[PATCH v2 0/8] Tegra GART driver clean up and optimization

From: Dmitry Osipenko
Date: Sat Aug 04 2018 - 10:35:35 EST


This patch-series makes GART driver one step closer to become actually
usable by addressing the following:

1. Thierry noticed that Memory Controller driver uses registers that belong
to GART in [0] and for now MC driver only reports the fact of GART's page
fault. The first two patches of the series are addressing this shortcoming
by providing integration of the MC driver with the GART.

[0] https://www.spinics.net/lists/linux-tegra/msg33072.html

2. Currently GART has bee kept disabled by the commit c7e3ca515e784
("iommu/tegra: gart: Do not register with bus"). If GART is re-enabled than
all devices in the system are getting assigned to the GART as it is a global
systems IOMMU provider. This is wrong simply because GART doesn't handle all
those devices. This series makes GART to accept only devices that are
explicitly assigned to GART in device tree using 'iommu' phandle.

3. This series makes a generic clean up of the driver, like removing dead code.

4. This series introduces and utilizes iotlb_sync_map() callback that was
previously suggested by Joerg Roedel in [1], optimizing mapping / unmapping

[1] https://www.spinics.net/lists/linux-tegra/msg32914.html


v2: Addressed review comments from Robin Murphy to v1 by moving devices
iommu_fwspec check to gart_iommu_add_device().

Dropped the "Provide single domain and group for all devices" patch from
the series for now because after some more considering it became not
exactly apparent whether that is what we need, that was also suggested
by Robin Murphy in the review comment. Maybe something like a runtime
IOMMU usage for devices would be a better solution, allowing to implement
transparent context switching of virtual IOMMU domains.

Some very minor code cleanups, reworded commit messages.

Dmitry Osipenko (8):
memory: tegra: Provide facility for integration with the GART driver
iommu/tegra: gart: Provide access to Memory Controller driver
iommu/tegra: gart: Clean up drivers module code
iommu/tegra: gart: Remove pr_fmt and clean up includes
iommu/tegra: gart: Clean up driver probe errors handling
iommu/tegra: gart: Ignore devices without IOMMU phandle in DT
iommu: Introduce iotlb_sync_map callback
iommu/tegra: gart: Optimize mapping / unmapping performance

drivers/iommu/iommu.c | 8 ++-
drivers/iommu/tegra-gart.c | 99 +++++++++++++++++++++++---------------
drivers/memory/tegra/mc.c | 26 ++++++++--
include/linux/iommu.h | 1 +
include/soc/tegra/mc.h | 13 +++++
5 files changed, 103 insertions(+), 44 deletions(-)