[patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

From: Matti Linnanvuori
Date: Mon Apr 28 2008 - 09:05:52 EST


From: Matti Linnanvuori <mattilinnanvuori@xxxxxxxxx>

Consistently use pdev as the variable of type struct pci_dev *.
Update DMA mapping documentation to use 'pdev' rather than 'dev' in
example code that calls routines expecting 'struct pci_device *', since 'dev'
might make readers think they're passing 'struct device *' parameters.
Bug 10397.

Signed-off-by: Matti Linnanvuori <mattilinnanvuori@xxxxxxxxx>

---

--- linux-2.6/Documentation/DMA-mapping.txt 2008-03-23 09:01:06.304511500 +0200
+++ linux/Documentation/DMA-mapping.txt 2008-04-06 06:56:11.821314500 +0300
@@ -315,9 +315,9 @@

dma_addr_t dma_handle;

- cpu_addr = pci_alloc_consistent(dev, size, &dma_handle);
+ cpu_addr = pci_alloc_consistent(pdev, size, &dma_handle);

-where dev is a struct pci_dev *. You should pass NULL for PCI like buses
+where pdev is a struct pci_dev *. You should pass NULL for PCI like buses
where devices don't have struct pci_dev (like ISA, EISA). This may be
called in interrupt context.

@@ -354,9 +354,9 @@

To unmap and free such a DMA region, you call:

- pci_free_consistent(dev, size, cpu_addr, dma_handle);
+ pci_free_consistent(pdev, size, cpu_addr, dma_handle);

-where dev, size are the same as in the above call and cpu_addr and
+where pdev, size are the same as in the above call and cpu_addr and
dma_handle are the values pci_alloc_consistent returned to you.
This function may not be called in interrupt context.

@@ -371,9 +371,9 @@

struct pci_pool *pool;

- pool = pci_pool_create(name, dev, size, align, alloc);
+ pool = pci_pool_create(name, pdev, size, align, alloc);

-The "name" is for diagnostics (like a kmem_cache name); dev and size
+The "name" is for diagnostics (like a kmem_cache name); pdev and size
are as above. The device's hardware alignment requirement for this
type of data is "align" (which is expressed in bytes, and must be a
power of two). If your device has no boundary crossing restrictions,
@@ -472,11 +472,11 @@
void *addr = buffer->ptr;
size_t size = buffer->len;

- dma_handle = pci_map_single(dev, addr, size, direction);
+ dma_handle = pci_map_single(pdev, addr, size, direction);

and to unmap it:

- pci_unmap_single(dev, dma_handle, size, direction);
+ pci_unmap_single(pdev, dma_handle, size, direction);

You should call pci_unmap_single when the DMA activity is finished, e.g.
from the interrupt which told you that the DMA transfer is done.
@@ -493,17 +493,17 @@
unsigned long offset = buffer->offset;
size_t size = buffer->len;

- dma_handle = pci_map_page(dev, page, offset, size, direction);
+ dma_handle = pci_map_page(pdev, page, offset, size, direction);

...

- pci_unmap_page(dev, dma_handle, size, direction);
+ pci_unmap_page(pdev, dma_handle, size, direction);

Here, "offset" means byte offset within the given page.

With scatterlists, you map a region gathered from several regions by:

- int i, count = pci_map_sg(dev, sglist, nents, direction);
+ int i, count = pci_map_sg(pdev, sglist, nents, direction);
struct scatterlist *sg;

for_each_sg(sglist, sg, count, i) {
@@ -527,7 +527,7 @@

To unmap a scatterlist, just call:

- pci_unmap_sg(dev, sglist, nents, direction);
+ pci_unmap_sg(pdev, sglist, nents, direction);

Again, make sure DMA activity has already finished.

@@ -550,11 +550,11 @@
So, firstly, just map it with pci_map_{single,sg}, and after each DMA
transfer call either:

- pci_dma_sync_single_for_cpu(dev, dma_handle, size, direction);
+ pci_dma_sync_single_for_cpu(pdev, dma_handle, size, direction);

or:

- pci_dma_sync_sg_for_cpu(dev, sglist, nents, direction);
+ pci_dma_sync_sg_for_cpu(pdev, sglist, nents, direction);

as appropriate.

@@ -562,7 +562,7 @@
finish accessing the data with the cpu, and then before actually
giving the buffer to the hardware call either:

- pci_dma_sync_single_for_device(dev, dma_handle, size, direction);
+ pci_dma_sync_single_for_device(pdev, dma_handle, size, direction);

or:

@@ -739,7 +739,7 @@

dma_addr_t dma_handle;

- dma_handle = pci_map_single(dev, addr, size, direction);
+ dma_handle = pci_map_single(pdev, addr, size, direction);
if (pci_dma_mapping_error(dma_handle)) {
/*
* reduce current DMA mapping usage,



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