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