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

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

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