1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * NHI specific operations
  4 *
  5 * Copyright (C) 2019, Intel Corporation
  6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
  7 */
  8
  9#include <linux/delay.h>
 10#include <linux/suspend.h>
 11
 12#include "nhi.h"
 13#include "nhi_regs.h"
 14#include "tb.h"
 15
 16/* Ice Lake specific NHI operations */
 17
 18#define ICL_LC_MAILBOX_TIMEOUT	500 /* ms */
 19
 20static int check_for_device(struct device *dev, void *data)
 21{
 22	return tb_is_switch(dev);
 23}
 24
 25static bool icl_nhi_is_device_connected(struct tb_nhi *nhi)
 26{
 27	struct tb *tb = pci_get_drvdata(nhi->pdev);
 28	int ret;
 29
 30	ret = device_for_each_child(&tb->root_switch->dev, NULL,
 31				    check_for_device);
 32	return ret > 0;
 33}
 34
 35static int icl_nhi_force_power(struct tb_nhi *nhi, bool power)
 36{
 37	u32 vs_cap;
 38
 39	/*
 40	 * The Thunderbolt host controller is present always in Ice Lake
 41	 * but the firmware may not be loaded and running (depending
 42	 * whether there is device connected and so on). Each time the
 43	 * controller is used we need to "Force Power" it first and wait
 44	 * for the firmware to indicate it is up and running. This "Force
 45	 * Power" is really not about actually powering on/off the
 46	 * controller so it is accessible even if "Force Power" is off.
 47	 *
 48	 * The actual power management happens inside shared ACPI power
 49	 * resources using standard ACPI methods.
 50	 */
 51	pci_read_config_dword(nhi->pdev, VS_CAP_22, &vs_cap);
 52	if (power) {
 53		vs_cap &= ~VS_CAP_22_DMA_DELAY_MASK;
 54		vs_cap |= 0x22 << VS_CAP_22_DMA_DELAY_SHIFT;
 55		vs_cap |= VS_CAP_22_FORCE_POWER;
 56	} else {
 57		vs_cap &= ~VS_CAP_22_FORCE_POWER;
 58	}
 59	pci_write_config_dword(nhi->pdev, VS_CAP_22, vs_cap);
 60
 61	if (power) {
 62		unsigned int retries = 350;
 63		u32 val;
 64
 65		/* Wait until the firmware tells it is up and running */
 66		do {
 67			pci_read_config_dword(nhi->pdev, VS_CAP_9, &val);
 68			if (val & VS_CAP_9_FW_READY)
 69				return 0;
 70			usleep_range(3000, 3100);
 71		} while (--retries);
 72
 73		return -ETIMEDOUT;
 74	}
 75
 76	return 0;
 77}
 78
 79static void icl_nhi_lc_mailbox_cmd(struct tb_nhi *nhi, enum icl_lc_mailbox_cmd cmd)
 80{
 81	u32 data;
 82
 83	data = (cmd << VS_CAP_19_CMD_SHIFT) & VS_CAP_19_CMD_MASK;
 84	pci_write_config_dword(nhi->pdev, VS_CAP_19, data | VS_CAP_19_VALID);
 85}
 86
 87static int icl_nhi_lc_mailbox_cmd_complete(struct tb_nhi *nhi, int timeout)
 88{
 89	unsigned long end;
 90	u32 data;
 91
 92	if (!timeout)
 93		goto clear;
 94
 95	end = jiffies + msecs_to_jiffies(timeout);
 96	do {
 97		pci_read_config_dword(nhi->pdev, VS_CAP_18, &data);
 98		if (data & VS_CAP_18_DONE)
 99			goto clear;
100		usleep_range(1000, 1100);
101	} while (time_before(jiffies, end));
102
103	return -ETIMEDOUT;
104
105clear:
106	/* Clear the valid bit */
107	pci_write_config_dword(nhi->pdev, VS_CAP_19, 0);
108	return 0;
109}
110
111static void icl_nhi_set_ltr(struct tb_nhi *nhi)
112{
113	u32 max_ltr, ltr;
114
115	pci_read_config_dword(nhi->pdev, VS_CAP_16, &max_ltr);
116	max_ltr &= 0xffff;
117	/* Program the same value for both snoop and no-snoop */
118	ltr = max_ltr << 16 | max_ltr;
119	pci_write_config_dword(nhi->pdev, VS_CAP_15, ltr);
120}
121
122static int icl_nhi_suspend(struct tb_nhi *nhi)
123{
124	struct tb *tb = pci_get_drvdata(nhi->pdev);
125	int ret;
126
127	if (icl_nhi_is_device_connected(nhi))
128		return 0;
129
130	if (tb_switch_is_icm(tb->root_switch)) {
131		/*
132		 * If there is no device connected we need to perform
133		 * both: a handshake through LC mailbox and force power
134		 * down before entering D3.
135		 */
136		icl_nhi_lc_mailbox_cmd(nhi, ICL_LC_PREPARE_FOR_RESET);
137		ret = icl_nhi_lc_mailbox_cmd_complete(nhi, ICL_LC_MAILBOX_TIMEOUT);
138		if (ret)
139			return ret;
140	}
141
142	return icl_nhi_force_power(nhi, false);
143}
144
145static int icl_nhi_suspend_noirq(struct tb_nhi *nhi, bool wakeup)
146{
147	struct tb *tb = pci_get_drvdata(nhi->pdev);
148	enum icl_lc_mailbox_cmd cmd;
149
150	if (!pm_suspend_via_firmware())
151		return icl_nhi_suspend(nhi);
152
153	if (!tb_switch_is_icm(tb->root_switch))
154		return 0;
155
156	cmd = wakeup ? ICL_LC_GO2SX : ICL_LC_GO2SX_NO_WAKE;
157	icl_nhi_lc_mailbox_cmd(nhi, cmd);
158	return icl_nhi_lc_mailbox_cmd_complete(nhi, ICL_LC_MAILBOX_TIMEOUT);
159}
160
161static int icl_nhi_resume(struct tb_nhi *nhi)
162{
163	int ret;
164
165	ret = icl_nhi_force_power(nhi, true);
166	if (ret)
167		return ret;
168
169	icl_nhi_set_ltr(nhi);
170	return 0;
171}
172
173static void icl_nhi_shutdown(struct tb_nhi *nhi)
174{
175	icl_nhi_force_power(nhi, false);
176}
177
178const struct tb_nhi_ops icl_nhi_ops = {
179	.init = icl_nhi_resume,
180	.suspend_noirq = icl_nhi_suspend_noirq,
181	.resume_noirq = icl_nhi_resume,
182	.runtime_suspend = icl_nhi_suspend,
183	.runtime_resume = icl_nhi_resume,
184	.shutdown = icl_nhi_shutdown,
185};