Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6

[safe/jmp/linux-2.6] / Documentation / DMA-mapping.txt

diff --git a/Documentation/DMA-mapping.txt b/Documentation/DMA-mapping.txt
index b49427a..ecad88d 100644 (file)
--- a/Documentation/DMA-mapping.txt
+++ b/Documentation/DMA-mapping.txt
@@ -26,7 +26,7 @@ mapped only for the time they are actually used and unmapped after the DMA
 transfer.
 
 The following API will work of course even on platforms where no such
-hardware exists, see e.g. include/asm-i386/pci.h for how it is implemented on
+hardware exists, see e.g. arch/x86/include/asm/pci.h for how it is implemented on
 top of the virt_to_bus interface.
 
 First of all, you should make sure
@@ -136,7 +136,7 @@ exactly why.
 The standard 32-bit addressing PCI device would do something like
 this:
 
-       if (pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+       if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
                printk(KERN_WARNING
                       "mydev: No suitable DMA available.\n");
                goto ignore_this_device;
@@ -155,9 +155,9 @@ all 64-bits when accessing streaming DMA:
 
        int using_dac;
 
-       if (!pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
+       if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) {
                using_dac = 1;
-       } else if (!pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+       } else if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
                using_dac = 0;
        } else {
                printk(KERN_WARNING
@@ -170,14 +170,14 @@ the case would look like this:
 
        int using_dac, consistent_using_dac;
 
-       if (!pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
+       if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(64))) {
                using_dac = 1;
                consistent_using_dac = 1;
-               pci_set_consistent_dma_mask(pdev, DMA_64BIT_MASK);
-       } else if (!pci_set_dma_mask(pdev, DMA_32BIT_MASK)) {
+               pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+       } else if (!pci_set_dma_mask(pdev, DMA_BIT_MASK(32))) {
                using_dac = 0;
                consistent_using_dac = 0;
-               pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK);
+               pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
        } else {
                printk(KERN_WARNING
                       "mydev: No suitable DMA available.\n");
@@ -192,7 +192,7 @@ check the return value from pci_set_consistent_dma_mask().
 Finally, if your device can only drive the low 24-bits of
 address during PCI bus mastering you might do something like:
 
-       if (pci_set_dma_mask(pdev, DMA_24BIT_MASK)) {
+       if (pci_set_dma_mask(pdev, DMA_BIT_MASK(24))) {
                printk(KERN_WARNING
                       "mydev: 24-bit DMA addressing not available.\n");
                goto ignore_this_device;
@@ -213,8 +213,8 @@ most specific mask.
 
 Here is pseudo-code showing how this might be done:
 
-       #define PLAYBACK_ADDRESS_BITS   DMA_32BIT_MASK
-       #define RECORD_ADDRESS_BITS     0x00ffffff
+       #define PLAYBACK_ADDRESS_BITS   DMA_BIT_MASK(32)
+       #define RECORD_ADDRESS_BITS     DMA_BIT_MASK(24)
 
        struct my_sound_card *card;
        struct pci_dev *pdev;
@@ -224,14 +224,14 @@ Here is pseudo-code showing how this might be done:
                card->playback_enabled = 1;
        } else {
                card->playback_enabled = 0;
-               printk(KERN_WARN "%s: Playback disabled due to DMA limitations.\n",
+               printk(KERN_WARNING "%s: Playback disabled due to DMA limitations.\n",
                       card->name);
        }
        if (!pci_set_dma_mask(pdev, RECORD_ADDRESS_BITS)) {
                card->record_enabled = 1;
        } else {
                card->record_enabled = 0;
-               printk(KERN_WARN "%s: Record disabled due to DMA limitations.\n",
+               printk(KERN_WARNING "%s: Record disabled due to DMA limitations.\n",
                       card->name);
        }
 
@@ -317,9 +317,9 @@ you should do:
 
        cpu_addr = pci_alloc_consistent(pdev, size, &dma_handle);
 
-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. 
+where pdev is a struct pci_dev *. This may be called in interrupt context.
+You should use dma_alloc_coherent (see DMA-API.txt) for buses
+where devices don't have struct pci_dev (like ISA, EISA).
 
 This argument is needed because the DMA translations may be bus
 specific (and often is private to the bus which the device is attached
@@ -332,7 +332,7 @@ __get_free_pages (but takes size instead of a page order).  If your
 driver needs regions sized smaller than a page, you may prefer using
 the pci_pool interface, described below.
 
-The consistent DMA mapping interfaces, for non-NULL dev, will by
+The consistent DMA mapping interfaces, for non-NULL pdev, will by
 default return a DMA address which is SAC (Single Address Cycle)
 addressable.  Even if the device indicates (via PCI dma mask) that it
 may address the upper 32-bits and thus perform DAC cycles, consistent
@@ -740,7 +740,7 @@ failure can be determined by:
        dma_addr_t dma_handle;
 
        dma_handle = pci_map_single(pdev, addr, size, direction);
-       if (pci_dma_mapping_error(dma_handle)) {
+       if (pci_dma_mapping_error(pdev, dma_handle)) {
                /*
                 * reduce current DMA mapping usage,
                 * delay and try again later or