[PATCH] PCI: Block config access during BIST

Some PCI adapters (eg.  ipr scsi adapters) have an exposure today in that they
issue BIST to the adapter to reset the card.  If, during the time it takes to
complete BIST, userspace attempts to access PCI config space, the host bus
bridge will master abort the access since the ipr adapter does not respond on
the PCI bus for a brief period of time when running BIST.  On PPC64 hardware,
this master abort results in the host PCI bridge isolating that PCI device
from the rest of the system, making the device unusable until Linux is
rebooted.  This patch is an attempt to close that exposure by introducing some
blocking code in the PCI code.  When blocked, writes will be humored and reads
will return the cached value.  Ben Herrenschmidt has also mentioned that he
plans to use this in PPC power management.

Signed-off-by: Brian King <brking@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/pci/access.c    |   89 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-sysfs.c |   20 +++++-----
 drivers/pci/pci.h       |    7 +++
 drivers/pci/proc.c      |   28 +++++++--------
 drivers/pci/syscall.c   |   14 +++----
 include/linux/pci.h     |    7 +++
 6 files changed, 134 insertions(+), 31 deletions(-)

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index d3f3dd42240d..6527b36c9a61 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -15,6 +15,13 @@ extern int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 extern int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
 extern int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t state);
 
+extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
+extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);
+extern int pci_user_read_config_dword(struct pci_dev *dev, int where, u32 *val);
+extern int pci_user_write_config_byte(struct pci_dev *dev, int where, u8 val);
+extern int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val);
+extern int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val);
+
 /* PCI /proc functions */
 #ifdef CONFIG_PROC_FS
 extern int pci_proc_attach_device(struct pci_dev *dev);