drivers/serial/serial_s5p.c

   1 /*
   2  * (C) Copyright 2009 SAMSUNG Electronics
   3  * Minkyu Kang <mk7.kang@samsung.com>
   4  * Heungjun Kim <riverful.kim@samsung.com>
   5  *
   6  * based on drivers/serial/s3c64xx.c
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  */
  23
  24 #include <common.h>
  25 #include <asm/io.h>
  26 #include <asm/arch/uart.h>
  27 #include <asm/arch/clk.h>
  28 #include <serial.h>
  29
  30 static inline struct s5p_uart *s5p_get_base_uart(int dev_index)
  31 {
  32         u32 offset = dev_index * sizeof(struct s5p_uart);
  33
  34         if (cpu_is_s5pc100())
  35                 return (struct s5p_uart *)(S5PC100_UART_BASE + offset);
  36         else
  37                 return (struct s5p_uart *)(S5PC110_UART_BASE + offset);
  38 }
  39
  40 /*
  41  * The coefficient, used to calculate the baudrate on S5P UARTs is
  42  * calculated as
  43  * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
  44  * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
  45  * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
  46  */
  47 static const int udivslot[] = {
  48         0,
  49         0x0080,
  50         0x0808,
  51         0x0888,
  52         0x2222,
  53         0x4924,
  54         0x4a52,
  55         0x54aa,
  56         0x5555,
  57         0xd555,
  58         0xd5d5,
  59         0xddd5,
  60         0xdddd,
  61         0xdfdd,
  62         0xdfdf,
  63         0xffdf,
  64 };
  65
  66 void serial_setbrg_dev(const int dev_index)
  67 {
  68         DECLARE_GLOBAL_DATA_PTR;
  69         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
  70         u32 pclk = get_pclk();
  71         u32 baudrate = gd->baudrate;
  72         u32 val;
  73
  74         val = pclk / baudrate;
  75
  76         writel(val / 16 - 1, &uart->ubrdiv);
  77         writew(udivslot[val % 16], &uart->udivslot);
  78 }
  79
  80 /*
  81  * Initialise the serial port with the given baudrate. The settings
  82  * are always 8 data bits, no parity, 1 stop bit, no start bits.
  83  */
  84 int serial_init_dev(const int dev_index)
  85 {
  86         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
  87
  88         /* reset and enable FIFOs, set triggers to the maximum */
  89         writel(0, &uart->ufcon);
  90         writel(0, &uart->umcon);
  91         /* 8N1 */
  92         writel(0x3, &uart->ulcon);
  93         /* No interrupts, no DMA, pure polling */
  94         writel(0x245, &uart->ucon);
  95
  96         serial_setbrg_dev(dev_index);
  97
  98         return 0;
  99 }
 100
 101 static int serial_err_check(const int dev_index, int op)
 102 {
 103         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 104         unsigned int mask;
 105
 106         /*
 107          * UERSTAT
 108          * Break Detect [3]
 109          * Frame Err    [2] : receive operation
 110          * Parity Err   [1] : receive operation
 111          * Overrun Err  [0] : receive operation
 112          */
 113         if (op)
 114                 mask = 0x8;
 115         else
 116                 mask = 0xf;
 117
 118         return readl(&uart->uerstat) & mask;
 119 }
 120
 121 /*
 122  * Read a single byte from the serial port. Returns 1 on success, 0
 123  * otherwise. When the function is succesfull, the character read is
 124  * written into its argument c.
 125  */
 126 int serial_getc_dev(const int dev_index)
 127 {
 128         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 129
 130         /* wait for character to arrive */
 131         while (!(readl(&uart->utrstat) & 0x1)) {
 132                 if (serial_err_check(dev_index, 0))
 133                         return 0;
 134         }
 135
 136         return (int)(readl(&uart->urxh) & 0xff);
 137 }
 138
 139 /*
 140  * Output a single byte to the serial port.
 141  */
 142 void serial_putc_dev(const char c, const int dev_index)
 143 {
 144         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 145
 146         /* wait for room in the tx FIFO */
 147         while (!(readl(&uart->utrstat) & 0x2)) {
 148                 if (serial_err_check(dev_index, 1))
 149                         return;
 150         }
 151
 152         writel(c, &uart->utxh);
 153
 154         /* If \n, also do \r */
 155         if (c == '\n')
 156                 serial_putc('\r');
 157 }
 158
 159 /*
 160  * Test whether a character is in the RX buffer
 161  */
 162 int serial_tstc_dev(const int dev_index)
 163 {
 164         struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 165
 166         return (int)(readl(&uart->utrstat) & 0x1);
 167 }
 168
 169 void serial_puts_dev(const char *s, const int dev_index)
 170 {
 171         while (*s)
 172                 serial_putc_dev(*s++, dev_index);
 173 }
 174
 175 /* Multi serial device functions */
 176 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \
 177 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \
 178 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \
 179 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \
 180 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \
 181 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \
 182 void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); }
 183
 184 #define INIT_S5P_SERIAL_STRUCTURE(port, name, bus) { \
 185         name, \
 186         bus, \
 187         s5p_serial##port##_init, \
 188         NULL, \
 189         s5p_serial##port##_setbrg, \
 190         s5p_serial##port##_getc, \
 191         s5p_serial##port##_tstc, \
 192         s5p_serial##port##_putc, \
 193         s5p_serial##port##_puts, }
 194
 195 DECLARE_S5P_SERIAL_FUNCTIONS(0);
 196 struct serial_device s5p_serial0_device =
 197         INIT_S5P_SERIAL_STRUCTURE(0, "s5pser0", "S5PUART0");
 198 DECLARE_S5P_SERIAL_FUNCTIONS(1);
 199 struct serial_device s5p_serial1_device =
 200         INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1", "S5PUART1");
 201 DECLARE_S5P_SERIAL_FUNCTIONS(2);
 202 struct serial_device s5p_serial2_device =
 203         INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2", "S5PUART2");
 204 DECLARE_S5P_SERIAL_FUNCTIONS(3);
 205 struct serial_device s5p_serial3_device =
 206         INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3", "S5PUART3");