// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2012 ARM Ltd. * Copyright (C) 2020 Google LLC */#include <linux/debugfs.h>#include <linux/dma-direct.h>#include <linux/dma-noncoherent.h>#include <linux/init.h>#include <linux/genalloc.h>#include <linux/set_memory.h>#include <linux/slab.h>#include <linux/workqueue.h> static struct gen_pool *atomic_pool_dma __ro_after_init;static unsigned long pool_size_dma;static struct gen_pool *atomic_pool_dma32 __ro_after_init;static unsigned long pool_size_dma32;static struct gen_pool *atomic_pool_kernel __ro_after_init;static unsigned long pool_size_kernel; /* Size can be defined by the coherent_pool command line */static size_t atomic_pool_size; /* Dynamic background expansion when the atomic pool is near capacity */static struct work_struct atomic_pool_work; static int __init early_coherent_pool(char *p){	atomic_pool_size = memparse(p, &p);	return 0;}early_param("coherent_pool", early_coherent_pool); static void __init dma_atomic_pool_debugfs_init(void){	struct dentry *root; 	root = debugfs_create_dir("dma_pools", NULL);	if (IS_ERR_OR_NULL(root))		return; 	debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);	debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);	debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);} static void dma_atomic_pool_size_add(gfp_t gfp, size_t size){	if (gfp & __GFP_DMA)		pool_size_dma += size;	else if (gfp & __GFP_DMA32)		pool_size_dma32 += size;	else		pool_size_kernel += size;} static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,			      gfp_t gfp){	unsigned int order;	struct page *page;	void *addr;	int ret = -ENOMEM; 	/* Cannot allocate larger than MAX_ORDER-1 */	order = min(get_order(pool_size), MAX_ORDER-1); 	do {		pool_size = 1 << (PAGE_SHIFT + order);		page = alloc_pages(gfp, order);	} while (!page && order-- > 0);	if (!page)		goto out; 	arch_dma_prep_coherent(page, pool_size); #ifdef CONFIG_DMA_DIRECT_REMAP	addr = dma_common_contiguous_remap(page, pool_size,					   pgprot_dmacoherent(PAGE_KERNEL),					   __builtin_return_address(0));	if (!addr)		goto free_page;#else	addr = page_to_virt(page);#endif	/*	 * Memory in the atomic DMA pools must be unencrypted, the pools do not	 * shrink so no re-encryption occurs in dma_direct_free_pages().	 */	ret = set_memory_decrypted((unsigned long)page_to_virt(page),				   1 << order);	if (ret)		goto remove_mapping;	ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),				pool_size, NUMA_NO_NODE);	if (ret)		goto encrypt_mapping; 	dma_atomic_pool_size_add(gfp, pool_size);	return 0; encrypt_mapping:	ret = set_memory_encrypted((unsigned long)page_to_virt(page),				   1 << order);	if (WARN_ON_ONCE(ret)) {		/* Decrypt succeeded but encrypt failed, purposely leak */		goto out;	}remove_mapping:#ifdef CONFIG_DMA_DIRECT_REMAP	dma_common_free_remap(addr, pool_size);#endiffree_page: __maybe_unused	__free_pages(page, order);out:	return ret;} static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp){	if (pool && gen_pool_avail(pool) < atomic_pool_size)		atomic_pool_expand(pool, gen_pool_size(pool), gfp);} static void atomic_pool_work_fn(struct work_struct *work){	if (IS_ENABLED(CONFIG_ZONE_DMA))		atomic_pool_resize(atomic_pool_dma,				   GFP_KERNEL | GFP_DMA);	if (IS_ENABLED(CONFIG_ZONE_DMA32))		atomic_pool_resize(atomic_pool_dma32,				   GFP_KERNEL | GFP_DMA32);	atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);} static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,						      gfp_t gfp){	struct gen_pool *pool;	int ret; 	pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);	if (!pool)		return NULL; 	gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); 	ret = atomic_pool_expand(pool, pool_size, gfp);	if (ret) {		gen_pool_destroy(pool);		pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",		       pool_size >> 10, &gfp);		return NULL;	} 	pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",		gen_pool_size(pool) >> 10, &gfp);	return pool;} static int __init dma_atomic_pool_init(void){	int ret = 0; 	/*	 * If coherent_pool was not used on the command line, default the pool	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.	 */	if (!atomic_pool_size) {		unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);		pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);		atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);	}	INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); 	atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,						    GFP_KERNEL);	if (!atomic_pool_kernel)		ret = -ENOMEM;	if (IS_ENABLED(CONFIG_ZONE_DMA)) {		atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,						GFP_KERNEL | GFP_DMA);		if (!atomic_pool_dma)			ret = -ENOMEM;	}	if (IS_ENABLED(CONFIG_ZONE_DMA32)) {		atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,						GFP_KERNEL | GFP_DMA32);		if (!atomic_pool_dma32)			ret = -ENOMEM;	} 	dma_atomic_pool_debugfs_init();	return ret;}postcore_initcall(dma_atomic_pool_init); static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev){	u64 phys_mask;	gfp_t gfp; 	gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,					  &phys_mask);	if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)		return atomic_pool_dma;	if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)		return atomic_pool_dma32;	return atomic_pool_kernel;} static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool){	if (bad_pool == atomic_pool_kernel)		return atomic_pool_dma32 ? : atomic_pool_dma; 	if (bad_pool == atomic_pool_dma32)		return atomic_pool_dma; 	return NULL;} static inline struct gen_pool *dma_guess_pool(struct device *dev,					      struct gen_pool *bad_pool){	if (bad_pool)		return dma_get_safer_pool(bad_pool); 	return dma_guess_pool_from_device(dev);} void *dma_alloc_from_pool(struct device *dev, size_t size,			  struct page **ret_page, gfp_t flags){	struct gen_pool *pool = NULL;	unsigned long val = 0;	void *ptr = NULL;	phys_addr_t phys; 	while (1) {		pool = dma_guess_pool(dev, pool);		if (!pool) {			WARN(1, "Failed to get suitable pool for %s\n",			     dev_name(dev));			break;		} 		val = gen_pool_alloc(pool, size);		if (!val)			continue; 		phys = gen_pool_virt_to_phys(pool, val);		if (dma_coherent_ok(dev, phys, size))			break; 		gen_pool_free(pool, val, size);		val = 0;	}  	if (val) {		*ret_page = pfn_to_page(__phys_to_pfn(phys));		ptr = (void *)val;		memset(ptr, 0, size); 		if (gen_pool_avail(pool) < atomic_pool_size)			schedule_work(&atomic_pool_work);	} 	return ptr;} bool dma_free_from_pool(struct device *dev, void *start, size_t size){	struct gen_pool *pool = NULL; 	while (1) {		pool = dma_guess_pool(dev, pool);		if (!pool)			return false; 		if (gen_pool_has_addr(pool, (unsigned long)start, size)) {			gen_pool_free(pool, (unsigned long)start, size);			return true;		}	}}