linux-toradex.git/Documentation/DMA-API.txt, branch v4.4.93

dma: remove external references to dma_supported

2015-11-09T23:11:24+00:00

Signed-off-by: Christoph Hellwig 
Acked-by: Greg Kroah-Hartman 
Cc: Alan Stern 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation: DMA API: Be more explicit that nents is always the same

2015-09-24T21:50:06+00:00

The nents argument to the DMA API functions operating on scatterlists is
always the same. The documentation used different argument names and the
matter was not mentioned in Documentation/DMA-API-HOWTO.txt at all. Fix
these.

Signed-off-by: Sakari Ailus 
Signed-off-by: Jonathan Corbet

mm: add dma_pool_zalloc() call to DMA API

2015-09-08T22:35:28+00:00

Add a wrapper function for dma_pool_alloc() to get zeroed memory.

Signed-off-by: Sean O. Stalley 
Cc: Vinod Koul 
Cc: Bjorn Helgaas 
Cc: Gilles Muller 
Cc: Nicolas Palix 
Cc: Michal Marek 
Cc: Sebastian Andrzej Siewior 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

PCI: Add pci_bus_addr_t

2015-05-29T22:21:45+00:00

David Ahern reported that d63e2e1f3df9 ("sparc/PCI: Clip bridge windows
to fit in upstream windows") fails to boot on sparc/T5-8:

  pci 0000:06:00.0: reg 0x184: can't handle BAR above 4GB (bus address 0x110204000)

The problem is that sparc64 assumed that dma_addr_t only needed to hold DMA
addresses, i.e., bus addresses returned via the DMA API (dma_map_single(),
etc.), while the PCI core assumed dma_addr_t could hold *any* bus address,
including raw BAR values.  On sparc64, all DMA addresses fit in 32 bits, so
dma_addr_t is a 32-bit type.  However, BAR values can be 64 bits wide, so
they don't fit in a dma_addr_t.  d63e2e1f3df9 added new checking that
tripped over this mismatch.

Add pci_bus_addr_t, which is wide enough to hold any PCI bus address,
including both raw BAR values and DMA addresses.  This will be 64 bits
on 64-bit platforms and on platforms with a 64-bit dma_addr_t.  Then
dma_addr_t only needs to be wide enough to hold addresses from the DMA API.

[bhelgaas: changelog, bugzilla, Kconfig to ensure pci_bus_addr_t is at
least as wide as dma_addr_t, documentation]
Fixes: d63e2e1f3df9 ("sparc/PCI: Clip bridge windows to fit in upstream windows")
Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: http://lkml.kernel.org/r/CAE9FiQU1gJY1LYrxs+ma5LCTEEe4xmtjRG0aXJ9K_Tsu+m9Wuw@mail.gmail.com
Link: http://lkml.kernel.org/r/1427857069-6789-1-git-send-email-yinghai@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=96231
Reported-by: David Ahern 
Tested-by: David Ahern 
Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas 
Acked-by: David S. Miller 
CC: stable@vger.kernel.org	# v3.19+

DMA-API: Capitalize "CPU" consistently

2014-05-26T23:28:27+00:00

Sometimes we used "cpu," other times "CPU."  Use "CPU" consistently.

Suggested-by: Randy Dunlap 
Signed-off-by: Bjorn Helgaas

DMA-API: Change dma_declare_coherent_memory() CPU address to phys_addr_t

2014-05-20T22:55:23+00:00

dma_declare_coherent_memory() takes two addresses for a region of memory: a
"bus_addr" and a "device_addr".  I think the intent is that "bus_addr" is
the physical address a *CPU* would use to access the region, and
"device_addr" is the bus address the *device* would use to address the
region.

Rename "bus_addr" to "phys_addr" and change its type to phys_addr_t.
Most callers already supply a phys_addr_t for this argument.  The others
supply a 32-bit integer (a constant, unsigned int, or __u32) and need no
change.

Use "unsigned long", not phys_addr_t, to hold PFNs.

No functional change (this could theoretically fix a truncation in a config
with 32-bit dma_addr_t and 64-bit phys_addr_t, but I don't think there are
any such cases involving this code).

Signed-off-by: Bjorn Helgaas 
Acked-by: Arnd Bergmann 
Acked-by: Greg Kroah-Hartman 
Acked-by: James Bottomley 
Acked-by: Randy Dunlap

DMA-API: Clarify physical/bus address distinction

2014-05-20T22:54:21+00:00

The DMA-API documentation sometimes refers to "physical addresses" when it
really means "bus addresses."  Sometimes these are identical, but they may
be different if the bridge leading to the bus performs address translation.
Update the documentation to use "bus address" when appropriate.

Also, consistently capitalize "DMA", use parens with function names, use
dev_printk() in examples, and reword a few sections for clarity.

No functional change; documentation changes only.

Signed-off-by: Bjorn Helgaas 
Acked-by: Greg Kroah-Hartman 
Acked-by: Arnd Bergmann 
Acked-by: James Bottomley 
Acked-by: Randy Dunlap

DMA-API: provide a helper to set both DMA and coherent DMA masks

2013-09-17T14:32:37+00:00

Provide a helper to set both the DMA and coherent DMA masks to the
same value - this avoids duplicated code in a number of drivers,
sometimes with buggy error handling, and also allows us identify
which drivers do things differently.

Signed-off-by: Russell King

dma-debug: New interfaces to debug dma mapping errors

2012-10-24T15:06:43+00:00

Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.

Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
        CONFIG_DMA_API_DEBUG enabled and disabled.

Signed-off-by: Shuah Khan 
Reviewed-by: Konrad Rzeszutek Wilk 
Signed-off-by: Joerg Roedel

include/linux/dma-mapping.h: add dma_zalloc_coherent()

2011-11-02T23:07:02+00:00

Lots of driver code does a dma_alloc_coherent() and then zeroes out the
memory with a memset.  Make it easy for them.

Cc: Alexandre Bounine 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds