package/uboot-lantiq/files/cpu/mips/ifx_asc.c

   1 /*
   2  * (C) Copyright 2003
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  * (C) Copyright 2009
   5  * Infineon Technologies AG, http://www.infineon.com
   6  *
   7  * See file CREDITS for list of people who contributed to this
   8  * project.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26 #include <config.h>
  27 #include <common.h>
  28 #include <asm/io.h>
  29 #include <asm/addrspace.h>
  30
  31 #include "ifx_asc.h"
  32
  33 #define SET_BIT(reg, mask)                      asc_writel(reg, asc_readl(reg) | (mask))
  34 #define CLEAR_BIT(reg, mask)                    asc_writel(reg, asc_readl(reg) & (~mask))
  35 #define SET_BITFIELD(reg, mask, off, val)       asc_writel(reg, (asc_readl(reg) & (~mask)) | (val << off) )
  36
  37 #undef DEBUG_ASC_RAW
  38 #ifdef DEBUG_ASC_RAW
  39 #define DEBUG_ASC_RAW_RX_BUF                    0xA0800000
  40 #define DEBUG_ASC_RAW_TX_BUF                    0xA0900000
  41 #endif
  42
  43 DECLARE_GLOBAL_DATA_PTR;
  44
  45 static IfxAsc_t *pAsc = (IfxAsc_t *)CKSEG1ADDR(CONFIG_SYS_IFX_ASC_BASE);
  46
  47 /*
  48  *             FDV            fASC
  49  * BaudRate = ----- * --------------------
  50  *             512    16 * (ReloadValue+1)
  51  */
  52
  53 /*
  54  *                  FDV          fASC
  55  * ReloadValue = ( ----- * --------------- ) - 1
  56  *                  512     16 * BaudRate
  57  */
  58 static void serial_divs(u32 baudrate, u32 fasc, u32 *pfdv, u32 *preload)
  59 {
  60    u32 clock = fasc / 16;
  61
  62    u32 fdv; /* best fdv */
  63    u32 reload = 0; /* best reload */
  64    u32 diff; /* smallest diff */
  65    u32 idiff; /* current diff */
  66    u32 ireload; /* current reload */
  67    u32 i; /* current fdv */
  68    u32 result; /* current resulting baudrate */
  69
  70    if (clock > 0x7FFFFF)
  71       clock /= 512;
  72    else
  73       baudrate *= 512;
  74
  75    fdv = 512; /* start with 1:1 fraction */
  76    diff = baudrate; /* highest possible */
  77
  78    /* i is the test fdv value -- start with the largest possible */
  79    for (i = 512; i > 0; i--)
  80    {
  81       ireload = (clock * i) / baudrate;
  82       if (ireload < 1)
  83          break; /* already invalid */
  84       result = (clock * i) / ireload;
  85
  86       idiff = (result > baudrate) ? (result - baudrate) : (baudrate - result);
  87       if (idiff == 0)
  88       {
  89          fdv = i;
  90          reload = ireload;
  91          break; /* can't do better */
  92       }
  93       else if (idiff < diff)
  94       {
  95          fdv = i; /* best so far */
  96          reload = ireload;
  97          diff = idiff; /* update lowest diff*/
  98       }
  99    }
 100
 101    *pfdv = (fdv == 512) ? 0 : fdv;
 102    *preload = reload - 1;
 103 }
 104
 105
 106 void serial_setbrg (void)
 107 {
 108         u32 ReloadValue, fdv;
 109
 110         serial_divs(gd->baudrate, get_bus_freq(0), &fdv, &ReloadValue);
 111
 112         /* Disable Baud Rate Generator; BG should only be written when R=0 */
 113         CLEAR_BIT(asc_con, ASCCON_R);
 114
 115         /* Enable Fractional Divider */
 116         SET_BIT(asc_con, ASCCON_FDE);   /* FDE = 1 */
 117
 118         /* Set fractional divider value */
 119         asc_writel(asc_fdv, fdv & ASCFDV_VALUE_MASK);
 120
 121         /* Set reload value in BG */
 122         asc_writel(asc_bg, ReloadValue);
 123
 124         /* Enable Baud Rate Generator */
 125         SET_BIT(asc_con, ASCCON_R);     /* R = 1 */
 126 }
 127
 128
 129 int serial_init (void)
 130 {
 131
 132         /* and we have to set CLC register*/
 133         CLEAR_BIT(asc_clc, ASCCLC_DISS);
 134         SET_BITFIELD(asc_clc, ASCCLC_RMCMASK, ASCCLC_RMCOFFSET, 0x0001);
 135
 136         /* initialy we are in async mode */
 137         asc_writel(asc_con, ASCCON_M_8ASYNC);
 138
 139         /* select input port */
 140         asc_writel(asc_pisel, CONSOLE_TTY & 0x1);
 141
 142         /* TXFIFO's filling level */
 143         SET_BITFIELD(asc_txfcon, ASCTXFCON_TXFITLMASK,
 144                         ASCTXFCON_TXFITLOFF, ASC_TXFIFO_FL);
 145         /* enable TXFIFO */
 146         SET_BIT(asc_txfcon, ASCTXFCON_TXFEN);
 147
 148         /* RXFIFO's filling level */
 149         SET_BITFIELD(asc_txfcon, ASCRXFCON_RXFITLMASK,
 150                         ASCRXFCON_RXFITLOFF, ASC_RXFIFO_FL);
 151         /* enable RXFIFO */
 152         SET_BIT(asc_rxfcon, ASCRXFCON_RXFEN);
 153
 154         /* set baud rate */
 155         serial_setbrg();
 156
 157         /* enable error signals &  Receiver enable  */
 158         SET_BIT(asc_whbstate, ASCWHBSTATE_SETREN|ASCCON_FEN|ASCCON_TOEN|ASCCON_ROEN);
 159
 160         return 0;
 161 }
 162
 163
 164 void serial_putc (const char c)
 165 {
 166         u32 txFl = 0;
 167 #ifdef DEBUG_ASC_RAW
 168         static u8 * debug = (u8 *) DEBUG_ASC_RAW_TX_BUF;
 169         *debug++=c;
 170 #endif
 171         if (c == '\n')
 172                 serial_putc ('\r');
 173         /* check do we have a free space in the TX FIFO */
 174         /* get current filling level */
 175         do {
 176                 txFl = ( asc_readl(asc_fstat) & ASCFSTAT_TXFFLMASK ) >> ASCFSTAT_TXFFLOFF;
 177         }
 178         while ( txFl == ASC_TXFIFO_FULL );
 179
 180         asc_writel(asc_tbuf, c); /* write char to Transmit Buffer Register */
 181
 182         /* check for errors */
 183         if ( asc_readl(asc_state) & ASCSTATE_TOE ) {
 184                 SET_BIT(asc_whbstate, ASCWHBSTATE_CLRTOE);
 185                 return;
 186         }
 187 }
 188
 189 void serial_puts (const char *s)
 190 {
 191         while (*s) {
 192                 serial_putc (*s++);
 193         }
 194 }
 195
 196 int serial_getc (void)
 197 {
 198         char c;
 199         while ((asc_readl(asc_fstat) & ASCFSTAT_RXFFLMASK) == 0 );
 200         c = (char)(asc_readl(asc_rbuf) & 0xff);
 201
 202 #ifdef  DEBUG_ASC_RAW
 203         static u8* debug=(u8*)(DEBUG_ASC_RAW_RX_BUF);
 204         *debug++=c;
 205 #endif
 206         return c;
 207 }
 208
 209
 210 int serial_tstc (void)
 211 {
 212         int res = 1;
 213
 214         if ( (asc_readl(asc_fstat) & ASCFSTAT_RXFFLMASK) == 0 ) {
 215                 res = 0;
 216         }
 217         return res;
 218 }