JTAG UART core eliminates the need for a separate RS-232 serial connection to a host PC for character I/O.
Hardware emulation based on: https://www.altera.com/en_US/pdfs/literature/ug/ug_embedded_ip.pdf (Please see "Register Map" on page 65) Signed-off-by: Juro Bystricky <juro.bystri...@intel.com> --- default-configs/nios2-softmmu.mak | 1 + hw/char/Makefile.objs | 1 + hw/char/altera_juart.c | 288 ++++++++++++++++++++++++++++++++++++++ include/hw/char/altera_juart.h | 46 ++++++ 4 files changed, 336 insertions(+) create mode 100644 hw/char/altera_juart.c create mode 100644 include/hw/char/altera_juart.h diff --git a/default-configs/nios2-softmmu.mak b/default-configs/nios2-softmmu.mak index 74dc70c..6159846 100644 --- a/default-configs/nios2-softmmu.mak +++ b/default-configs/nios2-softmmu.mak @@ -4,3 +4,4 @@ CONFIG_NIOS2=y CONFIG_SERIAL=y CONFIG_PTIMER=y CONFIG_ALTERA_TIMER=y +CONFIG_ALTERA_JUART=y diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs index 6ea76fe..f0d0e25 100644 --- a/hw/char/Makefile.objs +++ b/hw/char/Makefile.objs @@ -27,5 +27,6 @@ common-obj-$(CONFIG_LM32) += lm32_juart.o common-obj-$(CONFIG_LM32) += lm32_uart.o common-obj-$(CONFIG_MILKYMIST) += milkymist-uart.o common-obj-$(CONFIG_SCLPCONSOLE) += sclpconsole.o sclpconsole-lm.o +common-obj-$(CONFIG_ALTERA_JUART) += altera_juart.o obj-$(CONFIG_VIRTIO) += virtio-serial-bus.o diff --git a/hw/char/altera_juart.c b/hw/char/altera_juart.c new file mode 100644 index 0000000..0325ddc --- /dev/null +++ b/hw/char/altera_juart.c @@ -0,0 +1,288 @@ +/* + * QEMU model of the Altera JTAG UART. + * + * Copyright (c) 2016-2017 Intel Corporation. + * + * 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. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + * + * The Altera JTAG UART hardware registers are described in: + * https://www.altera.com/en_US/pdfs/literature/ug/ug_embedded_ip.pdf + * (In particular "Register Map" on page 65) + */ + +#include "qemu/osdep.h" +#include "hw/char/altera_juart.h" +#include "sysemu/sysemu.h" +#include "qemu/error-report.h" + +/* Data register */ +#define OFFSET_R_DATA 0 +#define DATA_RVALID BIT(15) +#define DATA_RAVAIL 0xFFFF0000 + +/* Control register */ +#define OFFSET_R_CONTROL 4 +#define CONTROL_RE BIT(0) +#define CONTROL_WE BIT(1) +#define CONTROL_RI BIT(8) +#define CONTROL_WI BIT(9) +#define CONTROL_AC BIT(10) +#define CONTROL_WSPACE 0xFFFF0000 + +#define CONTROL_WMASK (CONTROL_RE | CONTROL_WE | CONTROL_AC) + +#define TYPE_ALTERA_JUART "altera-juart" +#define ALTERA_JUART(obj) \ + OBJECT_CHECK(AlteraJUARTState, (obj), TYPE_ALTERA_JUART) + +/* + * The JTAG UART core generates an interrupt when either of the individual + * interrupt conditions is pending and enabled. + */ +static void altera_juart_update_irq(AlteraJUARTState *s) +{ + unsigned int irq; + + irq = ((s->jcontrol & CONTROL_WE) && (s->jcontrol & CONTROL_WI)) || + ((s->jcontrol & CONTROL_RE) && (s->jcontrol & CONTROL_RI)); + + qemu_set_irq(s->irq, irq); +} + +static uint64_t altera_juart_read(void *opaque, hwaddr addr, unsigned int size) +{ + AlteraJUARTState *s = opaque; + uint32_t r; + + switch (addr) { + case OFFSET_R_DATA: + r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & (s->rx_fifo_size - 1)]; + if (s->rx_fifo_len) { + s->rx_fifo_len--; + qemu_chr_fe_accept_input(&s->chr); + s->jdata = r | DATA_RVALID | (s->rx_fifo_len << 16); + s->jcontrol |= CONTROL_RI; + } else { + s->jdata = 0; + s->jcontrol &= ~CONTROL_RI; + } + + altera_juart_update_irq(s); + return s->jdata; + + case OFFSET_R_CONTROL: + return s->jcontrol; + } + + return 0; +} + +static void altera_juart_write(void *opaque, hwaddr addr, + uint64_t value, unsigned int size) +{ + AlteraJUARTState *s = opaque; + unsigned char c; + + switch (addr) { + case OFFSET_R_DATA: + c = value & 0xFF; + /* + * We do not decrement the write fifo, + * we "tranmsmit" instanteniously, CONTROL_WI always asserted + */ + s->jcontrol |= CONTROL_WI; + s->jdata = c; + qemu_chr_fe_write(&s->chr, &c, 1); + altera_juart_update_irq(s); + break; + + case OFFSET_R_CONTROL: + /* Only RE and WE are writable */ + value &= CONTROL_WMASK; + s->jcontrol &= ~CONTROL_WMASK; + s->jcontrol |= value; + + /* Writing 1 to AC clears it to 0 */ + if (value & CONTROL_AC) { + s->jcontrol &= ~CONTROL_AC; + } + altera_juart_update_irq(s); + break; + } +} + +static void altera_juart_receive(void *opaque, const uint8_t *buf, int size) +{ + int i; + AlteraJUARTState *s = opaque; + + for (i = 0; i < size; i++) { + s->rx_fifo[s->rx_fifo_pos] = buf[i]; + s->rx_fifo_pos++; + s->rx_fifo_pos &= (s->rx_fifo_size - 1); + s->rx_fifo_len++; + } + s->jcontrol |= CONTROL_RI; + altera_juart_update_irq(s); +} + +static int altera_juart_can_receive(void *opaque) +{ + AlteraJUARTState *s = opaque; + return s->rx_fifo_size - s->rx_fifo_len; +} + +static void altera_juart_reset(DeviceState *d) +{ + AlteraJUARTState *s = ALTERA_JUART(d); + + s->jdata = 0; + + /* The number of spaces available in the write FIFO */ + s->jcontrol = s->rx_fifo_size << 16; + s->rx_fifo_pos = 0; + s->rx_fifo_len = 0; +} + +static const MemoryRegionOps juart_ops = { + .read = altera_juart_read, + .write = altera_juart_write, + .endianness = DEVICE_LITTLE_ENDIAN, + .valid = { + .min_access_size = 4, + .max_access_size = 4 + } +}; + +static void altera_juart_init(Object *obj) +{ + SysBusDevice *sbd = SYS_BUS_DEVICE(obj); + AlteraJUARTState *s = ALTERA_JUART(obj); + + memory_region_init_io(&s->mmio, OBJECT(s), &juart_ops, s, + TYPE_ALTERA_JUART, 2 * 4); + sysbus_init_mmio(sbd, &s->mmio); + sysbus_init_irq(sbd, &s->irq); +} + +void altera_juart_create(int channel, const hwaddr addr, qemu_irq irq, uint32_t fifo_size) +{ + DeviceState *dev; + SysBusDevice *bus; + Chardev *chr; + const char chr_name[] = "juart"; + char label[ARRAY_SIZE(chr_name) + 1]; + bool fifo_size_ok; + uint32_t size; + + dev = qdev_create(NULL, TYPE_ALTERA_JUART); + + if (channel >= MAX_SERIAL_PORTS) { + error_report("Only %d serial ports are supported by QEMU", + MAX_SERIAL_PORTS); + exit(1); + } + + chr = serial_hds[channel]; + if (!chr) { + snprintf(label, ARRAY_SIZE(label), "%s%d", chr_name, channel); + chr = qemu_chr_new(label, "null"); + if (!chr) { + error_report("Can't assign serial port to altera juart%d", channel); + exit(1); + } + } + qdev_prop_set_chr(dev, "chardev", chr); + + /* + * FIFO size can be set from 8 to 32,768 bytes. + * Only powers of two are allowed. + */ + fifo_size_ok = false; + for (size = 8; size <= 32768; size *= 2) { + if (size == fifo_size) { + fifo_size_ok = true; + break; + } + } + + if (!fifo_size_ok) { + error_report("Invalid FIFO size: %u for juart%d", fifo_size, channel); + exit(1); + } + + qdev_prop_set_uint32(dev, "fifo-size", fifo_size); + bus = SYS_BUS_DEVICE(dev); + qdev_init_nofail(dev); + + if (addr != (hwaddr)-1) { + sysbus_mmio_map(bus, 0, addr); + } + + sysbus_connect_irq(bus, 0, irq); +} + +static const VMStateDescription vmstate_altera_juart = { + .name = "altera-juart" , + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_UINT32(jdata, AlteraJUARTState), + VMSTATE_UINT32(jcontrol, AlteraJUARTState), + VMSTATE_VBUFFER_UINT32(rx_fifo, AlteraJUARTState, 1, NULL, 0, rx_fifo_size), + VMSTATE_END_OF_LIST() + } +}; + +static void altera_juart_realize(DeviceState *dev, Error **errp) +{ + AlteraJUARTState *s = ALTERA_JUART(dev); + qemu_chr_fe_set_handlers(&s->chr, altera_juart_can_receive, + altera_juart_receive, NULL, s, NULL, true); + s->rx_fifo = g_malloc(s->rx_fifo_size); +} + +static void altera_juart_unrealize(DeviceState *dev, Error **errp) +{ + AlteraJUARTState *s = ALTERA_JUART(dev); + g_free(s->rx_fifo); +} + +static Property altera_juart_props[] = { + DEFINE_PROP_CHR("chardev", AlteraJUARTState, chr), + DEFINE_PROP_UINT32("fifo-size", AlteraJUARTState, rx_fifo_size, DEFAULT_FIFO_SIZE), + DEFINE_PROP_END_OF_LIST(), +}; + +static void altera_juart_class_init(ObjectClass *oc, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(oc); + + dc->realize = altera_juart_realize; + dc->unrealize = altera_juart_unrealize; + dc->props = altera_juart_props; + dc->vmsd = &vmstate_altera_juart; + dc->reset = altera_juart_reset; + dc->desc = "Altera JTAG UART"; +} + +static const TypeInfo altera_juart_info = { + .name = TYPE_ALTERA_JUART, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(AlteraJUARTState), + .instance_init = altera_juart_init, + .class_init = altera_juart_class_init, +}; + +static void altera_juart_register(void) +{ + type_register_static(&altera_juart_info); +} + +type_init(altera_juart_register) diff --git a/include/hw/char/altera_juart.h b/include/hw/char/altera_juart.h new file mode 100644 index 0000000..8b0a4a6 --- /dev/null +++ b/include/hw/char/altera_juart.h @@ -0,0 +1,46 @@ +/* + * Altera JTAG UART emulation + * + * Copyright (c) 2016-2017 Intel Corporation. + * + * 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. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef ALTERA_JUART_H +#define ALTERA_JUART_H + +#include "hw/sysbus.h" +#include "sysemu/char.h" + +/* + * The read and write FIFO depths can be set from 8 to 32,768 bytes. + * Only powers of two are allowed. A depth of 64 is generally optimal for + * performance, and larger values are rarely necessary. + */ + +#define DEFAULT_FIFO_SIZE 64 + +typedef struct AlteraJUARTState { + SysBusDevice busdev; + MemoryRegion mmio; + CharBackend chr; + qemu_irq irq; + + unsigned int rx_fifo_size; + unsigned int rx_fifo_pos; + unsigned int rx_fifo_len; + uint32_t jdata; + uint32_t jcontrol; + uint8_t *rx_fifo; +} AlteraJUARTState; + +void altera_juart_create(int channel, const hwaddr addr, qemu_irq irq, + uint32_t fifo_size); + +#endif /* ALTERA_JUART_H */ -- 2.7.4
