Many embedded drm devices do not have a IOMMU and no dedicated
memory for graphics. These devices use CMA (Contiguous Memory
Allocator) backed graphics memory. This patch provides helper
functions to be able to share the code.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
Lars-Peter, please let me know if this fits your needs or if you are missing
something.
drivers/gpu/drm/Kconfig | 6 +
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/drm_gem_cma_helper.c | 321 ++++++++++++++++++++++++++++++++++
include/drm/drm_gem_cma_helper.h | 47 +++++
4 files changed, 375 insertions(+)
create mode 100644 drivers/gpu/drm/drm_gem_cma_helper.c
create mode 100644 include/drm/drm_gem_cma_helper.h
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index e354bc0..f62717e 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -53,6 +53,12 @@ config DRM_TTM
GPU memory types. Will be enabled automatically if a device driver
uses it.
+config DRM_GEM_CMA_HELPER
+ tristate
+ depends on DRM
+ help
+ Choose this if you need the GEM cma helper functions
+
config DRM_TDFX
tristate "3dfx Banshee/Voodoo3+"
depends on DRM && PCI
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index c20da5b..9a0d98a 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -15,6 +15,7 @@ drm-y := drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
drm_trace_points.o drm_global.o drm_prime.o
drm-$(CONFIG_COMPAT) += drm_ioc32.o
+drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o
drm-usb-y := drm_usb.o
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
new file mode 100644
index 0000000..75534ff
--- /dev/null
+++ b/drivers/gpu/drm/drm_gem_cma_helper.c
@@ -0,0 +1,321 @@
+/*
+ * drm gem cma (contiguous memory allocator) helper functions
+ *
+ * Copyright (C) 2012 Sascha Hauer, Pengutronix
+ *
+ * Based on Samsung Exynos code
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 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 <drm/drmP.h>
+#include <drm/drm.h>
+#include <drm/drm_gem_cma_helper.h>
+
+static unsigned int convert_to_vm_err_msg(int msg)
+{
+ unsigned int out_msg;
+
+ switch (msg) {
+ case 0:
+ case -ERESTARTSYS:
+ case -EINTR:
+ out_msg = VM_FAULT_NOPAGE;
+ break;
+
+ case -ENOMEM:
+ out_msg = VM_FAULT_OOM;
+ break;
+
+ default:
+ out_msg = VM_FAULT_SIGBUS;
+ break;
+ }
+
+ return out_msg;
+}
+
+static unsigned int get_gem_mmap_offset(struct drm_gem_object *obj)
+{
+ return (unsigned int)obj->map_list.hash.key << PAGE_SHIFT;
+}
+
+static void drm_gem_cma_buf_destroy(struct drm_device *drm,
+ struct drm_gem_cma_obj *cma_obj)
+{
+ dma_free_writecombine(drm->dev, cma_obj->base.size, cma_obj->vaddr,
+ cma_obj->paddr);
+}
+
+/*
+ * drm_gem_cma_create - allocate an object with the given size
+ *
+ * returns a struct drm_gem_cma_obj* on success or ERR_PTR values
+ * on failure.
+ */
+struct drm_gem_cma_obj *drm_gem_cma_create(struct drm_device *drm,
+ unsigned int size)
+{
+ struct drm_gem_cma_obj *cma_obj;
+ struct drm_gem_object *gem_obj;
+ int ret;
+
+ size = roundup(size, PAGE_SIZE);
+
+ cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
+ if (!cma_obj)
+ return ERR_PTR(-ENOMEM);
+
+ cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
+ (dma_addr_t *)&cma_obj->paddr,
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!cma_obj->vaddr) {
+ dev_err(drm->dev, "failed to allocate buffer with size %d\n", size);
+ ret = -ENOMEM;
+ goto err_dma_alloc;
+ }
+
+ gem_obj = &cma_obj->base;
+
+ ret = drm_gem_object_init(drm, gem_obj, size);
+ if (ret)
+ goto err_obj_init;
+
+ ret = drm_gem_create_mmap_offset(gem_obj);
+ if (ret)
+ goto err_create_mmap_offset;
+
+ return cma_obj;
+
+err_create_mmap_offset:
+ drm_gem_object_release(gem_obj);
+
+err_obj_init:
+ drm_gem_cma_buf_destroy(drm, cma_obj);
+
+err_dma_alloc:
+ kfree(cma_obj);
+
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_create);
+
+/*
+ * drm_gem_cma_create_with_handle - allocate an object with the given
+ * size and create a gem handle on it
+ *
+ * returns a struct drm_gem_cma_obj* on success or ERR_PTR values
+ * on failure.
+ */
+struct drm_gem_cma_obj *drm_gem_cma_create_with_handle(
+ struct drm_file *file_priv,
+ struct drm_device *drm, unsigned int size,
+ unsigned int *handle)
+{
+ struct drm_gem_cma_obj *cma_obj;
+ struct drm_gem_object *gem_obj;
+ int ret;
+
+ cma_obj = drm_gem_cma_create(drm, size);
+ if (IS_ERR(cma_obj))
+ return cma_obj;
+
+ gem_obj = &cma_obj->base;
+
+ /*
+ * allocate a id of idr table where the obj is registered
+ * and handle has the id what user can see.
+ */
+ ret = drm_gem_handle_create(file_priv, gem_obj, handle);
+ if (ret)
+ goto err_handle_create;
+
+ /* drop reference from allocate - handle holds it now. */
+ drm_gem_object_unreference_unlocked(gem_obj);
+
+ return cma_obj;
+
+err_handle_create:
+ drm_gem_cma_free_object(gem_obj);
+
+ return ERR_PTR(ret);
+}
+
+static int drm_gem_cma_mmap_buffer(struct file *filp,
+ struct vm_area_struct *vma)
+{
+ struct drm_gem_object *gem_obj = filp->private_data;
+ struct drm_gem_cma_obj *cma_obj = to_dma_alloc_gem_obj(gem_obj);
+ unsigned long pfn, vm_size;
+
+ vma->vm_flags |= VM_IO | VM_RESERVED;
+
+ vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
+ vma->vm_file = filp;
+
+ vm_size = vma->vm_end - vma->vm_start;
+
+ /* check if user-requested size is valid. */
+ if (vm_size > gem_obj->size)
+ return -EINVAL;
+
+ /*
+ * get page frame number to physical memory to be mapped
+ * to user space.
+ */
+ pfn = cma_obj->paddr >> PAGE_SHIFT;
+
+ if (remap_pfn_range(vma, vma->vm_start, pfn, vm_size,
+ vma->vm_page_prot)) {
+ dev_err(gem_obj->dev->dev, "failed to remap pfn range.\n");
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static const struct file_operations drm_gem_cma_fops = {
+ .mmap = drm_gem_cma_mmap_buffer,
+};
+
+/*
+ * drm_gem_cma_free_object - (struct drm_driver)->gem_free_object callback
+ * function
+ */
+void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
+{
+ struct drm_gem_cma_obj *cma_obj;
+
+ if (gem_obj->map_list.map)
+ drm_gem_free_mmap_offset(gem_obj);
+
+ drm_gem_object_release(gem_obj);
+
+ cma_obj = to_dma_alloc_gem_obj(gem_obj);
+
+ drm_gem_cma_buf_destroy(gem_obj->dev, cma_obj);
+
+ kfree(cma_obj);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
+
+/*
+ * drm_gem_cma_dumb_create - (struct drm_driver)->dumb_create callback
+ * function
+ *
+ * This aligns the pitch and size arguments to the minimum required. wrap
+ * this into your own function if you need bigger alignment.
+ */
+int drm_gem_cma_dumb_create(struct drm_file *file_priv,
+ struct drm_device *dev, struct drm_mode_create_dumb *args)
+{
+ struct drm_gem_cma_obj *cma_obj;
+
+ if (args->pitch < args->width * args->bpp >> 3)
+ args->pitch = args->width * args->bpp >> 3;
+
+ if (args->size < args->pitch * args->height)
+ args->size = args->pitch * args->height;
+
+ cma_obj = drm_gem_cma_create_with_handle(file_priv, dev,
+ args->size, &args->handle);
+ if (IS_ERR(cma_obj))
+ return PTR_ERR(cma_obj);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
+
+/*
+ * drm_gem_cma_dumb_map_offset - (struct drm_driver)->dumb_map_offset callback
+ * function
+ */
+int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
+ struct drm_device *drm, uint32_t handle, uint64_t *offset)
+{
+ struct drm_gem_cma_obj *cma_obj;
+ struct drm_gem_object *gem_obj;
+
+ mutex_lock(&drm->struct_mutex);
+
+ gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
+ if (!gem_obj) {
+ dev_err(drm->dev, "failed to lookup gem object\n");
+ mutex_unlock(&drm->struct_mutex);
+ return -EINVAL;
+ }
+
+ cma_obj = to_dma_alloc_gem_obj(gem_obj);
+
+ *offset = get_gem_mmap_offset(&cma_obj->base);
+
+ drm_gem_object_unreference(gem_obj);
+
+ mutex_unlock(&drm->struct_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
+
+/*
+ * drm_gem_cma_fault - (struct vm_operations_struct)->fault callback function
+ */
+int drm_gem_cma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct drm_gem_object *gem_obj = vma->vm_private_data;
+ struct drm_gem_cma_obj *cma_obj = to_dma_alloc_gem_obj(gem_obj);
+ struct drm_device *dev = gem_obj->dev;
+ unsigned long pfn;
+ pgoff_t page_offset;
+ int ret;
+
+ page_offset = ((unsigned long)vmf->virtual_address -
+ vma->vm_start) >> PAGE_SHIFT;
+
+ mutex_lock(&dev->struct_mutex);
+
+ pfn = (cma_obj->paddr >> PAGE_SHIFT) + page_offset;
+
+ ret = vm_insert_mixed(vma, (unsigned long)vmf->virtual_address, pfn);
+
+ mutex_unlock(&dev->struct_mutex);
+
+ return convert_to_vm_err_msg(ret);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_fault);
+
+/*
+ * drm_gem_cma_mmap - (struct file_operation)->mmap callback function
+ */
+int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ int ret;
+
+ ret = drm_gem_mmap(filp, vma);
+ if (ret)
+ return ret;
+
+ vma->vm_flags &= ~VM_PFNMAP;
+ vma->vm_flags |= VM_MIXEDMAP;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
+
+/*
+ * drm_gem_cma_dumb_destroy - (struct drm_driver)->dumb_destroy callback function
+ */
+int drm_gem_cma_dumb_destroy(struct drm_file *file_priv,
+ struct drm_device *drm, unsigned int handle)
+{
+ return drm_gem_handle_delete(file_priv, handle);
+}
+EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_destroy);
diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
new file mode 100644
index 0000000..53b007c
--- /dev/null
+++ b/include/drm/drm_gem_cma_helper.h
@@ -0,0 +1,47 @@
+#ifndef __DRM_GEM_DMA_ALLOC_HELPER_H__
+#define __DRM_GEM_DMA_ALLOC_HELPER_H__
+
+struct drm_gem_cma_obj {
+ struct drm_gem_object base;
+ dma_addr_t paddr;
+ void __iomem *vaddr;
+};
+
+#define to_dma_alloc_gem_obj(x) \
+ container_of(x, struct drm_gem_cma_obj, base)
+
+/* free gem object. */
+void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);
+
+/* create memory region for drm framebuffer. */
+int drm_gem_cma_dumb_create(struct drm_file *file_priv,
+ struct drm_device *drm, struct drm_mode_create_dumb *args);
+
+/* map memory region for drm framebuffer to user space. */
+int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
+ struct drm_device *drm, uint32_t handle, uint64_t *offset);
+
+/* page fault handler and mmap fault address(virtual) to physical memory. */
+int drm_gem_cma_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
+
+/* set vm_flags and we can change the vm attribute to other one at here. */
+int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma);
+
+/*
+ * destroy memory region allocated.
+ * - a gem handle and physical memory region pointed by a gem object
+ * would be released by drm_gem_handle_delete().
+ */
+int drm_gem_cma_dumb_destroy(struct drm_file *file_priv,
+ struct drm_device *drm, unsigned int handle);
+
+/* allocate physical memory. */
+struct drm_gem_cma_obj *drm_gem_cma_create(struct drm_device *drm,
+ unsigned int size);
+
+struct drm_gem_cma_obj *drm_gem_cma_create_with_handle(
+ struct drm_file *file_priv,
+ struct drm_device *drm, unsigned int size,
+ unsigned int *handle);
+
+#endif
--
1.7.10
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