[PATCH v9 02/26] PCI: Ensure a bridge has I/O and MEM access for hot-added devices

[Sergei Miroshnichenko <s.miroshnichenko@yadro.com>]

During hot-adding a device, its bridge may be already pci_is_enabled(), but
without the I/O and/or MEM access bits, which may be required by this new
device: these bits are set during first enabling the bridge, and they must
be checked again.

When hot-adding to the following bridge:

  +-[0020:00]---00.0-[01-0d]----00.0-[02-0d]----04.0-[03-0d]--   <-   00.0

this patch sets up the MEM bit in the downstream port 0020:02:04.0, needed
for 0020:08:00.0:

  [ 1037.698206] pci 0020:00:00.0: PCI bridge to [bus 01-0d]
  [ 1037.698785] pci 0020:00:00.0:   bridge window [mem 0x3fe800000000-0x3fe8017fffff]
  [ 1037.698874] pci 0020:00:00.0:   bridge window [mem 0x240000000000-0x2400ffffffff 64bit pref]
  [ 1037.699002] pcieport 0020:02:04.0: enabling device (0545 -> 0547)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  [ 1037.699114] pcieport 0020:03:00.0: enabling device (0540 -> 0542)
  [ 1037.699198] pciehp 0020:04:09.0:pcie204: Slot #41 AttnBtn+ PwrCtrl+ MRL- AttnInd+ PwrInd+ HotPlug+ Surprise- Interlock- NoCompl- LLActRep+
  [ 1037.699285] pciehp 0020:04:09.0:pcie204: Slot(41): Card present
  [ 1037.699346] pciehp 0020:04:09.0:pcie204: Slot(41): Already enabled

Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
---
 drivers/pci/pci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 076b908127fe..b7bbc462a0b3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1868,6 +1868,10 @@ static void pci_enable_bridge(struct pci_dev *dev)
 		pci_enable_bridge(bridge);
 
 	if (pci_is_enabled(dev)) {
+		retval = pci_reenable_device(dev);
+		if (retval)
+			pci_err(dev, "Error reenabling bridge, continuing\n");
+
 		if (!dev->is_busmaster)
 			pci_set_master(dev);
 		mutex_unlock(&dev->enable_mutex);
-- 
2.24.1