drivers/ps2ser.c

   1 /***********************************************************************
   2  *
   3  * (C) Copyright 2004
   4  * DENX Software Engineering
   5  * Wolfgang Denk, wd@denx.de
   6  * All rights reserved.
   7  *
   8  * Simple 16550A serial driver
   9  *
  10  * Originally from linux source (drivers/char/ps2ser.c)
  11  *
  12  * Used by the PS/2 multiplexer driver (ps2mult.c)
  13  *
  14  ***********************************************************************/
  15
  16 #include <common.h>
  17
  18 #ifdef CONFIG_PS2SERIAL
  19
  20 #include <asm/io.h>
  21 #include <asm/atomic.h>
  22 #include <ps2mult.h>
  23
  24 /* #define      DEBUG */
  25
  26 #define PS2SER_BAUD     57600
  27
  28 static int      ps2ser_getc_hw(void);
  29 static void     ps2ser_interrupt(void *dev_id);
  30
  31 extern struct   serial_state rs_table[]; /* in serial.c */
  32 static struct   serial_state *state = rs_table + CONFIG_PS2SERIAL;
  33
  34 static u_char   ps2buf[PS2BUF_SIZE];
  35 static atomic_t ps2buf_cnt;
  36 static int      ps2buf_in_idx;
  37 static int      ps2buf_out_idx;
  38
  39
  40 static inline unsigned int ps2ser_in(int offset)
  41 {
  42         return readb((unsigned long) state->iomem_base + offset);
  43 }
  44
  45 static inline void ps2ser_out(int offset, int value)
  46 {
  47         writeb(value, (unsigned long) state->iomem_base + offset);
  48 }
  49
  50 int ps2ser_init(void)
  51 {
  52         int quot = state->baud_base / PS2SER_BAUD;
  53         unsigned cval = 0x3; /* 8N1 - 8 data bits, no parity bits, 1 stop bit */
  54
  55           /* Set speed, enable interrupts, enable FIFO
  56            */
  57         ps2ser_out(UART_LCR, cval | UART_LCR_DLAB);
  58         ps2ser_out(UART_DLL, quot & 0xff);
  59         ps2ser_out(UART_DLM, quot >> 8);
  60         ps2ser_out(UART_LCR, cval);
  61         ps2ser_out(UART_IER, UART_IER_RDI);
  62         ps2ser_out(UART_MCR, UART_MCR_OUT2 | UART_MCR_DTR | UART_MCR_RTS);
  63         ps2ser_out(UART_FCR,
  64             UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
  65
  66         /* If we read 0xff from the LSR, there is no UART here
  67          */
  68         if (ps2ser_in(UART_LSR) == 0xff) {
  69                 printf ("ps2ser.c: no UART found\n");
  70                 return -1;
  71         }
  72
  73         irq_install_handler(state->irq, ps2ser_interrupt, NULL);
  74
  75         return 0;
  76 }
  77
  78 void ps2ser_putc(int chr)
  79 {
  80 #ifdef DEBUG
  81         printf(">>>> 0x%02x\n", chr);
  82 #endif
  83
  84         while (!(ps2ser_in(UART_LSR) & UART_LSR_THRE));
  85
  86         ps2ser_out(UART_TX, chr);
  87 }
  88
  89 static int ps2ser_getc_hw(void)
  90 {
  91         int res = -1;
  92
  93         if (ps2ser_in(UART_LSR) & UART_LSR_DR) {
  94                 res = (ps2ser_in(UART_RX));
  95         }
  96
  97         return res;
  98 }
  99
 100 int ps2ser_getc(void)
 101 {
 102         volatile int chr;
 103         int flags;
 104
 105 #ifdef DEBUG
 106         printf("<< ");
 107 #endif
 108
 109         flags = disable_interrupts();
 110
 111         do {
 112                 if (atomic_read(&ps2buf_cnt) != 0) {
 113                         chr = ps2buf[ps2buf_out_idx++];
 114                         ps2buf_out_idx &= (PS2BUF_SIZE - 1);
 115                         atomic_dec(&ps2buf_cnt);
 116                 } else {
 117                         chr = ps2ser_getc_hw();
 118                 }
 119         }
 120         while (chr < 0);
 121
 122         if (flags) enable_interrupts();
 123
 124 #ifdef DEBUG
 125         printf("0x%02x\n", chr);
 126 #endif
 127
 128         return chr;
 129 }
 130
 131 int ps2ser_check(void)
 132 {
 133         int flags;
 134
 135         flags = disable_interrupts();
 136         ps2ser_interrupt(NULL);
 137         if (flags) enable_interrupts();
 138
 139         return atomic_read(&ps2buf_cnt);
 140 }
 141
 142 static void ps2ser_interrupt(void *dev_id)
 143 {
 144         int chr;
 145         int iir;
 146
 147         do {
 148                 chr = ps2ser_getc_hw();
 149                 iir = ps2ser_in(UART_IIR);
 150                 if (chr < 0) continue;
 151
 152                 if (atomic_read(&ps2buf_cnt) < PS2BUF_SIZE) {
 153                         ps2buf[ps2buf_in_idx++] = chr;
 154                         ps2buf_in_idx &= (PS2BUF_SIZE - 1);
 155                         atomic_inc(&ps2buf_cnt);
 156                 } else {
 157                         printf ("ps2ser.c: buffer overflow\n");
 158                 }
 159         } while (iir & UART_IIR_RDI);
 160
 161         if (atomic_read(&ps2buf_cnt)) {
 162                 ps2mult_callback(atomic_read(&ps2buf_cnt));
 163         }
 164 }
 165
 166 #endif /* CONFIG_PS2SERIAL */