// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2013-2014,2018 The Linux Foundation. All rights reserved.
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* Copyright (C) 2000-2004 Russell King
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/gfp.h>
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#include <linux/errno.h>
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#include <linux/list.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/dma-contiguous.h>
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#include <linux/highmem.h>
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#include <linux/memblock.h>
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#include <linux/slab.h>
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#include <linux/iommu.h>
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#include <linux/io.h>
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#include <linux/vmalloc.h>
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#include <linux/sizes.h>
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#include <linux/spinlock.h>
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struct removed_region {
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phys_addr_t base;
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int nr_pages;
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unsigned long *bitmap;
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struct mutex lock;
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};
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#define NO_KERNEL_MAPPING_DUMMY 0x2222
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static int dma_init_removed_memory(phys_addr_t phys_addr, size_t size,
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struct removed_region **mem)
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{
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struct removed_region *dma_mem = NULL;
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int pages = size >> PAGE_SHIFT;
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int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
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dma_mem = kzalloc(sizeof(struct removed_region), GFP_KERNEL);
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if (!dma_mem)
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goto out;
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dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!dma_mem->bitmap)
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goto free1_out;
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dma_mem->base = phys_addr;
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dma_mem->nr_pages = pages;
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mutex_init(&dma_mem->lock);
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*mem = dma_mem;
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return 0;
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free1_out:
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kfree(dma_mem);
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out:
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return -ENOMEM;
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}
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static int dma_assign_removed_region(struct device *dev,
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struct removed_region *mem)
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{
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if (dev->removed_mem)
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return -EBUSY;
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dev->removed_mem = mem;
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return 0;
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}
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void *removed_alloc(struct device *dev, size_t size, dma_addr_t *handle,
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gfp_t gfp, unsigned long attrs)
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{
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bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
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bool skip_zeroing = attrs & DMA_ATTR_SKIP_ZEROING;
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int pageno;
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unsigned long order;
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void __iomem *addr = NULL;
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struct removed_region *dma_mem = dev->removed_mem;
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int nbits;
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unsigned int align;
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if (!gfpflags_allow_blocking(gfp))
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return NULL;
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size = PAGE_ALIGN(size);
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nbits = size >> PAGE_SHIFT;
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order = get_order(size);
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if (order > get_order(SZ_1M))
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order = get_order(SZ_1M);
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align = (1 << order) - 1;
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mutex_lock(&dma_mem->lock);
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pageno = bitmap_find_next_zero_area(dma_mem->bitmap, dma_mem->nr_pages,
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0, nbits, align);
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if (pageno < dma_mem->nr_pages) {
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phys_addr_t base = dma_mem->base + pageno * PAGE_SIZE;
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*handle = base;
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bitmap_set(dma_mem->bitmap, pageno, nbits);
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if (no_kernel_mapping && skip_zeroing) {
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addr = (void *)NO_KERNEL_MAPPING_DUMMY;
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goto out;
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}
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addr = ioremap_wc(base, size);
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if (WARN_ON(!addr)) {
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bitmap_clear(dma_mem->bitmap, pageno, nbits);
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} else {
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if (!skip_zeroing)
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memset_io(addr, 0, size);
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if (no_kernel_mapping) {
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iounmap(addr);
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addr = (void *)NO_KERNEL_MAPPING_DUMMY;
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}
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*handle = base;
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}
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}
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out:
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mutex_unlock(&dma_mem->lock);
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return addr;
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}
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int removed_mmap(struct device *dev, struct vm_area_struct *vma,
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void *cpu_addr, dma_addr_t dma_addr, size_t size,
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unsigned long attrs)
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{
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return -ENXIO;
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}
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void removed_free(struct device *dev, size_t size, void *cpu_addr,
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dma_addr_t handle, unsigned long attrs)
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{
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bool no_kernel_mapping = attrs & DMA_ATTR_NO_KERNEL_MAPPING;
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struct removed_region *dma_mem = dev->removed_mem;
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size = PAGE_ALIGN(size);
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if (!no_kernel_mapping)
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iounmap(cpu_addr);
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mutex_lock(&dma_mem->lock);
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bitmap_clear(dma_mem->bitmap, (handle - dma_mem->base) >> PAGE_SHIFT,
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size >> PAGE_SHIFT);
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mutex_unlock(&dma_mem->lock);
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}
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static dma_addr_t removed_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir,
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unsigned long attrs)
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{
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return ~(dma_addr_t)0;
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}
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static void removed_unmap_page(struct device *dev, dma_addr_t dma_handle,
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size_t size, enum dma_data_direction dir,
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unsigned long attrs)
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{
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}
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static int removed_map_sg(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction dir,
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unsigned long attrs)
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{
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return 0;
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}
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static void removed_unmap_sg(struct device *dev,
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struct scatterlist *sg, int nents,
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enum dma_data_direction dir,
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unsigned long attrs)
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{
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}
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static void removed_sync_single_for_cpu(struct device *dev,
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dma_addr_t dma_handle, size_t size,
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enum dma_data_direction dir)
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{
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}
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void removed_sync_single_for_device(struct device *dev,
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dma_addr_t dma_handle, size_t size,
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enum dma_data_direction dir)
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{
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}
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void removed_sync_sg_for_cpu(struct device *dev,
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struct scatterlist *sg, int nents,
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enum dma_data_direction dir)
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{
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}
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void removed_sync_sg_for_device(struct device *dev,
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struct scatterlist *sg, int nents,
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enum dma_data_direction dir)
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{
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}
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static void __iomem *removed_remap(struct device *dev, void *cpu_addr,
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dma_addr_t handle, size_t size, unsigned long attrs)
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{
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return ioremap_wc(handle, size);
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}
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void removed_unremap(struct device *dev, void *remapped_address, size_t size)
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{
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iounmap(remapped_address);
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}
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const struct dma_map_ops removed_dma_ops = {
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.alloc = removed_alloc,
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.free = removed_free,
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.mmap = removed_mmap,
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.map_page = removed_map_page,
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.unmap_page = removed_unmap_page,
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.map_sg = removed_map_sg,
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.unmap_sg = removed_unmap_sg,
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.sync_single_for_cpu = removed_sync_single_for_cpu,
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.sync_single_for_device = removed_sync_single_for_device,
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.sync_sg_for_cpu = removed_sync_sg_for_cpu,
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.sync_sg_for_device = removed_sync_sg_for_device,
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.remap = removed_remap,
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.unremap = removed_unremap,
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};
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EXPORT_SYMBOL(removed_dma_ops);
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#ifdef CONFIG_OF_RESERVED_MEM
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#include <linux/of.h>
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#include <linux/of_fdt.h>
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#include <linux/of_reserved_mem.h>
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static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)
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{
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struct removed_region *mem = rmem->priv;
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if (!mem && dma_init_removed_memory(rmem->base, rmem->size, &mem)) {
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pr_info("Reserved memory: failed to init DMA memory pool at %pa, size %ld MiB\n",
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&rmem->base, (unsigned long)rmem->size / SZ_1M);
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return -EINVAL;
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}
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set_dma_ops(dev, &removed_dma_ops);
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rmem->priv = mem;
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dma_assign_removed_region(dev, mem);
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return 0;
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}
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static void rmem_dma_device_release(struct reserved_mem *rmem,
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struct device *dev)
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{
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dev->dma_mem = NULL;
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}
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static const struct reserved_mem_ops removed_mem_ops = {
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.device_init = rmem_dma_device_init,
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.device_release = rmem_dma_device_release,
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};
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static int __init removed_dma_setup(struct reserved_mem *rmem)
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{
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rmem->ops = &removed_mem_ops;
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pr_info("Removed memory: created DMA memory pool at %pa, size %ld MiB\n",
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&rmem->base, (unsigned long)rmem->size / SZ_1M);
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return 0;
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}
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RESERVEDMEM_OF_DECLARE(dma, "removed-dma-pool", removed_dma_setup);
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#endif
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