diff options
Diffstat (limited to 'hw/max111x.c')
| -rw-r--r-- | hw/max111x.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/hw/max111x.c b/hw/max111x.c new file mode 100644 index 0000000..2844665 --- /dev/null +++ b/hw/max111x.c @@ -0,0 +1,188 @@ +/* + * Maxim MAX1110/1111 ADC chip emulation. + * + * Copyright (c) 2006 Openedhand Ltd. + * Written by Andrzej Zaborowski <balrog@zabor.org> + * + * This code is licensed under the GNU GPLv2. + */ + +#include "ssi.h" + +typedef struct { + SSISlave ssidev; + qemu_irq interrupt; + uint8_t tb1, rb2, rb3; + int cycle; + + int input[8]; + int inputs, com; +} MAX111xState; + +/* Control-byte bitfields */ +#define CB_PD0 (1 << 0) +#define CB_PD1 (1 << 1) +#define CB_SGL (1 << 2) +#define CB_UNI (1 << 3) +#define CB_SEL0 (1 << 4) +#define CB_SEL1 (1 << 5) +#define CB_SEL2 (1 << 6) +#define CB_START (1 << 7) + +#define CHANNEL_NUM(v, b0, b1, b2) \ + ((((v) >> (2 + (b0))) & 4) | \ + (((v) >> (3 + (b1))) & 2) | \ + (((v) >> (4 + (b2))) & 1)) + +static uint32_t max111x_read(MAX111xState *s) +{ + if (!s->tb1) + return 0; + + switch (s->cycle ++) { + case 1: + return s->rb2; + case 2: + return s->rb3; + } + + return 0; +} + +/* Interpret a control-byte */ +static void max111x_write(MAX111xState *s, uint32_t value) +{ + int measure, chan; + + /* Ignore the value if START bit is zero */ + if (!(value & CB_START)) + return; + + s->cycle = 0; + + if (!(value & CB_PD1)) { + s->tb1 = 0; + return; + } + + s->tb1 = value; + + if (s->inputs == 8) + chan = CHANNEL_NUM(value, 1, 0, 2); + else + chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2); + + if (value & CB_SGL) + measure = s->input[chan] - s->com; + else + measure = s->input[chan] - s->input[chan ^ 1]; + + if (!(value & CB_UNI)) + measure ^= 0x80; + + s->rb2 = (measure >> 2) & 0x3f; + s->rb3 = (measure << 6) & 0xc0; + + /* FIXME: When should the IRQ be lowered? */ + qemu_irq_raise(s->interrupt); +} + +static uint32_t max111x_transfer(SSISlave *dev, uint32_t value) +{ + MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev); + max111x_write(s, value); + return max111x_read(s); +} + +static void max111x_save(QEMUFile *f, void *opaque) +{ + MAX111xState *s = (MAX111xState *) opaque; + int i; + + qemu_put_8s(f, &s->tb1); + qemu_put_8s(f, &s->rb2); + qemu_put_8s(f, &s->rb3); + qemu_put_be32(f, s->inputs); + qemu_put_be32(f, s->com); + for (i = 0; i < s->inputs; i ++) + qemu_put_byte(f, s->input[i]); +} + +static int max111x_load(QEMUFile *f, void *opaque, int version_id) +{ + MAX111xState *s = (MAX111xState *) opaque; + int i; + + qemu_get_8s(f, &s->tb1); + qemu_get_8s(f, &s->rb2); + qemu_get_8s(f, &s->rb3); + if (s->inputs != qemu_get_be32(f)) + return -EINVAL; + s->com = qemu_get_be32(f); + for (i = 0; i < s->inputs; i ++) + s->input[i] = qemu_get_byte(f); + + return 0; +} + +static int max111x_init(SSISlave *dev, int inputs) +{ + MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev); + + qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1); + + s->inputs = inputs; + /* TODO: add a user interface for setting these */ + s->input[0] = 0xf0; + s->input[1] = 0xe0; + s->input[2] = 0xd0; + s->input[3] = 0xc0; + s->input[4] = 0xb0; + s->input[5] = 0xa0; + s->input[6] = 0x90; + s->input[7] = 0x80; + s->com = 0; + + register_savevm(&dev->qdev, "max111x", -1, 0, + max111x_save, max111x_load, s); + return 0; +} + +static int max1110_init(SSISlave *dev) +{ + return max111x_init(dev, 8); +} + +static int max1111_init(SSISlave *dev) +{ + return max111x_init(dev, 4); +} + +void max111x_set_input(DeviceState *dev, int line, uint8_t value) +{ + MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, SSI_SLAVE_FROM_QDEV(dev)); + assert(line >= 0 && line < s->inputs); + s->input[line] = value; +} + +static SSISlaveInfo max1110_info = { + .qdev.name = "max1110", + .qdev.size = sizeof(MAX111xState), + .init = max1110_init, + .transfer = max111x_transfer +}; + +static SSISlaveInfo max1111_info = { + .qdev.name = "max1111", + .qdev.size = sizeof(MAX111xState), + .init = max1111_init, + .transfer = max111x_transfer +}; + +static void max111x_register_devices(void) +{ + ssi_register_slave(&max1110_info); + ssi_register_slave(&max1111_info); +} + +device_init(max111x_register_devices) |