diff mbox

[V3,0/8] IOMMU probe deferral support

Message ID 12cfb59f-f7ca-d4df-eb7f-42348e357979@samsung.com
State New
Headers show

Commit Message

Marek Szyprowski Oct. 10, 2016, 12:36 p.m. UTC 
Hi Sricharan,


On 2016-10-04 19:03, Sricharan R wrote:
> Initial post from Laurent Pinchart[1]. This is

> series calls the dma ops configuration for the devices

> at a generic place so that it works for all busses.

> The dma_configure_ops for a device is now called during

> the device_attach callback just before the probe of the

> bus/driver is called. Similarly dma_deconfigure is called during

> device/driver_detach path.

>

>

> pci_bus_add_devices    (platform/amba)(_device_create/driver_register)

>         |                         |

> pci_bus_add_device     (device_add/driver_register)

>         |                         |

> device_attach           device_initial_probe

>         |                         |

> __device_attach_driver    __device_attach_driver

>         |

> driver_probe_device

>         |

> really_probe

>         |

> dma_configure

>

>   Similarly on the device/driver_unregister path __device_release_driver is

>   called which inturn calls dma_deconfigure.

>

>   If the ACPI bus code follows the same, we can add acpi_dma_configure

>   at the same place as of_dma_configure.

>

>   This series is based on the recently merged Generic DT bindings for

>   PCI IOMMUs and ARM SMMU from Robin Murphy robin.murphy@arm.com [2]

>

>   This time tested this with platform and pci device for probe deferral

>   and reprobe on arm64 based platform. There is an issue on the cleanup

>   path for arm64 though, where there is WARN_ON if the dma_ops is reset while

>   device is attached to an domain in arch_teardown_dma_ops.

>   But with iommu_groups created from the iommu driver, the device is always

>   attached to a domain/default_domain. So so the WARN has to be removed/handled

>   probably.


Thanks for continuing work on this feature! Your can add my:

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>


It works fine with Exynos SYSMMU driver, although a patch is needed to fix
infinite loop due to list corruption (same element is added twice if master
device fails with deferred probe):

From: Marek Szyprowski <m.szyprowski@samsung.com>

Date: Mon, 10 Oct 2016 14:22:42 +0200
Subject: [PATCH] iommu/exynos: ensure that sysmmu is added only once to its
  master

Since adding IOMMU deferred probing support, of_xlate() callback might
be called more than once for given master device (for example it happens
when masters device driver fails with EPROBE_DEFER), so ensure that
SYSMMU controller is added to its master device (owner) only once.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

---
  drivers/iommu/exynos-iommu.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

-- 
1.9.1


>

>   Previous post of this series [3].

>

>   [V3]

>       * Removed the patch to split dma_masks/dma_ops configuration separately

>         based on review comments that both masks and ops are required only

>         during the device probe time.

>

>       * Reworked the series based on Generic DT bindings series [2].

>

>       * Added call to iommu's remove_device in the cleanup path for arm and arm64.

>

>       * Removed the notifier trick in arm64 to handle early device registration.

>

>       * Added reset of dma_ops in cleanup path for arm based on comments.

>

>       * Fixed the pci_iommu_configure path and tested with PCI device as well.

>   

>       * Fixed a bug to return the correct iommu_ops from patch 7 [4] in last post.

>

>       * Fixed few other cosmetic comments.

>    

>   [V2]

>       * Updated the Initial post to call dma_configure/deconfigure from generic code

>   

>       * Added iommu add_device callback from of_iommu_configure path

>

>   [V1]

>       * Initial post

>

> [1] http://lists.linuxfoundation.org/pipermail/iommu/2015-May/013016.html

> [2] http://www.spinics.net/lists/devicetree/msg142943.html

> [3] https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13941.html

> [4] https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13940.html

>

>

>

> Laurent Pinchart (4):

>    arm: dma-mapping: Don't override dma_ops in arch_setup_dma_ops()

>    of: dma: Move range size workaround to of_dma_get_range()

>    of: dma: Make of_dma_deconfigure() public

>    iommu: of: Handle IOMMU lookup failure with deferred probing or error

>

> Sricharan R (4):

>    drivers: platform: Configure dma operations at probe time

>    arm: dma-mapping: Reset the device's dma_ops

>    arm/arm64: dma-mapping: Call iommu's remove_device callback during

>      device detach

>    arm64: dma-mapping: Remove the notifier trick to handle early setting

>      of dma_ops

>

>   arch/arm/mm/dma-mapping.c   |  18 ++++++++

>   arch/arm64/mm/dma-mapping.c | 107 +++++---------------------------------------

>   drivers/base/dd.c           |  10 +++++

>   drivers/base/dma-mapping.c  |  11 +++++

>   drivers/iommu/of_iommu.c    |  47 +++++++++++++++++--

>   drivers/of/address.c        |  20 ++++++++-

>   drivers/of/device.c         |  34 +++++++-------

>   drivers/of/platform.c       |   9 ----

>   drivers/pci/probe.c         |   5 +--

>   include/linux/dma-mapping.h |   3 ++

>   include/linux/of_device.h   |   7 ++-

>   11 files changed, 138 insertions(+), 133 deletions(-)

>


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland


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diff mbox

Patch

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 30808e91b775..1525a86eb829 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1253,7 +1253,7 @@  static int exynos_iommu_of_xlate(struct device *dev,
  {
      struct exynos_iommu_owner *owner = dev->archdata.iommu;
      struct platform_device *sysmmu = of_find_device_by_node(spec->np);
-    struct sysmmu_drvdata *data;
+    struct sysmmu_drvdata *data, *entry;

      if (!sysmmu)
          return -ENODEV;
@@ -1271,6 +1271,10 @@  static int exynos_iommu_of_xlate(struct device *dev,
          dev->archdata.iommu = owner;
      }

+    list_for_each_entry(entry, &owner->controllers, owner_node)
+        if (entry == data)
+            return 0;
+
      list_add_tail(&data->owner_node, &owner->controllers);
      return 0;
  }