summaryrefslogtreecommitdiff
path: root/Documentation/core-api
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/core-api')
-rw-r--r--Documentation/core-api/dma-api.rst49
-rw-r--r--Documentation/core-api/genericirq.rst2
-rw-r--r--Documentation/core-api/kernel-api.rst6
-rw-r--r--Documentation/core-api/workqueue.rst2
-rw-r--r--Documentation/core-api/xarray.rst16
5 files changed, 56 insertions, 19 deletions
diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst
index ea0413276ddb..75cb757bbff0 100644
--- a/Documentation/core-api/dma-api.rst
+++ b/Documentation/core-api/dma-api.rst
@@ -519,10 +519,9 @@ routines, e.g.:::
Part II - Non-coherent DMA allocations
--------------------------------------
-These APIs allow to allocate pages in the kernel direct mapping that are
-guaranteed to be DMA addressable. This means that unlike dma_alloc_coherent,
-virt_to_page can be called on the resulting address, and the resulting
-struct page can be used for everything a struct page is suitable for.
+These APIs allow to allocate pages that are guaranteed to be DMA addressable
+by the passed in device, but which need explicit management of memory ownership
+for the kernel vs the device.
If you don't understand how cache line coherency works between a processor and
an I/O device, you should not be using this part of the API.
@@ -537,7 +536,7 @@ an I/O device, you should not be using this part of the API.
This routine allocates a region of <size> bytes of consistent memory. It
returns a pointer to the allocated region (in the processor's virtual address
space) or NULL if the allocation failed. The returned memory may or may not
-be in the kernels direct mapping. Drivers must not call virt_to_page on
+be in the kernel direct mapping. Drivers must not call virt_to_page on
the returned memory region.
It also returns a <dma_handle> which may be cast to an unsigned integer the
@@ -565,7 +564,45 @@ reused.
Free a region of memory previously allocated using dma_alloc_noncoherent().
dev, size and dma_handle and dir must all be the same as those passed into
dma_alloc_noncoherent(). cpu_addr must be the virtual address returned by
-the dma_alloc_noncoherent().
+dma_alloc_noncoherent().
+
+::
+
+ struct page *
+ dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ enum dma_data_direction dir, gfp_t gfp)
+
+This routine allocates a region of <size> bytes of non-coherent memory. It
+returns a pointer to first struct page for the region, or NULL if the
+allocation failed. The resulting struct page can be used for everything a
+struct page is suitable for.
+
+It also returns a <dma_handle> which may be cast to an unsigned integer the
+same width as the bus and given to the device as the DMA address base of
+the region.
+
+The dir parameter specified if data is read and/or written by the device,
+see dma_map_single() for details.
+
+The gfp parameter allows the caller to specify the ``GFP_`` flags (see
+kmalloc()) for the allocation, but rejects flags used to specify a memory
+zone such as GFP_DMA or GFP_HIGHMEM.
+
+Before giving the memory to the device, dma_sync_single_for_device() needs
+to be called, and before reading memory written by the device,
+dma_sync_single_for_cpu(), just like for streaming DMA mappings that are
+reused.
+
+::
+
+ void
+ dma_free_pages(struct device *dev, size_t size, struct page *page,
+ dma_addr_t dma_handle, enum dma_data_direction dir)
+
+Free a region of memory previously allocated using dma_alloc_pages().
+dev, size and dma_handle and dir must all be the same as those passed into
+dma_alloc_noncoherent(). page must be the pointer returned by
+dma_alloc_pages().
::
diff --git a/Documentation/core-api/genericirq.rst b/Documentation/core-api/genericirq.rst
index 8f06d885c310..f959c9b53f61 100644
--- a/Documentation/core-api/genericirq.rst
+++ b/Documentation/core-api/genericirq.rst
@@ -419,6 +419,7 @@ functions which are exported.
.. kernel-doc:: kernel/irq/manage.c
.. kernel-doc:: kernel/irq/chip.c
+ :export:
Internal Functions Provided
===========================
@@ -431,6 +432,7 @@ functions.
.. kernel-doc:: kernel/irq/handle.c
.. kernel-doc:: kernel/irq/chip.c
+ :internal:
Credits
=======
diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst
index 4ac53a1363f6..741aa37dc181 100644
--- a/Documentation/core-api/kernel-api.rst
+++ b/Documentation/core-api/kernel-api.rst
@@ -231,12 +231,6 @@ Refer to the file kernel/module.c for more information.
Hardware Interfaces
===================
-Interrupt Handling
-------------------
-
-.. kernel-doc:: kernel/irq/manage.c
- :export:
-
DMA Channels
------------
diff --git a/Documentation/core-api/workqueue.rst b/Documentation/core-api/workqueue.rst
index 00a5ba51e63f..541d31de8926 100644
--- a/Documentation/core-api/workqueue.rst
+++ b/Documentation/core-api/workqueue.rst
@@ -396,3 +396,5 @@ Kernel Inline Documentations Reference
======================================
.. kernel-doc:: include/linux/workqueue.h
+
+.. kernel-doc:: kernel/workqueue.c
diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst
index 640934b6f7b4..a137a0e6d068 100644
--- a/Documentation/core-api/xarray.rst
+++ b/Documentation/core-api/xarray.rst
@@ -475,13 +475,15 @@ or iterations will move the index to the first index in the range.
Each entry will only be returned once, no matter how many indices it
occupies.
-Using xas_next() or xas_prev() with a multi-index xa_state
-is not supported. Using either of these functions on a multi-index entry
-will reveal sibling entries; these should be skipped over by the caller.
-
-Storing ``NULL`` into any index of a multi-index entry will set the entry
-at every index to ``NULL`` and dissolve the tie. Splitting a multi-index
-entry into entries occupying smaller ranges is not yet supported.
+Using xas_next() or xas_prev() with a multi-index xa_state is not
+supported. Using either of these functions on a multi-index entry will
+reveal sibling entries; these should be skipped over by the caller.
+
+Storing ``NULL`` into any index of a multi-index entry will set the
+entry at every index to ``NULL`` and dissolve the tie. A multi-index
+entry can be split into entries occupying smaller ranges by calling
+xas_split_alloc() without the xa_lock held, followed by taking the lock
+and calling xas_split().
Functions and structures
========================