PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies

In a struct pcie_link_state, link->root points to the pcie_link_state of
the root of the PCIe hierarchy.  For the topmost link, this points to
itself (link->root = link).  For others, we copy the pointer from the
parent (link->root = link->parent->root).

Previously we recognized that Root Ports originated PCIe hierarchies, but
we treated PCI/PCI-X to PCIe Bridges as being in the middle of the
hierarchy, and when we tried to copy the pointer from link->parent->root,
there was no parent, and we dereferenced a NULL pointer:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
  IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820

Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just
like Root Ports do, so link->root for these devices should also point to
itself.

Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411
Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181
Tested-by: lists@ssl-mail.com
Tested-by: Jayachandran C. <jnair@caviumnetworks.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v4.2+

path: root/sound/oss/ad1848.h

#include <linux/interrupt.h>

#define AD_F_CS4231     0x0001  /* Returned if a CS4232 (or compatible) detected */
#define AD_F_CS4248     0x0001  /* Returned if a CS4248 (or compatible) detected */

#define         AD1848_SET_XTAL         1
#define         AD1848_MIXER_REROUTE    2

#define AD1848_REROUTE(oldctl, newctl) \
                ad1848_control(AD1848_MIXER_REROUTE, ((oldctl)<<8)|(newctl))
		

int ad1848_init(char *name, struct resource *ports, int irq, int dma_playback,
	int dma_capture, int share_dma, int *osp, struct module *owner);
void ad1848_unload (int io_base, int irq, int dma_playback, int dma_capture, int share_dma);

int ad1848_detect (struct resource *ports, int *flags, int *osp);
int ad1848_control(int cmd, int arg);

void attach_ms_sound(struct address_info * hw_config, struct resource *ports, struct module * owner);

int probe_ms_sound(struct address_info *hw_config, struct resource *ports);
void unload_ms_sound(struct address_info *hw_info);