DRM: Armada: Add Armada DRM driver

This patch adds support for the pair of LCD controllers on the Marvell
Armada 510 SoCs.  This driver supports:
- multiple contiguous scanout buffers for video and graphics
- shm backed cacheable buffer objects for X pixmaps for Vivante GPU
  acceleration
- dual lcd0 and lcd1 crt operation
- video overlay on each LCD crt via DRM planes
- page flipping of the main scanout buffers
- DRM prime for buffer export/import

This driver is trivial to extend to other Armada SoCs.

Included in this commit is the core driver with no output support; output
support is platform and encoder driver dependent.

Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 611 insertions, 0 deletions

diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
new file mode 100644
index 000000000000..9f2356bae7fd
--- /dev/null
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -0,0 +1,611 @@
+/*
+ * Copyright (C) 2012 Russell King
+ *
+ * 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.
+ */
+#include <linux/dma-buf.h>
+#include <linux/dma-mapping.h>
+#include <linux/shmem_fs.h>
+#include <drm/drmP.h>
+#include "armada_drm.h"
+#include "armada_gem.h"
+#include <drm/armada_drm.h>
+#include "armada_ioctlP.h"
+
+static int armada_gem_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct armada_gem_object *obj = drm_to_armada_gem(vma->vm_private_data);
+	unsigned long addr = (unsigned long)vmf->virtual_address;
+	unsigned long pfn = obj->phys_addr >> PAGE_SHIFT;
+	int ret;
+
+	pfn += (addr - vma->vm_start) >> PAGE_SHIFT;
+	ret = vm_insert_pfn(vma, addr, pfn);
+
+	switch (ret) {
+	case 0:
+	case -EBUSY:
+		return VM_FAULT_NOPAGE;
+	case -ENOMEM:
+		return VM_FAULT_OOM;
+	default:
+		return VM_FAULT_SIGBUS;
+	}
+}
+
+const struct vm_operations_struct armada_gem_vm_ops = {
+	.fault	= armada_gem_vm_fault,
+	.open	= drm_gem_vm_open,
+	.close	= drm_gem_vm_close,
+};
+
+static size_t roundup_gem_size(size_t size)
+{
+	return roundup(size, PAGE_SIZE);
+}
+
+/* dev->struct_mutex is held here */
+void armada_gem_free_object(struct drm_gem_object *obj)
+{
+	struct armada_gem_object *dobj = drm_to_armada_gem(obj);
+
+	DRM_DEBUG_DRIVER("release obj %p\n", dobj);
+
+	drm_gem_free_mmap_offset(&dobj->obj);
+
+	if (dobj->page) {
+		/* page backed memory */
+		unsigned int order = get_order(dobj->obj.size);
+		__free_pages(dobj->page, order);
+	} else if (dobj->linear) {
+		/* linear backed memory */
+		drm_mm_remove_node(dobj->linear);
+		kfree(dobj->linear);
+		if (dobj->addr)
+			iounmap(dobj->addr);
+	}
+
+	if (dobj->obj.import_attach) {
+		/* We only ever display imported data */
+		dma_buf_unmap_attachment(dobj->obj.import_attach, dobj->sgt,
+					 DMA_TO_DEVICE);
+		drm_prime_gem_destroy(&dobj->obj, NULL);
+	}
+
+	drm_gem_object_release(&dobj->obj);
+
+	kfree(dobj);
+}
+
+int
+armada_gem_linear_back(struct drm_device *dev, struct armada_gem_object *obj)
+{
+	struct armada_private *priv = dev->dev_private;
+	size_t size = obj->obj.size;
+
+	if (obj->page || obj->linear)
+		return 0;
+
+	/*
+	 * If it is a small allocation (typically cursor, which will
+	 * be 32x64 or 64x32 ARGB pixels) try to get it from the system.
+	 * Framebuffers will never be this small (our minimum size for
+	 * framebuffers is larger than this anyway.)  Such objects are
+	 * only accessed by the CPU so we don't need any special handing
+	 * here.
+	 */
+	if (size <= 8192) {
+		unsigned int order = get_order(size);
+		struct page *p = alloc_pages(GFP_KERNEL, order);
+
+		if (p) {
+			obj->addr = page_address(p);
+			obj->phys_addr = page_to_phys(p);
+			obj->page = p;
+
+			memset(obj->addr, 0, PAGE_ALIGN(size));
+		}
+	}
+
+	/*
+	 * We could grab something from CMA if it's enabled, but that
+	 * involves building in a problem:
+	 *
+	 * CMA's interface uses dma_alloc_coherent(), which provides us
+	 * with an CPU virtual address and a device address.
+	 *
+	 * The CPU virtual address may be either an address in the kernel
+	 * direct mapped region (for example, as it would be on x86) or
+	 * it may be remapped into another part of kernel memory space
+	 * (eg, as it would be on ARM.)  This means virt_to_phys() on the
+	 * returned virtual address is invalid depending on the architecture
+	 * implementation.
+	 *
+	 * The device address may also not be a physical address; it may
+	 * be that there is some kind of remapping between the device and
+	 * system RAM, which makes the use of the device address also
+	 * unsafe to re-use as a physical address.
+	 *
+	 * This makes DRM usage of dma_alloc_coherent() in a generic way
+	 * at best very questionable and unsafe.
+	 */
+
+	/* Otherwise, grab it from our linear allocation */
+	if (!obj->page) {
+		struct drm_mm_node *node;
+		unsigned align = min_t(unsigned, size, SZ_2M);
+		void __iomem *ptr;
+		int ret;
+
+		node = kzalloc(sizeof(*node), GFP_KERNEL);
+		if (!node)
+			return -ENOSPC;
+
+		mutex_lock(&dev->struct_mutex);
+		ret = drm_mm_insert_node(&priv->linear, node, size, align,
+					 DRM_MM_SEARCH_DEFAULT);
+		mutex_unlock(&dev->struct_mutex);
+		if (ret) {
+			kfree(node);
+			return ret;
+		}
+
+		obj->linear = node;
+
+		/* Ensure that the memory we're returning is cleared. */
+		ptr = ioremap_wc(obj->linear->start, size);
+		if (!ptr) {
+			mutex_lock(&dev->struct_mutex);
+			drm_mm_remove_node(obj->linear);
+			mutex_unlock(&dev->struct_mutex);
+			kfree(obj->linear);
+			obj->linear = NULL;
+			return -ENOMEM;
+		}
+
+		memset_io(ptr, 0, size);
+		iounmap(ptr);
+
+		obj->phys_addr = obj->linear->start;
+		obj->dev_addr = obj->linear->start;
+	}
+
+	DRM_DEBUG_DRIVER("obj %p phys %#x dev %#x\n",
+			 obj, obj->phys_addr, obj->dev_addr);
+
+	return 0;
+}
+
+void *
+armada_gem_map_object(struct drm_device *dev, struct armada_gem_object *dobj)
+{
+	/* only linear objects need to be ioremap'd */
+	if (!dobj->addr && dobj->linear)
+		dobj->addr = ioremap_wc(dobj->phys_addr, dobj->obj.size);
+	return dobj->addr;
+}
+
+struct armada_gem_object *
+armada_gem_alloc_private_object(struct drm_device *dev, size_t size)
+{
+	struct armada_gem_object *obj;
+
+	size = roundup_gem_size(size);
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
+
+	drm_gem_private_object_init(dev, &obj->obj, size);
+	obj->dev_addr = DMA_ERROR_CODE;
+
+	DRM_DEBUG_DRIVER("alloc private obj %p size %zu\n", obj, size);
+
+	return obj;
+}
+
+struct armada_gem_object *armada_gem_alloc_object(struct drm_device *dev,
+	size_t size)
+{
+	struct armada_gem_object *obj;
+	struct address_space *mapping;
+
+	size = roundup_gem_size(size);
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
+
+	if (drm_gem_object_init(dev, &obj->obj, size)) {
+		kfree(obj);
+		return NULL;
+	}
+
+	obj->dev_addr = DMA_ERROR_CODE;
+
+	mapping = obj->obj.filp->f_path.dentry->d_inode->i_mapping;
+	mapping_set_gfp_mask(mapping, GFP_HIGHUSER | __GFP_RECLAIMABLE);
+
+	DRM_DEBUG_DRIVER("alloc obj %p size %zu\n", obj, size);
+
+	return obj;
+}
+
+/* Dumb alloc support */
+int armada_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
+	struct drm_mode_create_dumb *args)
+{
+	struct armada_gem_object *dobj;
+	u32 handle;
+	size_t size;
+	int ret;
+
+	args->pitch = armada_pitch(args->width, args->bpp);
+	args->size = size = args->pitch * args->height;
+
+	dobj = armada_gem_alloc_private_object(dev, size);
+	if (dobj == NULL)
+		return -ENOMEM;
+
+	ret = armada_gem_linear_back(dev, dobj);
+	if (ret)
+		goto err;
+
+	ret = drm_gem_handle_create(file, &dobj->obj, &handle);
+	if (ret)
+		goto err;
+
+	args->handle = handle;
+
+	/* drop reference from allocate - handle holds it now */
+	DRM_DEBUG_DRIVER("obj %p size %zu handle %#x\n", dobj, size, handle);
+ err:
+	drm_gem_object_unreference_unlocked(&dobj->obj);
+	return ret;
+}
+
+int armada_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
+	uint32_t handle, uint64_t *offset)
+{
+	struct armada_gem_object *obj;
+	int ret = 0;
+
+	mutex_lock(&dev->struct_mutex);
+	obj = armada_gem_object_lookup(dev, file, handle);
+	if (!obj) {
+		DRM_ERROR("failed to lookup gem object\n");
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+
+	/* Don't allow imported objects to be mapped */
+	if (obj->obj.import_attach) {
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+
+	ret = drm_gem_create_mmap_offset(&obj->obj);
+	if (ret == 0) {
+		*offset = drm_vma_node_offset_addr(&obj->obj.vma_node);
+		DRM_DEBUG_DRIVER("handle %#x offset %llx\n", handle, *offset);
+	}
+
+	drm_gem_object_unreference(&obj->obj);
+ err_unlock:
+	mutex_unlock(&dev->struct_mutex);
+
+	return ret;
+}
+
+int armada_gem_dumb_destroy(struct drm_file *file, struct drm_device *dev,
+	uint32_t handle)
+{
+	return drm_gem_handle_delete(file, handle);
+}
+
+/* Private driver gem ioctls */
+int armada_gem_create_ioctl(struct drm_device *dev, void *data,
+	struct drm_file *file)
+{
+	struct drm_armada_gem_create *args = data;
+	struct armada_gem_object *dobj;
+	size_t size;
+	u32 handle;
+	int ret;
+
+	if (args->size == 0)
+		return -ENOMEM;
+
+	size = args->size;
+
+	dobj = armada_gem_alloc_object(dev, size);
+	if (dobj == NULL)
+		return -ENOMEM;
+
+	ret = drm_gem_handle_create(file, &dobj->obj, &handle);
+	if (ret)
+		goto err;
+
+	args->handle = handle;
+
+	/* drop reference from allocate - handle holds it now */
+	DRM_DEBUG_DRIVER("obj %p size %zu handle %#x\n", dobj, size, handle);
+ err:
+	drm_gem_object_unreference_unlocked(&dobj->obj);
+	return ret;
+}
+
+/* Map a shmem-backed object into process memory space */
+int armada_gem_mmap_ioctl(struct drm_device *dev, void *data,
+	struct drm_file *file)
+{
+	struct drm_armada_gem_mmap *args = data;
+	struct armada_gem_object *dobj;
+	unsigned long addr;
+
+	dobj = armada_gem_object_lookup(dev, file, args->handle);
+	if (dobj == NULL)
+		return -ENOENT;
+
+	if (!dobj->obj.filp) {
+		drm_gem_object_unreference(&dobj->obj);
+		return -EINVAL;
+	}
+
+	addr = vm_mmap(dobj->obj.filp, 0, args->size, PROT_READ | PROT_WRITE,
+		       MAP_SHARED, args->offset);
+	drm_gem_object_unreference(&dobj->obj);
+	if (IS_ERR_VALUE(addr))
+		return addr;
+
+	args->addr = addr;
+
+	return 0;
+}
+
+int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data,
+	struct drm_file *file)
+{
+	struct drm_armada_gem_pwrite *args = data;
+	struct armada_gem_object *dobj;
+	char __user *ptr;
+	int ret;
+
+	DRM_DEBUG_DRIVER("handle %u off %u size %u ptr 0x%llx\n",
+		args->handle, args->offset, args->size, args->ptr);
+
+	if (args->size == 0)
+		return 0;
+
+	ptr = (char __user *)(uintptr_t)args->ptr;
+
+	if (!access_ok(VERIFY_READ, ptr, args->size))
+		return -EFAULT;
+
+	ret = fault_in_multipages_readable(ptr, args->size);
+	if (ret)
+		return ret;
+
+	dobj = armada_gem_object_lookup(dev, file, args->handle);
+	if (dobj == NULL)
+		return -ENOENT;
+
+	/* Must be a kernel-mapped object */
+	if (!dobj->addr)
+		return -EINVAL;
+
+	if (args->offset > dobj->obj.size ||
+	    args->size > dobj->obj.size - args->offset) {
+		DRM_ERROR("invalid size: object size %u\n", dobj->obj.size);
+		ret = -EINVAL;
+		goto unref;
+	}
+
+	if (copy_from_user(dobj->addr + args->offset, ptr, args->size)) {
+		ret = -EFAULT;
+	} else if (dobj->update) {
+		dobj->update(dobj->update_data);
+		ret = 0;
+	}
+
+ unref:
+	drm_gem_object_unreference_unlocked(&dobj->obj);
+	return ret;
+}
+
+/* Prime support */
+struct sg_table *
+armada_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
+	enum dma_data_direction dir)
+{
+	struct drm_gem_object *obj = attach->dmabuf->priv;
+	struct armada_gem_object *dobj = drm_to_armada_gem(obj);
+	struct scatterlist *sg;
+	struct sg_table *sgt;
+	int i, num;
+
+	sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
+	if (!sgt)
+		return NULL;
+
+	if (dobj->obj.filp) {
+		struct address_space *mapping;
+		gfp_t gfp;
+		int count;
+
+		count = dobj->obj.size / PAGE_SIZE;
+		if (sg_alloc_table(sgt, count, GFP_KERNEL))
+			goto free_sgt;
+
+		mapping = file_inode(dobj->obj.filp)->i_mapping;
+		gfp = mapping_gfp_mask(mapping);
+
+		for_each_sg(sgt->sgl, sg, count, i) {
+			struct page *page;
+
+			page = shmem_read_mapping_page_gfp(mapping, i, gfp);
+			if (IS_ERR(page)) {
+				num = i;
+				goto release;
+			}
+
+			sg_set_page(sg, page, PAGE_SIZE, 0);
+		}
+
+		if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0) {
+			num = sgt->nents;
+			goto release;
+		}
+	} else if (dobj->page) {
+		/* Single contiguous page */
+		if (sg_alloc_table(sgt, 1, GFP_KERNEL))
+			goto free_sgt;
+
+		sg_set_page(sgt->sgl, dobj->page, dobj->obj.size, 0);
+
+		if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0)
+			goto free_table;
+	} else if (dobj->linear) {
+		/* Single contiguous physical region - no struct page */
+		if (sg_alloc_table(sgt, 1, GFP_KERNEL))
+			goto free_sgt;
+		sg_dma_address(sgt->sgl) = dobj->dev_addr;
+		sg_dma_len(sgt->sgl) = dobj->obj.size;
+	} else {
+		goto free_sgt;
+	}
+	return sgt;
+
+ release:
+	for_each_sg(sgt->sgl, sg, num, i)
+		page_cache_release(sg_page(sg));
+ free_table:
+	sg_free_table(sgt);
+ free_sgt:
+	kfree(sgt);
+	return NULL;
+}
+
+static void armada_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
+	struct sg_table *sgt, enum dma_data_direction dir)
+{
+	struct drm_gem_object *obj = attach->dmabuf->priv;
+	struct armada_gem_object *dobj = drm_to_armada_gem(obj);
+	int i;
+
+	if (!dobj->linear)
+		dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+
+	if (dobj->obj.filp) {
+		struct scatterlist *sg;
+		for_each_sg(sgt->sgl, sg, sgt->nents, i)
+			page_cache_release(sg_page(sg));
+	}
+
+	sg_free_table(sgt);
+	kfree(sgt);
+}
+
+static void *armada_gem_dmabuf_no_kmap(struct dma_buf *buf, unsigned long n)
+{
+	return NULL;
+}
+
+static void
+armada_gem_dmabuf_no_kunmap(struct dma_buf *buf, unsigned long n, void *addr)
+{
+}
+
+static int
+armada_gem_dmabuf_mmap(struct dma_buf *buf, struct vm_area_struct *vma)
+{
+	return -EINVAL;
+}
+
+static const struct dma_buf_ops armada_gem_prime_dmabuf_ops = {
+	.map_dma_buf	= armada_gem_prime_map_dma_buf,
+	.unmap_dma_buf	= armada_gem_prime_unmap_dma_buf,
+	.release	= drm_gem_dmabuf_release,
+	.kmap_atomic	= armada_gem_dmabuf_no_kmap,
+	.kunmap_atomic	= armada_gem_dmabuf_no_kunmap,
+	.kmap		= armada_gem_dmabuf_no_kmap,
+	.kunmap		= armada_gem_dmabuf_no_kunmap,
+	.mmap		= armada_gem_dmabuf_mmap,
+};
+
+struct dma_buf *
+armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj,
+	int flags)
+{
+	return dma_buf_export(obj, &armada_gem_prime_dmabuf_ops, obj->size,
+			      O_RDWR);
+}
+
+struct drm_gem_object *
+armada_gem_prime_import(struct drm_device *dev, struct dma_buf *buf)
+{
+	struct dma_buf_attachment *attach;
+	struct armada_gem_object *dobj;
+
+	if (buf->ops == &armada_gem_prime_dmabuf_ops) {
+		struct drm_gem_object *obj = buf->priv;
+		if (obj->dev == dev) {
+			/*
+			 * Importing our own dmabuf(s) increases the
+			 * refcount on the gem object itself.
+			 */
+			drm_gem_object_reference(obj);
+			dma_buf_put(buf);
+			return obj;
+		}
+	}
+
+	attach = dma_buf_attach(buf, dev->dev);
+	if (IS_ERR(attach))
+		return ERR_CAST(attach);
+
+	dobj = armada_gem_alloc_private_object(dev, buf->size);
+	if (!dobj) {
+		dma_buf_detach(buf, attach);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	dobj->obj.import_attach = attach;
+
+	/*
+	 * Don't call dma_buf_map_attachment() here - it maps the
+	 * scatterlist immediately for DMA, and this is not always
+	 * an appropriate thing to do.
+	 */
+	return &dobj->obj;
+}
+
+int armada_gem_map_import(struct armada_gem_object *dobj)
+{
+	int ret;
+
+	dobj->sgt = dma_buf_map_attachment(dobj->obj.import_attach,
+					  DMA_TO_DEVICE);
+	if (!dobj->sgt) {
+		DRM_ERROR("dma_buf_map_attachment() returned NULL\n");
+		return -EINVAL;
+	}
+	if (IS_ERR(dobj->sgt)) {
+		ret = PTR_ERR(dobj->sgt);
+		dobj->sgt = NULL;
+		DRM_ERROR("dma_buf_map_attachment() error: %d\n", ret);
+		return ret;
+	}
+	if (dobj->sgt->nents > 1) {
+		DRM_ERROR("dma_buf_map_attachment() returned an (unsupported) scattered list\n");
+		return -EINVAL;
+	}
+	if (sg_dma_len(dobj->sgt->sgl) < dobj->obj.size) {
+		DRM_ERROR("dma_buf_map_attachment() returned a small buffer\n");
+		return -EINVAL;
+	}
+	dobj->dev_addr = sg_dma_address(dobj->sgt->sgl);
+	return 0;
+}