hw/i2c/pm_smbus.c

   1 /*
   2  * PC SMBus implementation
   3  * splitted from acpi.c
   4  *
   5  * Copyright (c) 2006 Fabrice Bellard
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License version 2 as published by the Free Software Foundation.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/>.
  19  */
  20 #include "hw/hw.h"
  21 #include "hw/i386/pc.h"
  22 #include "hw/i2c/pm_smbus.h"
  23 #include "hw/i2c/smbus.h"
  24
  25 /* no save/load? */
  26
  27 #define SMBHSTSTS       0x00
  28 #define SMBHSTCNT       0x02
  29 #define SMBHSTCMD       0x03
  30 #define SMBHSTADD       0x04
  31 #define SMBHSTDAT0      0x05
  32 #define SMBHSTDAT1      0x06
  33 #define SMBBLKDAT       0x07
  34
  35 #define STS_HOST_BUSY   (1)
  36 #define STS_INTR        (1<<1)
  37 #define STS_DEV_ERR     (1<<2)
  38 #define STS_BUS_ERR     (1<<3)
  39 #define STS_FAILED      (1<<4)
  40 #define STS_SMBALERT    (1<<5)
  41 #define STS_INUSE_STS   (1<<6)
  42 #define STS_BYTE_DONE   (1<<7)
  43 /* Signs of successfully transaction end :
  44 *  ByteDoneStatus = 1 (STS_BYTE_DONE) and INTR = 1 (STS_INTR )
  45 */
  46
  47 //#define DEBUG
  48
  49 #ifdef DEBUG
  50 # define SMBUS_DPRINTF(format, ...)     printf(format, ## __VA_ARGS__)
  51 #else
  52 # define SMBUS_DPRINTF(format, ...)     do { } while (0)
  53 #endif
  54
  55
  56 static void smb_transaction(PMSMBus *s)
  57 {
  58     uint8_t prot = (s->smb_ctl >> 2) & 0x07;
  59     uint8_t read = s->smb_addr & 0x01;
  60     uint8_t cmd = s->smb_cmd;
  61     uint8_t addr = s->smb_addr >> 1;
  62     I2CBus *bus = s->smbus;
  63     int ret;
  64
  65     SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);
  66     /* Transaction isn't exec if STS_DEV_ERR bit set */
  67     if ((s->smb_stat & STS_DEV_ERR) != 0)  {
  68         goto error;
  69     }
  70     switch(prot) {
  71     case 0x0:
  72         ret = smbus_quick_command(bus, addr, read);
  73         goto done;
  74     case 0x1:
  75         if (read) {
  76             ret = smbus_receive_byte(bus, addr);
  77             goto data8;
  78         } else {
  79             ret = smbus_send_byte(bus, addr, cmd);
  80             goto done;
  81         }
  82     case 0x2:
  83         if (read) {
  84             ret = smbus_read_byte(bus, addr, cmd);
  85             goto data8;
  86         } else {
  87             ret = smbus_write_byte(bus, addr, cmd, s->smb_data0);
  88             goto done;
  89         }
  90         break;
  91     case 0x3:
  92         if (read) {
  93             ret = smbus_read_word(bus, addr, cmd);
  94             goto data16;
  95         } else {
  96             ret = smbus_write_word(bus, addr, cmd, (s->smb_data1 << 8) | s->smb_data0);
  97             goto done;
  98         }
  99         break;
 100     case 0x5:
 101         if (read) {
 102             ret = smbus_read_block(bus, addr, cmd, s->smb_data);
 103             goto data8;
 104         } else {
 105             ret = smbus_write_block(bus, addr, cmd, s->smb_data, s->smb_data0);
 106             goto done;
 107         }
 108         break;
 109     default:
 110         goto error;
 111     }
 112     abort();
 113
 114 data16:
 115     if (ret < 0) {
 116         goto error;
 117     }
 118     s->smb_data1 = ret >> 8;
 119 data8:
 120     if (ret < 0) {
 121         goto error;
 122     }
 123     s->smb_data0 = ret;
 124 done:
 125     if (ret < 0) {
 126         goto error;
 127     }
 128     s->smb_stat |= STS_BYTE_DONE | STS_INTR;
 129     return;
 130
 131 error:
 132     s->smb_stat |= STS_DEV_ERR;
 133     return;
 134
 135 }
 136
 137 static void smb_ioport_writeb(void *opaque, hwaddr addr, uint64_t val,
 138                               unsigned width)
 139 {
 140     PMSMBus *s = opaque;
 141
 142     SMBUS_DPRINTF("SMB writeb port=0x%04" HWADDR_PRIx
 143                   " val=0x%02" PRIx64 "\n", addr, val);
 144     switch(addr) {
 145     case SMBHSTSTS:
 146         s->smb_stat = (~(val & 0xff)) & s->smb_stat;
 147         s->smb_index = 0;
 148         break;
 149     case SMBHSTCNT:
 150         s->smb_ctl = val;
 151         if (val & 0x40)
 152             smb_transaction(s);
 153         break;
 154     case SMBHSTCMD:
 155         s->smb_cmd = val;
 156         break;
 157     case SMBHSTADD:
 158         s->smb_addr = val;
 159         break;
 160     case SMBHSTDAT0:
 161         s->smb_data0 = val;
 162         break;
 163     case SMBHSTDAT1:
 164         s->smb_data1 = val;
 165         break;
 166     case SMBBLKDAT:
 167         s->smb_data[s->smb_index++] = val;
 168         if (s->smb_index > 31)
 169             s->smb_index = 0;
 170         break;
 171     default:
 172         break;
 173     }
 174 }
 175
 176 static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width)
 177 {
 178     PMSMBus *s = opaque;
 179     uint32_t val;
 180
 181     switch(addr) {
 182     case SMBHSTSTS:
 183         val = s->smb_stat;
 184         break;
 185     case SMBHSTCNT:
 186         s->smb_index = 0;
 187         val = s->smb_ctl & 0x1f;
 188         break;
 189     case SMBHSTCMD:
 190         val = s->smb_cmd;
 191         break;
 192     case SMBHSTADD:
 193         val = s->smb_addr;
 194         break;
 195     case SMBHSTDAT0:
 196         val = s->smb_data0;
 197         break;
 198     case SMBHSTDAT1:
 199         val = s->smb_data1;
 200         break;
 201     case SMBBLKDAT:
 202         val = s->smb_data[s->smb_index++];
 203         if (s->smb_index > 31)
 204             s->smb_index = 0;
 205         break;
 206     default:
 207         val = 0;
 208         break;
 209     }
 210     SMBUS_DPRINTF("SMB readb port=0x%04" HWADDR_PRIx " val=0x%02x\n", addr, val);
 211     return val;
 212 }
 213
 214 static const MemoryRegionOps pm_smbus_ops = {
 215     .read = smb_ioport_readb,
 216     .write = smb_ioport_writeb,
 217     .valid.min_access_size = 1,
 218     .valid.max_access_size = 1,
 219     .endianness = DEVICE_LITTLE_ENDIAN,
 220 };
 221
 222 void pm_smbus_init(DeviceState *parent, PMSMBus *smb)
 223 {
 224     smb->smbus = i2c_init_bus(parent, "i2c");
 225     memory_region_init_io(&smb->io, OBJECT(parent), &pm_smbus_ops, smb,
 226                           "pm-smbus", 64);
 227 }