From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752784Ab2K3E7x (ORCPT ); Thu, 29 Nov 2012 23:59:53 -0500 Received: from mail-da0-f46.google.com ([209.85.210.46]:49192 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751181Ab2K3E7v (ORCPT ); Thu, 29 Nov 2012 23:59:51 -0500 Message-ID: <50B83D34.2030006@gmail.com> Date: Fri, 30 Nov 2012 12:59:32 +0800 From: Mark Zhang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Hiroshi Doyu CC: "m.szyprowski@samsung.com" , "swarren@wwwdotorg.org" , "joro@8bytes.org" , "James.Bottomley@HansenPartnership.com" , "arnd@arndb.de" , Krishna Reddy , "linux@arm.linux.org.uk" , "minchan@kernel.org" , "chunsang.jeong@linaro.org" , "linux-kernel@vger.kernel.org" , "subashrp@gmail.com" , "linaro-mm-sig@lists.linaro.org" , "linux-mm@kvack.org" , "iommu@lists.linux-foundation.org" , "linux-tegra@vger.kernel.org" , "kyungmin.park@samsung.com" , "pullip.cho@samsung.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 1/1] ARM: tegra: bus_notifier registers IOMMU devices(was: How to specify IOMMU'able devices in DT) References: <20120924124452.41070ed2ee9944d930cffffc@nvidia.com><054901cd9a45$db1a7ea0$914f7be0$%szyprowski@samsung.com><20120924.145014.1452596970914043018.hdoyu@nvidia.com> <20121128.154832.539666140149950229.hdoyu@nvidia.com> In-Reply-To: <20121128.154832.539666140149950229.hdoyu@nvidia.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/28/2012 09:48 PM, Hiroshi Doyu wrote: > Hiroshi Doyu wrote @ Mon, 24 Sep 2012 14:50:14 +0300 (EEST): > ... >>>>> On Mon, 2012-09-24 at 12:04 +0300, Hiroshi Doyu wrote: >>>>>> diff --git a/drivers/base/platform.c b/drivers/base/platform.c >>>>>> index a1a7225..9eae3be 100644 >>>>>> --- a/drivers/base/platform.c >>>>>> +++ b/drivers/base/platform.c >>>>>> @@ -21,6 +21,8 @@ >>>>>> #include >>>>>> #include >>>>>> >>>>>> +#include >>>>>> + >>>>>> #include "base.h" >>>>>> >>>>>> #define to_platform_driver(drv) (container_of((drv), struct >>>>>> platform_driver, \ >>>>>> @@ -305,8 +307,19 @@ int platform_device_add(struct platform_device >>>>>> *pdev) >>>>>> dev_name(&pdev->dev), dev_name(pdev->dev.parent)); >>>>>> >>>>>> ret = device_add(&pdev->dev); >>>>>> - if (ret == 0) >>>>>> - return ret; >>>>>> + if (ret) >>>>>> + goto failed; >>>>>> + >>>>>> +#ifdef CONFIG_PLATFORM_ENABLE_IOMMU >>>>>> + if (platform_bus_type.map && !pdev->dev.archdata.mapping) { >>>>>> + ret = arm_iommu_attach_device(&pdev->dev, >>>>>> + platform_bus_type.map); >>>>>> + if (ret) >>>>>> + goto failed; >>>>> >>>>> This is horrible ... you're adding an architecture specific callback >>>>> into our generic code; that's really a no-no. If the concept of >>>>> CONFIG_PLATFORM_ENABE_IOMMU is useful to more than just arm, then this >>>>> could become a generic callback. >>>> >>>> As mentioned in the original, this is a heck to explain what is >>>> needed. I am looking for some generic solution for how to specify >>>> IOMMU info for each platform devices. I'm guessing that some other SoC >>>> may have the similar requirements on the above. As you mentioned, this >>>> solution should be a generic, not arch specific. >>> >>> Please read more about bus notifiers. IMHO a good example is provided in >>> the following thread: >>> http://www.mail-archive.com/linux-samsung-soc@vger.kernel.org/msg12238.html >> >> This bus notifier seems enough flexible to afford the variation of >> IOMMU map info, like Tegra ASID, which could be platform-specific, and >> the other could be common too. There's already iommu_bus_notifier >> too. I'll try to implement something base on this. > > Experimentally implemented as below. With the followig patch, each > device could specify its own map in DT, and automatically the device > would be attached to the map. > > There is a case that some devices share a map. This patch doesn't > suppor such case yet. > > From 8cb75bb6f3a8535a077e0e85265f87c1f1289bfd Mon Sep 17 00:00:00 2001 > From: Hiroshi Doyu > Date: Wed, 28 Nov 2012 14:47:04 +0200 > Subject: [PATCH 1/1] ARM: tegra: bus_notifier registers IOMMU devices > > platform_bus notifier registers IOMMU devices if dma-window is > specified. > > Its format is: > dma-window = <"start" "size">; > ex) > dma-window = <0x12345000 0x8000>; > > Signed-off-by: Hiroshi Doyu > --- > arch/arm/mach-tegra/board-dt-tegra30.c | 40 ++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/arch/arm/mach-tegra/board-dt-tegra30.c b/arch/arm/mach-tegra/board-dt-tegra30.c > index a2b6cf1..570d718 100644 > --- a/arch/arm/mach-tegra/board-dt-tegra30.c > +++ b/arch/arm/mach-tegra/board-dt-tegra30.c > @@ -30,9 +30,11 @@ > #include > #include > #include > +#include > > #include > #include > +#include > > #include "board.h" > #include "clock.h" > @@ -86,10 +88,48 @@ static __initdata struct tegra_clk_init_table tegra_dt_clk_init_table[] = { > { NULL, NULL, 0, 0}, > }; > > +#ifdef CONFIG_ARM_DMA_USE_IOMMU > +static int tegra_iommu_device_notifier(struct notifier_block *nb, > + unsigned long event, void *_dev) > +{ > + struct dma_iommu_mapping *map = NULL; > + struct device *dev = _dev; > + dma_addr_t base; > + size_t size; > + int err; > + > + switch (event) { > + case BUS_NOTIFY_ADD_DEVICE: > + err = of_get_dma_window(dev->of_node, NULL, 0, NULL, &base, > + &size); > + if (!err) > + map = arm_iommu_create_mapping(&platform_bus_type, > + base, size, 0); > + if (IS_ERR_OR_NULL(map)) > + break; > + if (arm_iommu_attach_device(dev, map)) Add "arm_iommu_release_mapping" here. And finally we see this patch, that's great. :) > + dev_err(dev, "Failed to attach %s\n", dev_name(dev)); > + dev_dbg(dev, "Attached %s to map %p\n", dev_name(dev), map); > + break; > + } > + return NOTIFY_DONE; > +} > +#else > +#define tegra_iommu_device_notifier NULL > +#endif > + > +static struct notifier_block tegra_iommu_device_nb = { > + .notifier_call = tegra_iommu_device_notifier, > +}; > + > static void __init tegra30_dt_init(void) > { > tegra_clk_init_from_table(tegra_dt_clk_init_table); > > + if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) > + bus_register_notifier(&platform_bus_type, > + &tegra_iommu_device_nb); > + > of_platform_populate(NULL, of_default_bus_match_table, > tegra30_auxdata_lookup, NULL); > } >