1 /* 2 * Copyright (C) 2012 Michal Simek <monstr@monstr.eu> 3 * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved. 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <clk.h> 9 #include <common.h> 10 #include <debug_uart.h> 11 #include <dm.h> 12 #include <errno.h> 13 #include <fdtdec.h> 14 #include <watchdog.h> 15 #include <asm/io.h> 16 #include <linux/compiler.h> 17 #include <serial.h> 18 #include <asm/arch/hardware.h> 19 20 DECLARE_GLOBAL_DATA_PTR; 21 22 #define ZYNQ_UART_SR_TXEMPTY (1 << 3) /* TX FIFO empty */ 23 #define ZYNQ_UART_SR_TXACTIVE (1 << 11) /* TX active */ 24 #define ZYNQ_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */ 25 26 #define ZYNQ_UART_CR_TX_EN 0x00000010 /* TX enabled */ 27 #define ZYNQ_UART_CR_RX_EN 0x00000004 /* RX enabled */ 28 #define ZYNQ_UART_CR_TXRST 0x00000002 /* TX logic reset */ 29 #define ZYNQ_UART_CR_RXRST 0x00000001 /* RX logic reset */ 30 31 #define ZYNQ_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */ 32 33 struct uart_zynq { 34 u32 control; /* 0x0 - Control Register [8:0] */ 35 u32 mode; /* 0x4 - Mode Register [10:0] */ 36 u32 reserved1[4]; 37 u32 baud_rate_gen; /* 0x18 - Baud Rate Generator [15:0] */ 38 u32 reserved2[4]; 39 u32 channel_sts; /* 0x2c - Channel Status [11:0] */ 40 u32 tx_rx_fifo; /* 0x30 - FIFO [15:0] or [7:0] */ 41 u32 baud_rate_divider; /* 0x34 - Baud Rate Divider [7:0] */ 42 }; 43 44 struct zynq_uart_priv { 45 struct uart_zynq *regs; 46 }; 47 48 /* Set up the baud rate in gd struct */ 49 static void _uart_zynq_serial_setbrg(struct uart_zynq *regs, 50 unsigned long clock, unsigned long baud) 51 { 52 /* Calculation results. */ 53 unsigned int calc_bauderror, bdiv, bgen; 54 unsigned long calc_baud = 0; 55 56 /* Covering case where input clock is so slow */ 57 if (clock < 1000000 && baud > 4800) 58 baud = 4800; 59 60 /* master clock 61 * Baud rate = ------------------ 62 * bgen * (bdiv + 1) 63 * 64 * Find acceptable values for baud generation. 65 */ 66 for (bdiv = 4; bdiv < 255; bdiv++) { 67 bgen = clock / (baud * (bdiv + 1)); 68 if (bgen < 2 || bgen > 65535) 69 continue; 70 71 calc_baud = clock / (bgen * (bdiv + 1)); 72 73 /* 74 * Use first calculated baudrate with 75 * an acceptable (<3%) error 76 */ 77 if (baud > calc_baud) 78 calc_bauderror = baud - calc_baud; 79 else 80 calc_bauderror = calc_baud - baud; 81 if (((calc_bauderror * 100) / baud) < 3) 82 break; 83 } 84 85 writel(bdiv, ®s->baud_rate_divider); 86 writel(bgen, ®s->baud_rate_gen); 87 } 88 89 /* Initialize the UART, with...some settings. */ 90 static void _uart_zynq_serial_init(struct uart_zynq *regs) 91 { 92 /* RX/TX enabled & reset */ 93 writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \ 94 ZYNQ_UART_CR_RXRST, ®s->control); 95 writel(ZYNQ_UART_MR_PARITY_NONE, ®s->mode); /* 8 bit, no parity */ 96 } 97 98 static int _uart_zynq_serial_putc(struct uart_zynq *regs, const char c) 99 { 100 if (!(readl(®s->channel_sts) & ZYNQ_UART_SR_TXEMPTY)) 101 return -EAGAIN; 102 103 writel(c, ®s->tx_rx_fifo); 104 105 return 0; 106 } 107 108 int zynq_serial_setbrg(struct udevice *dev, int baudrate) 109 { 110 struct zynq_uart_priv *priv = dev_get_priv(dev); 111 unsigned long clock; 112 113 int ret; 114 struct clk clk; 115 116 ret = clk_get_by_index(dev, 0, &clk); 117 if (ret < 0) { 118 dev_err(dev, "failed to get clock\n"); 119 return ret; 120 } 121 122 clock = clk_get_rate(&clk); 123 if (IS_ERR_VALUE(clock)) { 124 dev_err(dev, "failed to get rate\n"); 125 return clock; 126 } 127 debug("%s: CLK %ld\n", __func__, clock); 128 129 ret = clk_enable(&clk); 130 if (ret && ret != -ENOSYS) { 131 dev_err(dev, "failed to enable clock\n"); 132 return ret; 133 } 134 135 _uart_zynq_serial_setbrg(priv->regs, clock, baudrate); 136 137 return 0; 138 } 139 140 static int zynq_serial_probe(struct udevice *dev) 141 { 142 struct zynq_uart_priv *priv = dev_get_priv(dev); 143 144 _uart_zynq_serial_init(priv->regs); 145 146 return 0; 147 } 148 149 static int zynq_serial_getc(struct udevice *dev) 150 { 151 struct zynq_uart_priv *priv = dev_get_priv(dev); 152 struct uart_zynq *regs = priv->regs; 153 154 if (readl(®s->channel_sts) & ZYNQ_UART_SR_RXEMPTY) 155 return -EAGAIN; 156 157 return readl(®s->tx_rx_fifo); 158 } 159 160 static int zynq_serial_putc(struct udevice *dev, const char ch) 161 { 162 struct zynq_uart_priv *priv = dev_get_priv(dev); 163 164 return _uart_zynq_serial_putc(priv->regs, ch); 165 } 166 167 static int zynq_serial_pending(struct udevice *dev, bool input) 168 { 169 struct zynq_uart_priv *priv = dev_get_priv(dev); 170 struct uart_zynq *regs = priv->regs; 171 172 if (input) 173 return !(readl(®s->channel_sts) & ZYNQ_UART_SR_RXEMPTY); 174 else 175 return !!(readl(®s->channel_sts) & ZYNQ_UART_SR_TXACTIVE); 176 } 177 178 static int zynq_serial_ofdata_to_platdata(struct udevice *dev) 179 { 180 struct zynq_uart_priv *priv = dev_get_priv(dev); 181 182 priv->regs = (struct uart_zynq *)devfdt_get_addr(dev); 183 184 return 0; 185 } 186 187 static const struct dm_serial_ops zynq_serial_ops = { 188 .putc = zynq_serial_putc, 189 .pending = zynq_serial_pending, 190 .getc = zynq_serial_getc, 191 .setbrg = zynq_serial_setbrg, 192 }; 193 194 static const struct udevice_id zynq_serial_ids[] = { 195 { .compatible = "xlnx,xuartps" }, 196 { .compatible = "cdns,uart-r1p8" }, 197 { .compatible = "cdns,uart-r1p12" }, 198 { } 199 }; 200 201 U_BOOT_DRIVER(serial_zynq) = { 202 .name = "serial_zynq", 203 .id = UCLASS_SERIAL, 204 .of_match = zynq_serial_ids, 205 .ofdata_to_platdata = zynq_serial_ofdata_to_platdata, 206 .priv_auto_alloc_size = sizeof(struct zynq_uart_priv), 207 .probe = zynq_serial_probe, 208 .ops = &zynq_serial_ops, 209 .flags = DM_FLAG_PRE_RELOC, 210 }; 211 212 #ifdef CONFIG_DEBUG_UART_ZYNQ 213 static inline void _debug_uart_init(void) 214 { 215 struct uart_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE; 216 217 _uart_zynq_serial_init(regs); 218 _uart_zynq_serial_setbrg(regs, CONFIG_DEBUG_UART_CLOCK, 219 CONFIG_BAUDRATE); 220 } 221 222 static inline void _debug_uart_putc(int ch) 223 { 224 struct uart_zynq *regs = (struct uart_zynq *)CONFIG_DEBUG_UART_BASE; 225 226 while (_uart_zynq_serial_putc(regs, ch) == -EAGAIN) 227 WATCHDOG_RESET(); 228 } 229 230 DEBUG_UART_FUNCS 231 232 #endif 233