This patch contains 2 workaround for the System MMU v3.x.
System MMU v3.2 and v3.3 has FLPD cache that caches first level page
table entries to reduce page table walking latency. However, the
FLPD cache is filled with a first level page table entry even though
it is not accessed by a master H/W because System MMU v3.3
speculatively prefetches page table entries that may be accessed
in the near future by the master H/W.
The prefetched FLPD cache entries are not invalidated by iommu_unmap()
because iommu_unmap() only unmaps and invalidates the page table
entries that is mapped.
Because exynos-iommu driver discards a second level page table when
it needs to be replaced with another second level page table or
a first level page table entry with 1MB mapping, It is required to
invalidate FLPD cache that may contain the first level page table
entry that points to the second level page table.
Another workaround of System MMU v3.3 is initializing the first level
page table entries with the second level page table which is filled
with all zeros. This prevents System MMU prefetches 'fault' first
level page table entry which may lead page fault on access to 16MiB
wide.
System MMU 3.x fetches consecutive page table entries by a page
table walking to maximize bus utilization and to minimize TLB miss
panelty.
Unfortunately, functional problem is raised with the fetching behavior
because it fetches 'fault' page table entries that specifies no
translation information and that a valid translation information will
be written to in the near future. The logic in the System MMU generates
page fault with the cached fault entries that is no longer coherent
with the page table which is updated.
There is another workaround that must be implemented by I/O virtual
memory manager: any two consecutive I/O virtual memory area must have
a hole between the two that is larger than or equal to 128KiB.
Also, next I/O virtual memory area must be started from the next
128KiB boundary.
0 128K 256K 384K 512K
|-------------|---------------|-----------------|----------------|
|area1---------------->|.........hole...........|<--- area2 -----
The constraint is depicted above.
The size is selected by the calculation followed:
- System MMU can fetch consecutive 64 page table entries at once
64 * 4KiB = 256KiB. This is the size between 128K ~ 384K of the
above picture. This style of fetching is 'block fetch'. It fetches
the page table entries predefined consecutive page table entries
including the entry that is the reason of the page table walking.
- System MMU can prefetch upto consecutive 32 page table entries.
This is the size between 256K ~ 384K.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This turns on FLPD_CACHE, ACGEN and SYSSEL.
FLPD_CACHE is a cache of 1st level page table entries that contains
the address of a 2nd level page table to reduce latency of page table
walking.
ACGEN is architectural clock gating that gates clocks by System MMU
itself if it is not active. Note that ACGEN is different from clock
gating by the CPU. ACGEN just gates clocks to the internal logic of
System MMU while clock gating by the CPU gates clocks to the System
MMU.
SYSSEL selects System MMU version in some Exynos SoCs. Some Exynos
SoCs have an option to select System MMU versions exclusively because
the SoCs adopts new System MMU version experimentally.
This also always selects LRU as TLB replacement policy. Selecting TLB
replacement policy is deprecated from System MMU 3.2. TLB in System
MMU 3.3 has single TLB replacement policy, LRU. The bit of MMU_CFG
selecting TLB replacement policy is remained as reserved.
QoS value of page table walking is set to 15 (highst value). System
MMU 3.3 can inherit QoS value of page table walking from its master
H/W's transaction. This new feature is enabled by default and QoS
value written to MMU_CFG is ignored.
This patch also adds simplifies the sysmmu version checking by
introducing some macros.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit adds device tree support for System MMU.
Also, system mmu handling is improved. Previously, an IOMMU domain is
bound to a System MMU which is not correct. This patch binds an IOMMU
domain with the master device of a System MMU.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This patch adds a description of the device tree binding for the
Samsung Exynos System MMU.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Some redundant error message is removed and some error messages
are changed to error level from debug level.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Patch written by Antonios Motakis <a.motakis@virtualopensystems.com>:
IOMMU groups are expected by certain users of the IOMMU API,
e.g. VFIO. Since each device is behind its own System MMU, we
can allocate a new IOMMU group for each device.
Reviewed-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Shaik Ameeer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit introduces sysmmu_pte_t for page table entries and
sysmmu_iova_t vor I/O virtual address that is manipulated by
exynos-iommu driver. The purpose of the typedef is to remove
dependencies to the driver code from the change of CPU architecture
from 32 bit to 64 bit.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Since acquiring read_lock is not more frequent than write_lock, it is
not beneficial to use rwlock, this commit changes rwlock to spinlock.
Reviewed-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit removes custom fault handler. The device drivers that
need to register fault handler can register
with iommu_set_fault_handler().
CC: Grant Grundler <grundler@chromium.org>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This patch gates clocks of master H/W as well as clocks of System MMU
if master clocks are specified.
Some Exynos SoCs (i.e. GScalers in Exynos5250) have dependencies in
the gating clocks of master H/W and its System MMU. If a H/W is the
case, accessing control registers of System MMU is prohibited unless
both of the gating clocks of System MMU and its master H/W.
CC: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This patch removes dbgname member from sysmmu_drvdata structure.
Kernel message for debugging already has the name of a single
System MMU node. It also removes some compilation warnings.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Checking if the probing device has a parent device was just to discover
if the probing device is involved in a power domain when the power
domain controlled by Samsung's custom implementation.
Since generic IO power domain is applied, it is required to remove
the condition to see if the probing device has a parent device.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit adds cache flush for removed small and large page entries
in exynos_iommu_unmap(). Missing cache flush of removed page table
entries can cause missing page fault interrupt when a master IP
accesses an unmapped area.
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Tested-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Prefetch buffer is a cache of System MMU 3.x and caches a block of
page table entries to make effect of larger page with small pages.
However, how to control prefetch buffers and the specifications of
prefetch buffers different from minor versions of System MMU v3.
Prefetch buffers must be controled with care because there are some
restrictions in H/W design.
The interface and implementation to initiate prefetch buffers will
be prepared later.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
L2TLB is 8-way set-associative TLB with 512 entries. The number of
sets is 64.
A single 4KB(small page) translation information is cached
only to a set whose index is the same with the lower 6 bits of the page
frame number.
A single 64KB(large page) translation information can be
cached to any 16 sets whose top two bits of their indices are the same
with the bit [5:4] of the page frame number.
A single 1MB(section) or larger translation information can be cached to
any set in the TLB.
It is required to invalidate entire sets that may cache the target
translation information to guarantee that the L2TLB has no stale data.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Since kmalloc() does not guarantee that the allignment of 1KiB when it
allocates 1KiB, it is required to allocate lv2 page table from own
slab that guarantees alignment of 1KiB
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This patch changes not to panic on any error when updating page table.
Instead prints error messages with callstack.
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Commit 25e9d28d92 (ARM: EXYNOS: remove system mmu initialization from
exynos tree) removed arch/arm/mach-exynos/mach/sysmmu.h header without
removing remaining use of it from exynos-iommu driver, thus causing a
compilation error.
This patch fixes the error by removing respective include line
from exynos-iommu.c.
Use of __pa and __va macro is changed to virt_to_phys and phys_to_virt
which are recommended in driver code. printk formatting of physical
address is also fixed to %pa.
Also System MMU driver is changed to control only a single instance
of System MMU at a time. Since a single instance of System MMU has only
a single clock descriptor for its clock gating, single address range
for control registers, there is no need to obtain two or more clock
descriptors and ioremaped region.
CC: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Fix build when BNX2X_SRIOV is not enabled.
Change one parameter struct from bnx2 to bnx2x and don't return a value
from a void function.
drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.h:576:48: warning: 'struct bnx2' declared inside parameter list [enabled by default]
drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.h:576:48: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.h:576:60: warning: 'return' with a value, in function returning void [enabled by default]
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for OMAP3 ROM Random Number Generator via
pdata-quirks.
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
In the comments, LCD pins 16-23 were numbered in the wrong order.
Fix this and use proper pinmux constants for all entries while we
are at it.
Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
Cc: Benoit Parrot <bparrot@ti.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
[tony@atomide.com: updated description]
Signed-off-by: Tony Lindgren <tony@atomide.com>
- properly release neigh_ifinfo in batadv_iv_ogm_process_per_outif()
- properly release orig_ifinfo->router when freeing orig_ifinfo
- properly release neigh_node objects during periodic check
- properly release neigh_info objects when the related hard_iface
is free'd
These changes are all very important because they fix some
reference counting imbalances that lead to the
impossibility of releasing the netdev object used by
batman-adv on shutdown.
The consequence is that such object cannot be destroyed by
the networking stack (the refcounter does not reach zero)
thus bringing the system in hanging state during a normal
reboot operation or a network reconfiguration.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=GsPT
-----END PGP SIGNATURE-----
Merge tag 'batman-adv-fix-for-davem' of git://git.open-mesh.org/linux-merge
Included changes:
- properly release neigh_ifinfo in batadv_iv_ogm_process_per_outif()
- properly release orig_ifinfo->router when freeing orig_ifinfo
- properly release neigh_node objects during periodic check
- properly release neigh_info objects when the related hard_iface
is free'd
These changes are all very important because they fix some
reference counting imbalances that lead to the
impossibility of releasing the netdev object used by
batman-adv on shutdown.
The consequence is that such object cannot be destroyed by
the networking stack (the refcounter does not reach zero)
thus bringing the system in hanging state during a normal
reboot operation or a network reconfiguration.
That's not necessary and makes the code not as neat as it could be.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The input field in struct v4l2_buffer no longer exists but has been replaced
by a reserved field. Remove the field documentation.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
V4L2_MBUS_FRAME_DESC_FL_BLOB intends to say the receiver must use 1D DMA to
receive the image, as the format does not have line offsets. This typically
includes all compressed formats.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Since commit 7e98056964("ipv6: router reachability probing"), a router falls
into NUD_FAILED will be probed.
Now if function rt6_select() selects a router which neighbour state is NUD_FAILED,
and at the same time function rt6_probe() changes the neighbour state to NUD_PROBE,
then function dst_neigh_output() can directly send packets, but actually the
neighbour still is unreachable. If we set nud_state to NUD_INCOMPLETE instead
NUD_PROBE, packets will not be sent out until the neihbour is reachable.
In addition, because the route should be probes with a single NS, so we must
set neigh->probes to neigh_max_probes(), then the neigh timer timeout and function
neigh_timer_handler() will not send other NS Messages.
Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the sub-device is registered, increment the use count of the sub-device
owner only if it's different from the owner of the driver for the media
device. This avoids increasing the use count by the module itself and thus
making it possible to unload it when it's not in use.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
mdev->fops->owner is actually the owner of the very same module which
implements media_device_register(), so it can't be unloaded anyway. Instead,
use THIS_MODULE through a macro as does video_register_device().
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
VIDIOC_SUBDEV_[GS]_FRAME_INTERVAL IOCTLs argument structs contain the pad
field but the validity check was missing. There should be no implications
security-wise from this since no driver currently uses the pad field in the
struct.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This is already available from saa7134_dev.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Don't calculate this for every buffer, store it globally instead.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This will make the next patch a bit easier to read.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
saa7134-alsa used low-level videobuf functions to allocate and sync
DMA buffers. Replace this with saa7134-specific code. These functions
will not be available when we convert to vb2.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Just white space and coding style changes to reduce the noise in the
following patches.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This solves this bug:
https://bugzilla.kernel.org/show_bug.cgi?id=73361
The problem is that when you quit tvtime it calls STREAMOFF, but then it queues a
bunch of buffers for no good reason before closing the file descriptor.
In the past closing the fd would free the vb queue since that was part of the file
handle struct. Since that was moved to the global struct that no longer happened.
This wouldn't be a problem, but the extra QBUF calls that tvtime does meant that
the buffer list in videobuf (q->stream) contained buffers, so REQBUFS would fail
with -EBUSY.
The solution is to init the list head explicitly when releasing the file
descriptor and to not free the video resource when calling streamoff.
The real fix will hopefully go into kernel 3.16 when the vb2 conversion is
merged. Basically the saa7134 driver with the old videobuf is so full of holes it
ain't funny anymore, so consider this a band-aid for kernels 3.14 and 15.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: stable@vger.kernel.org # for v3.14 and up
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
cgroup_tree_mutex was introduced to work around the circular
dependency between cgroup_mutex and kernfs active protection - some
kernfs file and directory operations needed cgroup_mutex putting
cgroup_mutex under active protection but cgroup also needs to be able
to access cgroup hierarchies and cftypes to determine which
kernfs_nodes need to be removed. cgroup_tree_mutex nested above both
cgroup_mutex and kernfs active protection and used to protect the
hierarchy and cftypes. While this worked, it added a lot of double
lockings and was generally cumbersome.
kernfs provides a mechanism to opt out of active protection and cgroup
was already using it for removal and subtree_control. There's no
reason to mix both methods of avoiding circular locking dependency and
the preceding cgroup_kn_lock_live() changes applied it to all relevant
cgroup kernfs operations making it unnecessary to nest cgroup_mutex
under kernfs active protection. The previous patch reversed the
original lock ordering and put cgroup_mutex above kernfs active
protection.
After these changes, all cgroup_tree_mutex usages are now accompanied
by cgroup_mutex making the former completely redundant. This patch
removes cgroup_tree_mutex and all its usages.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
After the recent cgroup_kn_lock_live() changes, cgroup_mutex is no
longer nested below kernfs active protection. The two don't have any
relationship now.
This patch nests kernfs active protection under cgroup_mutex. All
cftype operations now require both cgroup_tree_mutex and cgroup_mutex,
temporary cgroup_mutex releases over kernfs operations are removed,
and cgroup_add/rm_cftypes() grab both mutexes.
This makes cgroup_tree_mutex redundant, which will be removed by the
next patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Make __cgroup_procs_write() and cgroup_release_agent_write() use
cgroup_kn_lock_live() and cgroup_kn_unlock() instead of
cgroup_lock_live_group(). This puts the operations under both
cgroup_tree_mutex and cgroup_mutex protection without circular
dependency from kernfs active protection. Also, this means that
cgroup_mutex is no longer nested below kernfs active protection.
There is no longer any place where the two locks interact.
This leaves cgroup_lock_live_group() without any user. Removed.
This will help simplifying cgroup locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_mkdir(), cgroup_rmdir() and cgroup_subtree_control_write()
share the logic to break active protection so that they can grab
cgroup_tree_mutex which nests above active protection and/or remove
self. Factor out this logic into cgroup_kn_lock_live() and
cgroup_kn_unlock().
This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
The ->priv field of a cgroup directory kernfs_node points back to the
cgroup. This field is RCU cleared in cgroup_destroy_locked() for
non-kernfs accesses from css_tryget_from_dir() and
cgroupstats_build().
As these are only applicable to cgroups which finished creation
successfully and fully initialized cgroups are always removed by
cgroup_rmdir(), this can be safely moved to the end of cgroup_rmdir().
This will help simplifying cgroup locking and shouldn't introduce any
behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Move cgroup_lock_live_group() invocation upwards to right below
cgroup_tree_mutex in cgroup_subtree_control_write(). This is to help
the planned locking simplification.
This doesn't make any userland-visible behavioral changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup_mkdir() is the sole user of cgroup_create(). Let's collapse
the latter into the former. This will help simplifying locking.
While at it, remove now stale comment about inode locking.
This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Reorganize cgroup_create() so that all paths share unlock out path.
* All err_* labels are renamed to out_* as they're now shared by both
success and failure paths.
* @err renamed to @ret for the similar reason as above and so that
it's more consistent with other functions.
* cgroup memory allocation moved after locking so that freeing failed
cgroup happens before unlocking. While this moves more code inside
critical section, memory allocations inside cgroup locking are
already pretty common and this is unlikely to make any noticeable
difference.
* While at it, replace a stray @parent->root dereference with @root.
This reorganization will help simplifying locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Now that cgroup_subtree_control_write() has access to the associated
kernfs_open_file and thus the kernfs_node, there's no need to cache it
in cgroup->control_kn on creation. Remove cgroup->control_kn and use
@of->kn directly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
