This new export type exposes to userspace the SRAM area as a DMA-BUF Heap, this allows for allocations of DMA-BUFs that can be consumed by various DMA-BUF supporting devices. Signed-off-by: Andrew Davis <afd@xxxxxx> --- Changes from v2: - Make sram_dma_heap_allocate static (kernel test robot) - Rebase on v6.5-rc1 drivers/misc/Kconfig | 7 + drivers/misc/Makefile | 1 + drivers/misc/sram-dma-heap.c | 245 +++++++++++++++++++++++++++++++++++ drivers/misc/sram.c | 6 + drivers/misc/sram.h | 16 +++ 5 files changed, 275 insertions(+) create mode 100644 drivers/misc/sram-dma-heap.c diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 75e427f124b28..ee34dfb61605f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -448,6 +448,13 @@ config SRAM config SRAM_EXEC bool +config SRAM_DMA_HEAP + bool "Export on-chip SRAM pools using DMA-Heaps" + depends on DMABUF_HEAPS && SRAM + help + This driver allows the export of on-chip SRAM marked as both pool + and exportable to userspace using the DMA-Heaps interface. + config DW_XDATA_PCIE depends on PCI tristate "Synopsys DesignWare xData PCIe driver" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index f2a4d1ff65d46..5e7516bfaa8de 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o obj-$(CONFIG_SRAM) += sram.o obj-$(CONFIG_SRAM_EXEC) += sram-exec.o +obj-$(CONFIG_SRAM_DMA_HEAP) += sram-dma-heap.o obj-$(CONFIG_GENWQE) += genwqe/ obj-$(CONFIG_ECHO) += echo/ obj-$(CONFIG_CXL_BASE) += cxl/ diff --git a/drivers/misc/sram-dma-heap.c b/drivers/misc/sram-dma-heap.c new file mode 100644 index 0000000000000..c054c04dff33e --- /dev/null +++ b/drivers/misc/sram-dma-heap.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SRAM DMA-Heap userspace exporter + * + * Copyright (C) 2019-2022 Texas Instruments Incorporated - https://www.ti.com/ + * Andrew Davis <afd@xxxxxx> + */ + +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/genalloc.h> +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/scatterlist.h> +#include <linux/slab.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> + +#include "sram.h" + +struct sram_dma_heap { + struct dma_heap *heap; + struct gen_pool *pool; +}; + +struct sram_dma_heap_buffer { + struct gen_pool *pool; + struct list_head attachments; + struct mutex attachments_lock; + unsigned long len; + void *vaddr; + phys_addr_t paddr; +}; + +struct dma_heap_attachment { + struct device *dev; + struct sg_table *table; + struct list_head list; +}; + +static int dma_heap_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a; + struct sg_table *table; + + a = kzalloc(sizeof(*a), GFP_KERNEL); + if (!a) + return -ENOMEM; + + table = kmalloc(sizeof(*table), GFP_KERNEL); + if (!table) { + kfree(a); + return -ENOMEM; + } + if (sg_alloc_table(table, 1, GFP_KERNEL)) { + kfree(table); + kfree(a); + return -ENOMEM; + } + sg_set_page(table->sgl, pfn_to_page(PFN_DOWN(buffer->paddr)), buffer->len, 0); + + a->table = table; + a->dev = attachment->dev; + INIT_LIST_HEAD(&a->list); + + attachment->priv = a; + + mutex_lock(&buffer->attachments_lock); + list_add(&a->list, &buffer->attachments); + mutex_unlock(&buffer->attachments_lock); + + return 0; +} + +static void dma_heap_detatch(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + struct dma_heap_attachment *a = attachment->priv; + + mutex_lock(&buffer->attachments_lock); + list_del(&a->list); + mutex_unlock(&buffer->attachments_lock); + + sg_free_table(a->table); + kfree(a->table); + kfree(a); +} + +static struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment, + enum dma_data_direction direction) +{ + struct dma_heap_attachment *a = attachment->priv; + struct sg_table *table = a->table; + + /* + * As this heap is backed by uncached SRAM memory we do not need to + * perform any sync operations on the buffer before allowing device + * domain access. For this reason we use SKIP_CPU_SYNC and also do + * not use or provide begin/end_cpu_access() dma-buf functions. + */ + if (!dma_map_sg_attrs(attachment->dev, table->sgl, table->nents, + direction, DMA_ATTR_SKIP_CPU_SYNC)) + return ERR_PTR(-ENOMEM); + + return table; +} + +static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, + struct sg_table *table, + enum dma_data_direction direction) +{ + dma_unmap_sg_attrs(attachment->dev, table->sgl, table->nents, + direction, DMA_ATTR_SKIP_CPU_SYNC); +} + +static void dma_heap_dma_buf_release(struct dma_buf *dmabuf) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); + kfree(buffer); +} + +static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + int ret; + + /* SRAM mappings are not cached */ + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + ret = vm_iomap_memory(vma, buffer->paddr, buffer->len); + if (ret) + pr_err("Could not map buffer to userspace\n"); + + return ret; +} + +static int dma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) +{ + struct sram_dma_heap_buffer *buffer = dmabuf->priv; + + iosys_map_set_vaddr(map, buffer->vaddr); + + return 0; +} + +static const struct dma_buf_ops sram_dma_heap_buf_ops = { + .attach = dma_heap_attach, + .detach = dma_heap_detatch, + .map_dma_buf = dma_heap_map_dma_buf, + .unmap_dma_buf = dma_heap_unmap_dma_buf, + .release = dma_heap_dma_buf_release, + .mmap = dma_heap_mmap, + .vmap = dma_heap_vmap, +}; + +static struct dma_buf *sram_dma_heap_allocate(struct dma_heap *heap, + unsigned long len, + unsigned long fd_flags, + unsigned long heap_flags) +{ + struct sram_dma_heap *sram_dma_heap = dma_heap_get_drvdata(heap); + struct sram_dma_heap_buffer *buffer; + + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dmabuf; + int ret = 0; + + buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + buffer->pool = sram_dma_heap->pool; + INIT_LIST_HEAD(&buffer->attachments); + mutex_init(&buffer->attachments_lock); + buffer->len = len; + + buffer->vaddr = (void *)gen_pool_alloc(buffer->pool, buffer->len); + if (!buffer->vaddr) { + ret = -ENOMEM; + goto free_buffer; + } + + buffer->paddr = gen_pool_virt_to_phys(buffer->pool, (unsigned long)buffer->vaddr); + if (buffer->paddr == -1) { + ret = -ENOMEM; + goto free_pool; + } + + /* create the dmabuf */ + exp_info.exp_name = dma_heap_get_name(heap); + exp_info.ops = &sram_dma_heap_buf_ops; + exp_info.size = buffer->len; + exp_info.flags = fd_flags; + exp_info.priv = buffer; + dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(dmabuf)) { + ret = PTR_ERR(dmabuf); + goto free_pool; + } + + return dmabuf; + +free_pool: + gen_pool_free(buffer->pool, (unsigned long)buffer->vaddr, buffer->len); +free_buffer: + kfree(buffer); + + return ERR_PTR(ret); +} + +static struct dma_heap_ops sram_dma_heap_ops = { + .allocate = sram_dma_heap_allocate, +}; + +int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part) +{ + struct sram_dma_heap *sram_dma_heap; + struct dma_heap_export_info exp_info; + + dev_info(sram->dev, "Exporting SRAM Heap '%s'\n", block->label); + + sram_dma_heap = kzalloc(sizeof(*sram_dma_heap), GFP_KERNEL); + if (!sram_dma_heap) + return -ENOMEM; + sram_dma_heap->pool = part->pool; + + exp_info.name = kasprintf(GFP_KERNEL, "sram_%s", block->label); + exp_info.ops = &sram_dma_heap_ops; + exp_info.priv = sram_dma_heap; + sram_dma_heap->heap = dma_heap_add(&exp_info); + if (IS_ERR(sram_dma_heap->heap)) { + int ret = PTR_ERR(sram_dma_heap->heap); + kfree(sram_dma_heap); + return ret; + } + + return 0; +} diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 5757adf418b1d..6dd173a2fba8e 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -120,6 +120,12 @@ static int sram_add_partition(struct sram_dev *sram, struct sram_reserve *block, ret = sram_add_pool(sram, block, start, part); if (ret) return ret; + + if (block->export) { + ret = sram_add_dma_heap(sram, block, start, part); + if (ret) + return ret; + } } if (block->export) { ret = sram_add_export(sram, block, start, part); diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h index 397205b8bf6ff..062bdd25fa068 100644 --- a/drivers/misc/sram.h +++ b/drivers/misc/sram.h @@ -60,4 +60,20 @@ static inline int sram_add_protect_exec(struct sram_partition *part) return -ENODEV; } #endif /* CONFIG_SRAM_EXEC */ + +#ifdef CONFIG_SRAM_DMA_HEAP +int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part); +#else +static inline int sram_add_dma_heap(struct sram_dev *sram, + struct sram_reserve *block, + phys_addr_t start, + struct sram_partition *part) +{ + return 0; +} +#endif /* CONFIG_SRAM_DMA_HEAP */ + #endif /* __SRAM_H */ -- 2.39.2
