diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index aee73cf251b..533aeb5fcbe 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -18,6 +18,7 @@ #include <linux/log2.h> #include <linux/pci-aspm.h> #include <linux/pm_wakeup.h> +#include <linux/interrupt.h> #include <asm/dma.h> /* isa_dma_bridge_buggy */ #include "pci.h" @@ -1746,6 +1747,103 @@ EXPORT_SYMBOL(pci_set_dma_seg_boundary); #endif /** + * pci_execute_reset_function() - Reset a PCI device function + * @dev: Device function to reset + * + * Some devices allow an individual function to be reset without affecting + * other functions in the same device. The PCI device must be responsive + * to PCI config space in order to use this function. + * + * The device function is presumed to be unused when this function is called. + * Resetting the device will make the contents of PCI configuration space + * random, so any caller of this must be prepared to reinitialise the + * device including MSI, bus mastering, BARs, decoding IO and memory spaces, + * etc. + * + * Returns 0 if the device function was successfully reset or -ENOTTY if the + * device doesn't support resetting a single function. + */ +int pci_execute_reset_function(struct pci_dev *dev) +{ + u16 status; + u32 cap; + int exppos = pci_find_capability(dev, PCI_CAP_ID_EXP); + + if (!exppos) + return -ENOTTY; + pci_read_config_dword(dev, exppos + PCI_EXP_DEVCAP, &cap); + if (!(cap & PCI_EXP_DEVCAP_FLR)) + return -ENOTTY; + + pci_block_user_cfg_access(dev); + + /* Wait for Transaction Pending bit clean */ + msleep(100); + pci_read_config_word(dev, exppos + PCI_EXP_DEVSTA, &status); + if (status & PCI_EXP_DEVSTA_TRPND) { + dev_info(&dev->dev, "Busy after 100ms while trying to reset; " + "sleeping for 1 second\n"); + ssleep(1); + pci_read_config_word(dev, exppos + PCI_EXP_DEVSTA, &status); + if (status & PCI_EXP_DEVSTA_TRPND) + dev_info(&dev->dev, "Still busy after 1s; " + "proceeding with reset anyway\n"); + } + + pci_write_config_word(dev, exppos + PCI_EXP_DEVCTL, + PCI_EXP_DEVCTL_BCR_FLR); + mdelay(100); + + pci_unblock_user_cfg_access(dev); + return 0; +} +EXPORT_SYMBOL_GPL(pci_execute_reset_function); + +/** + * pci_reset_function() - quiesce and reset a PCI device function + * @dev: Device function to reset + * + * Some devices allow an individual function to be reset without affecting + * other functions in the same device. The PCI device must be responsive + * to PCI config space in order to use this function. + * + * This function does not just reset the PCI portion of a device, but + * clears all the state associated with the device. This function differs + * from pci_execute_reset_function in that it saves and restores device state + * over the reset. + * + * Returns 0 if the device function was successfully reset or -ENOTTY if the + * device doesn't support resetting a single function. + */ +int pci_reset_function(struct pci_dev *dev) +{ + u32 cap; + int exppos = pci_find_capability(dev, PCI_CAP_ID_EXP); + int r; + + if (!exppos) + return -ENOTTY; + pci_read_config_dword(dev, exppos + PCI_EXP_DEVCAP, &cap); + if (!(cap & PCI_EXP_DEVCAP_FLR)) + return -ENOTTY; + + if (!dev->msi_enabled && !dev->msix_enabled) + disable_irq(dev->irq); + pci_save_state(dev); + + pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE); + + r = pci_execute_reset_function(dev); + + pci_restore_state(dev); + if (!dev->msi_enabled && !dev->msix_enabled) + enable_irq(dev->irq); + + return r; +} +EXPORT_SYMBOL_GPL(pci_reset_function); + +/** * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count * @dev: PCI device to query * |