Re: [PATCH 03/13] dma: Document address_space_map/address_space_unmap() prototypes

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Fri, Sep 04, 2020 at 05:44:29PM +0200, Philippe Mathieu-Daudé wrote:
> Add documentation based on address_space_map / address_space_unmap.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  include/sysemu/dma.h | 30 +++++++++++++++++++++++++++++-
>  1 file changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
> index 80c5bc3e02d..19bc9ad1b69 100644
> --- a/include/sysemu/dma.h
> +++ b/include/sysemu/dma.h
> @@ -1,7 +1,7 @@
>  /*
>   * 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
>   * (GNU GPL), version 2 or later.
> @@ -125,6 +125,20 @@ 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);
>  
> +/**
> + * address_space_map: Map a physical memory region into a DMA controller
> + *                    virtual address

It may be easier to understand this if you change DMA controller virtual address
to host virtual address.

Either way:
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>



> + *
> + * 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,
>                                     dma_addr_t addr, dma_addr_t *len,
>                                     DMADirection dir)
> @@ -138,6 +152,20 @@ static inline void *dma_memory_map(AddressSpace *as,
>      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,
>                                      void *buffer, dma_addr_t len,
>                                      DMADirection dir, dma_addr_t access_len)
> -- 
> 2.26.2
>