DmaMap¶

Lets a device reach part of a memory object by DMA.

Number	Selector	Blocking	Since
`0x0B` SVC_MANAGEMEMORY	`MNGMEM_DMAMAP (4)`	no	2.0

DmaMapResult DmaMap(Handle dev, Handle mem, size_t offset, size_t len, DmaDir dir);

Registers: (&args) -> r0 status, r1 bus address, r2 id

Cached memory is cleaned and invalidated at map time; use DmaSync() around later transfers. The mapping belongs to the device, not the caller, so it survives the driver exiting; DmaAdopt() lets a restarted driver take it over.

Parameters¶

Name	Direction	Description
`dev`	in	Device handle with PERM_MAP.
`mem`	in	MEM_CONTIG memory object with PERM_MAP.
`offset`	in	Page-aligned byte offset into `mem`.
`len`	in	Page-aligned length; must fit in `mem`.
`dir`	in	Direction of the transfers.

Returns¶

The status, the address the device must use, and the mapping id.

Errors¶

Error	Condition
`ERR_BADHANDLE`	`dev` or `mem` is not a live handle.
`ERR_BADTYPE`	`dev` is not a device, or `mem` is not MEM_CONTIG memory.
`ERR_NOPERM`	A handle lacks PERM_MAP.
`ERR_BADARG`	Bad direction, misaligned or out-of-range window, or beyond the device's DMA reach.
`ERR_NOMEM`	The device has no mapping slots left.
`ERR_BADPTR`	The argument block is unreadable.