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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2014-10-28 13:41:11 -0400
committerSteven Rostedt <rostedt@goodmis.org>2014-10-28 13:41:11 -0400
commit1f6898212ad6415405ab589b602d6f60bb0d83ef (patch)
tree2baf775a1128bcd0b15b1b4a9213df14597d32be /Documentation
parent5b55c23934a2d5fb61cf0a82ade85042783308c9 (diff)
parent2ffe8469f55805a0ce527bdf32ee85857dfad87a (diff)
Merge tag 'v3.12.27' into v3.12-rt
This is the 3.12.27 stable release Conflicts: arch/sparc/mm/init_64.c
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/DMA-API-HOWTO.txt37
-rw-r--r--Documentation/DMA-API.txt8
-rw-r--r--Documentation/x86/x86_64/mm.txt2
3 files changed, 32 insertions, 15 deletions
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 14129f149a75..5e983031cc11 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -101,14 +101,23 @@ style to do this even if your device holds the default setting,
because this shows that you did think about these issues wrt. your
device.
-The query is performed via a call to dma_set_mask():
+The query is performed via a call to dma_set_mask_and_coherent():
- int dma_set_mask(struct device *dev, u64 mask);
+ int dma_set_mask_and_coherent(struct device *dev, u64 mask);
-The query for consistent allocations is performed via a call to
-dma_set_coherent_mask():
+which will query the mask for both streaming and coherent APIs together.
+If you have some special requirements, then the following two separate
+queries can be used instead:
- int dma_set_coherent_mask(struct device *dev, u64 mask);
+ The query for streaming mappings is performed via a call to
+ dma_set_mask():
+
+ int dma_set_mask(struct device *dev, u64 mask);
+
+ The query for consistent allocations is performed via a call
+ to dma_set_coherent_mask():
+
+ int dma_set_coherent_mask(struct device *dev, u64 mask);
Here, dev is a pointer to the device struct of your device, and mask
is a bit mask describing which bits of an address your device
@@ -137,7 +146,7 @@ exactly why.
The standard 32-bit addressing device would do something like this:
- if (dma_set_mask(dev, DMA_BIT_MASK(32))) {
+ if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))) {
printk(KERN_WARNING
"mydev: No suitable DMA available.\n");
goto ignore_this_device;
@@ -171,22 +180,20 @@ the case would look like this:
int using_dac, consistent_using_dac;
- if (!dma_set_mask(dev, DMA_BIT_MASK(64))) {
+ if (!dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64))) {
using_dac = 1;
consistent_using_dac = 1;
- dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
- } else if (!dma_set_mask(dev, DMA_BIT_MASK(32))) {
+ } else if (!dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))) {
using_dac = 0;
consistent_using_dac = 0;
- dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
} else {
printk(KERN_WARNING
"mydev: No suitable DMA available.\n");
goto ignore_this_device;
}
-dma_set_coherent_mask() will always be able to set the same or a
-smaller mask as dma_set_mask(). However for the rare case that a
+The coherent coherent mask will always be able to set the same or a
+smaller mask as the streaming mask. However for the rare case that a
device driver only uses consistent allocations, one would have to
check the return value from dma_set_coherent_mask().
@@ -199,9 +206,9 @@ address you might do something like:
goto ignore_this_device;
}
-When dma_set_mask() is successful, and returns zero, the kernel saves
-away this mask you have provided. The kernel will use this
-information later when you make DMA mappings.
+When dma_set_mask() or dma_set_mask_and_coherent() is successful, and
+returns zero, the kernel saves away this mask you have provided. The
+kernel will use this information later when you make DMA mappings.
There is a case which we are aware of at this time, which is worth
mentioning in this documentation. If your device supports multiple
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index 78a6c569d204..e865279cec58 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -142,6 +142,14 @@ internal API for use by the platform than an external API for use by
driver writers.
int
+dma_set_mask_and_coherent(struct device *dev, u64 mask)
+
+Checks to see if the mask is possible and updates the device
+streaming and coherent DMA mask parameters if it is.
+
+Returns: 0 if successful and a negative error if not.
+
+int
dma_set_mask(struct device *dev, u64 mask)
Checks to see if the mask is possible and updates the device
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index 881582f75c9c..bd4370487b07 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -12,6 +12,8 @@ ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
... unused hole ...
+ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
+... unused hole ...
ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping, from phys 0
ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space
ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls