linux-toradex.git/Documentation/PCI/MSI-HOWTO.txt, branch v4.4.28

doc:pci: Fix typo in Documentation/PCI

2015-03-20T13:41:56+00:00

This patch fix spelling typo in Documentation/PCI.

Signed-off-by: Masanari Iida 
Signed-off-by: Jonathan Corbet

MSI-HOWTO.txt: remove reference on IRQF_DISABLED

2015-03-20T13:41:55+00:00

The IRQF_DISABLED is a NOOP and scheduled to be removed.  According to Ingo
Molnar in commit e58aa3d2d0cc01ad8d6f7f640a0670433f794922 (genirq: Run irq
handlers with interrupts disabled), running IRQ handlers with interrupts
enabled can cause stack overflows when the interrupt line of the issuing
device is still active.

This patch removes IRQF_DISABLED from this documentation.  It was
mentioned to be a solution to avoid deadlocks when a device uses
multiple interrupts.  As the flag is a NOOP this solution does not work
anymore.

Signed-off-by: Valentin Rothberg 
Signed-off-by: Jonathan Corbet

doc: replace "practise" with "practice" in Documentation

2014-06-19T13:28:56+00:00

To keep the Documentation consistent either
"practise" or "practice" should be used.

Since there are 3 lines with "practise"

  ~/linux/Documentation$ grep -r practise * | wc -l
  3

and 108 lines with "practice"

  ~/linux/Documentation$ grep -r practice * | wc -l
  108

this patch converts "practise" to "practice".

Signed-off-by: Jeremiah Mahler 
Signed-off-by: Jiri Kosina

PCI/MSI: Add pci_enable_msi_exact() and pci_enable_msix_exact()

2014-02-13T17:48:02+00:00

The new functions are special cases for pci_enable_msi_range() and
pci_enable_msix_range() when a particular number of MSI or MSI-X
is needed.

By contrast with pci_enable_msi_range() and pci_enable_msix_range()
functions, pci_enable_msi_exact() and pci_enable_msix_exact()
return zero in case of success, which indicates MSI or MSI-X
interrupts have been successfully allocated.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas

PCI/MSI: Fix cut-and-paste errors in documentation

2014-02-13T17:47:56+00:00

Function pci_enable_msi_range() is used in examples where
pci_enable_msix_range() should have been used instead.

Reported-by: Bjorn Helgaas 
Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas

PCI/MSI: Add pci_enable_msi() documentation back

2014-02-13T17:47:51+00:00

We deprecated pci_enable_msi() in 302a2523c277 ("PCI/MSI: Add
pci_enable_msi_range() and pci_enable_msix_range()").

But we changed our minds after noticing that:

  - pci_enable_msi() doesn't have confusing return values like
    pci_enable_msi_block() and pci_enable_msix() did, and

  - pci_enable_msi() has a hundred or so callers that we don't want to
    change.

This adds back the pci_enable_msi() documentation.

[bhelgaas: changelog]
Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas

PCI/MSI: Add pci_enable_msi_range() and pci_enable_msix_range()

2014-01-04T00:17:55+00:00

This adds pci_enable_msi_range(), which supersedes the pci_enable_msi()
and pci_enable_msi_block() MSI interfaces.

It also adds pci_enable_msix_range(), which supersedes the
pci_enable_msix() MSI-X interface.

The old interfaces have three categories of return values:

    negative: failure; caller should not retry
    positive: failure; value indicates number of interrupts that *could*
	have been allocated, and caller may retry with a smaller request
    zero: success; at least as many interrupts allocated as requested

It is error-prone to handle these three cases correctly in drivers.

The new functions return either a negative error code or a number of
successfully allocated MSI/MSI-X interrupts, which is expected to lead to
clearer device driver code.

pci_enable_msi(), pci_enable_msi_block() and pci_enable_msix() still exist
unchanged, but are deprecated and may be removed after callers are updated.

[bhelgaas: tweak changelog]
Suggested-by: Ben Hutchings 
Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Tejun Heo

PCI/MSI: Add pci_msix_vec_count()

2014-01-04T00:17:55+00:00

This creates an MSI-X counterpart for pci_msi_vec_count().  Device drivers
can use this function to obtain maximum number of MSI-X interrupts the
device supports and use that number in a subsequent call to
pci_enable_msix().

pci_msix_vec_count() supersedes pci_msix_table_size() and returns a
negative errno if device does not support MSI-X interrupts.  After this
update, callers must always check the returned value.

The only user of pci_msix_table_size() was the PCI-Express port driver,
which is also updated by this change.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Tejun Heo

PCI/MSI: Remove pci_enable_msi_block_auto()

2014-01-04T00:17:55+00:00

The new pci_msi_vec_count() interface makes pci_enable_msi_block_auto()
superfluous.

Drivers can use pci_msi_vec_count() to learn the maximum number of MSIs
supported by the device, and then call pci_enable_msi_block().

pci_enable_msi_block_auto() was introduced recently, and its only user is
the AHCI driver, which is also updated by this change.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas 
Acked-by: Tejun Heo

PCI/MSI: Add pci_msi_vec_count()

2014-01-04T00:17:55+00:00

Device drivers can use this interface to obtain the maximum number of MSI
interrupts the device supports and use that number, e.g., in a subsequent
call to pci_enable_msi_block().

Signed-off-by: Alexander Gordeev 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Tejun Heo