1 /* 2 * Copyright (C) 2004-2006 Atmel Corporation 3 * 4 * Modified to support C structur SoC access by 5 * Andreas Bießmann <biessmann@corscience.de> 6 * 7 * SPDX-License-Identifier: GPL-2.0+ 8 */ 9 #include <common.h> 10 #include <dm.h> 11 #include <errno.h> 12 #include <watchdog.h> 13 #include <serial.h> 14 #include <linux/compiler.h> 15 16 #include <asm/io.h> 17 #ifdef CONFIG_DM_SERIAL 18 #include <asm/arch/atmel_serial.h> 19 #endif 20 #include <asm/arch/clk.h> 21 #include <asm/arch/hardware.h> 22 23 #include "atmel_usart.h" 24 25 DECLARE_GLOBAL_DATA_PTR; 26 27 static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id, 28 int baudrate) 29 { 30 unsigned long divisor; 31 unsigned long usart_hz; 32 33 /* 34 * Master Clock 35 * Baud Rate = -------------- 36 * 16 * CD 37 */ 38 usart_hz = get_usart_clk_rate(id); 39 divisor = (usart_hz / 16 + baudrate / 2) / baudrate; 40 writel(USART3_BF(CD, divisor), &usart->brgr); 41 } 42 43 static void atmel_serial_init_internal(atmel_usart3_t *usart) 44 { 45 /* 46 * Just in case: drain transmitter register 47 * 1000us is enough for baudrate >= 9600 48 */ 49 if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY))) 50 __udelay(1000); 51 52 writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr); 53 } 54 55 static void atmel_serial_activate(atmel_usart3_t *usart) 56 { 57 writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) 58 | USART3_BF(USCLKS, USART3_USCLKS_MCK) 59 | USART3_BF(CHRL, USART3_CHRL_8) 60 | USART3_BF(PAR, USART3_PAR_NONE) 61 | USART3_BF(NBSTOP, USART3_NBSTOP_1)), 62 &usart->mr); 63 writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr); 64 /* 100us is enough for the new settings to be settled */ 65 __udelay(100); 66 } 67 68 #ifndef CONFIG_DM_SERIAL 69 static void atmel_serial_setbrg(void) 70 { 71 atmel_serial_setbrg_internal((atmel_usart3_t *)CONFIG_USART_BASE, 72 CONFIG_USART_ID, gd->baudrate); 73 } 74 75 static int atmel_serial_init(void) 76 { 77 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 78 79 atmel_serial_init_internal(usart); 80 serial_setbrg(); 81 atmel_serial_activate(usart); 82 83 return 0; 84 } 85 86 static void atmel_serial_putc(char c) 87 { 88 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 89 90 if (c == '\n') 91 serial_putc('\r'); 92 93 while (!(readl(&usart->csr) & USART3_BIT(TXRDY))); 94 writel(c, &usart->thr); 95 } 96 97 static int atmel_serial_getc(void) 98 { 99 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 100 101 while (!(readl(&usart->csr) & USART3_BIT(RXRDY))) 102 WATCHDOG_RESET(); 103 return readl(&usart->rhr); 104 } 105 106 static int atmel_serial_tstc(void) 107 { 108 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 109 return (readl(&usart->csr) & USART3_BIT(RXRDY)) != 0; 110 } 111 112 static struct serial_device atmel_serial_drv = { 113 .name = "atmel_serial", 114 .start = atmel_serial_init, 115 .stop = NULL, 116 .setbrg = atmel_serial_setbrg, 117 .putc = atmel_serial_putc, 118 .puts = default_serial_puts, 119 .getc = atmel_serial_getc, 120 .tstc = atmel_serial_tstc, 121 }; 122 123 void atmel_serial_initialize(void) 124 { 125 serial_register(&atmel_serial_drv); 126 } 127 128 __weak struct serial_device *default_serial_console(void) 129 { 130 return &atmel_serial_drv; 131 } 132 #endif 133 134 #ifdef CONFIG_DM_SERIAL 135 136 struct atmel_serial_priv { 137 atmel_usart3_t *usart; 138 }; 139 140 int atmel_serial_setbrg(struct udevice *dev, int baudrate) 141 { 142 struct atmel_serial_priv *priv = dev_get_priv(dev); 143 144 atmel_serial_setbrg_internal(priv->usart, 0 /* ignored */, baudrate); 145 atmel_serial_activate(priv->usart); 146 147 return 0; 148 } 149 150 static int atmel_serial_getc(struct udevice *dev) 151 { 152 struct atmel_serial_priv *priv = dev_get_priv(dev); 153 154 if (!(readl(&priv->usart->csr) & USART3_BIT(RXRDY))) 155 return -EAGAIN; 156 157 return readl(&priv->usart->rhr); 158 } 159 160 static int atmel_serial_putc(struct udevice *dev, const char ch) 161 { 162 struct atmel_serial_priv *priv = dev_get_priv(dev); 163 164 if (!(readl(&priv->usart->csr) & USART3_BIT(TXRDY))) 165 return -EAGAIN; 166 167 writel(ch, &priv->usart->thr); 168 169 return 0; 170 } 171 172 static int atmel_serial_pending(struct udevice *dev, bool input) 173 { 174 struct atmel_serial_priv *priv = dev_get_priv(dev); 175 uint32_t csr = readl(&priv->usart->csr); 176 177 if (input) 178 return csr & USART3_BIT(RXRDY) ? 1 : 0; 179 else 180 return csr & USART3_BIT(TXEMPTY) ? 0 : 1; 181 } 182 183 static const struct dm_serial_ops atmel_serial_ops = { 184 .putc = atmel_serial_putc, 185 .pending = atmel_serial_pending, 186 .getc = atmel_serial_getc, 187 .setbrg = atmel_serial_setbrg, 188 }; 189 190 static int atmel_serial_probe(struct udevice *dev) 191 { 192 struct atmel_serial_platdata *plat = dev->platdata; 193 struct atmel_serial_priv *priv = dev_get_priv(dev); 194 195 priv->usart = (atmel_usart3_t *)plat->base_addr; 196 atmel_serial_init_internal(priv->usart); 197 198 return 0; 199 } 200 201 U_BOOT_DRIVER(serial_atmel) = { 202 .name = "serial_atmel", 203 .id = UCLASS_SERIAL, 204 .probe = atmel_serial_probe, 205 .ops = &atmel_serial_ops, 206 .flags = DM_FLAG_PRE_RELOC, 207 .priv_auto_alloc_size = sizeof(struct atmel_serial_priv), 208 }; 209 #endif 210