// SPDX-License-Identifier: GPL-2.0-only /* * Dynamic DMA mapping support. * * This implementation is a fallback for platforms that do not support * I/O TLBs (aka DMA address translation hardware). * Copyright (C) 2000 Asit Mallick <[email protected]> * Copyright (C) 2000 Goutham Rao <[email protected]> * Copyright (C) 2000, 2003 Hewlett-Packard Co * David Mosberger-Tang <[email protected]> * * 03/05/07 davidm Switch from PCI-DMA to generic device DMA API. * 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid * unnecessary i-cache flushing. * 04/07/.. ak Better overflow handling. Assorted fixes. * 05/09/10 linville Add support for syncing ranges, support syncing for * DMA_BIDIRECTIONAL mappings, miscellaneous cleanup. * 08/12/11 beckyb Add highmem support */ #define pr_fmt(fmt) … #include <linux/cache.h> #include <linux/cc_platform.h> #include <linux/ctype.h> #include <linux/debugfs.h> #include <linux/dma-direct.h> #include <linux/dma-map-ops.h> #include <linux/export.h> #include <linux/gfp.h> #include <linux/highmem.h> #include <linux/io.h> #include <linux/iommu-helper.h> #include <linux/init.h> #include <linux/memblock.h> #include <linux/mm.h> #include <linux/pfn.h> #include <linux/rculist.h> #include <linux/scatterlist.h> #include <linux/set_memory.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/swiotlb.h> #include <linux/types.h> #ifdef CONFIG_DMA_RESTRICTED_POOL #include <linux/of.h> #include <linux/of_fdt.h> #include <linux/of_reserved_mem.h> #include <linux/slab.h> #endif #define CREATE_TRACE_POINTS #include <trace/events/swiotlb.h> #define SLABS_PER_PAGE … /* * Minimum IO TLB size to bother booting with. Systems with mainly * 64bit capable cards will only lightly use the swiotlb. If we can't * allocate a contiguous 1MB, we're probably in trouble anyway. */ #define IO_TLB_MIN_SLABS … #define INVALID_PHYS_ADDR … /** * struct io_tlb_slot - IO TLB slot descriptor * @orig_addr: The original address corresponding to a mapped entry. * @alloc_size: Size of the allocated buffer. * @list: The free list describing the number of free entries available * from each index. * @pad_slots: Number of preceding padding slots. Valid only in the first * allocated non-padding slot. */ struct io_tlb_slot { … }; static bool swiotlb_force_bounce; static bool swiotlb_force_disable; #ifdef CONFIG_SWIOTLB_DYNAMIC static void swiotlb_dyn_alloc(struct work_struct *work); static struct io_tlb_mem io_tlb_default_mem = …; #else /* !CONFIG_SWIOTLB_DYNAMIC */ static struct io_tlb_mem io_tlb_default_mem; #endif /* CONFIG_SWIOTLB_DYNAMIC */ static unsigned long default_nslabs = …; static unsigned long default_nareas; /** * struct io_tlb_area - IO TLB memory area descriptor * * This is a single area with a single lock. * * @used: The number of used IO TLB block. * @index: The slot index to start searching in this area for next round. * @lock: The lock to protect the above data structures in the map and * unmap calls. */ struct io_tlb_area { … }; /* * Round up number of slabs to the next power of 2. The last area is going * be smaller than the rest if default_nslabs is not power of two. * The number of slot in an area should be a multiple of IO_TLB_SEGSIZE, * otherwise a segment may span two or more areas. It conflicts with free * contiguous slots tracking: free slots are treated contiguous no matter * whether they cross an area boundary. * * Return true if default_nslabs is rounded up. */ static bool round_up_default_nslabs(void) { … } /** * swiotlb_adjust_nareas() - adjust the number of areas and slots * @nareas: Desired number of areas. Zero is treated as 1. * * Adjust the default number of areas in a memory pool. * The default size of the memory pool may also change to meet minimum area * size requirements. */ static void swiotlb_adjust_nareas(unsigned int nareas) { … } /** * limit_nareas() - get the maximum number of areas for a given memory pool size * @nareas: Desired number of areas. * @nslots: Total number of slots in the memory pool. * * Limit the number of areas to the maximum possible number of areas in * a memory pool of the given size. * * Return: Maximum possible number of areas. */ static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots) { … } static int __init setup_io_tlb_npages(char *str) { … } early_param(…); unsigned long swiotlb_size_or_default(void) { … } void __init swiotlb_adjust_size(unsigned long size) { … } void swiotlb_print_info(void) { … } static inline unsigned long io_tlb_offset(unsigned long val) { … } static inline unsigned long nr_slots(u64 val) { … } /* * Early SWIOTLB allocation may be too early to allow an architecture to * perform the desired operations. This function allows the architecture to * call SWIOTLB when the operations are possible. It needs to be called * before the SWIOTLB memory is used. */ void __init swiotlb_update_mem_attributes(void) { … } static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start, unsigned long nslabs, bool late_alloc, unsigned int nareas) { … } /** * add_mem_pool() - add a memory pool to the allocator * @mem: Software IO TLB allocator. * @pool: Memory pool to be added. */ static void add_mem_pool(struct io_tlb_mem *mem, struct io_tlb_pool *pool) { … } static void __init *swiotlb_memblock_alloc(unsigned long nslabs, unsigned int flags, int (*remap)(void *tlb, unsigned long nslabs)) { … } /* * Statically reserve bounce buffer space and initialize bounce buffer data * structures for the software IO TLB used to implement the DMA API. */ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, int (*remap)(void *tlb, unsigned long nslabs)) { … } void __init swiotlb_init(bool addressing_limit, unsigned int flags) { … } /* * Systems with larger DMA zones (those that don't support ISA) can * initialize the swiotlb later using the slab allocator if needed. * This should be just like above, but with some error catching. */ int swiotlb_init_late(size_t size, gfp_t gfp_mask, int (*remap)(void *tlb, unsigned long nslabs)) { … } void __init swiotlb_exit(void) { … } #ifdef CONFIG_SWIOTLB_DYNAMIC /** * alloc_dma_pages() - allocate pages to be used for DMA * @gfp: GFP flags for the allocation. * @bytes: Size of the buffer. * @phys_limit: Maximum allowed physical address of the buffer. * * Allocate pages from the buddy allocator. If successful, make the allocated * pages decrypted that they can be used for DMA. * * Return: Decrypted pages, %NULL on allocation failure, or ERR_PTR(-EAGAIN) * if the allocated physical address was above @phys_limit. */ static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit) { … } /** * swiotlb_alloc_tlb() - allocate a dynamic IO TLB buffer * @dev: Device for which a memory pool is allocated. * @bytes: Size of the buffer. * @phys_limit: Maximum allowed physical address of the buffer. * @gfp: GFP flags for the allocation. * * Return: Allocated pages, or %NULL on allocation failure. */ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, u64 phys_limit, gfp_t gfp) { … } /** * swiotlb_free_tlb() - free a dynamically allocated IO TLB buffer * @vaddr: Virtual address of the buffer. * @bytes: Size of the buffer. */ static void swiotlb_free_tlb(void *vaddr, size_t bytes) { … } /** * swiotlb_alloc_pool() - allocate a new IO TLB memory pool * @dev: Device for which a memory pool is allocated. * @minslabs: Minimum number of slabs. * @nslabs: Desired (maximum) number of slabs. * @nareas: Number of areas. * @phys_limit: Maximum DMA buffer physical address. * @gfp: GFP flags for the allocations. * * Allocate and initialize a new IO TLB memory pool. The actual number of * slabs may be reduced if allocation of @nslabs fails. If even * @minslabs cannot be allocated, this function fails. * * Return: New memory pool, or %NULL on allocation failure. */ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev, unsigned long minslabs, unsigned long nslabs, unsigned int nareas, u64 phys_limit, gfp_t gfp) { … } /** * swiotlb_dyn_alloc() - dynamic memory pool allocation worker * @work: Pointer to dyn_alloc in struct io_tlb_mem. */ static void swiotlb_dyn_alloc(struct work_struct *work) { … } /** * swiotlb_dyn_free() - RCU callback to free a memory pool * @rcu: RCU head in the corresponding struct io_tlb_pool. */ static void swiotlb_dyn_free(struct rcu_head *rcu) { … } /** * __swiotlb_find_pool() - find the IO TLB pool for a physical address * @dev: Device which has mapped the DMA buffer. * @paddr: Physical address within the DMA buffer. * * Find the IO TLB memory pool descriptor which contains the given physical * address, if any. This function is for use only when the dev is known to * be using swiotlb. Use swiotlb_find_pool() for the more general case * when this condition is not met. * * Return: Memory pool which contains @paddr, or %NULL if none. */ struct io_tlb_pool *__swiotlb_find_pool(struct device *dev, phys_addr_t paddr) { … } /** * swiotlb_del_pool() - remove an IO TLB pool from a device * @dev: Owning device. * @pool: Memory pool to be removed. */ static void swiotlb_del_pool(struct device *dev, struct io_tlb_pool *pool) { … } #endif /* CONFIG_SWIOTLB_DYNAMIC */ /** * swiotlb_dev_init() - initialize swiotlb fields in &struct device * @dev: Device to be initialized. */ void swiotlb_dev_init(struct device *dev) { … } /** * swiotlb_align_offset() - Get required offset into an IO TLB allocation. * @dev: Owning device. * @align_mask: Allocation alignment mask. * @addr: DMA address. * * Return the minimum offset from the start of an IO TLB allocation which is * required for a given buffer address and allocation alignment to keep the * device happy. * * First, the address bits covered by min_align_mask must be identical in the * original address and the bounce buffer address. High bits are preserved by * choosing a suitable IO TLB slot, but bits below IO_TLB_SHIFT require extra * padding bytes before the bounce buffer. * * Second, @align_mask specifies which bits of the first allocated slot must * be zero. This may require allocating additional padding slots, and then the * offset (in bytes) from the first such padding slot is returned. */ static unsigned int swiotlb_align_offset(struct device *dev, unsigned int align_mask, u64 addr) { … } /* * Bounce: copy the swiotlb buffer from or back to the original dma location */ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir, struct io_tlb_pool *mem) { … } static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx) { … } /* * Carefully handle integer overflow which can occur when boundary_mask == ~0UL. */ static inline unsigned long get_max_slots(unsigned long boundary_mask) { … } static unsigned int wrap_area_index(struct io_tlb_pool *mem, unsigned int index) { … } /* * Track the total used slots with a global atomic value in order to have * correct information to determine the high water mark. The mem_used() * function gives imprecise results because there's no locking across * multiple areas. */ #ifdef CONFIG_DEBUG_FS static void inc_used_and_hiwater(struct io_tlb_mem *mem, unsigned int nslots) { … } static void dec_used(struct io_tlb_mem *mem, unsigned int nslots) { … } #else /* !CONFIG_DEBUG_FS */ static void inc_used_and_hiwater(struct io_tlb_mem *mem, unsigned int nslots) { } static void dec_used(struct io_tlb_mem *mem, unsigned int nslots) { } #endif /* CONFIG_DEBUG_FS */ #ifdef CONFIG_SWIOTLB_DYNAMIC #ifdef CONFIG_DEBUG_FS static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots) { … } static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots) { … } #else /* !CONFIG_DEBUG_FS */ static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots) { } static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots) { } #endif /* CONFIG_DEBUG_FS */ #endif /* CONFIG_SWIOTLB_DYNAMIC */ /** * swiotlb_search_pool_area() - search one memory area in one pool * @dev: Device which maps the buffer. * @pool: Memory pool to be searched. * @area_index: Index of the IO TLB memory area to be searched. * @orig_addr: Original (non-bounced) IO buffer address. * @alloc_size: Total requested size of the bounce buffer, * including initial alignment padding. * @alloc_align_mask: Required alignment of the allocated buffer. * * Find a suitable sequence of IO TLB entries for the request and allocate * a buffer from the given IO TLB memory area. * This function takes care of locking. * * Return: Index of the first allocated slot, or -1 on error. */ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool, int area_index, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask) { … } #ifdef CONFIG_SWIOTLB_DYNAMIC /** * swiotlb_search_area() - search one memory area in all pools * @dev: Device which maps the buffer. * @start_cpu: Start CPU number. * @cpu_offset: Offset from @start_cpu. * @orig_addr: Original (non-bounced) IO buffer address. * @alloc_size: Total requested size of the bounce buffer, * including initial alignment padding. * @alloc_align_mask: Required alignment of the allocated buffer. * @retpool: Used memory pool, updated on return. * * Search one memory area in all pools for a sequence of slots that match the * allocation constraints. * * Return: Index of the first allocated slot, or -1 on error. */ static int swiotlb_search_area(struct device *dev, int start_cpu, int cpu_offset, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask, struct io_tlb_pool **retpool) { … } /** * swiotlb_find_slots() - search for slots in the whole swiotlb * @dev: Device which maps the buffer. * @orig_addr: Original (non-bounced) IO buffer address. * @alloc_size: Total requested size of the bounce buffer, * including initial alignment padding. * @alloc_align_mask: Required alignment of the allocated buffer. * @retpool: Used memory pool, updated on return. * * Search through the whole software IO TLB to find a sequence of slots that * match the allocation constraints. * * Return: Index of the first allocated slot, or -1 on error. */ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask, struct io_tlb_pool **retpool) { … } #else /* !CONFIG_SWIOTLB_DYNAMIC */ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, size_t alloc_size, unsigned int alloc_align_mask, struct io_tlb_pool **retpool) { struct io_tlb_pool *pool; int start, i; int index; *retpool = pool = &dev->dma_io_tlb_mem->defpool; i = start = raw_smp_processor_id() & (pool->nareas - 1); do { index = swiotlb_search_pool_area(dev, pool, i, orig_addr, alloc_size, alloc_align_mask); if (index >= 0) return index; if (++i >= pool->nareas) i = 0; } while (i != start); return -1; } #endif /* CONFIG_SWIOTLB_DYNAMIC */ #ifdef CONFIG_DEBUG_FS /** * mem_used() - get number of used slots in an allocator * @mem: Software IO TLB allocator. * * The result is accurate in this version of the function, because an atomic * counter is available if CONFIG_DEBUG_FS is set. * * Return: Number of used slots. */ static unsigned long mem_used(struct io_tlb_mem *mem) { … } #else /* !CONFIG_DEBUG_FS */ /** * mem_pool_used() - get number of used slots in a memory pool * @pool: Software IO TLB memory pool. * * The result is not accurate, see mem_used(). * * Return: Approximate number of used slots. */ static unsigned long mem_pool_used(struct io_tlb_pool *pool) { int i; unsigned long used = 0; for (i = 0; i < pool->nareas; i++) used += pool->areas[i].used; return used; } /** * mem_used() - get number of used slots in an allocator * @mem: Software IO TLB allocator. * * The result is not accurate, because there is no locking of individual * areas. * * Return: Approximate number of used slots. */ static unsigned long mem_used(struct io_tlb_mem *mem) { #ifdef CONFIG_SWIOTLB_DYNAMIC struct io_tlb_pool *pool; unsigned long used = 0; rcu_read_lock(); list_for_each_entry_rcu(pool, &mem->pools, node) used += mem_pool_used(pool); rcu_read_unlock(); return used; #else return mem_pool_used(&mem->defpool); #endif } #endif /* CONFIG_DEBUG_FS */ /** * swiotlb_tbl_map_single() - bounce buffer map a single contiguous physical area * @dev: Device which maps the buffer. * @orig_addr: Original (non-bounced) physical IO buffer address * @mapping_size: Requested size of the actual bounce buffer, excluding * any pre- or post-padding for alignment * @alloc_align_mask: Required start and end alignment of the allocated buffer * @dir: DMA direction * @attrs: Optional DMA attributes for the map operation * * Find and allocate a suitable sequence of IO TLB slots for the request. * The allocated space starts at an alignment specified by alloc_align_mask, * and the size of the allocated space is rounded up so that the total amount * of allocated space is a multiple of (alloc_align_mask + 1). If * alloc_align_mask is zero, the allocated space may be at any alignment and * the size is not rounded up. * * The returned address is within the allocated space and matches the bits * of orig_addr that are specified in the DMA min_align_mask for the device. As * such, this returned address may be offset from the beginning of the allocated * space. The bounce buffer space starting at the returned address for * mapping_size bytes is initialized to the contents of the original IO buffer * area. Any pre-padding (due to an offset) and any post-padding (due to * rounding-up the size) is not initialized. */ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, size_t mapping_size, unsigned int alloc_align_mask, enum dma_data_direction dir, unsigned long attrs) { … } static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr, struct io_tlb_pool *mem) { … } #ifdef CONFIG_SWIOTLB_DYNAMIC /** * swiotlb_del_transient() - delete a transient memory pool * @dev: Device which mapped the buffer. * @tlb_addr: Physical address within a bounce buffer. * @pool: Pointer to the transient memory pool to be checked and deleted. * * Check whether the address belongs to a transient SWIOTLB memory pool. * If yes, then delete the pool. * * Return: %true if @tlb_addr belonged to a transient pool that was released. */ static bool swiotlb_del_transient(struct device *dev, phys_addr_t tlb_addr, struct io_tlb_pool *pool) { … } #else /* !CONFIG_SWIOTLB_DYNAMIC */ static inline bool swiotlb_del_transient(struct device *dev, phys_addr_t tlb_addr, struct io_tlb_pool *pool) { return false; } #endif /* CONFIG_SWIOTLB_DYNAMIC */ /* * tlb_addr is the physical address of the bounce buffer to unmap. */ void __swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr, size_t mapping_size, enum dma_data_direction dir, unsigned long attrs, struct io_tlb_pool *pool) { … } void __swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir, struct io_tlb_pool *pool) { … } void __swiotlb_sync_single_for_cpu(struct device *dev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir, struct io_tlb_pool *pool) { … } /* * Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing * to the device copy the data into it as well. */ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size, enum dma_data_direction dir, unsigned long attrs) { … } size_t swiotlb_max_mapping_size(struct device *dev) { … } /** * is_swiotlb_allocated() - check if the default software IO TLB is initialized */ bool is_swiotlb_allocated(void) { … } bool is_swiotlb_active(struct device *dev) { … } /** * default_swiotlb_base() - get the base address of the default SWIOTLB * * Get the lowest physical address used by the default software IO TLB pool. */ phys_addr_t default_swiotlb_base(void) { … } /** * default_swiotlb_limit() - get the address limit of the default SWIOTLB * * Get the highest physical address used by the default software IO TLB pool. */ phys_addr_t default_swiotlb_limit(void) { … } #ifdef CONFIG_DEBUG_FS #ifdef CONFIG_SWIOTLB_DYNAMIC static unsigned long mem_transient_used(struct io_tlb_mem *mem) { … } static int io_tlb_transient_used_get(void *data, u64 *val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); #endif /* CONFIG_SWIOTLB_DYNAMIC */ static int io_tlb_used_get(void *data, u64 *val) { … } static int io_tlb_hiwater_get(void *data, u64 *val) { … } static int io_tlb_hiwater_set(void *data, u64 val) { … } DEFINE_DEBUGFS_ATTRIBUTE(…); DEFINE_DEBUGFS_ATTRIBUTE(…); static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem, const char *dirname) { … } static int __init swiotlb_create_default_debugfs(void) { … } late_initcall(swiotlb_create_default_debugfs); #else /* !CONFIG_DEBUG_FS */ static inline void swiotlb_create_debugfs_files(struct io_tlb_mem *mem, const char *dirname) { } #endif /* CONFIG_DEBUG_FS */ #ifdef CONFIG_DMA_RESTRICTED_POOL struct page *swiotlb_alloc(struct device *dev, size_t size) { … } bool swiotlb_free(struct device *dev, struct page *page, size_t size) { … } static int rmem_swiotlb_device_init(struct reserved_mem *rmem, struct device *dev) { … } static void rmem_swiotlb_device_release(struct reserved_mem *rmem, struct device *dev) { … } static const struct reserved_mem_ops rmem_swiotlb_ops = …; static int __init rmem_swiotlb_setup(struct reserved_mem *rmem) { … } RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup); #endif /* CONFIG_DMA_RESTRICTED_POOL */
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