517 lines
17 KiB
C
517 lines
17 KiB
C
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Pointer abstraction for IO/system memory
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*/
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#ifndef __IOSYS_MAP_H__
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#define __IOSYS_MAP_H__
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#include <linux/compiler_types.h>
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#include <linux/io.h>
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#include <linux/string.h>
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/**
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* DOC: overview
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*
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* When accessing a memory region, depending on its location, users may have to
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* access it with I/O operations or memory load/store operations. For example,
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* copying to system memory could be done with memcpy(), copying to I/O memory
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* would be done with memcpy_toio().
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*
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* .. code-block:: c
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*
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* void *vaddr = ...; // pointer to system memory
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* memcpy(vaddr, src, len);
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*
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* void *vaddr_iomem = ...; // pointer to I/O memory
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* memcpy_toio(vaddr_iomem, src, len);
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*
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* The user of such pointer may not have information about the mapping of that
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* region or may want to have a single code path to handle operations on that
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* buffer, regardless if it's located in system or IO memory. The type
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* :c:type:`struct iosys_map <iosys_map>` and its helpers abstract that so the
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* buffer can be passed around to other drivers or have separate duties inside
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* the same driver for allocation, read and write operations.
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*
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* Open-coding access to :c:type:`struct iosys_map <iosys_map>` is considered
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* bad style. Rather then accessing its fields directly, use one of the provided
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* helper functions, or implement your own. For example, instances of
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* :c:type:`struct iosys_map <iosys_map>` can be initialized statically with
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* IOSYS_MAP_INIT_VADDR(), or at runtime with iosys_map_set_vaddr(). These
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* helpers will set an address in system memory.
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*
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* .. code-block:: c
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*
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* struct iosys_map map = IOSYS_MAP_INIT_VADDR(0xdeadbeaf);
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*
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* iosys_map_set_vaddr(&map, 0xdeadbeaf);
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*
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* To set an address in I/O memory, use IOSYS_MAP_INIT_VADDR_IOMEM() or
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* iosys_map_set_vaddr_iomem().
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*
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* .. code-block:: c
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*
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* struct iosys_map map = IOSYS_MAP_INIT_VADDR_IOMEM(0xdeadbeaf);
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*
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* iosys_map_set_vaddr_iomem(&map, 0xdeadbeaf);
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*
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* Instances of struct iosys_map do not have to be cleaned up, but
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* can be cleared to NULL with iosys_map_clear(). Cleared mappings
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* always refer to system memory.
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*
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* .. code-block:: c
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*
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* iosys_map_clear(&map);
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*
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* Test if a mapping is valid with either iosys_map_is_set() or
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* iosys_map_is_null().
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*
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* .. code-block:: c
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*
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* if (iosys_map_is_set(&map) != iosys_map_is_null(&map))
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* // always true
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*
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* Instances of :c:type:`struct iosys_map <iosys_map>` can be compared for
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* equality with iosys_map_is_equal(). Mappings that point to different memory
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* spaces, system or I/O, are never equal. That's even true if both spaces are
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* located in the same address space, both mappings contain the same address
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* value, or both mappings refer to NULL.
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*
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* .. code-block:: c
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*
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* struct iosys_map sys_map; // refers to system memory
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* struct iosys_map io_map; // refers to I/O memory
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*
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* if (iosys_map_is_equal(&sys_map, &io_map))
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* // always false
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*
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* A set up instance of struct iosys_map can be used to access or manipulate the
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* buffer memory. Depending on the location of the memory, the provided helpers
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* will pick the correct operations. Data can be copied into the memory with
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* iosys_map_memcpy_to(). The address can be manipulated with iosys_map_incr().
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*
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* .. code-block:: c
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*
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* const void *src = ...; // source buffer
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* size_t len = ...; // length of src
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*
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* iosys_map_memcpy_to(&map, src, len);
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* iosys_map_incr(&map, len); // go to first byte after the memcpy
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*/
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/**
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* struct iosys_map - Pointer to IO/system memory
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* @vaddr_iomem: The buffer's address if in I/O memory
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* @vaddr: The buffer's address if in system memory
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* @is_iomem: True if the buffer is located in I/O memory, or false
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* otherwise.
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*/
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struct iosys_map {
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union {
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void __iomem *vaddr_iomem;
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void *vaddr;
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};
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bool is_iomem;
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};
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/**
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* IOSYS_MAP_INIT_VADDR - Initializes struct iosys_map to an address in system memory
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* @vaddr_: A system-memory address
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*/
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#define IOSYS_MAP_INIT_VADDR(vaddr_) \
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{ \
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.vaddr = (vaddr_), \
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.is_iomem = false, \
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}
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/**
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* IOSYS_MAP_INIT_VADDR_IOMEM - Initializes struct iosys_map to an address in I/O memory
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* @vaddr_iomem_: An I/O-memory address
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*/
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#define IOSYS_MAP_INIT_VADDR_IOMEM(vaddr_iomem_) \
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{ \
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.vaddr_iomem = (vaddr_iomem_), \
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.is_iomem = true, \
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}
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/**
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* IOSYS_MAP_INIT_OFFSET - Initializes struct iosys_map from another iosys_map
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* @map_: The dma-buf mapping structure to copy from
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* @offset_: Offset to add to the other mapping
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*
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* Initializes a new iosys_map struct based on another passed as argument. It
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* does a shallow copy of the struct so it's possible to update the back storage
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* without changing where the original map points to. It is the equivalent of
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* doing:
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*
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* .. code-block:: c
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*
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* iosys_map map = other_map;
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* iosys_map_incr(&map, &offset);
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*
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* Example usage:
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*
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* .. code-block:: c
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*
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* void foo(struct device *dev, struct iosys_map *base_map)
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* {
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* ...
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* struct iosys_map map = IOSYS_MAP_INIT_OFFSET(base_map, FIELD_OFFSET);
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* ...
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* }
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*
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* The advantage of using the initializer over just increasing the offset with
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* iosys_map_incr() like above is that the new map will always point to the
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* right place of the buffer during its scope. It reduces the risk of updating
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* the wrong part of the buffer and having no compiler warning about that. If
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* the assignment to IOSYS_MAP_INIT_OFFSET() is forgotten, the compiler can warn
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* about the use of uninitialized variable.
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*/
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#define IOSYS_MAP_INIT_OFFSET(map_, offset_) ({ \
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struct iosys_map copy = *map_; \
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iosys_map_incr(©, offset_); \
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copy; \
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})
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/**
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* iosys_map_set_vaddr - Sets a iosys mapping structure to an address in system memory
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* @map: The iosys_map structure
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* @vaddr: A system-memory address
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*
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* Sets the address and clears the I/O-memory flag.
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*/
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static inline void iosys_map_set_vaddr(struct iosys_map *map, void *vaddr)
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{
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map->vaddr = vaddr;
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map->is_iomem = false;
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}
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/**
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* iosys_map_set_vaddr_iomem - Sets a iosys mapping structure to an address in I/O memory
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* @map: The iosys_map structure
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* @vaddr_iomem: An I/O-memory address
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*
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* Sets the address and the I/O-memory flag.
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*/
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static inline void iosys_map_set_vaddr_iomem(struct iosys_map *map,
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void __iomem *vaddr_iomem)
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{
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map->vaddr_iomem = vaddr_iomem;
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map->is_iomem = true;
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}
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/**
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* iosys_map_is_equal - Compares two iosys mapping structures for equality
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* @lhs: The iosys_map structure
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* @rhs: A iosys_map structure to compare with
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*
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* Two iosys mapping structures are equal if they both refer to the same type of memory
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* and to the same address within that memory.
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*
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* Returns:
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* True is both structures are equal, or false otherwise.
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*/
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static inline bool iosys_map_is_equal(const struct iosys_map *lhs,
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const struct iosys_map *rhs)
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{
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if (lhs->is_iomem != rhs->is_iomem)
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return false;
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else if (lhs->is_iomem)
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return lhs->vaddr_iomem == rhs->vaddr_iomem;
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else
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return lhs->vaddr == rhs->vaddr;
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}
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/**
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* iosys_map_is_null - Tests for a iosys mapping to be NULL
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* @map: The iosys_map structure
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*
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* Depending on the state of struct iosys_map.is_iomem, tests if the
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* mapping is NULL.
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*
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* Returns:
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* True if the mapping is NULL, or false otherwise.
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*/
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static inline bool iosys_map_is_null(const struct iosys_map *map)
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{
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if (map->is_iomem)
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return !map->vaddr_iomem;
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return !map->vaddr;
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}
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/**
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* iosys_map_is_set - Tests if the iosys mapping has been set
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* @map: The iosys_map structure
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*
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* Depending on the state of struct iosys_map.is_iomem, tests if the
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* mapping has been set.
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*
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* Returns:
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* True if the mapping is been set, or false otherwise.
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*/
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static inline bool iosys_map_is_set(const struct iosys_map *map)
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{
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return !iosys_map_is_null(map);
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}
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/**
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* iosys_map_clear - Clears a iosys mapping structure
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* @map: The iosys_map structure
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*
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* Clears all fields to zero, including struct iosys_map.is_iomem, so
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* mapping structures that were set to point to I/O memory are reset for
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* system memory. Pointers are cleared to NULL. This is the default.
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*/
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static inline void iosys_map_clear(struct iosys_map *map)
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{
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if (map->is_iomem) {
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map->vaddr_iomem = NULL;
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map->is_iomem = false;
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} else {
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map->vaddr = NULL;
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}
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}
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/**
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* iosys_map_memcpy_to - Memcpy into offset of iosys_map
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* @dst: The iosys_map structure
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* @dst_offset: The offset from which to copy
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* @src: The source buffer
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* @len: The number of byte in src
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*
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* Copies data into a iosys_map with an offset. The source buffer is in
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* system memory. Depending on the buffer's location, the helper picks the
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* correct method of accessing the memory.
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*/
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static inline void iosys_map_memcpy_to(struct iosys_map *dst, size_t dst_offset,
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const void *src, size_t len)
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{
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if (dst->is_iomem)
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memcpy_toio(dst->vaddr_iomem + dst_offset, src, len);
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else
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memcpy(dst->vaddr + dst_offset, src, len);
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}
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/**
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* iosys_map_memcpy_from - Memcpy from iosys_map into system memory
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* @dst: Destination in system memory
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* @src: The iosys_map structure
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* @src_offset: The offset from which to copy
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* @len: The number of byte in src
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*
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* Copies data from a iosys_map with an offset. The dest buffer is in
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* system memory. Depending on the mapping location, the helper picks the
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* correct method of accessing the memory.
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*/
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static inline void iosys_map_memcpy_from(void *dst, const struct iosys_map *src,
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size_t src_offset, size_t len)
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{
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if (src->is_iomem)
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memcpy_fromio(dst, src->vaddr_iomem + src_offset, len);
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else
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memcpy(dst, src->vaddr + src_offset, len);
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}
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/**
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* iosys_map_incr - Increments the address stored in a iosys mapping
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* @map: The iosys_map structure
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* @incr: The number of bytes to increment
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*
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* Increments the address stored in a iosys mapping. Depending on the
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* buffer's location, the correct value will be updated.
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*/
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static inline void iosys_map_incr(struct iosys_map *map, size_t incr)
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{
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if (map->is_iomem)
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map->vaddr_iomem += incr;
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else
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map->vaddr += incr;
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}
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/**
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* iosys_map_memset - Memset iosys_map
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* @dst: The iosys_map structure
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* @offset: Offset from dst where to start setting value
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* @value: The value to set
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* @len: The number of bytes to set in dst
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*
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* Set value in iosys_map. Depending on the buffer's location, the helper
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* picks the correct method of accessing the memory.
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*/
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static inline void iosys_map_memset(struct iosys_map *dst, size_t offset,
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int value, size_t len)
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{
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if (dst->is_iomem)
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memset_io(dst->vaddr_iomem + offset, value, len);
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else
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memset(dst->vaddr + offset, value, len);
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}
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#ifdef CONFIG_64BIT
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#define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_) \
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u64: val_ = readq(vaddr_iomem_)
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#define __iosys_map_wr_io_u64_case(val_, vaddr_iomem_) \
|
||
|
|
u64: writeq(val_, vaddr_iomem_)
|
||
|
|
#else
|
||
|
|
#define __iosys_map_rd_io_u64_case(val_, vaddr_iomem_) \
|
||
|
|
u64: memcpy_fromio(&(val_), vaddr_iomem_, sizeof(u64))
|
||
|
|
#define __iosys_map_wr_io_u64_case(val_, vaddr_iomem_) \
|
||
|
|
u64: memcpy_toio(vaddr_iomem_, &(val_), sizeof(u64))
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#define __iosys_map_rd_io(val__, vaddr_iomem__, type__) _Generic(val__, \
|
||
|
|
u8: val__ = readb(vaddr_iomem__), \
|
||
|
|
u16: val__ = readw(vaddr_iomem__), \
|
||
|
|
u32: val__ = readl(vaddr_iomem__), \
|
||
|
|
__iosys_map_rd_io_u64_case(val__, vaddr_iomem__))
|
||
|
|
|
||
|
|
#define __iosys_map_rd_sys(val__, vaddr__, type__) \
|
||
|
|
val__ = READ_ONCE(*(type__ *)(vaddr__))
|
||
|
|
|
||
|
|
#define __iosys_map_wr_io(val__, vaddr_iomem__, type__) _Generic(val__, \
|
||
|
|
u8: writeb(val__, vaddr_iomem__), \
|
||
|
|
u16: writew(val__, vaddr_iomem__), \
|
||
|
|
u32: writel(val__, vaddr_iomem__), \
|
||
|
|
__iosys_map_wr_io_u64_case(val__, vaddr_iomem__))
|
||
|
|
|
||
|
|
#define __iosys_map_wr_sys(val__, vaddr__, type__) \
|
||
|
|
WRITE_ONCE(*(type__ *)(vaddr__), val__)
|
||
|
|
|
||
|
|
/**
|
||
|
|
* iosys_map_rd - Read a C-type value from the iosys_map
|
||
|
|
*
|
||
|
|
* @map__: The iosys_map structure
|
||
|
|
* @offset__: The offset from which to read
|
||
|
|
* @type__: Type of the value being read
|
||
|
|
*
|
||
|
|
* Read a C type value (u8, u16, u32 and u64) from iosys_map. For other types or
|
||
|
|
* if pointer may be unaligned (and problematic for the architecture supported),
|
||
|
|
* use iosys_map_memcpy_from().
|
||
|
|
*
|
||
|
|
* Returns:
|
||
|
|
* The value read from the mapping.
|
||
|
|
*/
|
||
|
|
#define iosys_map_rd(map__, offset__, type__) ({ \
|
||
|
|
type__ val; \
|
||
|
|
if ((map__)->is_iomem) { \
|
||
|
|
__iosys_map_rd_io(val, (map__)->vaddr_iomem + (offset__), type__);\
|
||
|
|
} else { \
|
||
|
|
__iosys_map_rd_sys(val, (map__)->vaddr + (offset__), type__); \
|
||
|
|
} \
|
||
|
|
val; \
|
||
|
|
})
|
||
|
|
|
||
|
|
/**
|
||
|
|
* iosys_map_wr - Write a C-type value to the iosys_map
|
||
|
|
*
|
||
|
|
* @map__: The iosys_map structure
|
||
|
|
* @offset__: The offset from the mapping to write to
|
||
|
|
* @type__: Type of the value being written
|
||
|
|
* @val__: Value to write
|
||
|
|
*
|
||
|
|
* Write a C type value (u8, u16, u32 and u64) to the iosys_map. For other types
|
||
|
|
* or if pointer may be unaligned (and problematic for the architecture
|
||
|
|
* supported), use iosys_map_memcpy_to()
|
||
|
|
*/
|
||
|
|
#define iosys_map_wr(map__, offset__, type__, val__) ({ \
|
||
|
|
type__ val = (val__); \
|
||
|
|
if ((map__)->is_iomem) { \
|
||
|
|
__iosys_map_wr_io(val, (map__)->vaddr_iomem + (offset__), type__);\
|
||
|
|
} else { \
|
||
|
|
__iosys_map_wr_sys(val, (map__)->vaddr + (offset__), type__); \
|
||
|
|
} \
|
||
|
|
})
|
||
|
|
|
||
|
|
/**
|
||
|
|
* iosys_map_rd_field - Read a member from a struct in the iosys_map
|
||
|
|
*
|
||
|
|
* @map__: The iosys_map structure
|
||
|
|
* @struct_offset__: Offset from the beggining of the map, where the struct
|
||
|
|
* is located
|
||
|
|
* @struct_type__: The struct describing the layout of the mapping
|
||
|
|
* @field__: Member of the struct to read
|
||
|
|
*
|
||
|
|
* Read a value from iosys_map considering its layout is described by a C struct
|
||
|
|
* starting at @struct_offset__. The field offset and size is calculated and its
|
||
|
|
* value read. If the field access would incur in un-aligned access, then either
|
||
|
|
* iosys_map_memcpy_from() needs to be used or the architecture must support it.
|
||
|
|
* For example: suppose there is a @struct foo defined as below and the value
|
||
|
|
* ``foo.field2.inner2`` needs to be read from the iosys_map:
|
||
|
|
*
|
||
|
|
* .. code-block:: c
|
||
|
|
*
|
||
|
|
* struct foo {
|
||
|
|
* int field1;
|
||
|
|
* struct {
|
||
|
|
* int inner1;
|
||
|
|
* int inner2;
|
||
|
|
* } field2;
|
||
|
|
* int field3;
|
||
|
|
* } __packed;
|
||
|
|
*
|
||
|
|
* This is the expected memory layout of a buffer using iosys_map_rd_field():
|
||
|
|
*
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | Address | Content |
|
||
|
|
* +==============================+==========================+
|
||
|
|
* | buffer + 0000 | start of mmapped buffer |
|
||
|
|
* | | pointed by iosys_map |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | ... | ... |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | buffer + ``struct_offset__`` | start of ``struct foo`` |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | ... | ... |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | buffer + wwww | ``foo.field2.inner2`` |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | ... | ... |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | buffer + yyyy | end of ``struct foo`` |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | ... | ... |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
* | buffer + zzzz | end of mmaped buffer |
|
||
|
|
* +------------------------------+--------------------------+
|
||
|
|
*
|
||
|
|
* Values automatically calculated by this macro or not needed are denoted by
|
||
|
|
* wwww, yyyy and zzzz. This is the code to read that value:
|
||
|
|
*
|
||
|
|
* .. code-block:: c
|
||
|
|
*
|
||
|
|
* x = iosys_map_rd_field(&map, offset, struct foo, field2.inner2);
|
||
|
|
*
|
||
|
|
* Returns:
|
||
|
|
* The value read from the mapping.
|
||
|
|
*/
|
||
|
|
#define iosys_map_rd_field(map__, struct_offset__, struct_type__, field__) ({ \
|
||
|
|
struct_type__ *s; \
|
||
|
|
iosys_map_rd(map__, struct_offset__ + offsetof(struct_type__, field__), \
|
||
|
|
typeof(s->field__)); \
|
||
|
|
})
|
||
|
|
|
||
|
|
/**
|
||
|
|
* iosys_map_wr_field - Write to a member of a struct in the iosys_map
|
||
|
|
*
|
||
|
|
* @map__: The iosys_map structure
|
||
|
|
* @struct_offset__: Offset from the beggining of the map, where the struct
|
||
|
|
* is located
|
||
|
|
* @struct_type__: The struct describing the layout of the mapping
|
||
|
|
* @field__: Member of the struct to read
|
||
|
|
* @val__: Value to write
|
||
|
|
*
|
||
|
|
* Write a value to the iosys_map considering its layout is described by a C
|
||
|
|
* struct starting at @struct_offset__. The field offset and size is calculated
|
||
|
|
* and the @val__ is written. If the field access would incur in un-aligned
|
||
|
|
* access, then either iosys_map_memcpy_to() needs to be used or the
|
||
|
|
* architecture must support it. Refer to iosys_map_rd_field() for expected
|
||
|
|
* usage and memory layout.
|
||
|
|
*/
|
||
|
|
#define iosys_map_wr_field(map__, struct_offset__, struct_type__, field__, val__) ({ \
|
||
|
|
struct_type__ *s; \
|
||
|
|
iosys_map_wr(map__, struct_offset__ + offsetof(struct_type__, field__), \
|
||
|
|
typeof(s->field__), val__); \
|
||
|
|
})
|
||
|
|
|
||
|
|
#endif /* __IOSYS_MAP_H__ */
|