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Diffstat (limited to 'qemu/hw/char/digic-uart.c')
| -rw-r--r-- | qemu/hw/char/digic-uart.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/qemu/hw/char/digic-uart.c b/qemu/hw/char/digic-uart.c new file mode 100644 index 000000000..6d44576ff --- /dev/null +++ b/qemu/hw/char/digic-uart.c @@ -0,0 +1,197 @@ +/* + * QEMU model of the Canon DIGIC UART block. + * + * Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com> + * + * This model is based on reverse engineering efforts + * made by CHDK (http://chdk.wikia.com) and + * Magic Lantern (http://www.magiclantern.fm) projects + * contributors. + * + * See "Serial terminal" docs here: + * http://magiclantern.wikia.com/wiki/Register_Map#Misc_Registers + * + * The QEMU model of the Milkymist UART block by Michael Walle + * is used as a template. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include "hw/hw.h" +#include "hw/sysbus.h" +#include "sysemu/char.h" + +#include "hw/char/digic-uart.h" + +enum { + ST_RX_RDY = (1 << 0), + ST_TX_RDY = (1 << 1), +}; + +static uint64_t digic_uart_read(void *opaque, hwaddr addr, + unsigned size) +{ + DigicUartState *s = opaque; + uint64_t ret = 0; + + addr >>= 2; + + switch (addr) { + case R_RX: + s->reg_st &= ~(ST_RX_RDY); + ret = s->reg_rx; + break; + + case R_ST: + ret = s->reg_st; + break; + + default: + qemu_log_mask(LOG_UNIMP, + "digic-uart: read access to unknown register 0x" + TARGET_FMT_plx, addr << 2); + } + + return ret; +} + +static void digic_uart_write(void *opaque, hwaddr addr, uint64_t value, + unsigned size) +{ + DigicUartState *s = opaque; + unsigned char ch = value; + + addr >>= 2; + + switch (addr) { + case R_TX: + if (s->chr) { + qemu_chr_fe_write_all(s->chr, &ch, 1); + } + break; + + case R_ST: + /* + * Ignore write to R_ST. + * + * The point is that this register is actively used + * during receiving and transmitting symbols, + * but we don't know the function of most of bits. + * + * Ignoring writes to R_ST is only a simplification + * of the model. It has no perceptible side effects + * for existing guests. + */ + break; + + default: + qemu_log_mask(LOG_UNIMP, + "digic-uart: write access to unknown register 0x" + TARGET_FMT_plx, addr << 2); + } +} + +static const MemoryRegionOps uart_mmio_ops = { + .read = digic_uart_read, + .write = digic_uart_write, + .valid = { + .min_access_size = 4, + .max_access_size = 4, + }, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static int uart_can_rx(void *opaque) +{ + DigicUartState *s = opaque; + + return !(s->reg_st & ST_RX_RDY); +} + +static void uart_rx(void *opaque, const uint8_t *buf, int size) +{ + DigicUartState *s = opaque; + + assert(uart_can_rx(opaque)); + + s->reg_st |= ST_RX_RDY; + s->reg_rx = *buf; +} + +static void uart_event(void *opaque, int event) +{ +} + +static void digic_uart_reset(DeviceState *d) +{ + DigicUartState *s = DIGIC_UART(d); + + s->reg_rx = 0; + s->reg_st = ST_TX_RDY; +} + +static void digic_uart_realize(DeviceState *dev, Error **errp) +{ + DigicUartState *s = DIGIC_UART(dev); + + /* FIXME use a qdev chardev prop instead of qemu_char_get_next_serial() */ + s->chr = qemu_char_get_next_serial(); + if (s->chr) { + qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s); + } +} + +static void digic_uart_init(Object *obj) +{ + DigicUartState *s = DIGIC_UART(obj); + + memory_region_init_io(&s->regs_region, OBJECT(s), &uart_mmio_ops, s, + TYPE_DIGIC_UART, 0x18); + sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->regs_region); +} + +static const VMStateDescription vmstate_digic_uart = { + .name = "digic-uart", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(reg_rx, DigicUartState), + VMSTATE_UINT32(reg_st, DigicUartState), + VMSTATE_END_OF_LIST() + } +}; + +static void digic_uart_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->realize = digic_uart_realize; + dc->reset = digic_uart_reset; + dc->vmsd = &vmstate_digic_uart; + /* Reason: realize() method uses qemu_char_get_next_serial() */ + dc->cannot_instantiate_with_device_add_yet = true; +} + +static const TypeInfo digic_uart_info = { + .name = TYPE_DIGIC_UART, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(DigicUartState), + .instance_init = digic_uart_init, + .class_init = digic_uart_class_init, +}; + +static void digic_uart_register_types(void) +{ + type_register_static(&digic_uart_info); +} + +type_init(digic_uart_register_types) |