aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/staging/vme/vme_api.txt
diff options
context:
space:
mode:
authorH. Peter Anvin <hpa@zytor.com>2010-04-29 16:53:17 -0700
committerH. Peter Anvin <hpa@zytor.com>2010-04-29 16:53:17 -0700
commitd9c5841e22231e4e49fd0a1004164e6fce59b7a6 (patch)
treee1f589c46b3ff79bbe7b1b2469f6362f94576da6 /drivers/staging/vme/vme_api.txt
parentx86: Fix LOCK_PREFIX_HERE for uniprocessor build (diff)
parentx86-64: Reduce SMP locks table size (diff)
downloadlinux-dev-d9c5841e22231e4e49fd0a1004164e6fce59b7a6.tar.xz
linux-dev-d9c5841e22231e4e49fd0a1004164e6fce59b7a6.zip
Merge branch 'x86/asm' into x86/atomic
Merge reason: Conflict between LOCK_PREFIX_HERE and relative alternatives pointers Resolved Conflicts: arch/x86/include/asm/alternative.h arch/x86/kernel/alternative.c Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'drivers/staging/vme/vme_api.txt')
-rw-r--r--drivers/staging/vme/vme_api.txt27
1 files changed, 19 insertions, 8 deletions
diff --git a/drivers/staging/vme/vme_api.txt b/drivers/staging/vme/vme_api.txt
index a5c1b1cd5fcc..a910a0c4388b 100644
--- a/drivers/staging/vme/vme_api.txt
+++ b/drivers/staging/vme/vme_api.txt
@@ -77,16 +77,21 @@ driver in question:
struct vme_resource * vme_slave_request(struct device *dev,
vme_address_t aspace, vme_cycle_t cycle);
- struct vme_resource *vme_dma_request(struct device *dev);
+ struct vme_resource *vme_dma_request(struct device *dev,
+ vme_dma_route_t route);
For slave windows these attributes are split into those of type 'vme_address_t'
-and 'vme_cycle_t'. Master windows add a further set of attributes 'vme_cycle_t'.
-These attributes are defined as bitmasks and as such any combination of the
-attributes can be requested for a single window, the core will assign a window
-that meets the requirements, returning a pointer of type vme_resource that
-should be used to identify the allocated resource when it is used. If an
-unallocated window fitting the requirements can not be found a NULL pointer will
-be returned.
+and 'vme_cycle_t'. Master windows add a further set of attributes
+'vme_cycle_t'. These attributes are defined as bitmasks and as such any
+combination of the attributes can be requested for a single window, the core
+will assign a window that meets the requirements, returning a pointer of type
+vme_resource that should be used to identify the allocated resource when it is
+used. For DMA controllers, the request function requires the potential
+direction of any transfers to be provided in the route attributes. This is
+typically VME-to-MEM and/or MEM-to-VME, though some hardware can support
+VME-to-VME and MEM-to-MEM transfers as well as test pattern generation. If an
+unallocated window fitting the requirements can not be found a NULL pointer
+will be returned.
Functions are also provided to free window allocations once they are no longer
required. These functions should be passed the pointer to the resource provided
@@ -237,6 +242,12 @@ covered under "Transfer Attributes"):
struct vme_dma_attr *src, struct vme_dma_attr *dest,
size_t count);
+NOTE: The detailed attributes of the transfers source and destination
+ are not checked until an entry is added to a DMA list, the request
+ for a DMA channel purely checks the directions in which the
+ controller is expected to transfer data. As a result it is
+ possible for this call to return an error, for example if the
+ source or destination is in an unsupported VME address space.
Transfer Attributes
-------------------