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
14 unsigned int reset_status;
15 EXPORT_SYMBOL(reset_status);
16
17 static void do_hw_reset(void);
18
19 static int reset_gpio = -1;
20
init_gpio_reset(int gpio,int output,int level)21 int 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
41 out:
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 */
do_gpio_reset(void)53 static 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
do_hw_reset(void)74 static 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
pxa_restart(enum reboot_mode mode,const char * cmd)89 void 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