X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=Documentation%2FDMA-mapping.txt;h=01f24e94bdb630ddecb6511ffa0f02119ff54c55;hb=bba7fc0a21d76ef951cdac6d11896dc6b5a9ffa7;hp=b49427aa8510f5fe080613ce5304cbf9ae3cc345;hpb=819e32377e401669d2c010f1a0ce12fe43ea5261;p=safe%2Fjmp%2Flinux-2.6 diff --git a/Documentation/DMA-mapping.txt b/Documentation/DMA-mapping.txt index b49427a..01f24e9 100644 --- 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; @@ -213,7 +213,7 @@ most specific mask. Here is pseudo-code showing how this might be done: - #define PLAYBACK_ADDRESS_BITS DMA_32BIT_MASK + #define PLAYBACK_ADDRESS_BITS DMA_BIT_MASK(32) #define RECORD_ADDRESS_BITS 0x00ffffff struct my_sound_card *card; @@ -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