[mirror_ubuntu-eoan-kernel.git] / drivers / thunderbolt / cap.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - capabilities lookup
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2018, Intel Corporation
 */

#include <linux/slab.h>
#include <linux/errno.h>

#include "tb.h"

#define CAP_OFFSET_MAX		0xff
#define VSE_CAP_OFFSET_MAX	0xffff

struct tb_cap_any {
	union {
		struct tb_cap_basic basic;
		struct tb_cap_extended_short extended_short;
		struct tb_cap_extended_long extended_long;
	};
} __packed;

/**
 * tb_port_find_cap() - Find port capability
 * @port: Port to find the capability for
 * @cap: Capability to look
 *
 * Returns offset to start of capability or %-ENOENT if no such
 * capability was found. Negative errno is returned if there was an
 * error.
 */
int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
{
	u32 offset;

	/*
	 * DP out adapters claim to implement TMU capability but in
	 * reality they do not so we hard code the adapter specific
	 * capability offset here.
	 */
	if (port->config.type == TB_TYPE_DP_HDMI_OUT)
		offset = 0x39;
	else
		offset = 0x1;

	do {
		struct tb_cap_any header;
		int ret;

		ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
		if (ret)
			return ret;

		if (header.basic.cap == cap)
			return offset;

		offset = header.basic.next;
	} while (offset);

	return -ENOENT;
}

static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
{
	int offset = sw->config.first_cap_offset;

	while (offset > 0 && offset < CAP_OFFSET_MAX) {
		struct tb_cap_any header;
		int ret;

		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
		if (ret)
			return ret;

		if (header.basic.cap == cap)
			return offset;

		offset = header.basic.next;
	}

	return -ENOENT;
}

/**
 * tb_switch_find_vse_cap() - Find switch vendor specific capability
 * @sw: Switch to find the capability for
 * @vsec: Vendor specific capability to look
 *
 * Functions enumerates vendor specific capabilities (VSEC) of a switch
 * and returns offset when capability matching @vsec is found. If no
 * such capability is found returns %-ENOENT. In case of error returns
 * negative errno.
 */
int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
{
	struct tb_cap_any header;
	int offset;

	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
	if (offset < 0)
		return offset;

	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
		int ret;

		ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
		if (ret)
			return ret;

		/*
		 * Extended vendor specific capabilities come in two
		 * flavors: short and long. The latter is used when
		 * offset is over 0xff.
		 */
		if (offset >= CAP_OFFSET_MAX) {
			if (header.extended_long.vsec_id == vsec)
				return offset;
			offset = header.extended_long.next;
		} else {
			if (header.extended_short.vsec_id == vsec)
				return offset;
			if (!header.extended_short.length)
				return -ENOENT;
			offset = header.extended_short.next;
		}
	}

	return -ENOENT;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
e2b8785e	2	/*
15c6784c	3	* Thunderbolt driver - capabilities lookup
e2b8785e AN	4	*
e2b8785e AN	5	* Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
15c6784c	6	* Copyright (C) 2018, Intel Corporation
e2b8785e AN	7	*/
	8
	9	#include <linux/slab.h>
	10	#include <linux/errno.h>
	11
	12	#include "tb.h"
	13
da2da04b MW	14	#define CAP_OFFSET_MAX 0xff
da2da04b MW	15	#define VSE_CAP_OFFSET_MAX 0xffff
e2b8785e AN	16
	17	struct tb_cap_any {
	18	union {
	19	struct tb_cap_basic basic;
	20	struct tb_cap_extended_short extended_short;
	21	struct tb_cap_extended_long extended_long;
	22	};
	23	} __packed;
	24
da2da04b MW	25	/**
	26	* tb_port_find_cap() - Find port capability
	27	* @port: Port to find the capability for
	28	* @cap: Capability to look
	29	*
	30	* Returns offset to start of capability or %-ENOENT if no such
	31	* capability was found. Negative errno is returned if there was an
	32	* error.
	33	*/
	34	int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
e2b8785e	35	{
da2da04b	36	u32 offset;
e2b8785e	37
da2da04b MW	38	/*
	39	* DP out adapters claim to implement TMU capability but in
	40	* reality they do not so we hard code the adapter specific
	41	* capability offset here.
	42	*/
	43	if (port->config.type == TB_TYPE_DP_HDMI_OUT)
	44	offset = 0x39;
e2b8785e	45	else
da2da04b MW	46	offset = 0x1;
	47
	48	do {
	49	struct tb_cap_any header;
	50	int ret;
	51
	52	ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
	53	if (ret)
	54	return ret;
	55
	56	if (header.basic.cap == cap)
	57	return offset;
	58
	59	offset = header.basic.next;
	60	} while (offset);
	61
	62	return -ENOENT;
e2b8785e AN	63	}
e2b8785e AN	64
da2da04b	65	static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
e2b8785e	66	{
da2da04b MW	67	int offset = sw->config.first_cap_offset;
	68
	69	while (offset > 0 && offset < CAP_OFFSET_MAX) {
	70	struct tb_cap_any header;
	71	int ret;
	72
	73	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
	74	if (ret)
	75	return ret;
	76
	77	if (header.basic.cap == cap)
	78	return offset;
	79
	80	offset = header.basic.next;
e2b8785e	81	}
da2da04b MW	82
da2da04b MW	83	return -ENOENT;
e2b8785e AN	84	}
	85
	86	/**
da2da04b MW	87	* tb_switch_find_vse_cap() - Find switch vendor specific capability
	88	* @sw: Switch to find the capability for
	89	* @vsec: Vendor specific capability to look
e2b8785e	90	*
da2da04b MW	91	* Functions enumerates vendor specific capabilities (VSEC) of a switch
	92	* and returns offset when capability matching @vsec is found. If no
	93	* such capability is found returns %-ENOENT. In case of error returns
	94	* negative errno.
e2b8785e	95	*/
da2da04b	96	int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
e2b8785e	97	{
e2b8785e	98	struct tb_cap_any header;
da2da04b MW	99	int offset;
	100
	101	offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
	102	if (offset < 0)
	103	return offset;
	104
	105	while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
	106	int ret;
	107
	108	ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
	109	if (ret)
	110	return ret;
	111
	112	/*
	113	* Extended vendor specific capabilities come in two
	114	* flavors: short and long. The latter is used when
	115	* offset is over 0xff.
	116	*/
	117	if (offset >= CAP_OFFSET_MAX) {
	118	if (header.extended_long.vsec_id == vsec)
e2b8785e	119	return offset;
da2da04b MW	120	offset = header.extended_long.next;
	121	} else {
	122	if (header.extended_short.vsec_id == vsec)
	123	return offset;
	124	if (!header.extended_short.length)
	125	return -ENOENT;
	126	offset = header.extended_short.next;
e2b8785e	127	}
e2b8785e	128	}
da2da04b MW	129
da2da04b MW	130	return -ENOENT;
e2b8785e	131	}