[PATCH v9 00/16] iommu/exynos: Fixes and Enhancements of System MMU driver with DT

Cho KyongHo
2013-08-08T09:37:10Z

The current exynos-iommu(System MMU) driver does not work autonomously
since it is lack of support for power management of peripheral blocks.
For example, MFC device driver must ensure that its System MMU is disabled
before MFC block is power-down not to invalidate IOTLB in the System MMU
when I/O memory mapping is changed. Because a System MMU resides in the
same H/W block, access to control registers of System MMU while the H/W
block is turned off must be prohibited.

This set of changes solves the above problem with setting each System MMUs
as the parent of the device which owns the System MMU to receive the
information when the device is turned off or turned on.

Another big change to the driver is the support for devicetree.
The bindings for System MMU is described in
Documentation/devicetree/bindings/arm/samsung/system-mmu.txt

In addition, this patchset also includes several bug fixes and enhancements
of the current driver.

Change log:
v9:
- Rebased on the following branches
git.linaro.org/git-ro/people/mturquette/linux.git/clk-next
git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git/samsung-next
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master (3.11-rc4)
- Split "add bus notifier for registering System MMU" into 5 patches
- Call clk_prepare() that was missing in v8.
- Fixed base address of sysmmu_tv in exynos4210.dtsi
- BUG_ON() instead of return -EADDRINUSE when trying mapping on an mapped area
- Moved camif_top to 317 in drivers/clk/samsung/clk-exynos5250.c
- Removed 'iommu' property from 'codec'(mfc) node
- Does not make 'master' clock to be the parent of 'sysmmu' clock.
'master' clock is enabled before accessing control registers of System MMU
and disabled after the access.

v8:
- Reordered patch list: moved "change rwloc to spinlock" to the last.
- Fixed remained bug in "fix page table maintenance".
- Always return 0 from exynos_iommu_attach_device().
- Removed prefetch buffer setting when System MMU is enabled
due to the restriction of prefetch buffers:
A prefetch buffer must not hit from more than one DMA.
For instance with GScalers, if a single prefetch buffer is initialized
with 0x0 ~ 0xFFFFFFFF and a GScaler works on source buffer at 0x10000000
and target buffer @ 0x20000000, the System MMU may be got deadlock.
Clients must initialize prefetch buffers with custom function defined
in exynos-iommu drivers whenever they need to enable prefetch buffers.
- The clock of System MMU has no relationship with the clock of its master H/W.
The clock of master H/W is always enabled when exynos-iommu driver needs to
access MMIO area and disabled as soon as the access finishes.
- Removed err_page variable used in exynos_iommu_unmap() in the previous patch
"fix page table maintenance".
- Split a big patch "add bus notifier for registering System MMU".
Extracted the following 2 patches: 9/12 and 10/12.
- And some additional fixes...

v7:
- Rebased on the stable 3.10
- Registered PM domains and gate clocks with DT
- Changed connection method between a System MMU and its master H/W
'mmu-master' property in the node of System MMU
--> 'iommu' property in the node of master H/W
- Marking device descriptor of master H/W of a System MMU with bus notifier.
- Power management (PM_RUNTIME, PM_SLEEP) of System MMUs with gpd_dev_ops
of Generic IO Powerdomain. gpd_dev_ops are set to the master H/Ws
before they are probed in the bus notifier.
- Removed additional debugging features like debugfs entries and
version names.
- Removed support for advanced features of System MMU 3.2 and 3.3
the current IOMMU API cannot handle the feature
(A kind of L2 TLB that fetches several consequence page table entries.
It must be initialized by the driver of master H/W whenever it works.)

v6:
- Rebased on the branch, next/iommu-exynos of
git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git

v5:
- new bugfix: patch 01
- Reordered patches
* patch 01 ~ 05: Bugfix and enhancements of the existing driver
* patch 06 ~ 10: Device Tree support and callbacks for power management
* patch 11 : System MMU 3.2 and 3.3 support
* patch 12 ~ 14: Debugging features
- Additional code compaction

v4:
- Remove Change-Id from v3 patches
- Change the order of the third and the first patch
Thanks to Kukjin Kim.
- Fix memory leak when allocating and assigning exynos_iommu_owner to client
device if the client device has multiple System MMUs.
Thanks to Rahul Sharma.

v3:
- Fix prefetch buffer flag definition for System MMU 3.3 (patch 10/12)
- Fix incorrect setting for SET_RUNTIME_PM_OPS (patch 09/12)
Thanks to Prathyush.

v2:
- Split the patch to iommu/exynos into 9 patches
- Support for System MMU 3.3
- Some code compaction

Patch summary:

Diffstats:
.../devicetree/bindings/clock/exynos5250-clock.txt | 26 +
.../bindings/iommu/samsung,exynos4210-sysmmu.txt | 103 ++
arch/arm/boot/dts/exynos4.dtsi | 122 +++
arch/arm/boot/dts/exynos4210.dtsi | 25 +
arch/arm/boot/dts/exynos4x12.dtsi | 82 ++
arch/arm/boot/dts/exynos5250.dtsi | 290 ++++++
drivers/clk/samsung/clk-exynos4.c | 27 +-
drivers/clk/samsung/clk-exynos5250.c | 57 +-
drivers/iommu/Kconfig | 5 +-
drivers/iommu/exynos-iommu.c | 1061 +++++++++++++-------
10 files changed, 1423 insertions(+), 375 deletions(-)