1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/kernel.h>
3#include <linux/module.h>
4#include <linux/delay.h>
5#include <linux/gpio.h>
6#include <linux/io.h>
7#include <asm/proc-fns.h>
8#include <asm/system_misc.h>
9
10#include "regs-ost.h"
11#include "reset.h"
12#include "smemc.h"
13#include "generic.h"
14
15static void do_hw_reset(void);
16
17static int reset_gpio = -1;
18
19int init_gpio_reset(int gpio, int output, int level)
20{
21	int rc;
22
23	rc = gpio_request(gpio, "reset generator");
24	if (rc) {
25		printk(KERN_ERR "Can't request reset_gpio\n");
26		goto out;
27	}
28
29	if (output)
30		rc = gpio_direction_output(gpio, level);
31	else
32		rc = gpio_direction_input(gpio);
33	if (rc) {
34		printk(KERN_ERR "Can't configure reset_gpio\n");
35		gpio_free(gpio);
36		goto out;
37	}
38
39out:
40	if (!rc)
41		reset_gpio = gpio;
42
43	return rc;
44}
45
46/*
47 * Trigger GPIO reset.
48 * This covers various types of logic connecting gpio pin
49 * to RESET pins (nRESET or GPIO_RESET):
50 */
51static void do_gpio_reset(void)
52{
53	BUG_ON(reset_gpio == -1);
54
55	/* drive it low */
56	gpio_direction_output(reset_gpio, 0);
57	mdelay(2);
58	/* rising edge or drive high */
59	gpio_set_value(reset_gpio, 1);
60	mdelay(2);
61	/* falling edge */
62	gpio_set_value(reset_gpio, 0);
63
64	/* give it some time */
65	mdelay(10);
66
67	WARN_ON(1);
68	/* fallback */
69	do_hw_reset();
70}
71
72static void do_hw_reset(void)
73{
74	/* Initialize the watchdog and let it fire */
75	writel_relaxed(OWER_WME, OWER);
76	writel_relaxed(OSSR_M3, OSSR);
77	/* ... in 100 ms */
78	writel_relaxed(readl_relaxed(OSCR) + 368640, OSMR3);
79	/*
80	 * SDRAM hangs on watchdog reset on Marvell PXA270 (erratum 71)
81	 * we put SDRAM into self-refresh to prevent that
82	 */
83	while (1)
84		writel_relaxed(MDREFR_SLFRSH, MDREFR);
85}
86
87void pxa_restart(enum reboot_mode mode, const char *cmd)
88{
89	local_irq_disable();
90	local_fiq_disable();
91
92	clear_reset_status(RESET_STATUS_ALL);
93
94	switch (mode) {
95	case REBOOT_SOFT:
96		/* Jump into ROM at address 0 */
97		soft_restart(0);
98		break;
99	case REBOOT_GPIO:
100		do_gpio_reset();
101		break;
102	case REBOOT_HARD:
103	default:
104		do_hw_reset();
105		break;
106	}
107}
108