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dma: Document address_space_map/address_space_unmap() prototypes

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Add documentation based on address_space_map / address_space_unmap.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201023151923.3243652-4-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Philippe Mathieu-Daudé 2020-10-23 17:19:16 +02:00 • committed by Paolo Bonzini
parent 169cbac12d
commit 9c211ad2ca
1 changed files with 28 additions and 1 deletions
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29
include/sysemu/dma.h
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@ -1,7 +1,7 @@
/* /*
* DMA helper functions * DMA helper functions
* *
* Copyright (c) 2009 Red Hat * Copyright (c) 2009, 2020 Red Hat
* *
* This work is licensed under the terms of the GNU General Public License * This work is licensed under the terms of the GNU General Public License
* (GNU GPL), version 2 or later. * (GNU GPL), version 2 or later.
@ -125,6 +125,19 @@ static inline int dma_memory_write(AddressSpace *as, dma_addr_t addr,
int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len); int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len);
/**
* address_space_map: Map a physical memory region into a host virtual address.
*
* May map a subset of the requested range, given by and returned in @plen.
* May return %NULL and set *@plen to zero(0), if resources needed to perform
* the mapping are exhausted.
* Use only for reads OR writes - not for read-modify-write operations.
*
* @as: #AddressSpace to be accessed
* @addr: address within that address space
* @len: pointer to length of buffer; updated on return
* @dir: indicates the transfer direction
*/
static inline void *dma_memory_map(AddressSpace *as, static inline void *dma_memory_map(AddressSpace *as,
dma_addr_t addr, dma_addr_t *len, dma_addr_t addr, dma_addr_t *len,
DMADirection dir) DMADirection dir)
@ -138,6 +151,20 @@ static inline void *dma_memory_map(AddressSpace *as,
return p; return p;
} }
/**
* address_space_unmap: Unmaps a memory region previously mapped
* by dma_memory_map()
*
* Will also mark the memory as dirty if @dir == %DMA_DIRECTION_FROM_DEVICE.
* @access_len gives the amount of memory that was actually read or written
* by the caller.
*
* @as: #AddressSpace used
* @buffer: host pointer as returned by address_space_map()
* @len: buffer length as returned by address_space_map()
* @dir: indicates the transfer direction
* @access_len: amount of data actually transferred
*/
static inline void dma_memory_unmap(AddressSpace *as, static inline void dma_memory_unmap(AddressSpace *as,
void *buffer, dma_addr_t len, void *buffer, dma_addr_t len,
DMADirection dir, dma_addr_t access_len) DMADirection dir, dma_addr_t access_len)