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2016-03-21dma-buf: Update docs for SYNC ioctlDaniel Vetter
Just a bit of wording polish plus mentioning that it can fail and must be restarted. Requested by Sumit. v2: Fix them typos (Hans). Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tiago Vignatti <tiago.vignatti@intel.com> Cc: Stéphane Marchesin <marcheu@chromium.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@intel.com> CC: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: intel-gfx@lists.freedesktop.org Cc: devel@driverdev.osuosl.org Cc: Hans Verkuil <hverkuil@xs4all.nl> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2016-03-19dma-buf, drm, ion: Propagate error code from dma_buf_start_cpu_access()Chris Wilson
Drivers, especially i915.ko, can fail during the initial migration of a dma-buf for CPU access. However, the error code from the driver was not being propagated back to ioctl and so userspace was blissfully ignorant of the failure. Rendering corruption ensues. Whilst fixing the ioctl to return the error code from dma_buf_start_cpu_access(), also do the same for dma_buf_end_cpu_access(). For most drivers, dma_buf_end_cpu_access() cannot fail. i915.ko however, as most drivers would, wants to avoid being uninterruptible (as would be required to guarrantee no failure when flushing the buffer to the device). As userspace already has to handle errors from the SYNC_IOCTL, take advantage of this to be able to restart the syscall across signals. This fixes a coherency issue for i915.ko as well as reducing the uninterruptible hold upon its BKL, the struct_mutex. Fixes commit c11e391da2a8fe973c3c2398452000bed505851e Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Thu Feb 11 20:04:51 2016 -0200 dma-buf: Add ioctls to allow userspace to flush Testcase: igt/gem_concurrent_blit/*dmabuf*interruptible Testcase: igt/prime_mmap_coherency/ioctl-errors Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tiago Vignatti <tiago.vignatti@intel.com> Cc: Stéphane Marchesin <marcheu@chromium.org> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@intel.com> CC: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: intel-gfx@lists.freedesktop.org Cc: devel@driverdev.osuosl.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1458331359-2634-1-git-send-email-chris@chris-wilson.co.uk
2016-02-12dma-buf: Add ioctls to allow userspace to flushDaniel Vetter
The userspace might need some sort of cache coherency management e.g. when CPU and GPU domains are being accessed through dma-buf at the same time. To circumvent this problem there are begin/end coherency markers, that forward directly to existing dma-buf device drivers vfunc hooks. Userspace can make use of those markers through the DMA_BUF_IOCTL_SYNC ioctl. The sequence would be used like following: - mmap dma-buf fd - for each drawing/upload cycle in CPU 1. SYNC_START ioctl, 2. read/write to mmap area 3. SYNC_END ioctl. This can be repeated as often as you want (with the new data being consumed by the GPU or say scanout device) - munmap once you don't need the buffer any more v2 (Tiago): Fix header file type names (u64 -> __u64) v3 (Tiago): Add documentation. Use enum dma_buf_sync_flags to the begin/end dma-buf functions. Check for overflows in start/length. v4 (Tiago): use 2d regions for sync. v5 (Tiago): forget about 2d regions (v4); use _IOW in DMA_BUF_IOCTL_SYNC and remove range information from struct dma_buf_sync. v6 (Tiago): use __u64 structured padded flags instead enum. Adjust documentation about the recommendation on using sync ioctls. v7 (Tiago): Alex' nit on flags definition and being even more wording in the doc about sync usage. v9 (Tiago): remove useless is_dma_buf_file check. Fix sync.flags conditionals and its mask order check. Add <linux/types.h> include in dma-buf.h. Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Reviewed-by: Stéphane Marchesin <marcheu@chromium.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1455228291-29640-1-git-send-email-tiago.vignatti@intel.com
2016-02-09dma-buf: Remove range-based flushTiago Vignatti
This patch removes range-based information used for optimizations in begin_cpu_access and end_cpu_access. We don't have any user nor implementation using range-based flush. It seems a consensus that if we ever want something like that again (or even more robust using 2D, 3D sub-range regions) we can use the upcoming dma-buf sync ioctl for such. Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com> Reviewed-by: Stéphane Marchesin <marcheu@chromium.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1450820214-12509-3-git-send-email-tiago.vignatti@intel.com
2015-10-30dma-buf/fence: add fence_wait_any_timeout function v2Christian König
Waiting for the first fence in an array of fences to signal. This is useful for device driver specific resource managers and also Vulkan needs something similar. v2: more parameter checks, handling for timeout==0, remove NULL entry support, better callback removal. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
2015-05-21dma-buf: Minor coding style fixesJagan Teki
- WARNING: Missing a blank line after declarations - WARNING: line over 80 characters - WARNING: please, no space before tabs Signed-off-by: Jagan Teki <jteki@openedev.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2015-05-13dma-buf: add ref counting for module as exporterSumit Semwal
Add reference counting on a kernel module that exports dma-buf and implements its operations. This prevents the module from being unloaded while DMABUF file is in use. The original patch [1] was submitted by Tomasz Stanislawski, but this is a simpler way to do it. v3: call module_put() as late as possible, per gregkh's comment. v2: move owner to struct dma_buf, and use DEFINE_DMA_BUF_EXPORT_INFO macro to simplify the change. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> [1]: https://lkml.org/lkml/2012/8/8/163
2015-04-21dma-buf: cleanup dma_buf_export() to make it easily extensibleSumit Semwal
At present, dma_buf_export() takes a series of parameters, which makes it difficult to add any new parameters for exporters, if required. Make it simpler by moving all these parameters into a struct, and pass the struct * as parameter to dma_buf_export(). While at it, unite dma_buf_export_named() with dma_buf_export(), and change all callers accordingly. Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Acked-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2015-01-22reservation: Remove shadowing local variable 'ret'Michel Dänzer
It was causing the return value of fence_is_signaled to be ignored, making reservation objects signal too early. Cc: stable@vger.kernel.org Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2015-01-22dma-buf/fence: don't wait when specified timeout is zeroJammy Zhou
When specified timeout is zero for fence_wait_timeout, just check if the fence is signaled or not without wait. Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-By: Maarten Lankhorst <maarten.lankhorst@canonical.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2015-01-22reservation: wait only with non-zero timeout specified (v3)Jammy Zhou
When the timeout value passed to reservation_object_wait_timeout_rcu is zero, no wait should be done if the fences are not signaled. Return '1' for idle and '0' for busy if the specified timeout is '0' to keep consistent with the case of non-zero timeout. v2: call fence_put if not signaled in the case of timeout==0 v3: switch to reservation_object_test_signaled_rcu Signed-off-by: Jammy Zhou <Jammy.Zhou@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-By: Maarten Lankhorst <maarten.lankhorst@canonical.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2014-11-03treewide: Fix typo in Documentation/DocBook/device-driversMasanari Iida
This patch fix speeling typo found in html files within Documentation/DocBook/device-drivers. It is because html files are generated from comments in source, so I have to fix comments in the source. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2014-10-09dma-buf: don't open-code atomic_long_read()Al Viro
... not to mention that even atomic_long_read() is too low-level here - there's file_count(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-08-28dma-buf/fence: Fix a kerneldoc warningThierry Reding
kerneldoc doesn't know how to parse variables, so don't let it try. Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
2014-07-08reservation: add suppport for read-only access using rcuMaarten Lankhorst
This adds some extra functions to deal with rcu. reservation_object_get_fences_rcu() will obtain the list of shared and exclusive fences without obtaining the ww_mutex. reservation_object_wait_timeout_rcu() will wait on all fences of the reservation_object, without obtaining the ww_mutex. reservation_object_test_signaled_rcu() will test if all fences of the reservation_object are signaled without using the ww_mutex. reservation_object_get_excl and reservation_object_get_list require the reservation object to be held, updating requires write_seqcount_begin/end. If only the exclusive fence is needed, rcu_dereference followed by fence_get_rcu can be used, if the shared fences are needed it's recommended to use the supplied functions. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Reviewed-By: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08reservation: update api and add some helpersMaarten Lankhorst
Move the list of shared fences to a struct, and return it in reservation_object_get_list(). Add reservation_object_get_excl to get the exclusive fence. Add reservation_object_reserve_shared(), which reserves space in the reservation_object for 1 more shared fence. reservation_object_add_shared_fence() and reservation_object_add_excl_fence() are used to assign a new fence to a reservation_object pointer, to complete a reservation. Changes since v1: - Add reservation_object_get_excl, reorder code a bit. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08dma-buf: add poll support, v3Maarten Lankhorst
Thanks to Fengguang Wu for spotting a missing static cast. v2: - Kill unused variable need_shared. v3: - Clarify the BUG() in dma_buf_release some more. (Rob Clark) Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08dma-buf: use reservation objectsMaarten Lankhorst
This allows reservation objects to be used in dma-buf. it's required for implementing polling support on the fences that belong to a dma-buf. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com> #drivers/media/v4l2-core/ Acked-by: Thomas Hellstrom <thellstrom@vmware.com> #drivers/gpu/drm/ttm Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> #drivers/gpu/drm/armada/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08seqno-fence: Hardware dma-buf implementation of fencing (v6)Maarten Lankhorst
This type of fence can be used with hardware synchronization for simple hardware that can block execution until the condition (dma_buf[offset] - value) >= 0 has been met when WAIT_GEQUAL is used, or (dma_buf[offset] != 0) has been met when WAIT_NONZERO is set. A software fallback still has to be provided in case the fence is used with a device that doesn't support this mechanism. It is useful to expose this for graphics cards that have an op to support this. Some cards like i915 can export those, but don't have an option to wait, so they need the software fallback. I extended the original patch by Rob Clark. v1: Original v2: Renamed from bikeshed to seqno, moved into dma-fence.c since not much was left of the file. Lots of documentation added. v3: Use fence_ops instead of custom callbacks. Moved to own file to avoid circular dependency between dma-buf.h and fence.h v4: Add spinlock pointer to seqno_fence_init v5: Add condition member to allow wait for != 0. Fix small style errors pointed out by checkpatch. v6: Move to a separate file. Fix up api changes in fences. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Reviewed-by: Rob Clark <robdclark@gmail.com> #v4 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08fence: dma-buf cross-device synchronization (v18)Maarten Lankhorst
A fence can be attached to a buffer which is being filled or consumed by hw, to allow userspace to pass the buffer without waiting to another device. For example, userspace can call page_flip ioctl to display the next frame of graphics after kicking the GPU but while the GPU is still rendering. The display device sharing the buffer with the GPU would attach a callback to get notified when the GPU's rendering-complete IRQ fires, to update the scan-out address of the display, without having to wake up userspace. A driver must allocate a fence context for each execution ring that can run in parallel. The function for this takes an argument with how many contexts to allocate: + fence_context_alloc() A fence is transient, one-shot deal. It is allocated and attached to one or more dma-buf's. When the one that attached it is done, with the pending operation, it can signal the fence: + fence_signal() To have a rough approximation whether a fence is fired, call: + fence_is_signaled() The dma-buf-mgr handles tracking, and waiting on, the fences associated with a dma-buf. The one pending on the fence can add an async callback: + fence_add_callback() The callback can optionally be cancelled with: + fence_remove_callback() To wait synchronously, optionally with a timeout: + fence_wait() + fence_wait_timeout() When emitting a fence, call: + trace_fence_emit() To annotate that a fence is blocking on another fence, call: + trace_fence_annotate_wait_on(fence, on_fence) A default software-only implementation is provided, which can be used by drivers attaching a fence to a buffer when they have no other means for hw sync. But a memory backed fence is also envisioned, because it is common that GPU's can write to, or poll on some memory location for synchronization. For example: fence = custom_get_fence(...); if ((seqno_fence = to_seqno_fence(fence)) != NULL) { dma_buf *fence_buf = seqno_fence->sync_buf; get_dma_buf(fence_buf); ... tell the hw the memory location to wait ... custom_wait_on(fence_buf, seqno_fence->seqno_ofs, fence->seqno); } else { /* fall-back to sw sync * / fence_add_callback(fence, my_cb); } On SoC platforms, if some other hw mechanism is provided for synchronizing between IP blocks, it could be supported as an alternate implementation with it's own fence ops in a similar way. enable_signaling callback is used to provide sw signaling in case a cpu waiter is requested or no compatible hardware signaling could be used. The intention is to provide a userspace interface (presumably via eventfd) later, to be used in conjunction with dma-buf's mmap support for sw access to buffers (or for userspace apps that would prefer to do their own synchronization). v1: Original v2: After discussion w/ danvet and mlankhorst on #dri-devel, we decided that dma-fence didn't need to care about the sw->hw signaling path (it can be handled same as sw->sw case), and therefore the fence->ops can be simplified and more handled in the core. So remove the signal, add_callback, cancel_callback, and wait ops, and replace with a simple enable_signaling() op which can be used to inform a fence supporting hw->hw signaling that one or more devices which do not support hw signaling are waiting (and therefore it should enable an irq or do whatever is necessary in order that the CPU is notified when the fence is passed). v3: Fix locking fail in attach_fence() and get_fence() v4: Remove tie-in w/ dma-buf.. after discussion w/ danvet and mlankorst we decided that we need to be able to attach one fence to N dma-buf's, so using the list_head in dma-fence struct would be problematic. v5: [ Maarten Lankhorst ] Updated for dma-bikeshed-fence and dma-buf-manager. v6: [ Maarten Lankhorst ] I removed dma_fence_cancel_callback and some comments about checking if fence fired or not. This is broken by design. waitqueue_active during destruction is now fatal, since the signaller should be holding a reference in enable_signalling until it signalled the fence. Pass the original dma_fence_cb along, and call __remove_wait in the dma_fence_callback handler, so that no cleanup needs to be performed. v7: [ Maarten Lankhorst ] Set cb->func and only enable sw signaling if fence wasn't signaled yet, for example for hardware fences that may choose to signal blindly. v8: [ Maarten Lankhorst ] Tons of tiny fixes, moved __dma_fence_init to header and fixed include mess. dma-fence.h now includes dma-buf.h All members are now initialized, so kmalloc can be used for allocating a dma-fence. More documentation added. v9: Change compiler bitfields to flags, change return type of enable_signaling to bool. Rework dma_fence_wait. Added dma_fence_is_signaled and dma_fence_wait_timeout. s/dma// and change exports to non GPL. Added fence_is_signaled and fence_enable_sw_signaling calls, add ability to override default wait operation. v10: remove event_queue, use a custom list, export try_to_wake_up from scheduler. Remove fence lock and use a global spinlock instead, this should hopefully remove all the locking headaches I was having on trying to implement this. enable_signaling is called with this lock held. v11: Use atomic ops for flags, lifting the need for some spin_lock_irqsaves. However I kept the guarantee that after fence_signal returns, it is guaranteed that enable_signaling has either been called to completion, or will not be called any more. Add contexts and seqno to base fence implementation. This allows you to wait for less fences, by testing for seqno + signaled, and then only wait on the later fence. Add FENCE_TRACE, FENCE_WARN, and FENCE_ERR. This makes debugging easier. An CONFIG_DEBUG_FENCE will be added to turn off the FENCE_TRACE spam, and another runtime option can turn it off at runtime. v12: Add CONFIG_FENCE_TRACE. Add missing documentation for the fence->context and fence->seqno members. v13: Fixup CONFIG_FENCE_TRACE kconfig description. Move fence_context_alloc to fence. Simplify fence_later. Kill priv member to fence_cb. v14: Remove priv argument from fence_add_callback, oops! v15: Remove priv from documentation. Explicitly include linux/atomic.h. v16: Add trace events. Import changes required by android syncpoints. v17: Use wake_up_state instead of try_to_wake_up. (Colin Cross) Fix up commit description for seqno_fence. (Rob Clark) v18: Rename release_fence to fence_release. Move to drivers/dma-buf/. Rename __fence_is_signaled and __fence_signal to *_locked. Rename __fence_init to fence_init. Make fence_default_wait return a signed long, and fix wait ops too. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> #use smp_mb__before_atomic() Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-08dma-buf: move to drivers/dma-bufMaarten Lankhorst
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> Acked-by: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>