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 <mach/regs-ost.h>
11#include <mach/reset.h>
12#include <mach/smemc.h>
13
14unsigned int reset_status;
15EXPORT_SYMBOL(reset_status);
16
17static void do_hw_reset(void);
18
19static int reset_gpio = -1;
20
21int init_gpio_reset(int gpio, int output, int level)
22{
23	int rc;
24
25	rc = gpio_request(gpio, "reset generator");
26	if (rc) {
27		printk(KERN_ERR "Can't request reset_gpio\n");
28		goto out;
29	}
30
31	if (output)
32		rc = gpio_direction_output(gpio, level);
33	else
34		rc = gpio_direction_input(gpio);
35	if (rc) {
36		printk(KERN_ERR "Can't configure reset_gpio\n");
37		gpio_free(gpio);
38		goto out;
39	}
40
41out:
42	if (!rc)
43		reset_gpio = gpio;
44
45	return rc;
46}
47
48/*
49 * Trigger GPIO reset.
50 * This covers various types of logic connecting gpio pin
51 * to RESET pins (nRESET or GPIO_RESET):
52 */
53static void do_gpio_reset(void)
54{
55	BUG_ON(reset_gpio == -1);
56
57	/* drive it low */
58	gpio_direction_output(reset_gpio, 0);
59	mdelay(2);
60	/* rising edge or drive high */
61	gpio_set_value(reset_gpio, 1);
62	mdelay(2);
63	/* falling edge */
64	gpio_set_value(reset_gpio, 0);
65
66	/* give it some time */
67	mdelay(10);
68
69	WARN_ON(1);
70	/* fallback */
71	do_hw_reset();
72}
73
74static void do_hw_reset(void)
75{
76	/* Initialize the watchdog and let it fire */
77	writel_relaxed(OWER_WME, OWER);
78	writel_relaxed(OSSR_M3, OSSR);
79	/* ... in 100 ms */
80	writel_relaxed(readl_relaxed(OSCR) + 368640, OSMR3);
81	/*
82	 * SDRAM hangs on watchdog reset on Marvell PXA270 (erratum 71)
83	 * we put SDRAM into self-refresh to prevent that
84	 */
85	while (1)
86		writel_relaxed(MDREFR_SLFRSH, MDREFR);
87}
88
89void pxa_restart(enum reboot_mode mode, const char *cmd)
90{
91	local_irq_disable();
92	local_fiq_disable();
93
94	clear_reset_status(RESET_STATUS_ALL);
95
96	switch (mode) {
97	case REBOOT_SOFT:
98		/* Jump into ROM at address 0 */
99		soft_restart(0);
100		break;
101	case REBOOT_GPIO:
102		do_gpio_reset();
103		break;
104	case REBOOT_HARD:
105	default:
106		do_hw_reset();
107		break;
108	}
109}
110