qemu/hw/i2c/pm_smbus.c
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   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 "qemu/osdep.h"
  21#include "hw/hw.h"
  22#include "hw/i386/pc.h"
  23#include "hw/i2c/pm_smbus.h"
  24#include "hw/i2c/smbus.h"
  25
  26/* no save/load? */
  27
  28#define SMBHSTSTS       0x00
  29#define SMBHSTCNT       0x02
  30#define SMBHSTCMD       0x03
  31#define SMBHSTADD       0x04
  32#define SMBHSTDAT0      0x05
  33#define SMBHSTDAT1      0x06
  34#define SMBBLKDAT       0x07
  35
  36#define STS_HOST_BUSY   (1)
  37#define STS_INTR        (1<<1)
  38#define STS_DEV_ERR     (1<<2)
  39#define STS_BUS_ERR     (1<<3)
  40#define STS_FAILED      (1<<4)
  41#define STS_SMBALERT    (1<<5)
  42#define STS_INUSE_STS   (1<<6)
  43#define STS_BYTE_DONE   (1<<7)
  44/* Signs of successfully transaction end :
  45*  ByteDoneStatus = 1 (STS_BYTE_DONE) and INTR = 1 (STS_INTR )
  46*/
  47
  48//#define DEBUG
  49
  50#ifdef DEBUG
  51# define SMBUS_DPRINTF(format, ...)     printf(format, ## __VA_ARGS__)
  52#else
  53# define SMBUS_DPRINTF(format, ...)     do { } while (0)
  54#endif
  55
  56
  57static void smb_transaction(PMSMBus *s)
  58{
  59    uint8_t prot = (s->smb_ctl >> 2) & 0x07;
  60    uint8_t read = s->smb_addr & 0x01;
  61    uint8_t cmd = s->smb_cmd;
  62    uint8_t addr = s->smb_addr >> 1;
  63    I2CBus *bus = s->smbus;
  64    int ret;
  65
  66    SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);
  67    /* Transaction isn't exec if STS_DEV_ERR bit set */
  68    if ((s->smb_stat & STS_DEV_ERR) != 0)  {
  69        goto error;
  70    }
  71    switch(prot) {
  72    case 0x0:
  73        ret = smbus_quick_command(bus, addr, read);
  74        goto done;
  75    case 0x1:
  76        if (read) {
  77            ret = smbus_receive_byte(bus, addr);
  78            goto data8;
  79        } else {
  80            ret = smbus_send_byte(bus, addr, cmd);
  81            goto done;
  82        }
  83    case 0x2:
  84        if (read) {
  85            ret = smbus_read_byte(bus, addr, cmd);
  86            goto data8;
  87        } else {
  88            ret = smbus_write_byte(bus, addr, cmd, s->smb_data0);
  89            goto done;
  90        }
  91        break;
  92    case 0x3:
  93        if (read) {
  94            ret = smbus_read_word(bus, addr, cmd);
  95            goto data16;
  96        } else {
  97            ret = smbus_write_word(bus, addr, cmd, (s->smb_data1 << 8) | s->smb_data0);
  98            goto done;
  99        }
 100        break;
 101    case 0x5:
 102        if (read) {
 103            ret = smbus_read_block(bus, addr, cmd, s->smb_data);
 104            goto data8;
 105        } else {
 106            ret = smbus_write_block(bus, addr, cmd, s->smb_data, s->smb_data0);
 107            goto done;
 108        }
 109        break;
 110    default:
 111        goto error;
 112    }
 113    abort();
 114
 115data16:
 116    if (ret < 0) {
 117        goto error;
 118    }
 119    s->smb_data1 = ret >> 8;
 120data8:
 121    if (ret < 0) {
 122        goto error;
 123    }
 124    s->smb_data0 = ret;
 125done:
 126    if (ret < 0) {
 127        goto error;
 128    }
 129    s->smb_stat |= STS_BYTE_DONE | STS_INTR;
 130    return;
 131
 132error:
 133    s->smb_stat |= STS_DEV_ERR;
 134    return;
 135
 136}
 137
 138static void smb_ioport_writeb(void *opaque, hwaddr addr, uint64_t val,
 139                              unsigned width)
 140{
 141    PMSMBus *s = opaque;
 142
 143    SMBUS_DPRINTF("SMB writeb port=0x%04" HWADDR_PRIx
 144                  " val=0x%02" PRIx64 "\n", addr, val);
 145    switch(addr) {
 146    case SMBHSTSTS:
 147        s->smb_stat = (~(val & 0xff)) & s->smb_stat;
 148        s->smb_index = 0;
 149        break;
 150    case SMBHSTCNT:
 151        s->smb_ctl = val;
 152        if (val & 0x40)
 153            smb_transaction(s);
 154        break;
 155    case SMBHSTCMD:
 156        s->smb_cmd = val;
 157        break;
 158    case SMBHSTADD:
 159        s->smb_addr = val;
 160        break;
 161    case SMBHSTDAT0:
 162        s->smb_data0 = val;
 163        break;
 164    case SMBHSTDAT1:
 165        s->smb_data1 = val;
 166        break;
 167    case SMBBLKDAT:
 168        s->smb_data[s->smb_index++] = val;
 169        if (s->smb_index > 31)
 170            s->smb_index = 0;
 171        break;
 172    default:
 173        break;
 174    }
 175}
 176
 177static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width)
 178{
 179    PMSMBus *s = opaque;
 180    uint32_t val;
 181
 182    switch(addr) {
 183    case SMBHSTSTS:
 184        val = s->smb_stat;
 185        break;
 186    case SMBHSTCNT:
 187        s->smb_index = 0;
 188        val = s->smb_ctl & 0x1f;
 189        break;
 190    case SMBHSTCMD:
 191        val = s->smb_cmd;
 192        break;
 193    case SMBHSTADD:
 194        val = s->smb_addr;
 195        break;
 196    case SMBHSTDAT0:
 197        val = s->smb_data0;
 198        break;
 199    case SMBHSTDAT1:
 200        val = s->smb_data1;
 201        break;
 202    case SMBBLKDAT:
 203        val = s->smb_data[s->smb_index++];
 204        if (s->smb_index > 31)
 205            s->smb_index = 0;
 206        break;
 207    default:
 208        val = 0;
 209        break;
 210    }
 211    SMBUS_DPRINTF("SMB readb port=0x%04" HWADDR_PRIx " val=0x%02x\n", addr, val);
 212    return val;
 213}
 214
 215static const MemoryRegionOps pm_smbus_ops = {
 216    .read = smb_ioport_readb,
 217    .write = smb_ioport_writeb,
 218    .valid.min_access_size = 1,
 219    .valid.max_access_size = 1,
 220    .endianness = DEVICE_LITTLE_ENDIAN,
 221};
 222
 223void pm_smbus_init(DeviceState *parent, PMSMBus *smb)
 224{
 225    smb->smbus = i2c_init_bus(parent, "i2c");
 226    memory_region_init_io(&smb->io, OBJECT(parent), &pm_smbus_ops, smb,
 227                          "pm-smbus", 64);
 228}
 229