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/include/drm/i2c/tda998x.h

#ifndef __DRM_I2C_TDA998X_H__
#define __DRM_I2C_TDA998X_H__

#include <linux/hdmi.h>
#include <dt-bindings/display/tda998x.h>

enum {
	AFMT_UNUSED =	0,
	AFMT_SPDIF =	TDA998x_SPDIF,
	AFMT_I2S =	TDA998x_I2S,
};

struct tda998x_audio_params {
	u8 config;
	u8 format;
	unsigned sample_width;
	unsigned sample_rate;
	struct hdmi_audio_infoframe cea;
	u8 status[5];
};

struct tda998x_encoder_params {
	u8 swap_b:3;
	u8 mirr_b:1;
	u8 swap_a:3;
	u8 mirr_a:1;
	u8 swap_d:3;
	u8 mirr_d:1;
	u8 swap_c:3;
	u8 mirr_c:1;
	u8 swap_f:3;
	u8 mirr_f:1;
	u8 swap_e:3;
	u8 mirr_e:1;

	struct tda998x_audio_params audio_params;
};

#endif