From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Date: Mon, 19 Oct 2015 06:42:14 +0000 Subject: Re: [PATCH] iommu/ipmmu-vmsa: Drop LPAE Kconfig dependency Message-Id: <1739171.POGWkgX12k@avalon> List-Id: References: <20151019030253.6274.46547.sendpatchset@little-apple> In-Reply-To: <20151019030253.6274.46547.sendpatchset@little-apple> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Magnus Damm Cc: iommu@lists.linux-foundation.org, laurent.pinchart+renesas@ideasonboard.com, geert+renesas@glider.be, linux-sh@vger.kernel.org, joro@8bytes.org, linux-kernel@vger.kernel.org, horms+renesas@verge.net.au Hi Magnus, Thank you for the patch. On Monday 19 October 2015 12:02:53 Magnus Damm wrote: > From: Magnus Damm > > Neither the ARM page table code enabled by IOMMU_IO_PGTABLE_LPAE > nor the IPMMU_VMSA driver actually depends on ARM_LPAE, so get > rid of the dependency. > > Tested with ipmmu-vmsa on r8a7794 ALT and a kernel config using: > # CONFIG_ARM_LPAE is not set The driver only supports the 40-bits page table format for now, hence the dependency on LPAE, but it indeed seems that the dependency is bogus. As long as the 8 MSBs of the translated address are all 0 I assume the output 40-bit address is usable on a 32-bit physical address system. How have you tested the patch ? > Signed-off-by: Magnus Damm > --- > > drivers/iommu/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > --- 0001/drivers/iommu/Kconfig > +++ work/drivers/iommu/Kconfig 2015-10-18 14:58:09.080513000 +0900 > @@ -324,7 +324,6 @@ config SHMOBILE_IOMMU_L1SIZE > > config IPMMU_VMSA > bool "Renesas VMSA-compatible IPMMU" > - depends on ARM_LPAE > depends on ARCH_SHMOBILE || COMPILE_TEST > select IOMMU_API > select IOMMU_IO_PGTABLE_LPAE -- Regards, Laurent Pinchart From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752613AbbJSGl4 (ORCPT ); Mon, 19 Oct 2015 02:41:56 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:36089 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbbJSGly (ORCPT ); Mon, 19 Oct 2015 02:41:54 -0400 From: Laurent Pinchart To: Magnus Damm Cc: iommu@lists.linux-foundation.org, laurent.pinchart+renesas@ideasonboard.com, geert+renesas@glider.be, linux-sh@vger.kernel.org, joro@8bytes.org, linux-kernel@vger.kernel.org, horms+renesas@verge.net.au Subject: Re: [PATCH] iommu/ipmmu-vmsa: Drop LPAE Kconfig dependency Date: Mon, 19 Oct 2015 09:42:14 +0300 Message-ID: <1739171.POGWkgX12k@avalon> User-Agent: KMail/4.14.8 (Linux/4.0.5-gentoo; KDE/4.14.8; x86_64; ; ) In-Reply-To: <20151019030253.6274.46547.sendpatchset@little-apple> References: <20151019030253.6274.46547.sendpatchset@little-apple> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Magnus, Thank you for the patch. On Monday 19 October 2015 12:02:53 Magnus Damm wrote: > From: Magnus Damm > > Neither the ARM page table code enabled by IOMMU_IO_PGTABLE_LPAE > nor the IPMMU_VMSA driver actually depends on ARM_LPAE, so get > rid of the dependency. > > Tested with ipmmu-vmsa on r8a7794 ALT and a kernel config using: > # CONFIG_ARM_LPAE is not set The driver only supports the 40-bits page table format for now, hence the dependency on LPAE, but it indeed seems that the dependency is bogus. As long as the 8 MSBs of the translated address are all 0 I assume the output 40-bit address is usable on a 32-bit physical address system. How have you tested the patch ? > Signed-off-by: Magnus Damm > --- > > drivers/iommu/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > --- 0001/drivers/iommu/Kconfig > +++ work/drivers/iommu/Kconfig 2015-10-18 14:58:09.080513000 +0900 > @@ -324,7 +324,6 @@ config SHMOBILE_IOMMU_L1SIZE > > config IPMMU_VMSA > bool "Renesas VMSA-compatible IPMMU" > - depends on ARM_LPAE > depends on ARCH_SHMOBILE || COMPILE_TEST > select IOMMU_API > select IOMMU_IO_PGTABLE_LPAE -- Regards, Laurent Pinchart