On 11/28/2012 06:48 AM, Hiroshi Doyu wrote:
Hiroshi Doyu hdoyu@nvidia.com 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 <linux/slab.h> #include <linux/pm_runtime.h>
+#include <asm/dma-iommu.h>
#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 hdoyu@nvidia.com 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 hdoyu@nvidia.com
arch/arm/mach-tegra/board-dt-tegra30.c | 40 ++++++++++++++++++++++++++++++++
Shouldn't this patch be to the IOMMU driver itself, not the core Tegra code?