payloads/libpayload/drivers/serial/s5p.c

   1 /*
   2  * Copyright 2013 Google Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote products
  13  *    derived from this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <libpayload.h>
  29 #include <stdint.h>
  30
  31 struct s5p_uart
  32 {
  33         uint32_t ulcon;         // line control
  34         uint32_t ucon;          // control
  35         uint32_t ufcon;         // FIFO control
  36         uint32_t umcon;         // modem control
  37         uint32_t utrstat;       // Tx/Rx status
  38         uint32_t uerstat;       // Rx error status
  39         uint32_t ufstat;        // FIFO status
  40         uint32_t umstat;        // modem status
  41         uint32_t utxh;          // transmit buffer
  42         uint32_t urxh;          // receive buffer
  43         uint32_t ubrdiv;        // baud rate divisor
  44         uint32_t ufracval;      // divisor fractional value
  45         uint32_t uintp;         // interrupt pending
  46         uint32_t uints;         // interrupt source
  47         uint32_t uintm;         // interrupt mask
  48 };
  49
  50 static struct s5p_uart *uart_regs;
  51
  52 void serial_putchar(unsigned int c)
  53 {
  54         const uint32_t TxFifoFullBit = (0x1 << 24);
  55
  56         while (readl(&uart_regs->ufstat) & TxFifoFullBit)
  57         {;}
  58
  59         writeb(c, &uart_regs->utxh);
  60         if (c == '\n')
  61                 serial_putchar('\r');
  62 }
  63
  64 int serial_havechar(void)
  65 {
  66         const uint32_t DataReadyMask = (0xf << 0) | (0x1 << 8);
  67
  68         return (readl(&uart_regs->ufstat) & DataReadyMask) != 0;
  69 }
  70
  71 int serial_getchar(void)
  72 {
  73         while (!serial_havechar())
  74         {;}
  75
  76         return readb(&uart_regs->urxh);
  77 }
  78
  79 static struct console_output_driver s5p_serial_output =
  80 {
  81         .putchar = &serial_putchar
  82 };
  83
  84 static struct console_input_driver s5p_serial_input =
  85 {
  86         .havekey = &serial_havechar,
  87         .getchar = &serial_getchar,
  88         .input_type = CONSOLE_INPUT_TYPE_UART,
  89 };
  90
  91 void serial_init(void)
  92 {
  93         const struct cb_serial *const serial = phys_to_virt(lib_sysinfo.cb_serial);
  94
  95         if (!lib_sysinfo.cb_serial || !serial->baseaddr)
  96                 return;
  97
  98         uart_regs = (struct s5p_uart *)serial->baseaddr;
  99 }
 100
 101 void serial_console_init(void)
 102 {
 103         serial_init();
 104
 105         if (uart_regs) {
 106                 console_add_output_driver(&s5p_serial_output);
 107                 console_add_input_driver(&s5p_serial_input);
 108         }
 109 }