Linaro-mm-sig February 2014

linaro-mm-sig@lists.linaro.org

22 participants
19 discussions

[PATCH 0/6] dma-buf synchronization patches (updated)

by Maarten Lankhorst

The following series implements fence and converts dma-buf and android sync to use it. Patch 5 and 6 add support for polling to dma-buf, blocking until all fences are signaled. Patches that received some minor updates: - seqno fence (wait condition member added) - android (whitespace changes and a comment removed) - add poll support to dma-buf (added comment) --- Maarten Lankhorst (6): fence: dma-buf cross-device synchronization (v17) seqno-fence: Hardware dma-buf implementation of fencing (v5) dma-buf: use reservation objects android: convert sync to fence api, v5 reservation: add support for fences to enable cross-device synchronisation dma-buf: add poll support, v3 Documentation/DocBook/device-drivers.tmpl | 3 drivers/base/Kconfig | 9 drivers/base/Makefile | 2 drivers/base/dma-buf.c | 130 +++ drivers/base/fence.c | 467 ++++++++++++ drivers/gpu/drm/drm_prime.c | 8 drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 2 drivers/gpu/drm/i915/i915_gem_dmabuf.c | 2 drivers/gpu/drm/nouveau/nouveau_drm.c | 1 drivers/gpu/drm/nouveau/nouveau_gem.h | 1 drivers/gpu/drm/nouveau/nouveau_prime.c | 7 drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 drivers/gpu/drm/radeon/radeon_drv.c | 2 drivers/gpu/drm/radeon/radeon_prime.c | 8 drivers/gpu/drm/ttm/ttm_object.c | 2 drivers/media/v4l2-core/videobuf2-dma-contig.c | 2 drivers/staging/android/Kconfig | 1 drivers/staging/android/Makefile | 2 drivers/staging/android/ion/ion.c | 2 drivers/staging/android/sw_sync.c | 4 drivers/staging/android/sync.c | 903 ++++++++---------------- drivers/staging/android/sync.h | 82 +- drivers/staging/android/sync_debug.c | 247 +++++++ drivers/staging/android/trace/sync.h | 12 include/drm/drmP.h | 2 include/linux/dma-buf.h | 21 - include/linux/fence.h | 329 +++++++++ include/linux/reservation.h | 20 + include/linux/seqno-fence.h | 119 +++ include/trace/events/fence.h | 125 +++ 30 files changed, 1863 insertions(+), 654 deletions(-) create mode 100644 drivers/base/fence.c create mode 100644 drivers/staging/android/sync_debug.c create mode 100644 include/linux/fence.h create mode 100644 include/linux/seqno-fence.h create mode 100644 include/trace/events/fence.h -- Signature

10 years, 7 months

[RFC] dma-buf: Implement test module

by Thierry Reding

This is a simple test module that can be used to allocate, export and delete DMA-BUF objects. It can be used to test DMA-BUF sharing in systems that lack a real second driver. Signed-off-by: Thierry Reding <treding(a)nvidia.com> --- drivers/base/Kconfig | 4 + drivers/base/Makefile | 1 + drivers/base/dma-buf-test.c | 308 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 313 insertions(+) create mode 100644 drivers/base/dma-buf-test.c diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index e373671652b0..bed2abb9491b 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -200,6 +200,10 @@ config DMA_SHARED_BUFFER APIs extension; the file's descriptor can then be passed on to other driver. +config DMA_BUF_TEST + tristate "DMA-BUF test module" + depends on DMA_SHARED_BUFFER + config DMA_CMA bool "DMA Contiguous Memory Allocator" depends on HAVE_DMA_CONTIGUOUS && CMA diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 94e8a80e87f8..cad983b6626f 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_PINCTRL) += pinctrl.o ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG +obj-$(CONFIG_DMA_BUF_TEST) += dma-buf-test.o diff --git a/drivers/base/dma-buf-test.c b/drivers/base/dma-buf-test.c new file mode 100644 index 000000000000..f5498b74a09b --- /dev/null +++ b/drivers/base/dma-buf-test.c @@ -0,0 +1,308 @@ +#include <linux/dma-buf.h> +#include <linux/err.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +struct dmabuf_create { + __u32 flags; + __u32 size; +}; + +#define DMABUF_IOCTL_BASE 'D' +#define DMABUF_IOCTL_CREATE _IOWR(DMABUF_IOCTL_BASE, 0, struct dmabuf_create) +#define DMABUF_IOCTL_DELETE _IOWR(DMABUF_IOCTL_BASE, 1, int) +#define DMABUF_IOCTL_EXPORT _IOWR(DMABUF_IOCTL_BASE, 2, int) + +struct dmabuf_file { + struct dma_buf *buf; + dma_addr_t phys; + size_t size; + void *virt; +}; + +static int dmabuf_attach(struct dma_buf *buf, struct device *dev, + struct dma_buf_attachment *attach) +{ + return 0; +} + +static void dmabuf_detach(struct dma_buf *buf, + struct dma_buf_attachment *attach) +{ +} + +static struct sg_table *dmabuf_map_dma_buf(struct dma_buf_attachment *attach, + enum dma_data_direction dir) +{ + struct dmabuf_file *priv = attach->dmabuf->priv; + struct sg_table *sgt; + + sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); + if (!sgt) + return NULL; + + if (sg_alloc_table(sgt, 1, GFP_KERNEL)) { + kfree(sgt); + return NULL; + } + + sg_dma_address(sgt->sgl) = priv->phys; + sg_dma_len(sgt->sgl) = priv->size; + + return sgt; +} + +static void dmabuf_unmap_dma_buf(struct dma_buf_attachment *attach, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + sg_free_table(sgt); + kfree(sgt); +} + +static void dmabuf_release(struct dma_buf *buf) +{ +} + +static int dmabuf_begin_cpu_access(struct dma_buf *buf, size_t size, + size_t length, + enum dma_data_direction direction) +{ + return 0; +} + +static void dmabuf_end_cpu_access(struct dma_buf *buf, size_t size, + size_t length, + enum dma_data_direction direction) +{ +} + +static void *dmabuf_kmap_atomic(struct dma_buf *buf, unsigned long page) +{ + return NULL; +} + +static void dmabuf_kunmap_atomic(struct dma_buf *buf, unsigned long page, + void *vaddr) +{ +} + +static void *dmabuf_kmap(struct dma_buf *buf, unsigned long page) +{ + return NULL; +} + +static void dmabuf_kunmap(struct dma_buf *buf, unsigned long page, void *vaddr) +{ +} + +static void dmabuf_vm_open(struct vm_area_struct *vma) +{ +} + +static void dmabuf_vm_close(struct vm_area_struct *vma) +{ +} + +static int dmabuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + return 0; +} + +static const struct vm_operations_struct dmabuf_vm_ops = { + .open = dmabuf_vm_open, + .close = dmabuf_vm_close, + .fault = dmabuf_vm_fault, +}; + +static int dmabuf_mmap(struct dma_buf *buf, struct vm_area_struct *vma) +{ + pgprot_t prot = vm_get_page_prot(vma->vm_flags); + struct dmabuf_file *priv = buf->priv; + + vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_ops = &dmabuf_vm_ops; + vma->vm_private_data = priv; + vma->vm_page_prot = pgprot_writecombine(prot); + + return remap_pfn_range(vma, vma->vm_start, priv->phys >> PAGE_SHIFT, + vma->vm_end - vma->vm_start, vma->vm_page_prot); +} + +static void *dmabuf_vmap(struct dma_buf *buf) +{ + return NULL; +} + +static void dmabuf_vunmap(struct dma_buf *buf, void *vaddr) +{ +} + +static const struct dma_buf_ops dmabuf_ops = { + .attach = dmabuf_attach, + .detach = dmabuf_detach, + .map_dma_buf = dmabuf_map_dma_buf, + .unmap_dma_buf = dmabuf_unmap_dma_buf, + .release = dmabuf_release, + .begin_cpu_access = dmabuf_begin_cpu_access, + .end_cpu_access = dmabuf_end_cpu_access, + .kmap_atomic = dmabuf_kmap_atomic, + .kunmap_atomic = dmabuf_kunmap_atomic, + .kmap = dmabuf_kmap, + .kunmap = dmabuf_kunmap, + .mmap = dmabuf_mmap, + .vmap = dmabuf_vmap, + .vunmap = dmabuf_vunmap, +}; + +static int dmabuf_file_open(struct inode *inode, struct file *file) +{ + struct dmabuf_file *priv; + int ret = 0; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + file->private_data = priv; + + return ret; +} + +static int dmabuf_file_release(struct inode *inode, struct file *file) +{ + struct dmabuf_file *priv = file->private_data; + int ret = 0; + + if (priv->virt) + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + + if (priv->buf) + dma_buf_put(priv->buf); + + kfree(priv); + + return ret; +} + +static int dmabuf_ioctl_create(struct dmabuf_file *priv, const void __user *data) +{ + struct dmabuf_create args; + int ret = 0; + + if (priv->buf || priv->virt) + return -EBUSY; + + if (copy_from_user(&args, data, sizeof(args))) + return -EFAULT; + + priv->virt = dma_alloc_writecombine(NULL, args.size, &priv->phys, + GFP_KERNEL | __GFP_NOWARN); + if (!priv->virt) + return -ENOMEM; + + priv->buf = dma_buf_export(priv, &dmabuf_ops, args.size, args.flags); + if (!priv->buf) { + ret = -ENOMEM; + goto free; + } + + if (IS_ERR(priv->buf)) { + ret = PTR_ERR(priv->buf); + goto free; + } + + priv->size = args.size; + + return 0; + +free: + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + priv->virt = NULL; + return ret; +} + +static int dmabuf_ioctl_delete(struct dmabuf_file *priv, unsigned long flags) +{ + dma_free_writecombine(NULL, priv->size, priv->virt, priv->phys); + priv->virt = NULL; + priv->phys = 0; + priv->size = 0; + + dma_buf_put(priv->buf); + priv->buf = NULL; + + return 0; +} + +static int dmabuf_ioctl_export(struct dmabuf_file *priv, unsigned long flags) +{ + int err; + + get_dma_buf(priv->buf); + + err = dma_buf_fd(priv->buf, flags); + if (err < 0) + dma_buf_put(priv->buf); + + return err; +} + +static long dmabuf_file_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct dmabuf_file *priv = file->private_data; + long ret = 0; + + switch (cmd) { + case DMABUF_IOCTL_CREATE: + ret = dmabuf_ioctl_create(priv, (const void __user *)arg); + break; + + case DMABUF_IOCTL_DELETE: + ret = dmabuf_ioctl_delete(priv, arg); + break; + + case DMABUF_IOCTL_EXPORT: + ret = dmabuf_ioctl_export(priv, arg); + break; + + default: + ret = -ENOTTY; + break; + } + + return ret; +} + +static const struct file_operations dmabuf_fops = { + .owner = THIS_MODULE, + .open = dmabuf_file_open, + .release = dmabuf_file_release, + .unlocked_ioctl = dmabuf_file_ioctl, +}; + +static struct miscdevice dmabuf_device = { + .minor = 128, + .name = "dmabuf", + .fops = &dmabuf_fops, +}; + +static int __init dmabuf_init(void) +{ + return misc_register(&dmabuf_device); +} +module_init(dmabuf_init); + +static void __exit dmabuf_exit(void) +{ + misc_deregister(&dmabuf_device); +} +module_exit(dmabuf_exit); + +MODULE_AUTHOR("Thierry Reding <treding(a)nvidia.com>"); +MODULE_DESCRIPTION("DMA-BUF test driver"); +MODULE_LICENSE("GPL v2"); -- 1.8.4.2

10 years, 9 months

[PATCH v6 00/11] reserved-memory regions/CMA in devicetree, again

by Marek Szyprowski

Hello again! Here is another update of the support for reserved memory regions in device tree. I've fixes a few more minor issues pointed by Grant. See changelog for more details. The initial code for this feature were posted here [1], merged as commit 9d8eab7af79cb4ce2de5de39f82c455b1f796963 ("drivers: of: add initialization code for dma reserved memory") and later reverted by commit 1931ee143b0ab72924944bc06e363d837ba05063. For more information, see [2]. Finally a new bindings has been proposed [3] and Josh Cartwright a few days ago prepared some code which implements those bindings [4]. This finally pushed me again to find some time to finish this task and review the code. Josh agreed to give me the ownership of this series to continue preparing them for mainline inclusion. For more information please refer to the changlelog and links below. [1]: http://lkml.kernel.org/g/1377527959-5080-1-git-send-email-m.szyprowski@sams… [2]: http://lkml.kernel.org/g/1381476448-14548-1-git-send-email-m.szyprowski@sam… [3]: http://lkml.kernel.org/g/20131030134702.19B57C402A0@trevor.secretlab.ca [4]: http://thread.gmane.org/gmane.linux.documentation/19579 Changelog: v6: - removed the need for "#memory-region-cells" property - fixed compilation issues on some systems - some other minor code cleanups v5: https://lkml.org/lkml/2014/2/21/147 - sliced main patch into several smaller patches on Grant's request - fixed coding style issues pointed by Grant - use node->phandle value directly instead of parsing properties manually v4: https://lkml.org/lkml/2014/2/20/150 - dynamic allocations are processed after all static reservations has been done - moved code for handling static reservations to drivers/of/fdt.c - removed node matching by string comparison, now phandle values are used directly - moved code for DMA and CMA handling directly to drivers/base/dma-{coherent,contiguous}.c - added checks for proper #size-cells, #address-cells, ranges properties in /reserved-memory node - even more code cleanup - added init code for ARM64 and PowerPC v3: http://article.gmane.org/gmane.linux.documentation/20169/ - refactored memory reservation code, created common code to parse reg, size, align, alloc-ranges properties - added support for multiple tuples in 'reg' property - memory is reserved regardless of presence of the driver for its compatible - prepared arch specific hooks for memory reservation (defaults use memblock calls) - removed node matching by string during device initialization - CMA init code: added checks for required region alignment - more code cleanup here and there v2: http://thread.gmane.org/gmane.linux.documentation/19870/ - removed copying of the node name - split shared-dma-pool handling into separate files (one for CMA and one for dma_declare_coherent based implementations) for making the code easier to understand - added support for AMBA devices, changed prototypes to use struct decice instead of struct platform_device - renamed some functions to better match other names used in drivers/of/ - restructured the rest of the code a bit for better readability - added 'reusable' property to exmaple linux,cma node in documentation - exclusive dma (dma_coherent) is used for only handling 'shared-dma-pool' regions without 'reusable' property and CMA is used only for handling 'shared-dma-pool' regions with 'reusable' property. v1: http://thread.gmane.org/gmane.linux.documentation/19579 - initial version prepared by Josh Cartwright Summary: Grant Likely (1): of: document bindings for reserved-memory nodes Marek Szyprowski (10): drivers: of: add initialization code for static reserved memory drivers: of: add initialization code for dynamic reserved memory drivers: of: add support for custom reserved memory drivers drivers: of: add automated assignment of reserved regions to client devices drivers: of: initialize and assign reserved memory to newly created devices drivers: dma-coherent: add initialization from device tree drivers: dma-contiguous: add initialization from device tree arm: add support for reserved memory defined by device tree arm64: add support for reserved memory defined by device tree powerpc: add support for reserved memory defined by device tree .../bindings/reserved-memory/reserved-memory.txt | 136 ++++++++++ arch/arm/Kconfig | 1 + arch/arm/mm/init.c | 2 + arch/arm64/Kconfig | 1 + arch/arm64/mm/init.c | 1 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/prom.c | 3 + drivers/base/dma-coherent.c | 40 +++ drivers/base/dma-contiguous.c | 129 +++++++-- drivers/of/Kconfig | 6 + drivers/of/Makefile | 1 + drivers/of/fdt.c | 140 ++++++++++ drivers/of/of_reserved_mem.c | 287 ++++++++++++++++++++ drivers/of/platform.c | 7 + include/asm-generic/vmlinux.lds.h | 11 + include/linux/of_fdt.h | 3 + include/linux/of_reserved_mem.h | 60 ++++ 17 files changed, 807 insertions(+), 22 deletions(-) create mode 100644 Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt create mode 100644 drivers/of/of_reserved_mem.c create mode 100644 include/linux/of_reserved_mem.h -- 1.7.9.5

10 years, 9 months

[PATCH 0/6] dma-buf synchronization patches

by Maarten Lankhorst

The following series implements fence and converts dma-buf and android sync to use it. Patch 6 and 7 add support for polling to dma-buf, blocking until all fences are signaled. I've dropped the extra patch to copy an export from the core, and instead use the public version of it. I've had to fix some fallout from the rebase, hopefully everything's clean now, and ready for -next. --- Maarten Lankhorst (6): fence: dma-buf cross-device synchronization (v17) seqno-fence: Hardware dma-buf implementation of fencing (v4) dma-buf: use reservation objects android: convert sync to fence api, v3 reservation: add support for fences to enable cross-device synchronisation dma-buf: add poll support, v2 Documentation/DocBook/device-drivers.tmpl | 3 drivers/base/Kconfig | 9 drivers/base/Makefile | 2 drivers/base/dma-buf.c | 123 +++ drivers/base/fence.c | 465 +++++++++++++ drivers/gpu/drm/drm_prime.c | 8 drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 2 drivers/gpu/drm/i915/i915_gem_dmabuf.c | 2 drivers/gpu/drm/nouveau/nouveau_drm.c | 1 drivers/gpu/drm/nouveau/nouveau_gem.h | 1 drivers/gpu/drm/nouveau/nouveau_prime.c | 7 drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 drivers/gpu/drm/radeon/radeon_drv.c | 2 drivers/gpu/drm/radeon/radeon_prime.c | 8 drivers/gpu/drm/ttm/ttm_object.c | 2 drivers/media/v4l2-core/videobuf2-dma-contig.c | 2 drivers/staging/android/Kconfig | 1 drivers/staging/android/Makefile | 2 drivers/staging/android/sw_sync.c | 4 drivers/staging/android/sync.c | 892 ++++++++---------------- drivers/staging/android/sync.h | 80 +- drivers/staging/android/sync_debug.c | 245 +++++++ drivers/staging/android/trace/sync.h | 12 include/drm/drmP.h | 2 include/linux/dma-buf.h | 21 - include/linux/fence.h | 329 +++++++++ include/linux/reservation.h | 18 include/linux/seqno-fence.h | 109 +++ include/trace/events/fence.h | 125 +++ 29 files changed, 1822 insertions(+), 657 deletions(-) create mode 100644 drivers/base/fence.c create mode 100644 drivers/staging/android/sync_debug.c create mode 100644 include/linux/fence.h create mode 100644 include/linux/seqno-fence.h create mode 100644 include/trace/events/fence.h -- Signature

10 years, 9 months

Re: [Linaro-mm-sig] [PATCH 2/6] seqno-fence: Hardware dma-buf implementation of fencing (v4)

by Maarten Lankhorst

op 17-02-14 19:41, Christian König schreef: > Am 17.02.2014 19:24, schrieb Rob Clark: >> On Mon, Feb 17, 2014 at 12:36 PM, Christian König >> <deathsimple(a)vodafone.de> wrote: >>> Am 17.02.2014 18:27, schrieb Rob Clark: >>> >>>> On Mon, Feb 17, 2014 at 11:56 AM, Christian König >>>> <deathsimple(a)vodafone.de> wrote: >>>>> Am 17.02.2014 16:56, schrieb 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. >>>>> >>>>> Can't we make that just "dma_buf[offset] != 0" instead? As far as I know >>>>> this way it would match the definition M$ uses in their WDDM >>>>> specification >>>>> and so make it much more likely that hardware supports it. >>>> well 'buf[offset] >= value' at least means the same slot can be used >>>> for multiple operations (with increasing values of 'value').. not sure >>>> if that is something people care about. >>>> >>>>> =value seems to be possible with adreno and radeon. I'm not really sure >>>>> about others (although I presume it as least supported for nv desktop >>>>> stuff). For hw that cannot do >=value, we can either have a different fence >>>>> implementation which uses the !=0 approach. Or change seqno-fence >>>>> implementation later if needed. But if someone has hw that can do !=0 but >>>>> not >=value, speak up now ;-) >>> >>> Here! Radeon can only do >=value on the DMA and 3D engine, but not with UVD >>> or VCE. And for the 3D engine it means draining the pipe, which isn't really >>> a good idea. >> hmm, ok.. forgot you have a few extra rings compared to me. Is UVD >> re-ordering from decode-order to display-order for you in hw? If not, >> I guess you need sw intervention anyways when a frame is done for >> frame re-ordering, so maybe hw->hw sync doesn't really matter as much >> as compared to gpu/3d->display. For dma<->3d interactions, seems like >> you would care more about hw<->hw sync, but I guess you aren't likely >> to use GPU A to do a resolve blit for GPU B.. > > No UVD isn't reordering, but since frame reordering is predictable you usually end up with pipelining everything to the hardware. E.g. you send the decode commands in decode order to the UVD block and if you have overlay active one of the frames are going to be the first to display and then you want to wait for it on the display side. > >> For 3D ring, I assume you probably want a CP_WAIT_FOR_IDLE before a >> CP_MEM_WRITE to update fence value in memory (for the one signalling >> the fence). But why would you need that before a CP_WAIT_REG_MEM (for >> the one waiting for the fence)? I don't exactly have documentation >> for adreno version of CP_WAIT_REG_{MEM,EQ,GTE}.. but PFP and ME >> appear to be same instruction set as r600, so I'm pretty sure they >> should have similar capabilities.. CP_WAIT_REG_MEM appears to be same >> but with 32bit gpu addresses vs 64b. > > You shouldn't use any of the CP commands for engine synchronization (neither for wait nor for signal). The PFP and ME are just the top of a quite deep pipeline and when you use any of the CP_WAIT functions you block them for something and that's draining the pipeline. > > With the semaphore and fence commands the values are just attached as prerequisite to the draw command, e.g. the CP setups the draw environment and issues the command, but the actual execution of it is delayed until the "!= 0" condition hits. And in the meantime the CP already prepares the next draw operation. > > But at least for compute queues wait semaphore aren't the perfect solution either. What you need then is a GPU scheduler that uses a kernel task for setting up the command submission for you when all prerequisites are meet. nouveau has sort of a scheduler in hardware. It can yield when waiting on a semaphore. And each process gets their own context and the timeslices can be adjusted. ;-) But I don't mind changing this patch when an actual user pops up. Nouveau can do a wait for (*sema & mask) != 0 only on nvc0 and newer, where mask can be chosen. But it can do == somevalue and >= somevalue on older relevant optimus hardware, so if we know that it was zero before and we know the sign of the new value that could work too. Adding ops and a separate mask later on when users pop up is fine with me, the original design here was chosen so I could map the intel status page read-only into the process specific nvidia vm. ~Maarten

10 years, 9 months

How to manage cached dmabuf importer private data?

by Hiroshi Doyu

Hi, We have a problem about how to manage cached dmabuf importer private data, where to keep, how to reuse and how to clean up. We want to keep some data in dmabuf importer side until an buffer is free'ed actually since a buffer can be reused again later in that importer subsystem so that that cache data doesn't have to be regenerated. This can be considered as some kind of caching this data. The scenario is: (1) Exporter passes a dmabuf to Importer. (2) Importer attaches a dev to a dmabuf. (3) Importer generates some data for a buffer for its own use. (4) Importer finishes its use of a buffer. (5) Importer detaches a dev from a dmabuf. (6) Again, Exporter passes a dmabuf fd to the same Importer. (7) Again, Importer attaches a dev to a dmabuf. (8) Importer wants to use the previously cached data from (2) without regenerating. (9) Again, Importer detaches a dev from a dmabuf. (10) Exporter free's a buffer along with a cached data from (2)/(8). At first I considered to use attachmenet private data, but apparently a life time of the attachment isn't equal to one of a buffer. A buffer lives longer than an attachment. Also Neither private data from dmabuf nor from attachment are for /Importer/. They are for Exporter's use from the comment in the header file. /** * struct dma_buf - shared buffer object .... * @priv: exporter specific private data for this buffer object. */ /** * struct dma_buf_attachment - holds device-buffer attachment data ... * @priv: exporter specific attachment data. ... */ This leads to the following 2 questions: One question is how to clean up the cached data at (10) since there's no way for Importer to trigger clean up at that time. I am considering to embed an /notifier/ in dmabuf when it's called at dmabuf release. Importer could register any callback in that notifier. At least this requires a dmabuf to have an notifier to be called at release. Does this sound acceptable? Or can we do the same outside of dmabuf framework? If there's more appropriate way, please let me know since I'm not so familier with drm side yet. Another question is where to keep that cached data. Usually that data is only valid within Impoter subsystem. So Imoporter could keep the list of that data in it as a global list along with a dmabuf pointer. When a dmabuf is imported, Importer can look up a global list if it's already cached. This list needs to be kept till a buffer is free'ed. Those can be implemented in the dmabuf exporter backend but we want to allow multiple allocators/exporters to do the same, and I want to avoid having something related to importer in exporter side. Any comment would be really appreciated.

10 years, 9 months

[PATCH v5 00/11] reserved-memory regions/CMA in devicetree, again

by Marek Szyprowski

Hi all! Ok, I hope that this is the last update of the patches which add basic support for dynamic allocation of memory reserved regions defined in device tree. This time I've mainly sliced the main patch into several smaller pieces to make the changes easier to understand and fixes some minor coding style issues. The initial code for this feature were posted here [1], merged as commit 9d8eab7af79cb4ce2de5de39f82c455b1f796963 ("drivers: of: add initialization code for dma reserved memory") and later reverted by commit 1931ee143b0ab72924944bc06e363d837ba05063. For more information, see [2]. Finally a new bindings has been proposed [3] and Josh Cartwright a few days ago prepared some code which implements those bindings [4]. This finally pushed me again to find some time to finish this task and review the code. Josh agreed to give me the ownership of this series to continue preparing them for mainline inclusion. For more information please refer to the changlelog and links below. [1]: http://lkml.kernel.org/g/1377527959-5080-1-git-send-email-m.szyprowski@sams… [2]: http://lkml.kernel.org/g/1381476448-14548-1-git-send-email-m.szyprowski@sam… [3]: http://lkml.kernel.org/g/20131030134702.19B57C402A0@trevor.secretlab.ca [4]: http://thread.gmane.org/gmane.linux.documentation/19579 Changelog: v5: - sliced main patch into several smaller patches on Grant's request - fixed coding style issues pointed by Grant - use node->phandle value directly instead of parsing properties manually v4: https://lkml.org/lkml/2014/2/20/150 - dynamic allocations are processed after all static reservations has been done - moved code for handling static reservations to drivers/of/fdt.c - removed node matching by string comparison, now phandle values are used directly - moved code for DMA and CMA handling directly to drivers/base/dma-{coherent,contiguous}.c - added checks for proper #size-cells, #address-cells, ranges properties in /reserved-memory node - even more code cleanup - added init code for ARM64 and PowerPC v3: http://article.gmane.org/gmane.linux.documentation/20169/ - refactored memory reservation code, created common code to parse reg, size, align, alloc-ranges properties - added support for multiple tuples in 'reg' property - memory is reserved regardless of presence of the driver for its compatible - prepared arch specific hooks for memory reservation (defaults use memblock calls) - removed node matching by string during device initialization - CMA init code: added checks for required region alignment - more code cleanup here and there v2: http://thread.gmane.org/gmane.linux.documentation/19870/ - removed copying of the node name - split shared-dma-pool handling into separate files (one for CMA and one for dma_declare_coherent based implementations) for making the code easier to understand - added support for AMBA devices, changed prototypes to use struct decice instead of struct platform_device - renamed some functions to better match other names used in drivers/of/ - restructured the rest of the code a bit for better readability - added 'reusable' property to exmaple linux,cma node in documentation - exclusive dma (dma_coherent) is used for only handling 'shared-dma-pool' regions without 'reusable' property and CMA is used only for handling 'shared-dma-pool' regions with 'reusable' property. v1: http://thread.gmane.org/gmane.linux.documentation/19579 - initial version prepared by Josh Cartwright Summary: Grant Likely (1): of: document bindings for reserved-memory nodes Marek Szyprowski (10): drivers: of: add initialization code for static reserved memory drivers: of: add initialization code for dynamic reserved memory drivers: of: add support for custom reserved memory drivers drivers: of: add automated assignment of reserved regions to client devices drivers: of: initialize and assign reserved memory to newly created devices drivers: dma-coherent: add initialization from device tree drivers: dma-contiguous: add initialization from device tree arm: add support for reserved memory defined by device tree arm64: add support for reserved memory defined by device tree powerpc: add support for reserved memory defined by device tree .../bindings/reserved-memory/reserved-memory.txt | 138 ++++++++++ arch/arm/Kconfig | 1 + arch/arm/mm/init.c | 2 + arch/arm64/Kconfig | 1 + arch/arm64/mm/init.c | 1 + arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/prom.c | 3 + drivers/base/dma-coherent.c | 41 +++ drivers/base/dma-contiguous.c | 130 +++++++-- drivers/of/Kconfig | 6 + drivers/of/Makefile | 1 + drivers/of/fdt.c | 134 +++++++++ drivers/of/of_reserved_mem.c | 291 ++++++++++++++++++++ drivers/of/platform.c | 7 + include/asm-generic/vmlinux.lds.h | 11 + include/linux/of_fdt.h | 3 + include/linux/of_reserved_mem.h | 61 ++++ 17 files changed, 810 insertions(+), 22 deletions(-) create mode 100644 Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt create mode 100644 drivers/of/of_reserved_mem.c create mode 100644 include/linux/of_reserved_mem.h -- 1.7.9.5

10 years, 9 months

Use of dma_buf_unmap_attachment in interrupt context?

by Hans Verkuil

A quick question: can dma_buf_unmap_attachment be called from interrupt context? It is the dmabuf equivalent to e.g. dma_sync_sg_for_cpu or dma_unmap_sg, and those can be called from interrupt context. I cannot see anything specific about this in the sources or dma-buf-sharing.txt. If it turns out that dma_buf_unmap_attachment can be called from atomic context, then that should be documented, I think. Regards, Hans

10 years, 9 months

CMA on AArch64

by Laura Abbott

Hi, I noticed there is currently no CMA support for AArch64. Is this already on someone's TODO list or is this still open? Thanks, Laura -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

10 years, 10 months

[PATCH 0/2] arm: dma-mapping: add dynamic resize of IOVA bitmap

by Marek Szyprowski

Hello, This patchset is a continuation of the work started by Andreas Herrmann to add support for dynamically resized bitmaps for IOMMU based DMA-mapping implementation for ARM architecture. Some more discussion and rationale has been discussed in the following thread: http://www.spinics.net/lists/arm-kernel/msg303732.html The first patch adds support for on-demand extending IO address space bitmap. It is based on the original work by Andreas Herrmann, but I decided to drop arm_iommu_create_mapping() api change part. The second patch removes the 'order' hack, which was used to reduce the size of a bitmap. The first patch solved the problem of too large io address space bitmaps, so the 'order' hack is no longer needed. The parameters of the arm_iommu_create_mapping() function can be then simplified by dropping 'order' parameter without any functional change of the whole subsystem. This parameter was already a bit misunderstood, so the overall result is also a little improvement of the API. Best regards Marek Szyprowski, PhD Samsung R&D Institute Poland Andreas Herrmann (1): arm: dma-mapping: Add support to extend DMA IOMMU mappings Marek Szyprowski (1): arm: dma-mapping: remove order parameter from arm_iommu_create_mapping() arch/arm/include/asm/dma-iommu.h | 12 ++- arch/arm/mm/dma-mapping.c | 144 +++++++++++++++++++++++------ drivers/gpu/drm/exynos/exynos_drm_drv.h | 2 - drivers/gpu/drm/exynos/exynos_drm_iommu.c | 6 +- drivers/gpu/drm/exynos/exynos_drm_iommu.h | 1 - drivers/iommu/shmobile-iommu.c | 2 +- 6 files changed, 124 insertions(+), 43 deletions(-) -- 1.7.9.5

10 years, 10 months

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Linaro-mm-sig February 2014