diff options
| -rw-r--r-- | Documentation/DocBook/device-drivers.tmpl | 2 | ||||
| -rw-r--r-- | MAINTAINERS | 2 | ||||
| -rw-r--r-- | drivers/dma-buf/Makefile | 2 | ||||
| -rw-r--r-- | drivers/dma-buf/seqno-fence.c | 73 | ||||
| -rw-r--r-- | include/linux/seqno-fence.h | 116 |
5 files changed, 193 insertions, 2 deletions
diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index e634657efb52..ed0ef00cd7bc 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl @@ -130,7 +130,9 @@ X!Edrivers/base/interface.c <sect1><title>Device Drivers DMA Management</title> !Edrivers/dma-buf/dma-buf.c !Edrivers/dma-buf/fence.c +!Edrivers/dma-buf/seqno-fence.c !Iinclude/linux/fence.h +!Iinclude/linux/seqno-fence.h !Iinclude/linux/reservation.h !Edrivers/base/dma-coherent.c !Edrivers/base/dma-mapping.c diff --git a/MAINTAINERS b/MAINTAINERS index 65c8f534b22f..7c97777dd1b3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2901,7 +2901,7 @@ L: linux-media@vger.kernel.org L: dri-devel@lists.freedesktop.org L: linaro-mm-sig@lists.linaro.org F: drivers/dma-buf/ -F: include/linux/dma-buf* include/linux/reservation.h include/linux/fence.h +F: include/linux/dma-buf* include/linux/reservation.h include/linux/*fence.h F: Documentation/dma-buf-sharing.txt T: git git://git.linaro.org/people/sumitsemwal/linux-dma-buf.git diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index d7825bfe630e..57a675f90cd0 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -1 +1 @@ -obj-y := dma-buf.o fence.o reservation.o +obj-y := dma-buf.o fence.o reservation.o seqno-fence.o diff --git a/drivers/dma-buf/seqno-fence.c b/drivers/dma-buf/seqno-fence.c new file mode 100644 index 000000000000..7d12a39a4b57 --- /dev/null +++ b/drivers/dma-buf/seqno-fence.c @@ -0,0 +1,73 @@ +/* + * seqno-fence, using a dma-buf to synchronize fencing + * + * Copyright (C) 2012 Texas Instruments + * Copyright (C) 2012-2014 Canonical Ltd + * Authors: + * Rob Clark <robdclark@gmail.com> + * Maarten Lankhorst <maarten.lankhorst@canonical.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/seqno-fence.h> + +static const char *seqno_fence_get_driver_name(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->get_driver_name(fence); +} + +static const char *seqno_fence_get_timeline_name(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->get_timeline_name(fence); +} + +static bool seqno_enable_signaling(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->enable_signaling(fence); +} + +static bool seqno_signaled(struct fence *fence) +{ + struct seqno_fence *seqno_fence = to_seqno_fence(fence); + return seqno_fence->ops->signaled && seqno_fence->ops->signaled(fence); +} + +static void seqno_release(struct fence *fence) +{ + struct seqno_fence *f = to_seqno_fence(fence); + + dma_buf_put(f->sync_buf); + if (f->ops->release) + f->ops->release(fence); + else + fence_free(&f->base); +} + +static signed long seqno_wait(struct fence *fence, bool intr, signed long timeout) +{ + struct seqno_fence *f = to_seqno_fence(fence); + return f->ops->wait(fence, intr, timeout); +} + +const struct fence_ops seqno_fence_ops = { + .get_driver_name = seqno_fence_get_driver_name, + .get_timeline_name = seqno_fence_get_timeline_name, + .enable_signaling = seqno_enable_signaling, + .signaled = seqno_signaled, + .wait = seqno_wait, + .release = seqno_release, +}; +EXPORT_SYMBOL(seqno_fence_ops); diff --git a/include/linux/seqno-fence.h b/include/linux/seqno-fence.h new file mode 100644 index 000000000000..3d6003de4b0d --- /dev/null +++ b/include/linux/seqno-fence.h @@ -0,0 +1,116 @@ +/* + * seqno-fence, using a dma-buf to synchronize fencing + * + * Copyright (C) 2012 Texas Instruments + * Copyright (C) 2012 Canonical Ltd + * Authors: + * Rob Clark <robdclark@gmail.com> + * Maarten Lankhorst <maarten.lankhorst@canonical.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#ifndef __LINUX_SEQNO_FENCE_H +#define __LINUX_SEQNO_FENCE_H + +#include <linux/fence.h> +#include <linux/dma-buf.h> + +enum seqno_fence_condition { + SEQNO_FENCE_WAIT_GEQUAL, + SEQNO_FENCE_WAIT_NONZERO +}; + +struct seqno_fence { + struct fence base; + + const struct fence_ops *ops; + struct dma_buf *sync_buf; + uint32_t seqno_ofs; + enum seqno_fence_condition condition; +}; + +extern const struct fence_ops seqno_fence_ops; + +/** + * to_seqno_fence - cast a fence to a seqno_fence + * @fence: fence to cast to a seqno_fence + * + * Returns NULL if the fence is not a seqno_fence, + * or the seqno_fence otherwise. + */ +static inline struct seqno_fence * +to_seqno_fence(struct fence *fence) +{ + if (fence->ops != &seqno_fence_ops) + return NULL; + return container_of(fence, struct seqno_fence, base); +} + +/** + * seqno_fence_init - initialize a seqno fence + * @fence: seqno_fence to initialize + * @lock: pointer to spinlock to use for fence + * @sync_buf: buffer containing the memory location to signal on + * @context: the execution context this fence is a part of + * @seqno_ofs: the offset within @sync_buf + * @seqno: the sequence # to signal on + * @ops: the fence_ops for operations on this seqno fence + * + * This function initializes a struct seqno_fence with passed parameters, + * and takes a reference on sync_buf which is released on fence destruction. + * + * A seqno_fence is a dma_fence which can complete in software when + * enable_signaling is called, but it also completes when + * (s32)((sync_buf)[seqno_ofs] - seqno) >= 0 is true + * + * The seqno_fence will take a refcount on the sync_buf until it's + * destroyed, but actual lifetime of sync_buf may be longer if one of the + * callers take a reference to it. + * + * Certain hardware have instructions to insert this type of wait condition + * in the command stream, so no intervention from software would be needed. + * This type of fence can be destroyed before completed, however a reference + * on the sync_buf dma-buf can be taken. It is encouraged to re-use the same + * dma-buf for sync_buf, since mapping or unmapping the sync_buf to the + * device's vm can be expensive. + * + * It is recommended for creators of seqno_fence to call fence_signal + * before destruction. This will prevent possible issues from wraparound at + * time of issue vs time of check, since users can check fence_is_signaled + * before submitting instructions for the hardware to wait on the fence. + * However, when ops.enable_signaling is not called, it doesn't have to be + * done as soon as possible, just before there's any real danger of seqno + * wraparound. + */ +static inline void +seqno_fence_init(struct seqno_fence *fence, spinlock_t *lock, + struct dma_buf *sync_buf, uint32_t context, + uint32_t seqno_ofs, uint32_t seqno, + enum seqno_fence_condition cond, + const struct fence_ops *ops) +{ + BUG_ON(!fence || !sync_buf || !ops); + BUG_ON(!ops->wait || !ops->enable_signaling || + !ops->get_driver_name || !ops->get_timeline_name); + + /* + * ops is used in fence_init for get_driver_name, so needs to be + * initialized first + */ + fence->ops = ops; + fence_init(&fence->base, &seqno_fence_ops, lock, context, seqno); + get_dma_buf(sync_buf); + fence->sync_buf = sync_buf; + fence->seqno_ofs = seqno_ofs; + fence->condition = cond; +} + +#endif /* __LINUX_SEQNO_FENCE_H */ |