From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753614AbcHQMGY (ORCPT ); Wed, 17 Aug 2016 08:06:24 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:34704 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752793AbcHQMGU (ORCPT ); Wed, 17 Aug 2016 08:06:20 -0400 From: Roger Quadros To: , CC: , , , , Roger Quadros , , Greg Kroah-Hartman , Russell King , Arnd Bergmann , Olof Johansson , Catalin Marinas , Linus Walleij Subject: [PATCH 1/1] ARM: dma: fix dma_max_pfn() Date: Wed, 17 Aug 2016 15:05:17 +0300 Message-ID: <1471435517-7840-2-git-send-email-rogerq@ti.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1471435517-7840-1-git-send-email-rogerq@ti.com> References: <1471435517-7840-1-git-send-email-rogerq@ti.com> 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 Since commit 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation"), dma_to_pfn() already returns the PFN with the physical memory start offset so we don't need to add it again. This fixes USB mass storage lock-up problem on systems that can't do DMA over the entire physical memory range (e.g.) Keystone 2 systems with 4GB RAM can only do DMA over the first 2GB. [K2E-EVM]. What happens there is that without this patch SCSI layer sets a wrong bounce buffer limit in scsi_calculate_bounce_limit() for the USB mass storage device. dma_max_pfn() evaluates to 0x8fffff and bounce_limit is set to 0x8fffff000 whereas maximum DMA'ble physical memory on Keystone 2 is 0x87fffffff. This results in non DMA'ble pages being given to the USB controller and hence the lock-up. NOTE: in the above case, USB-SCSI-device's dma_pfn_offset was showing as 0. This should have really been 0x780000 as on K2e, LOWMEM_START is 0x80000000 and HIGHMEM_START is 0x800000000. DMA zone is 2GB so dma_max_pfn should be 0x87ffff. The incorrect dma_pfn_offset for the USB storage device is because USB devices are not correctly inheriting the dma_pfn_offset from the USB host controller. This will be fixed by a separate patch. Fixes: 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation") Cc: stable@vger.kernel.org Cc: Greg Kroah-Hartman Cc: Russell King Cc: Arnd Bergmann Cc: Olof Johansson Cc: Catalin Marinas Cc: Linus Walleij Reported-by: Grygorii Strashko Signed-off-by: Roger Quadros --- arch/arm/include/asm/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index d009f79..bf02dbd 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -111,7 +111,7 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) /* The ARM override for dma_max_pfn() */ static inline unsigned long dma_max_pfn(struct device *dev) { - return PHYS_PFN_OFFSET + dma_to_pfn(dev, *dev->dma_mask); + return dma_to_pfn(dev, *dev->dma_mask); } #define dma_max_pfn(dev) dma_max_pfn(dev) -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: rogerq@ti.com (Roger Quadros) Date: Wed, 17 Aug 2016 15:05:17 +0300 Subject: [PATCH 1/1] ARM: dma: fix dma_max_pfn() In-Reply-To: <1471435517-7840-1-git-send-email-rogerq@ti.com> References: <1471435517-7840-1-git-send-email-rogerq@ti.com> Message-ID: <1471435517-7840-2-git-send-email-rogerq@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Since commit 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation"), dma_to_pfn() already returns the PFN with the physical memory start offset so we don't need to add it again. This fixes USB mass storage lock-up problem on systems that can't do DMA over the entire physical memory range (e.g.) Keystone 2 systems with 4GB RAM can only do DMA over the first 2GB. [K2E-EVM]. What happens there is that without this patch SCSI layer sets a wrong bounce buffer limit in scsi_calculate_bounce_limit() for the USB mass storage device. dma_max_pfn() evaluates to 0x8fffff and bounce_limit is set to 0x8fffff000 whereas maximum DMA'ble physical memory on Keystone 2 is 0x87fffffff. This results in non DMA'ble pages being given to the USB controller and hence the lock-up. NOTE: in the above case, USB-SCSI-device's dma_pfn_offset was showing as 0. This should have really been 0x780000 as on K2e, LOWMEM_START is 0x80000000 and HIGHMEM_START is 0x800000000. DMA zone is 2GB so dma_max_pfn should be 0x87ffff. The incorrect dma_pfn_offset for the USB storage device is because USB devices are not correctly inheriting the dma_pfn_offset from the USB host controller. This will be fixed by a separate patch. Fixes: 6ce0d2001692 ("ARM: dma: Use dma_pfn_offset for dma address translation") Cc: stable at vger.kernel.org Cc: Greg Kroah-Hartman Cc: Russell King Cc: Arnd Bergmann Cc: Olof Johansson Cc: Catalin Marinas Cc: Linus Walleij Reported-by: Grygorii Strashko Signed-off-by: Roger Quadros --- arch/arm/include/asm/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index d009f79..bf02dbd 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -111,7 +111,7 @@ static inline dma_addr_t virt_to_dma(struct device *dev, void *addr) /* The ARM override for dma_max_pfn() */ static inline unsigned long dma_max_pfn(struct device *dev) { - return PHYS_PFN_OFFSET + dma_to_pfn(dev, *dev->dma_mask); + return dma_to_pfn(dev, *dev->dma_mask); } #define dma_max_pfn(dev) dma_max_pfn(dev) -- 2.7.4