diff options
author | Alexander Gordeev <agordeev@redhat.com> | 2013-12-30 02:28:14 -0500 |
---|---|---|
committer | Bjorn Helgaas <bhelgaas@google.com> | 2014-01-03 19:17:55 -0500 |
commit | 7b92b4f61ec49cb1a5813298f35258bd7ecd3667 (patch) | |
tree | 3ca281ebb26a2885ff9ff5fd4e1b15393b6f7c20 /Documentation/PCI | |
parent | d1ac1d2622e8f0fd2a25127a8649d135b54db8a9 (diff) |
PCI/MSI: Remove pci_enable_msi_block_auto()
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 <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation/PCI')
-rw-r--r-- | Documentation/PCI/MSI-HOWTO.txt | 39 |
1 files changed, 6 insertions, 33 deletions
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index a8b41788dfde..aa4ad987510d 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt | |||
@@ -127,49 +127,22 @@ on the number of vectors that can be allocated; pci_enable_msi_block() | |||
127 | returns as soon as it finds any constraint that doesn't allow the | 127 | returns as soon as it finds any constraint that doesn't allow the |
128 | call to succeed. | 128 | call to succeed. |
129 | 129 | ||
130 | 4.2.3 pci_enable_msi_block_auto | 130 | 4.2.3 pci_disable_msi |
131 | |||
132 | int pci_enable_msi_block_auto(struct pci_dev *dev, int *count) | ||
133 | |||
134 | This variation on pci_enable_msi() call allows a device driver to request | ||
135 | the maximum possible number of MSIs. The MSI specification only allows | ||
136 | interrupts to be allocated in powers of two, up to a maximum of 2^5 (32). | ||
137 | |||
138 | If this function returns a positive number, it indicates that it has | ||
139 | succeeded and the returned value is the number of allocated interrupts. In | ||
140 | this case, the function enables MSI on this device and updates dev->irq to | ||
141 | be the lowest of the new interrupts assigned to it. The other interrupts | ||
142 | assigned to the device are in the range dev->irq to dev->irq + returned | ||
143 | value - 1. | ||
144 | |||
145 | If this function returns a negative number, it indicates an error and | ||
146 | the driver should not attempt to request any more MSI interrupts for | ||
147 | this device. | ||
148 | |||
149 | If the device driver needs to know the number of interrupts the device | ||
150 | supports it can pass the pointer count where that number is stored. The | ||
151 | device driver must decide what action to take if pci_enable_msi_block_auto() | ||
152 | succeeds, but returns a value less than the number of interrupts supported. | ||
153 | If the device driver does not need to know the number of interrupts | ||
154 | supported, it can set the pointer count to NULL. | ||
155 | |||
156 | 4.2.4 pci_disable_msi | ||
157 | 131 | ||
158 | void pci_disable_msi(struct pci_dev *dev) | 132 | void pci_disable_msi(struct pci_dev *dev) |
159 | 133 | ||
160 | This function should be used to undo the effect of pci_enable_msi() or | 134 | This function should be used to undo the effect of pci_enable_msi() or |
161 | pci_enable_msi_block() or pci_enable_msi_block_auto(). Calling it restores | 135 | pci_enable_msi_block(). Calling it restores dev->irq to the pin-based |
162 | dev->irq to the pin-based interrupt number and frees the previously | 136 | interrupt number and frees the previously allocated message signaled |
163 | allocated message signaled interrupt(s). The interrupt may subsequently be | 137 | interrupt(s). The interrupt may subsequently be assigned to another |
164 | assigned to another device, so drivers should not cache the value of | 138 | device, so drivers should not cache the value of dev->irq. |
165 | dev->irq. | ||
166 | 139 | ||
167 | Before calling this function, a device driver must always call free_irq() | 140 | Before calling this function, a device driver must always call free_irq() |
168 | on any interrupt for which it previously called request_irq(). | 141 | on any interrupt for which it previously called request_irq(). |
169 | Failure to do so results in a BUG_ON(), leaving the device with | 142 | Failure to do so results in a BUG_ON(), leaving the device with |
170 | MSI enabled and thus leaking its vector. | 143 | MSI enabled and thus leaking its vector. |
171 | 144 | ||
172 | 4.2.5 pci_msi_vec_count | 145 | 4.2.4 pci_msi_vec_count |
173 | 146 | ||
174 | int pci_msi_vec_count(struct pci_dev *dev) | 147 | int pci_msi_vec_count(struct pci_dev *dev) |
175 | 148 | ||