AbcHQMfq (ORCPT ); Wed, 17 Aug 2016 08:35:46 -0400 Received: from bear.ext.ti.com ([198.47.19.11]:53313 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752353AbcHQMfp (ORCPT ); Wed, 17 Aug 2016 08:35:45 -0400 From: Roger Quadros To: , CC: , , , , Roger Quadros Subject: [PATCH] usb: core: setup dma_pfn_offset for USB devices Date: Wed, 17 Aug 2016 15:35:28 +0300 Message-ID: <1471437328-8621-1-git-send-email-rogerq@ti.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If dma_pfn_offset is not inherited correctly from the host controller, it might result in sub-optimal configuration as bounce buffer limit might be set to less than optimal level. e.g. On Keystone 2 systems, dma_max_pfn() is 0x87FFFF and dma_mask_pfn is 0xFFFFF. Consider a mass storage use case: Without this patch, usb scsi host device (usb-storage) will get a dma_pfn_offset of 0 resulting in a dma_max_pfn() of 0xFFFFF within the scsi layer (scsi_calculate_bounce_limit()). This will result in bounce buffers being unnecessarily used. Hint: On 32-bit ARM platforms dma_max_pfn() = dma_mask_pfn + dma_pfn_offset Signed-off-by: Roger Quadros --- drivers/usb/core/message.c | 1 + drivers/usb/core/usb.c | 1 + 2 files changed, 2 insertions(+) diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 0406a59..6856b7a 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -1863,6 +1863,7 @@ free_interfaces: intf->dev.type = &usb_if_device_type; intf->dev.groups = usb_interface_groups; intf->dev.dma_mask = dev->dev.dma_mask; + intf->dev.dma_pfn_offset = dev->dev.dma_pfn_offset; INIT_WORK(&intf->reset_ws, __usb_queue_reset_device); intf->minor = -1; device_initialize(&intf->dev); diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 5e80697..d81791a 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -441,6 +441,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent, dev->dev.type = &usb_device_type; dev->dev.groups = usb_device_groups; dev->dev.dma_mask = bus->controller->dma_mask; + dev->dev.dma_pfn_offset = bus->controller->dma_pfn_offset; set_dev_node(&dev->dev, dev_to_node(bus->controller)); dev->state = USB_STATE_ATTACHED; dev->lpm_disable_count = 1; -- 2.7.4