diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/DMA-API.txt | 2 | ||||
-rw-r--r-- | Documentation/IO-mapping.txt | 4 | ||||
-rw-r--r-- | Documentation/block/biodoc.txt | 5 | ||||
-rw-r--r-- | Documentation/usb/dma.txt | 11 |
4 files changed, 12 insertions, 10 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 52441694fe03..2a3fcc55e981 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt | |||
@@ -5,7 +5,7 @@ | |||
5 | 5 | ||
6 | This document describes the DMA API. For a more gentle introduction | 6 | This document describes the DMA API. For a more gentle introduction |
7 | phrased in terms of the pci_ equivalents (and actual examples) see | 7 | phrased in terms of the pci_ equivalents (and actual examples) see |
8 | DMA-mapping.txt | 8 | Documentation/PCI/PCI-DMA-mapping.txt. |
9 | 9 | ||
10 | This API is split into two pieces. Part I describes the API and the | 10 | This API is split into two pieces. Part I describes the API and the |
11 | corresponding pci_ API. Part II describes the extensions to the API | 11 | corresponding pci_ API. Part II describes the extensions to the API |
diff --git a/Documentation/IO-mapping.txt b/Documentation/IO-mapping.txt index 86edb61bdee6..78a440695e11 100644 --- a/Documentation/IO-mapping.txt +++ b/Documentation/IO-mapping.txt | |||
@@ -1,6 +1,6 @@ | |||
1 | [ NOTE: The virt_to_bus() and bus_to_virt() functions have been | 1 | [ NOTE: The virt_to_bus() and bus_to_virt() functions have been |
2 | superseded by the functionality provided by the PCI DMA | 2 | superseded by the functionality provided by the PCI DMA interface |
3 | interface (see Documentation/DMA-mapping.txt). They continue | 3 | (see Documentation/PCI/PCI-DMA-mapping.txt). They continue |
4 | to be documented below for historical purposes, but new code | 4 | to be documented below for historical purposes, but new code |
5 | must not use them. --davidm 00/12/12 ] | 5 | must not use them. --davidm 00/12/12 ] |
6 | 6 | ||
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 3c5434c83daf..5d2480d33b43 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt | |||
@@ -186,8 +186,9 @@ a virtual address mapping (unlike the earlier scheme of virtual address | |||
186 | do not have a corresponding kernel virtual address space mapping) and | 186 | do not have a corresponding kernel virtual address space mapping) and |
187 | low-memory pages. | 187 | low-memory pages. |
188 | 188 | ||
189 | Note: Please refer to DMA-mapping.txt for a discussion on PCI high mem DMA | 189 | Note: Please refer to Documentation/PCI/PCI-DMA-mapping.txt for a discussion |
190 | aspects and mapping of scatter gather lists, and support for 64 bit PCI. | 190 | on PCI high mem DMA aspects and mapping of scatter gather lists, and support |
191 | for 64 bit PCI. | ||
191 | 192 | ||
192 | Special handling is required only for cases where i/o needs to happen on | 193 | Special handling is required only for cases where i/o needs to happen on |
193 | pages at physical memory addresses beyond what the device can support. In these | 194 | pages at physical memory addresses beyond what the device can support. In these |
diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt index e8b50b7de9d9..cfdcd16e3abf 100644 --- a/Documentation/usb/dma.txt +++ b/Documentation/usb/dma.txt | |||
@@ -6,8 +6,9 @@ in the kernel usb programming guide (kerneldoc, from the source code). | |||
6 | API OVERVIEW | 6 | API OVERVIEW |
7 | 7 | ||
8 | The big picture is that USB drivers can continue to ignore most DMA issues, | 8 | The big picture is that USB drivers can continue to ignore most DMA issues, |
9 | though they still must provide DMA-ready buffers (see DMA-mapping.txt). | 9 | though they still must provide DMA-ready buffers (see |
10 | That's how they've worked through the 2.4 (and earlier) kernels. | 10 | Documentation/PCI/PCI-DMA-mapping.txt). That's how they've worked through |
11 | the 2.4 (and earlier) kernels. | ||
11 | 12 | ||
12 | OR: they can now be DMA-aware. | 13 | OR: they can now be DMA-aware. |
13 | 14 | ||
@@ -62,8 +63,8 @@ and effects like cache-trashing can impose subtle penalties. | |||
62 | force a consistent memory access ordering by using memory barriers. It's | 63 | force a consistent memory access ordering by using memory barriers. It's |
63 | not using a streaming DMA mapping, so it's good for small transfers on | 64 | not using a streaming DMA mapping, so it's good for small transfers on |
64 | systems where the I/O would otherwise thrash an IOMMU mapping. (See | 65 | systems where the I/O would otherwise thrash an IOMMU mapping. (See |
65 | Documentation/DMA-mapping.txt for definitions of "coherent" and "streaming" | 66 | Documentation/PCI/PCI-DMA-mapping.txt for definitions of "coherent" and |
66 | DMA mappings.) | 67 | "streaming" DMA mappings.) |
67 | 68 | ||
68 | Asking for 1/Nth of a page (as well as asking for N pages) is reasonably | 69 | Asking for 1/Nth of a page (as well as asking for N pages) is reasonably |
69 | space-efficient. | 70 | space-efficient. |
@@ -93,7 +94,7 @@ WORKING WITH EXISTING BUFFERS | |||
93 | Existing buffers aren't usable for DMA without first being mapped into the | 94 | Existing buffers aren't usable for DMA without first being mapped into the |
94 | DMA address space of the device. However, most buffers passed to your | 95 | DMA address space of the device. However, most buffers passed to your |
95 | driver can safely be used with such DMA mapping. (See the first section | 96 | driver can safely be used with such DMA mapping. (See the first section |
96 | of DMA-mapping.txt, titled "What memory is DMA-able?") | 97 | of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?") |
97 | 98 | ||
98 | - When you're using scatterlists, you can map everything at once. On some | 99 | - When you're using scatterlists, you can map everything at once. On some |
99 | systems, this kicks in an IOMMU and turns the scatterlists into single | 100 | systems, this kicks in an IOMMU and turns the scatterlists into single |