diff options
| -rw-r--r-- | Documentation/PCI/MSI-HOWTO.txt | 39 | ||||
| -rw-r--r-- | drivers/ata/ahci.c | 56 | ||||
| -rw-r--r-- | drivers/pci/msi.c | 25 | ||||
| -rw-r--r-- | include/linux/pci.h | 7 |
4 files changed, 41 insertions, 86 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() returns as soon as it finds any constraint that doesn't allow the call to succeed. -4.2.3 pci_enable_msi_block_auto - -int pci_enable_msi_block_auto(struct pci_dev *dev, 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 +4.2.3 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() 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. +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. Before calling this function, a device driver must always call free_irq() on any interrupt for which it previously called request_irq(). Failure to do so results in a BUG_ON(), leaving the device with MSI enabled and thus leaking its vector. -4.2.5 pci_msi_vec_count +4.2.4 pci_msi_vec_count int pci_msi_vec_count(struct pci_dev *dev) diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index e2903d03180e..8516f4d47893 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1095,26 +1095,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host) {} #endif -int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv) +int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports, + struct ahci_host_priv *hpriv) { - int rc; - unsigned int maxvec; + int rc, nvec; - if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) { - rc = pci_enable_msi_block_auto(pdev, &maxvec); - if (rc > 0) { - if ((rc == maxvec) || (rc == 1)) - return rc; - /* - * Assume that advantage of multipe MSIs is negated, - * so fallback to single MSI mode to save resources - */ - pci_disable_msi(pdev); - if (!pci_enable_msi(pdev)) - return 1; - } - } + if (hpriv->flags & AHCI_HFLAG_NO_MSI) + goto intx; + + rc = pci_msi_vec_count(pdev); + if (rc < 0) + goto intx; + + /* + * If number of MSIs is less than number of ports then Sharing Last + * Message mode could be enforced. In this case assume that advantage + * of multipe MSIs is negated and use single MSI mode instead. + */ + if (rc < n_ports) + goto single_msi; + + nvec = rc; + rc = pci_enable_msi_block(pdev, nvec); + if (rc) + goto intx; + return nvec; + +single_msi: + rc = pci_enable_msi(pdev); + if (rc) + goto intx; + return 1; + +intx: pci_intx(pdev, 1); return 0; } @@ -1281,10 +1295,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar]; - n_msis = ahci_init_interrupts(pdev, hpriv); - if (n_msis > 1) - hpriv->flags |= AHCI_HFLAG_MULTI_MSI; - /* save initial config */ ahci_pci_save_initial_config(pdev, hpriv); @@ -1339,6 +1349,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) */ n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map)); + n_msis = ahci_init_interrupts(pdev, n_ports, hpriv); + if (n_msis > 1) + hpriv->flags |= AHCI_HFLAG_MULTI_MSI; + host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports); if (!host) return -ENOMEM; diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index ba6d0a9bdd39..76507ab13beb 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -911,31 +911,6 @@ int pci_enable_msi_block(struct pci_dev *dev, int nvec) } EXPORT_SYMBOL(pci_enable_msi_block); -int pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec) -{ - int ret, nvec; - - if (dev->current_state != PCI_D0) - return -EINVAL; - - ret = pci_msi_vec_count(dev); - if (ret < 0) - return ret; - - 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 6691de093f1c..86dcf006adcc 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1164,12 +1164,6 @@ static inline int pci_enable_msi_block(struct pci_dev *dev, int nvec) return -ENOSYS; } -static inline int -pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec) -{ - return -ENOSYS; -} - static inline void pci_msi_shutdown(struct pci_dev *dev) { } static inline void pci_disable_msi(struct pci_dev *dev) @@ -1202,7 +1196,6 @@ static inline int pci_msi_enabled(void) #else int pci_msi_vec_count(struct pci_dev *dev); int pci_enable_msi_block(struct pci_dev *dev, int nvec); -int pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec); void pci_msi_shutdown(struct pci_dev *dev); void pci_disable_msi(struct pci_dev *dev); int pci_msix_table_size(struct pci_dev *dev); |