Devices sharing buffers using dma-buf could benefit from sharing their constraints via struct device, and dma-buf framework would manage the common constraints for all attached devices per buffer.

With that information, we could have a 'generic' allocator helper in the form of a central dma-buf exporter, which can create dma-bufs, and allocate backing storage at the time of first call to dma_buf_map_attachment.

This allocation would utilise the constraint-mask by matching it to the right allocator from a pool of allocators, and then allocating buffer backing storage from this allocator.

The pool of allocators could be platform-dependent, allowing for platforms to hide the specifics of these allocators from the devices that access the dma-buf buffers.

A sample sequence could be: - get handle to cenalloc_device, - create a dmabuf using cenalloc_buffer_create; - use this dmabuf to attach each device, which has its constraints set in the constraints mask (dev->dma_params->access_constraints_mask) - at each dma_buf_attach() call, dma-buf will check to see if the constraint mask for the device requesting attachment is compatible with the constraints of devices already attached to the dma-buf; returns an error if it isn't. - after all devices have attached, the first call to dma_buf_map_attachment() will allocate the backing storage for the buffer. - follow the dma-buf api for map / unmap etc usage. - detach all attachments, - call cenalloc_buffer_free to free the buffer if refcount reaches zero;

** IMPORTANT** This mechanism of delayed allocation based on constraint-enablement will work *ONLY IF* the first map_attachment() call is made AFTER all attach() calls are done.

Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Cc: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org --- MAINTAINERS | 1 + drivers/cenalloc/cenalloc.c | 597 +++++++++++++++++++++++++++++++++++++++ drivers/cenalloc/cenalloc.h | 99 +++++++ drivers/cenalloc/cenalloc_priv.h | 188 ++++++++++++ 4 files changed, 885 insertions(+) create mode 100644 drivers/cenalloc/cenalloc.c create mode 100644 drivers/cenalloc/cenalloc.h create mode 100644 drivers/cenalloc/cenalloc_priv.h

diff --git a/MAINTAINERS b/MAINTAINERS index 40d4796..e88ac81 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3039,6 +3039,7 @@ L: linux-media@vger.kernel.org L: dri-devel@lists.freedesktop.org L: linaro-mm-sig@lists.linaro.org F: drivers/dma-buf/ +F: drivers/cenalloc/ F: include/linux/dma-buf* F: include/linux/reservation.h F: include/linux/*fence.h diff --git a/drivers/cenalloc/cenalloc.c b/drivers/cenalloc/cenalloc.c new file mode 100644 index 0000000..f278056 --- /dev/null +++ b/drivers/cenalloc/cenalloc.c @@ -0,0 +1,597 @@ +/* + * Allocator helper framework for constraints-aware dma-buf backing storage + * allocation. + * This allows constraint-sharing devices to deferred-allocate buffers shared + * via dma-buf. + * + * Copyright(C) 2014 Linaro Limited. All rights reserved. + * Author: Sumit Semwal sumit.semwal@linaro.org + * + * Structure for management of clients, buffers etc heavily derived from + * Android's ION framework. + * + * 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see http://www.gnu.org/licenses/. + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/rbtree.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/debugfs.h> +#include <linux/module.h> + +#include "cenalloc.h" +#include "cenalloc_priv.h" + +/* + * Constraints-aware allocator framework helper is meant to facilitate + * deferred allocation of backing storage for dma-buf buffers. + * It works for devices that can share their constraints via dma_params. + * These dma_params are then used by dma_buf_attach() to create a mask of + * common constraints. The cenalloc constraint helpers then allocate + * for the preferred allocator according to the constraint mask. + * Allocators and their corresponding constraint masks are pre-populated + * for a given system - likely at the time of platform initialization. + */ +/** + * struct cenalloc_device - the metadata of the cenalloc device node + * @dev: the actual misc device + * @buffers: an rb tree of all the existing buffers + * @buffer_lock: lock protecting the tree of buffers & handles + * @lock: rwsem protecting the tree of allocators + * @clients: list of all the clients created + * @allocators: list of all the allocators in the system + */ +struct cenalloc_device { + struct miscdevice dev; + struct rb_root buffers; + + struct mutex buffer_lock; + struct rw_semaphore lock; + + struct plist_head allocators; + +}; + + +/* this function should only be called while dev->buffer_lock is held */ +static void cenalloc_buffer_add(struct cenalloc_device *dev, + struct cenalloc_buffer *buffer) +{ + struct rb_node **p = &dev->buffers.rb_node; + struct rb_node *parent = NULL; + struct cenalloc_buffer *entry; + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct cenalloc_buffer, node); + + if (buffer < entry) { + p = &(*p)->rb_left; + } else if (buffer > entry) { + p = &(*p)->rb_right; + } else { + pr_err("%s: buffer already found.", __func__); + BUG(); + } + } + + rb_link_node(&buffer->node, parent, p); + rb_insert_color(&buffer->node, &dev->buffers); +} + +static struct dma_buf_ops ca_dma_buf_ops; + +static bool is_cenalloc_buffer(struct dma_buf *dmabuf); + +/* + * cenalloc_buffer_create creates a buffer, exports the dma-buf handle and + * associates a dma-buf handle with it. + * Returns: + * on success, pointer to the associated dma_buf; + * error if dma-buf cannot be exported or if it is out of memory. + */ +struct dma_buf *cenalloc_buffer_create(struct cenalloc_device *dev, + unsigned long len, + unsigned long align, + unsigned long flags) +{ + struct cenalloc_buffer *buffer; + struct dma_buf *dmabuf; + + buffer = kzalloc(sizeof(struct cenalloc_buffer), GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + + buffer->flags = flags; + kref_init(&buffer->ref); + + buffer->dev = dev; + buffer->size = len; + buffer->align = align; + + dmabuf = dma_buf_export(buffer, &ca_dma_buf_ops, buffer->size, O_RDWR, + NULL); + if (IS_ERR(dmabuf)) + goto err; + + buffer->dmabuf = dmabuf; + dmabuf->priv = buffer; + + mutex_init(&buffer->lock); + + mutex_lock(&dev->buffer_lock); + cenalloc_buffer_add(dev, buffer); + mutex_unlock(&dev->buffer_lock); + + return dmabuf; + +err: + kfree(buffer); + return ERR_CAST(dmabuf); +} +EXPORT_SYMBOL_GPL(cenalloc_buffer_create); + + +static void cenalloc_buffer_destroy(struct cenalloc_buffer *buffer) +{ + if (WARN_ON(buffer->kmap_cnt > 0)) + buffer->allocator->ops->unmap_kernel(buffer->allocator, buffer); + buffer->allocator->ops->unmap_dma(buffer->allocator, buffer); + buffer->allocator->ops->free(buffer); + kfree(buffer); +} + +static void _cenalloc_buffer_destroy(struct cenalloc_buffer *buffer) +{ + struct cenalloc_device *dev = buffer->dev; + + mutex_lock(&dev->buffer_lock); + rb_erase(&buffer->node, &dev->buffers); + mutex_unlock(&dev->buffer_lock); + + cenalloc_buffer_destroy(buffer); +} + +void cenalloc_buffer_free(struct dma_buf *dmabuf) +{ + if (is_cenalloc_buffer(dmabuf)) + dma_buf_put(dmabuf); +} +EXPORT_SYMBOL_GPL(cenalloc_buffer_free); + +int cenalloc_phys(struct dma_buf *dmabuf, + phys_addr_t *addr, size_t *len) +{ + struct cenalloc_buffer *buffer; + int ret; + + if (is_cenalloc_buffer(dmabuf)) + buffer = (struct cenalloc_buffer *)dmabuf->priv; + else + return -EINVAL; + + if (!buffer->allocator->ops->phys) { + pr_err("%s: cenalloc_phys is not implemented by this allocator.\n", + __func__); + return -ENODEV; + } + mutex_lock(&buffer->lock); + ret = buffer->allocator->ops->phys(buffer->allocator, buffer, addr, + len); + mutex_lock(&buffer->lock); + return ret; +} +EXPORT_SYMBOL_GPL(cenalloc_phys); + +static void *cenalloc_buffer_kmap_get(struct cenalloc_buffer *buffer) +{ + void *vaddr; + + if (buffer->kmap_cnt) { + buffer->kmap_cnt++; + return buffer->vaddr; + } + vaddr = buffer->allocator->ops->map_kernel(buffer->allocator, buffer); + if (WARN_ONCE(vaddr == NULL, + "allocator->ops->map_kernel should return ERR_PTR on error")) + return ERR_PTR(-EINVAL); + if (IS_ERR(vaddr)) + return vaddr; + buffer->vaddr = vaddr; + buffer->kmap_cnt++; + return vaddr; +} + +static void cenalloc_buffer_kmap_put(struct cenalloc_buffer *buffer) +{ + buffer->kmap_cnt--; + if (!buffer->kmap_cnt) { + buffer->allocator->ops->unmap_kernel(buffer->allocator, buffer); + buffer->vaddr = NULL; + } +} + +struct sg_table *cenalloc_sg_table(struct dma_buf *dmabuf) +{ + struct sg_table *table; + struct cenalloc_buffer *buffer; + + if (is_cenalloc_buffer(dmabuf)) + buffer = (struct cenalloc_buffer *)dmabuf->priv; + else { + pr_err("%s: invalid buffer passed to sg_table.\n", + __func__); + return ERR_PTR(-EINVAL); + } + + mutex_lock(&buffer->lock); + table = buffer->sg_table; + mutex_unlock(&buffer->lock); + return table; +} +EXPORT_SYMBOL_GPL(cenalloc_sg_table); + +/* + * dma_buf ops implementation + */ + +static void cenalloc_buffer_sync_for_device(struct cenalloc_buffer *buffer, + struct device *dev, + enum dma_data_direction direction); + +/* + * This will find the right allocator for the buffer passed; + * assumption is, that all the interested importers have called dma_buf_attach() + * with their right constraint masks before the first call to + * dma_buf_map_attachment(). + * At present, using the same priority based mechanism as ION. + */ +static int cenalloc_find_allocator(struct cenalloc_device *dev, + struct cenalloc_buffer *buf) +{ + struct cenalloc_allocator *allocator; + unsigned long constraints_mask = buf->dmabuf->access_constraints_mask; + size_t len = buf->size; + + /* + * traverse the list of allocators available in this system in priority + * order. If the allocator type is supported by the client, and matches + * the request of the caller allocate from it. Repeat until allocate + * has succeeded or all allocators have been tried. + */ + len = PAGE_ALIGN(len); + + if (!len) + return -EINVAL; + + plist_for_each_entry(allocator, &dev->allocators, node) { + /* if the caller didn't specify this allocator id */ + if (!((1 << allocator->id) & constraints_mask)) + continue; + buf->allocator = allocator; + } + + if (buf->allocator == NULL) + return -ENODEV; + + return 0; +} + +static struct sg_table *cenalloc_buffer_first_alloc( + struct cenalloc_buffer *buffer) +{ + struct cenalloc_allocator *allocator = buffer->allocator; + struct sg_table *table; + + int num_pages = PAGE_ALIGN(buffer->size) / PAGE_SIZE; + struct scatterlist *sg; + int ret, i, j, k = 0; + + mutex_lock(&buffer->lock); + ret = cenalloc_find_allocator(buffer->dev, buffer); + + if (ret) { + mutex_unlock(&buffer->lock); + return ERR_PTR(-ENODEV); + } + + ret = allocator->ops->allocate(allocator, buffer, buffer->size, + buffer->align, buffer->flags); + if (ret) + goto cannot_allocate; + + table = allocator->ops->map_dma(allocator, buffer); + if (WARN_ONCE(table == NULL, + "allocator->ops->map_dma should return ERR_PTR on error")) + table = ERR_PTR(-EINVAL); + + if (IS_ERR(table)) { + /* TODO: find the right way to handle an error here? */ + allocator->ops->free(buffer); + + mutex_unlock(&buffer->lock); + return ERR_CAST(table); + } + + buffer->pages = vmalloc(sizeof(struct page *) * num_pages); + if (!buffer->pages) { + ret = -ENOMEM; + goto cannot_allocate; + } + + for_each_sg(table->sgl, sg, table->nents, i) { + struct page *page = sg_page(sg); + + for (j = 0; j < sg->length / PAGE_SIZE; j++) + buffer->pages[k++] = page++; + } + + mutex_unlock(&buffer->lock); + + return table; + +cannot_allocate: + mutex_unlock(&buffer->lock); + return ERR_PTR(ret); +} + +static void cenalloc_buffer_sync_for_device(struct cenalloc_buffer *buffer, + struct device *dev, + enum dma_data_direction dir) +{ + + if (!buffer->allocator->ops->sync_for_device) { + pr_err("%s: this allocator does not define a method for sync-to-device\n", + __func__); + return; + } + + buffer->allocator->ops->sync_for_device(buffer->allocator, buffer, dev, + dir); + +} + +/* + * cenalloc_map_dma_buf() models delayed allocation; so if the buffer is not + * backed up by storage, the allocation shall happen here for the first time, + * based on the constraint_mask of the dma_buf, which is set based on devices + * currently attached to the dma_buf. + * + * IMP: Assumption is that all participating devices call dma_buf_attach() + * before the first dma_buf_map_attachment() is called. + * + * Migration is not supported at this time. + */ +static struct sg_table *cenalloc_map_dma_buf(struct dma_buf_attachment *attach, + enum dma_data_direction direction) +{ + struct dma_buf *dmabuf = attach->dmabuf; + struct cenalloc_buffer *buffer = dmabuf->priv; + struct sg_table *table = NULL; + + if (!buffer->sg_table) { + down_read(&(buffer->dev->lock)); + table = cenalloc_buffer_first_alloc(buffer); + up_read(&(buffer->dev->lock)); + if (IS_ERR(table)) + return table; + } + + mutex_lock(&buffer->lock); + buffer->sg_table = table; + + cenalloc_buffer_sync_for_device(buffer, attach->dev, direction); + mutex_unlock(&buffer->lock); + + return buffer->sg_table; + +} + +static void cenalloc_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + struct dma_buf *dmabuf = attachment->dmabuf; + struct cenalloc_buffer *buffer = dmabuf->priv; + + buffer->allocator->ops->unmap_dma(buffer->allocator, buffer); +} + +static int cenalloc_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{ + struct cenalloc_buffer *buffer = dmabuf->priv; + int ret = 0; + + if (!buffer->sg_table) { + pr_err( + "%s: buffer needs to be mapped first before userspace mapping\n", + __func__); + return -EINVAL; + } + + if (!buffer->allocator->ops->map_user) { + pr_err( + "%s: allocator does not define a method for userspace mapping\n", + __func__); + return -EINVAL; + } + + /* + * NOTE: For now, assume that the allocators will take care of any VMA + * management for the buffer - includes providing vma_ops, and / or + * managing mmap faults. + * struct cenalloc_buffer will still provide struct **pages, + * and also the vma area list for the buffer. + * This also allows for device-specific vma operations. + * + */ + + mutex_lock(&buffer->lock); + /* now map it to userspace */ + ret = buffer->allocator->ops->map_user(buffer->allocator, buffer, vma); + mutex_unlock(&buffer->lock); + + if (ret) + pr_err("%s: failure mapping buffer to userspace\n", + __func__); + + return ret; +} + +static void cenalloc_dma_buf_release(struct dma_buf *dmabuf) +{ + struct cenalloc_buffer *buffer = dmabuf->priv; + + _cenalloc_buffer_destroy(buffer); +} + + +static void *cenalloc_dma_buf_kmap(struct dma_buf *dmabuf, unsigned long offset) +{ + struct cenalloc_buffer *buffer = dmabuf->priv; + + return buffer->vaddr + offset * PAGE_SIZE; +} + +static void cenalloc_dma_buf_kunmap(struct dma_buf *dmabuf, + unsigned long offset, + void *ptr) +{ + /* TODO */ +} + +static int cenalloc_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, + size_t start, size_t len, + enum dma_data_direction dir) +{ + struct cenalloc_buffer *buffer = dmabuf->priv; + void *vaddr; + + if (!buffer->allocator->ops->map_kernel) { + pr_err("%s: map kernel is not implemented by this allocator.\n", + __func__); + return -ENODEV; + } + + mutex_lock(&buffer->lock); + vaddr = cenalloc_buffer_kmap_get(buffer); + mutex_unlock(&buffer->lock); + return PTR_ERR_OR_ZERO(vaddr); +} + +static void cenalloc_dma_buf_end_cpu_access(struct dma_buf *dmabuf, + size_t start, size_t len, + enum dma_data_direction dir) +{ + struct cenalloc_buffer *buffer = dmabuf->priv; + + mutex_lock(&buffer->lock); + cenalloc_buffer_kmap_put(buffer); + mutex_unlock(&buffer->lock); +} + +static struct dma_buf_ops ca_dma_buf_ops = { + .map_dma_buf = cenalloc_map_dma_buf, + .unmap_dma_buf = cenalloc_unmap_dma_buf, + .mmap = cenalloc_mmap, + .release = cenalloc_dma_buf_release, + .begin_cpu_access = cenalloc_dma_buf_begin_cpu_access, + .end_cpu_access = cenalloc_dma_buf_end_cpu_access, + .kmap = cenalloc_dma_buf_kmap, + .kunmap = cenalloc_dma_buf_kunmap, +}; + +static bool is_cenalloc_buffer(struct dma_buf *dmabuf) +{ + return(dmabuf->ops == &ca_dma_buf_ops); +} + +/** + * cenalloc_device_add_allocator: + * Adds an allocator to the cenalloc_device; This should be called at + * platform initialization time, for all allocators for the platform. + */ +void cenalloc_device_add_allocator(struct cenalloc_device *dev, + struct cenalloc_allocator *allocator) +{ + + if (!allocator->ops->allocate || !allocator->ops->free || + !allocator->ops->map_dma || !allocator->ops->unmap_dma) + pr_err("%s: can not add allocator with invalid ops struct.\n", + __func__); + + allocator->dev = dev; + down_write(&dev->lock); + /* use negative allocator->id to reverse the priority -- when traversing + the list later attempt higher id numbers first */ + plist_node_init(&allocator->node, -allocator->id); + plist_add(&allocator->node, &dev->allocators); + + up_write(&dev->lock); +} +EXPORT_SYMBOL_GPL(cenalloc_device_add_allocator); + +/* + * Device Init and Remove + */ +static struct cenalloc_device cenalloc_dev = { + .dev.minor = MISC_DYNAMIC_MINOR, + .dev.name = "cenalloc", + .dev.parent = NULL, +}; + +/* + * TODO: this mechanism of getting a cenalloc device isn't the best, + * Need to have a better way of getting handle to device. + */ +struct cenalloc_device *cenalloc_get_device(void) +{ + return &cenalloc_dev; +} +EXPORT_SYMBOL_GPL(cenalloc_get_device); + +static int __init cenalloc_device_init(void) +{ + int ret; + + ret = misc_register(&cenalloc_dev.dev); + if (ret) { + pr_err("cenalloc: failed to register misc device.\n"); + return ret; + } + + cenalloc_dev.buffers = RB_ROOT; + mutex_init(&cenalloc_dev.buffer_lock); + init_rwsem(&cenalloc_dev.lock); + plist_head_init(&cenalloc_dev.allocators); + return ret; +} + +static void __exit cenalloc_device_remove(void) +{ + misc_deregister(&cenalloc_dev.dev); + + /* XXX need to free the allocators? */ +} + +module_init(cenalloc_device_init); +module_exit(cenalloc_device_remove); + +MODULE_AUTHOR("Sumit Semwal sumit.semwal@linaro.org"); +MODULE_DESCRIPTION("Constraint Aware Central Allocation Helper"); +MODULE_LICENSE("GPL"); diff --git a/drivers/cenalloc/cenalloc.h b/drivers/cenalloc/cenalloc.h new file mode 100644 index 0000000..91e07b2 --- /dev/null +++ b/drivers/cenalloc/cenalloc.h @@ -0,0 +1,99 @@ +/* + * Header file for allocator helper framework for constraints-aware + * dma-buf backing storage allocation. + * + * Copyright(C) 2014 Linaro Limited. All rights reserved. + * Author: Sumit Semwal sumit.semwal@linaro.org + * + * Structure for management of device, buffers etc heavily derived from + * Android's ION framework. + * + * 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see http://www.gnu.org/licenses/. + */ + +#ifndef CENALLOC_H_ +#define CENALLOC_H_ + +#include <linux/types.h> +#include <linux/dma-buf.h> + +struct cenalloc_device; + +/** + * cenalloc_get_device: + * gets a reference to cenalloc_device; this should be used in the + * call to cenalloc_buffer_create. + * + * TODO: might need to have a better way of getting this device. + */ +const struct cenalloc_device *cenalloc_get_device(void); + +/** + * cenalloc_buffer_create: + * creates a cenalloc_buffer, associates a dma_buf buffer with it, + * and returns the dma_buf; other importers can then use references + * to this dma_buf and attach themselves to it. + * + * Note: Since this is delayed-allocation model, no actual allocation + * will happen at this call. + * + * @dev: cenalloc_device to create the buffer from + * @len: size of the buffer + * @align: alignment info, if any + * @flags: flags for the buffer, if any + * + */ +struct dma_buf *cenalloc_buffer_create(struct cenalloc_device *dev, + unsigned long len, + unsigned long align, + unsigned long flags); + +/** + * cenalloc_buffer_free: + * calls dma_buf_put(), which in turn may call allocator->free() + * if this was the last reference held. + * For dma-bufs created with cenalloc_buffer_create, this should be + * called instead of dma_buf_put() directly. + * + * @dma_buf: the dma_buf to free. + */ +void cenalloc_buffer_free(struct dma_buf *dmabuf); + +/** + * cenalloc_phys: + * returns the phys address and len associated with this buffer - this + * will get refined as the ION 'abuse' of phys_addr_t is corrected. + * This is valid only for buffers that are allocated from physically + * contiguous memory; its output is invalid otherwise. For such cases, + * cenalloc_sg_table() should be used instead. + * Will return -EINVAL if the buffer is invalid. + * + * @dmabuf: buffer for which phys address is needed + * @phys: pointer to the phys address + * @len: pointer to teh length of the buffer + * + */ +int cenalloc_phys(struct dma_buf *dmabuf, + phys_addr_t *addr, size_t *len); + +/** + * cenalloc_sg_table: + * returns the sg_table associated with the dma_buf. + * Will return -EINVAL in case of error. + * + * @dmabuf: handle to buffer who's sg_table is to be returned. + * + */ +struct sg_table *cenalloc_sg_table(struct dma_buf *dmabuf); + +#endif /* CENALLOC_H_ */ diff --git a/drivers/cenalloc/cenalloc_priv.h b/drivers/cenalloc/cenalloc_priv.h new file mode 100644 index 0000000..31f5e59 --- /dev/null +++ b/drivers/cenalloc/cenalloc_priv.h @@ -0,0 +1,188 @@ +/* + * Private header file for allocator helper framework for constraints-aware + * dma-buf backing storage allocation. + * + * Copyright(C) 2014 Linaro Limited. All rights reserved. + * Author: Sumit Semwal sumit.semwal@linaro.org + * + * Structure for management of clients, buffers etc heavily derived from + * Android's ION framework. + * + * 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see http://www.gnu.org/licenses/. + */ +#ifndef CENALLOC_PRIV_H_ +#define CENALLOC_PRIV_H_ + +#include <linux/device.h> +#include <linux/dma-direction.h> +#include <linux/kref.h> +#include <linux/mm_types.h> +#include <linux/mutex.h> +#include <linux/rbtree.h> +#include <linux/sched.h> +#include <linux/types.h> + +#include "cenalloc.h" + +/** + * TODO: Find a better way to generate and manage allocator IDs + * For now, define a couple of allocator types + * + * @CENALLOC_ALLOCATOR_SYSTEM: eg memory allocated via vmalloc + * @CENALLOC_ALLOCATOR_SYSTEM_CONTIG: eg memory allocated via kmalloc + * @CENALLOC_NUM_ALLOCATORS: helper for iterating over Allocators + * a bit mask is used to identify the + * allocators, so only 32 total allocator + * types are supported + */ +#define CENALLOC_ALLOCATOR_SYSTEM 0x1 +#define CENALLOC_ALLOCATOR_SYSTEM_CONTIG (CENALLOC_ALLOCATOR_SYSTEM + 1) + +#define CENALLOC_NUM_ALLOCATORS 32 + +#define CENALLOC_ALLOCATOR_SYSTEM_MASK (1 << CENALLOC_ALLOCATOR_SYSTEM) +#define CENALLOC_ALLOCATOR_SYSTEM_CONTIG_MASK \ + (1 << CENALLOC_ALLOCATOR_SYSTEM_CONTIG) + + +struct cenalloc_device; +/** + * struct cenalloc_buffer - metadata for a particular buffer + * @node: node in the cenalloc_device buffers tree + * @dev: back pointer to the cenalloc_device + * @allocator: back pointer to the allocator the buffer came from + * @flags: buffer specific flags + * @private_flags: internal buffer specific flags + * @size: size of the buffer + * @priv_virt: private data to the buffer representable as + * a void * + * @lock: protects the buffers cnt fields + * @pages: flat array of pages in the buffer -- used by fault + * handler and only valid for buffers that are faulted in + * @vmas: list of vma's mapping this buffer + * @sg_table: the sg table for the buffer if dmap_cnt is not zero + * @handle_count: count of handles referencing this buffer +*/ +struct cenalloc_buffer { + struct rb_node node; + struct cenalloc_device *dev; + struct cenalloc_allocator *allocator; + unsigned long flags; + unsigned long align; + unsigned long private_flags; + + size_t size; + + struct kref ref; + unsigned int kmap_cnt; + struct mutex lock; + void *vaddr; + struct page **pages; + struct list_head vmas; + + struct sg_table *sg_table; + struct dma_buf *dmabuf; +}; + +/** + * struct cenalloc_allocator_ops - ops to operate on a given allocator + * @allocate: allocate memory + * @free: free memory + * @phys: get physical address of a buffer (only define on + * physically contiguous allocators) + * @map_dma: map the memory for dma to a scatterlist + * @unmap_dma: unmap the memory for dma + * @map_kernel: map memory to the kernel + * @unmap_kernel: unmap memory to the kernel + * @map_user: map memory to userspace + * @sync_for_device: sync the memory for device + * + * allocate, phys, and map_user return 0 on success, -errno on error. + * map_dma and map_kernel return pointer on success, ERR_PTR on + * error. + */ +struct cenalloc_allocator_ops { + int (*allocate)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer, unsigned long len, + unsigned long align, unsigned long flags); + void (*free)(struct cenalloc_buffer *buffer); + int (*phys)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer, + phys_addr_t *addr, size_t *len); + struct sg_table * (*map_dma)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer); + void (*unmap_dma)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer); + void * (*map_kernel)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer); + void (*unmap_kernel)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer); + int (*map_user)(struct cenalloc_allocator *mapper, + struct cenalloc_buffer *buffer, + struct vm_area_struct *vma); + + void (*sync_for_device)(struct cenalloc_allocator *allocator, + struct cenalloc_buffer *buffer, + struct device *dev, + enum dma_data_direction dir); +}; + +/** + * struct cenalloc_allocator - represents a allocator in the system + * @node: rb node to put the allocator on the device's tree of + * allocators + * @dev: back pointer to the cenalloc_device + * @type: type of allocator + * @ops: ops struct as above + * @flags: flags + * @id: id of allocator, also indicates priority of this + * allocator when allocating. These MUST be unique. + * @name: used for debugging + * @debug_show: called when allocator debug file is read to add any + * allocator specific debug info to output + * + * Represents a pool of memory from which buffers can be allocated. In some + * systems the only allocator is regular system memory allocated via vmalloc. + * On others, some blocks might require large physically contiguous buffers + * that are allocated from a specially reserved allocator. + */ +struct cenalloc_allocator { + struct plist_node node; + struct cenalloc_device *dev; + unsigned long type; + struct cenalloc_allocator_ops *ops; + struct vm_operations_struct *vma_ops; + unsigned long flags; + unsigned int id; + const char *name; + + int (*debug_show)(struct cenalloc_allocator *allocator, + struct seq_file *, void *); +}; + +/** + * cenalloc_device_add_allocator - adds an allocator to the cenalloc device + * @dev: the device + * @allocator: the allocator to add + */ +void cenalloc_device_add_allocator(struct cenalloc_device *dev, + struct cenalloc_allocator *allocator); + +/** + * TODO: add some helpers for common allocator operations on buffers; + * some candidates might be: + * cenalloc_allocator_{map_kernel, unmap_kernel, map_user} + * some vma_* management operations + */ + +#endif /* CENALLOC_PRIV_H_ */

Add the build files for cenalloc, the constraints-enabled allocation helper framework for dma-buf.

Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Cc: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org --- drivers/Kconfig | 2 ++ drivers/Makefile | 1 + drivers/cenalloc/Kconfig | 8 ++++++++ drivers/cenalloc/Makefile | 3 +++ 4 files changed, 14 insertions(+) create mode 100644 drivers/cenalloc/Kconfig create mode 100644 drivers/cenalloc/Makefile

diff --git a/drivers/Kconfig b/drivers/Kconfig index 1a693d3..f40d2ce 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -182,4 +182,6 @@ source "drivers/ras/Kconfig"

source "drivers/thunderbolt/Kconfig"

+source "drivers/cenalloc/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index ebee555..a04e516 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -161,3 +161,4 @@ obj-$(CONFIG_POWERCAP) += powercap/ obj-$(CONFIG_MCB) += mcb/ obj-$(CONFIG_RAS) += ras/ obj-$(CONFIG_THUNDERBOLT) += thunderbolt/ +obj-$(CONFIG_CENALLOC) += cenalloc/ diff --git a/drivers/cenalloc/Kconfig b/drivers/cenalloc/Kconfig new file mode 100644 index 0000000..9472d5d --- /dev/null +++ b/drivers/cenalloc/Kconfig @@ -0,0 +1,8 @@ +menuconfig CENALLOC + bool "cenalloc helper functions" + default n + select ANON_INODES + help + This option enables the helper allocation framework for drivers using + dma-buf buffer-sharing. It uses constraints of participating devices + to help find out best suited allocator. diff --git a/drivers/cenalloc/Makefile b/drivers/cenalloc/Makefile new file mode 100644 index 0000000..d36b531 --- /dev/null +++ b/drivers/cenalloc/Makefile @@ -0,0 +1,3 @@ +# Makefile for the cenalloc helper + +obj-y += cenalloc.o