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PCI: add support for function level reset

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Sometimes, it's necessary to enable software's ability to quiesce and
reset endpoint hardware with function-level granularity, so provide
support for it.

The patch implement Function Level Reset(FLR) feature following PCI-e
spec. And this is the first step. We would add more generic method, like
D0/D3, to allow more devices support this function.

The patch contains two functions. pcie_reset_function() is the new
driver API, and, contains some action to quiesce a device.  The other
function is a helper:  pcie_execute_reset_function() just executes the
reset for a particular device function.

Current the usage model is in KVM. Function reset is necessary for
assigning device to a guest, or moving it between partitions.

For Function Level Reset(FLR), please refer to PCI Express spec chapter
6.6.2.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Sheng Yang
2008-10-21 17:38:25 +08:00
committed by Jesse Barnes
parent c4ed02fae7
commit 8dd7f8036c
3 changed files with 102 additions and 0 deletions
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2
include/linux/pci_regs.h
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@ -377,6 +377,7 @@
#define PCI_EXP_DEVCAP_RBER 0x8000 /* Role-Based Error Reporting */
#define PCI_EXP_DEVCAP_PWR_VAL 0x3fc0000 /* Slot Power Limit Value */
#define PCI_EXP_DEVCAP_PWR_SCL 0xc000000 /* Slot Power Limit Scale */
#define PCI_EXP_DEVCAP_FLR 0x10000000 /* Function Level Reset */
#define PCI_EXP_DEVCTL 8 /* Device Control */
#define PCI_EXP_DEVCTL_CERE 0x0001 /* Correctable Error Reporting En. */
#define PCI_EXP_DEVCTL_NFERE 0x0002 /* Non-Fatal Error Reporting Enable */
@ -389,6 +390,7 @@
#define PCI_EXP_DEVCTL_AUX_PME 0x0400 /* Auxiliary Power PM Enable */
#define PCI_EXP_DEVCTL_NOSNOOP_EN 0x0800 /* Enable No Snoop */
#define PCI_EXP_DEVCTL_READRQ 0x7000 /* Max_Read_Request_Size */
#define PCI_EXP_DEVCTL_BCR_FLR 0x8000 /* Bridge Configuration Retry / FLR */
#define PCI_EXP_DEVSTA 10 /* Device Status */
#define PCI_EXP_DEVSTA_CED 0x01 /* Correctable Error Detected */
#define PCI_EXP_DEVSTA_NFED 0x02 /* Non-Fatal Error Detected */