[PATCH -v2 2/2] PCI/IA64: fix pci_dev->enable_cnt balance when doing pci hotplug

[Yijing Wang <wangyijing@huawei.com>]

v1-->v2: use pci_assign_unassigned_resources() in pcibios_init()
         intead of directly calling pci_enable_bridges() in pci_acpi_scan_root()
         to avoid double enable pci bridges when hot add pci host bridge in IA64.

Under IA64 platform, we don't call pci_enable_bridges()
when scan all pci buses during system boot up. But under
X86 we do it. Further, IA64 don't assign the unassigned pci device
resource in boot path. This patch fix the pcie port device unbalanced
enable_cnt and make IA64 support pci device resource reassignment.

pcibios_assign_resources()
   pci_assign_unassigned_resources()
       ...........
       pci_enable_bridges()
          pci_enable_device()  first increase enable_cnt here

pcie_portdrv_probe()
   pcie_port_device_register()
       pci_enable_device()   second increase enable_cnt

Then when we doing hot remove

acpiphp_disable_slot()
   pci_stop_and_remove_bus_device()
       pci_stop_bus_device()
          .............
          pcie_portdrv_remove()
			  pcie_port_device_remove()
                  pci_disable_device()   first decrease enable_cnt  here
			  pci_disable_device()     second decrease enable_cnt

Following Warning info found under IA64 when doing pci hotplug.

------------[ cut here ]------------
WARNING: at drivers/pci/pci.c:1397 pci_disable_device+0x1c0/0x220()
Hardware name: MH8900
Device pcieport
disabling already-disabled device
Modules linked in: acpiphp ipv6 ipmi_si(+) ipmi_devintf ipmi_msghandler fuse vfaa
t fat dm_mod iTCO_wdt iTCO_vendor_support lpc_ich i2c_i801 mfd_core i2c_core sg
sd_mod crc_t10dif ext3 mbcache jbd ata_piix

Call Trace:
 [<a000000100015c00>] show_stack+0x80/0xa0
                                sp=e000000fd629fc00 bsp=e000000fd62996e0
 [<a000000100a9ca20>] dump_stack+0x30/0x50
                                sp=e000000fd629fdd0 bsp=e000000fd62996c8
 [<a000000100061960>] warn_slowpath_common+0xc0/0x100
                                sp=e000000fd629fdd0 bsp=e000000fd6299688
 [<a000000100061b50>] warn_slowpath_fmt+0x90/0xc0
                                sp=e000000fd629fdd0 bsp=e000000fd6299628
 [<a000000100495be0>] pci_disable_device+0x1c0/0x220
                                sp=e000000fd629fe10 bsp=e000000fd62995e8
 [<a0000001004b3ba0>] pcie_portdrv_remove+0xc0/0xe0
                                sp=e000000fd629fe10 bsp=e000000fd62995c8
 [<a000000100499670>] pci_device_remove+0x90/0x1e0
                                sp=e000000fd629fe10 bsp=e000000fd6299598
 [<a000000100636490>] __device_release_driver+0x150/0x280
                                sp=e000000fd629fe10 bsp=e000000fd6299560
 [<a000000100636830>] device_release_driver+0x30/0x60
                                sp=e000000fd629fe10 bsp=e000000fd6299538
 [<a000000100634a40>] bus_remove_device+0x2c0/0x3c0
                                sp=e000000fd629fe10 bsp=e000000fd62994f0
 [<a0000001006306d0>] device_del+0x290/0x440
                                sp=e000000fd629fe10 bsp=e000000fd62994a8
 [<a00000010048d550>] pci_stop_bus_device+0x150/0x200
                                sp=e000000fd629fe10 bsp=e000000fd6299478
 [<a00000010048d470>] pci_stop_bus_device+0x70/0x200
                                sp=e000000fd629fe10 bsp=e000000fd6299448
 [<a00000010048d470>] pci_stop_bus_device+0x70/0x200
                                sp=e000000fd629fe10 bsp=e000000fd6299418
 [<a00000010048d9a0>] pci_stop_and_remove_bus_device+0x20/0x60
                                sp=e000000fd629fe10 bsp=e000000fd62993f0
 [<a0000002089aa100>] acpiphp_disable_slot+0x240/0x4e0 [acpiphp]
                                sp=e000000fd629fe10 bsp=e000000fd62993a0
 [<a0000002089a8a30>] disable_slot+0x50/0x160 [acpiphp]
                                sp=e000000fd629fe20 bsp=e000000fd6299378
 [<a0000001004ba080>] power_write_file+0x140/0x2a0
                                sp=e000000fd629fe20 bsp=e000000fd6299348
 [<a0000001004a6320>] pci_slot_attr_store+0x60/0xa0
                                sp=e000000fd629fe20 bsp=e000000fd6299310
 [<a00000010032a100>] sysfs_write_file+0x240/0x340
                                sp=e000000fd629fe20 bsp=e000000fd62992b8
 [<a00000010023c910>] vfs_write+0x1b0/0x3a0
                                sp=e000000fd629fe20 bsp=e000000fd6299270
 [<a00000010023cc90>] sys_write+0x90/0xe0
                                sp=e000000fd629fe20 bsp=e000000fd62991f0
 [<a00000010000bce0>] ia64_ret_from_syscall+0x0/0x20
                                sp=e000000fd629fe30 bsp=e000000fd62991f0
 [<a000000000040720>] __kernel_syscall_via_break+0x0/0x20
                                sp=e000000fd62a0000 bsp=e000000fd62991f0
---[ end trace 34d87c78dbff78ce ]---
GSI 37 (level, low) -> CPU 15 (0x01e0) vector 68 unregistered
pcie_pme 0000:00:07.0:pcie01: unloading service driver pcie_pme
aer 0000:00:07.0:pcie02: unloading service driver aer

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
---
 arch/ia64/pci/pci.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index 60532ab..900660f 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -724,6 +724,7 @@ EXPORT_SYMBOL_GPL(dma_get_required_mask);
 static int __init pcibios_init(void)
 {
 	set_pci_dfl_cacheline_size();
+	pci_assign_unassigned_resources();
 	return 0;
 }
 
-- 
1.7.1