qemu

FORK: QEMU emulator
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versatile_i2c.c (3320B)

      1 /*
      2  * ARM SBCon two-wire serial bus interface (I2C bitbang)
      3  * a.k.a. ARM Versatile I2C controller
      4  *
      5  * Copyright (c) 2006-2007 CodeSourcery.
      6  * Copyright (c) 2012 Oskar Andero <oskar.andero@gmail.com>
      7  *
      8  * This file is derived from hw/realview.c by Paul Brook
      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
     12  * as published by the Free Software Foundation; either version 2
     13  * of 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, see <http://www.gnu.org/licenses/>.
     22  *
     23  */
     24 
     25 #include "qemu/osdep.h"
     26 #include "hw/i2c/arm_sbcon_i2c.h"
     27 #include "hw/registerfields.h"
     28 #include "qemu/log.h"
     29 #include "qemu/module.h"
     30 #include "qom/object.h"
     31 
     32 typedef ArmSbconI2CState VersatileI2CState;
     33 DECLARE_INSTANCE_CHECKER(VersatileI2CState, VERSATILE_I2C,
     34                          TYPE_VERSATILE_I2C)
     35 
     36 
     37 
     38 REG32(CONTROL_GET, 0)
     39 REG32(CONTROL_SET, 0)
     40 REG32(CONTROL_CLR, 4)
     41 
     42 #define SCL BIT(0)
     43 #define SDA BIT(1)
     44 
     45 static uint64_t versatile_i2c_read(void *opaque, hwaddr offset,
     46                                    unsigned size)
     47 {
     48     VersatileI2CState *s = (VersatileI2CState *)opaque;
     49 
     50     switch (offset) {
     51     case A_CONTROL_SET:
     52         return (s->out & 1) | (s->in << 1);
     53     default:
     54         qemu_log_mask(LOG_GUEST_ERROR,
     55                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
     56         return -1;
     57     }
     58 }
     59 
     60 static void versatile_i2c_write(void *opaque, hwaddr offset,
     61                                 uint64_t value, unsigned size)
     62 {
     63     VersatileI2CState *s = (VersatileI2CState *)opaque;
     64 
     65     switch (offset) {
     66     case A_CONTROL_SET:
     67         s->out |= value & 3;
     68         break;
     69     case A_CONTROL_CLR:
     70         s->out &= ~value;
     71         break;
     72     default:
     73         qemu_log_mask(LOG_GUEST_ERROR,
     74                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
     75     }
     76     bitbang_i2c_set(&s->bitbang, BITBANG_I2C_SCL, (s->out & SCL) != 0);
     77     s->in = bitbang_i2c_set(&s->bitbang, BITBANG_I2C_SDA, (s->out & SDA) != 0);
     78 }
     79 
     80 static const MemoryRegionOps versatile_i2c_ops = {
     81     .read = versatile_i2c_read,
     82     .write = versatile_i2c_write,
     83     .endianness = DEVICE_NATIVE_ENDIAN,
     84 };
     85 
     86 static void versatile_i2c_init(Object *obj)
     87 {
     88     DeviceState *dev = DEVICE(obj);
     89     VersatileI2CState *s = VERSATILE_I2C(obj);
     90     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
     91     I2CBus *bus;
     92 
     93     bus = i2c_init_bus(dev, "i2c");
     94     bitbang_i2c_init(&s->bitbang, bus);
     95     memory_region_init_io(&s->iomem, obj, &versatile_i2c_ops, s,
     96                           "arm_sbcon_i2c", 0x1000);
     97     sysbus_init_mmio(sbd, &s->iomem);
     98 }
     99 
    100 static const TypeInfo versatile_i2c_info = {
    101     .name          = TYPE_VERSATILE_I2C,
    102     .parent        = TYPE_SYS_BUS_DEVICE,
    103     .instance_size = sizeof(VersatileI2CState),
    104     .instance_init = versatile_i2c_init,
    105 };
    106 
    107 static void versatile_i2c_register_types(void)
    108 {
    109     type_register_static(&versatile_i2c_info);
    110 }
    111 
    112 type_init(versatile_i2c_register_types)