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 15 static void do_hw_reset(void); 16 17 static int reset_gpio = -1; 18 19 int 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 39 out: 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 */ 51 static 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 72 static 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 87 void 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