| Message ID | 6a425d611ce5c276ec6949fd6aadf575580e07fe.1346653435.git.agordeev@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Mon, Sep 3, 2012 at 2:19 AM, Alexander Gordeev <agordeev@redhat.com> wrote: > The new function pci_enable_msi_block_auto() tries to allocate maximum > possible number of MSIs up to the number the device supports. It > generalizes a pattern when pci_enable_msi_block() is contiguously called > until it succeeds or fails. > > Opposite to pci_enable_msi_block() which takes the number of MSIs to > allocate as a input parameter, pci_enable_msi_block_auto() could be used > by device drivers to obtain the number of assigned MSIs and the number > of MSIs the device supports. > > Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> I haven't looked at the other patches in this series, but if the x86/IRQ folks like them, I'm OK with this part. Since the series is mostly non-PCI, I think it makes the most sense to keep it all together and merge it through some x86 or IRQ tree, including this PCI bit. > --- > Documentation/PCI/MSI-HOWTO.txt | 37 ++++++++++++++++++++++++++++++++----- > drivers/pci/msi.c | 26 ++++++++++++++++++++++++++ > include/linux/pci.h | 7 +++++++ > 3 files changed, 65 insertions(+), 5 deletions(-) > > diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt > index 53e6fca..a091780 100644 > --- a/Documentation/PCI/MSI-HOWTO.txt > +++ b/Documentation/PCI/MSI-HOWTO.txt > @@ -127,15 +127,42 @@ on the number of vectors that can be allocated; pci_enable_msi_block() > returns as soon as it finds any constraint that doesn't allow the > call to succeed. > > -4.2.3 pci_disable_msi > +4.2.3 pci_enable_msi_block_auto > + > +int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *count) > + > +This variation on pci_enable_msi() call allows a device driver to request > +the maximum possible number of MSIs. The MSI specification only allows > +interrupts to be allocated in powers of two, up to a maximum of 2^5 (32). > + > +If this function returns a positive number, it indicates that it has > +succeeded and the returned value is the number of allocated interrupts. In > +this case, the function enables MSI on this device and updates dev->irq to > +be the lowest of the new interrupts assigned to it. The other interrupts > +assigned to the device are in the range dev->irq to dev->irq + returned > +value - 1. > + > +If this function returns a negative number, it indicates an error and > +the driver should not attempt to request any more MSI interrupts for > +this device. > + > +If the device driver needs to know the number of interrupts the device > +supports it can pass the pointer count where that number is stored. The > +device driver must decide what action to take if pci_enable_msi_block_auto() > +succeeds, but returns a value less than the number of interrupts supported. > +If the device driver does not need to know the number of interrupts > +supported, it can set the pointer count to NULL. > + > +4.2.4 pci_disable_msi > > void pci_disable_msi(struct pci_dev *dev) > > This function should be used to undo the effect of pci_enable_msi() or > -pci_enable_msi_block(). Calling it restores dev->irq to the pin-based > -interrupt number and frees the previously allocated message signaled > -interrupt(s). The interrupt may subsequently be assigned to another > -device, so drivers should not cache the value of dev->irq. > +pci_enable_msi_block() or pci_enable_msi_block_auto(). Calling it restores > +dev->irq to the pin-based interrupt number and frees the previously > +allocated message signaled interrupt(s). The interrupt may subsequently be > +assigned to another device, so drivers should not cache the value of > +dev->irq. > > Before calling this function, a device driver must always call free_irq() > on any interrupt for which it previously called request_irq(). > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > index f0752d1..690b268 100644 > --- a/drivers/pci/msi.c > +++ b/drivers/pci/msi.c > @@ -845,6 +845,32 @@ int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec) > } > EXPORT_SYMBOL(pci_enable_msi_block); > > +int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec) > +{ > + int ret, pos, nvec; > + u16 msgctl; > + > + pos = pci_find_capability(dev, PCI_CAP_ID_MSI); > + if (!pos) > + return -EINVAL; > + > + pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl); > + ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1); > + > + if (maxvec) > + *maxvec = ret; > + > + do { > + nvec = ret; > + ret = pci_enable_msi_block(dev, nvec); > + } while (ret > 0); > + > + if (ret < 0) > + return ret; > + return nvec; > +} > +EXPORT_SYMBOL(pci_enable_msi_block_auto); > + > void pci_msi_shutdown(struct pci_dev *dev) > { > struct msi_desc *desc; > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 5faa831..b8a9454 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1070,6 +1070,12 @@ static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec) > return -1; > } > > +static inline int > +pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec) > +{ > + return -1; > +} > + > static inline void pci_msi_shutdown(struct pci_dev *dev) > { } > static inline void pci_disable_msi(struct pci_dev *dev) > @@ -1101,6 +1107,7 @@ static inline int pci_msi_enabled(void) > } > #else > extern int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec); > +extern int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec); > extern void pci_msi_shutdown(struct pci_dev *dev); > extern void pci_disable_msi(struct pci_dev *dev); > extern int pci_msix_table_size(struct pci_dev *dev); > -- > 1.7.7.6 > > > -- > Regards, > Alexander Gordeev > agordeev@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 53e6fca..a091780 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -127,15 +127,42 @@ on the number of vectors that can be allocated; pci_enable_msi_block() returns as soon as it finds any constraint that doesn't allow the call to succeed. -4.2.3 pci_disable_msi +4.2.3 pci_enable_msi_block_auto + +int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *count) + +This variation on pci_enable_msi() call allows a device driver to request +the maximum possible number of MSIs. The MSI specification only allows +interrupts to be allocated in powers of two, up to a maximum of 2^5 (32). + +If this function returns a positive number, it indicates that it has +succeeded and the returned value is the number of allocated interrupts. In +this case, the function enables MSI on this device and updates dev->irq to +be the lowest of the new interrupts assigned to it. The other interrupts +assigned to the device are in the range dev->irq to dev->irq + returned +value - 1. + +If this function returns a negative number, it indicates an error and +the driver should not attempt to request any more MSI interrupts for +this device. + +If the device driver needs to know the number of interrupts the device +supports it can pass the pointer count where that number is stored. The +device driver must decide what action to take if pci_enable_msi_block_auto() +succeeds, but returns a value less than the number of interrupts supported. +If the device driver does not need to know the number of interrupts +supported, it can set the pointer count to NULL. + +4.2.4 pci_disable_msi void pci_disable_msi(struct pci_dev *dev) This function should be used to undo the effect of pci_enable_msi() or -pci_enable_msi_block(). Calling it restores dev->irq to the pin-based -interrupt number and frees the previously allocated message signaled -interrupt(s). The interrupt may subsequently be assigned to another -device, so drivers should not cache the value of dev->irq. +pci_enable_msi_block() or pci_enable_msi_block_auto(). Calling it restores +dev->irq to the pin-based interrupt number and frees the previously +allocated message signaled interrupt(s). The interrupt may subsequently be +assigned to another device, so drivers should not cache the value of +dev->irq. Before calling this function, a device driver must always call free_irq() on any interrupt for which it previously called request_irq(). diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index f0752d1..690b268 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -845,6 +845,32 @@ int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec) } EXPORT_SYMBOL(pci_enable_msi_block); +int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec) +{ + int ret, pos, nvec; + u16 msgctl; + + pos = pci_find_capability(dev, PCI_CAP_ID_MSI); + if (!pos) + return -EINVAL; + + pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl); + ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1); + + if (maxvec) + *maxvec = ret; + + do { + nvec = ret; + ret = pci_enable_msi_block(dev, nvec); + } while (ret > 0); + + if (ret < 0) + return ret; + return nvec; +} +EXPORT_SYMBOL(pci_enable_msi_block_auto); + void pci_msi_shutdown(struct pci_dev *dev) { struct msi_desc *desc; diff --git a/include/linux/pci.h b/include/linux/pci.h index 5faa831..b8a9454 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1070,6 +1070,12 @@ static inline int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec) return -1; } +static inline int +pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec) +{ + return -1; +} + static inline void pci_msi_shutdown(struct pci_dev *dev) { } static inline void pci_disable_msi(struct pci_dev *dev) @@ -1101,6 +1107,7 @@ static inline int pci_msi_enabled(void) } #else extern int pci_enable_msi_block(struct pci_dev *dev, unsigned int nvec); +extern int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec); extern void pci_msi_shutdown(struct pci_dev *dev); extern void pci_disable_msi(struct pci_dev *dev); extern int pci_msix_table_size(struct pci_dev *dev);
The new function pci_enable_msi_block_auto() tries to allocate maximum possible number of MSIs up to the number the device supports. It generalizes a pattern when pci_enable_msi_block() is contiguously called until it succeeds or fails. Opposite to pci_enable_msi_block() which takes the number of MSIs to allocate as a input parameter, pci_enable_msi_block_auto() could be used by device drivers to obtain the number of assigned MSIs and the number of MSIs the device supports. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> --- Documentation/PCI/MSI-HOWTO.txt | 37 ++++++++++++++++++++++++++++++++----- drivers/pci/msi.c | 26 ++++++++++++++++++++++++++ include/linux/pci.h | 7 +++++++ 3 files changed, 65 insertions(+), 5 deletions(-)