root / hw / xilinx_uartlite.c @ 18ebcc86
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/*
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* QEMU model of Xilinx uartlite.
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*
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* Copyright (c) 2009 Edgar E. Iglesias.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "sysbus.h" |
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#include "qemu-char.h" |
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#define DUART(x)
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#define R_RX 0 |
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#define R_TX 1 |
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#define R_STATUS 2 |
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#define R_CTRL 3 |
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#define R_MAX 4 |
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#define STATUS_RXVALID 0x01 |
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#define STATUS_RXFULL 0x02 |
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#define STATUS_TXEMPTY 0x04 |
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#define STATUS_TXFULL 0x08 |
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#define STATUS_IE 0x10 |
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#define STATUS_OVERRUN 0x20 |
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#define STATUS_FRAME 0x40 |
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#define STATUS_PARITY 0x80 |
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#define CONTROL_RST_TX 0x01 |
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#define CONTROL_RST_RX 0x02 |
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#define CONTROL_IE 0x10 |
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struct xlx_uartlite
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{ |
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SysBusDevice busdev; |
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MemoryRegion mmio; |
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CharDriverState *chr; |
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qemu_irq irq; |
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uint8_t rx_fifo[8];
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unsigned int rx_fifo_pos; |
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unsigned int rx_fifo_len; |
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uint32_t regs[R_MAX]; |
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}; |
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static void uart_update_irq(struct xlx_uartlite *s) |
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{ |
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unsigned int irq; |
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if (s->rx_fifo_len)
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s->regs[R_STATUS] |= STATUS_IE; |
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irq = (s->regs[R_STATUS] & STATUS_IE) && (s->regs[R_CTRL] & CONTROL_IE); |
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qemu_set_irq(s->irq, irq); |
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} |
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static void uart_update_status(struct xlx_uartlite *s) |
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{ |
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uint32_t r; |
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r = s->regs[R_STATUS]; |
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r &= ~7;
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r |= 1 << 2; /* Tx fifo is always empty. We are fast :) */ |
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r |= (s->rx_fifo_len == sizeof (s->rx_fifo)) << 1; |
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r |= (!!s->rx_fifo_len); |
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s->regs[R_STATUS] = r; |
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} |
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static uint64_t
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uart_read(void *opaque, target_phys_addr_t addr, unsigned int size) |
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{ |
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struct xlx_uartlite *s = opaque;
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uint32_t r = 0;
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addr >>= 2;
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switch (addr)
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{ |
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case R_RX:
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r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 7];
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if (s->rx_fifo_len)
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s->rx_fifo_len--; |
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uart_update_status(s); |
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uart_update_irq(s); |
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break;
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default:
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if (addr < ARRAY_SIZE(s->regs))
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r = s->regs[addr]; |
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DUART(qemu_log("%s addr=%x v=%x\n", __func__, addr, r));
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break;
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} |
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return r;
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} |
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static void |
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uart_write(void *opaque, target_phys_addr_t addr,
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uint64_t val64, unsigned int size) |
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{ |
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struct xlx_uartlite *s = opaque;
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uint32_t value = val64; |
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unsigned char ch = value; |
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addr >>= 2;
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switch (addr)
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{ |
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case R_STATUS:
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hw_error("write to UART STATUS?\n");
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break;
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case R_CTRL:
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if (value & CONTROL_RST_RX) {
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s->rx_fifo_pos = 0;
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s->rx_fifo_len = 0;
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} |
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s->regs[addr] = value; |
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break;
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case R_TX:
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if (s->chr)
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qemu_chr_fe_write(s->chr, &ch, 1);
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s->regs[addr] = value; |
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/* hax. */
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s->regs[R_STATUS] |= STATUS_IE; |
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break;
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default:
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DUART(printf("%s addr=%x v=%x\n", __func__, addr, value));
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if (addr < ARRAY_SIZE(s->regs))
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s->regs[addr] = value; |
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break;
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} |
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uart_update_status(s); |
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uart_update_irq(s); |
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} |
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static const MemoryRegionOps uart_ops = { |
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.read = uart_read, |
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.write = uart_write, |
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.endianness = DEVICE_NATIVE_ENDIAN, |
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.valid = { |
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.min_access_size = 1,
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.max_access_size = 4
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} |
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}; |
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static void uart_rx(void *opaque, const uint8_t *buf, int size) |
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{ |
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struct xlx_uartlite *s = opaque;
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/* Got a byte. */
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if (s->rx_fifo_len >= 8) { |
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printf("WARNING: UART dropped char.\n");
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return;
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} |
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s->rx_fifo[s->rx_fifo_pos] = *buf; |
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s->rx_fifo_pos++; |
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s->rx_fifo_pos &= 0x7;
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s->rx_fifo_len++; |
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uart_update_status(s); |
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uart_update_irq(s); |
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} |
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static int uart_can_rx(void *opaque) |
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{ |
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struct xlx_uartlite *s = opaque;
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int r;
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r = s->rx_fifo_len < sizeof(s->rx_fifo);
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if (!r)
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printf("cannot receive!\n");
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return r;
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} |
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static void uart_event(void *opaque, int event) |
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{ |
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} |
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static int xilinx_uartlite_init(SysBusDevice *dev) |
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{ |
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struct xlx_uartlite *s = FROM_SYSBUS(typeof (*s), dev);
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sysbus_init_irq(dev, &s->irq); |
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uart_update_status(s); |
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memory_region_init_io(&s->mmio, &uart_ops, s, "xilinx-uartlite", R_MAX * 4); |
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sysbus_init_mmio_region(dev, &s->mmio); |
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s->chr = qdev_init_chardev(&dev->qdev); |
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if (s->chr)
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qemu_chr_add_handlers(s->chr, uart_can_rx, uart_rx, uart_event, s); |
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return 0; |
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} |
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static void xilinx_uart_register(void) |
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{ |
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sysbus_register_dev("xilinx,uartlite", sizeof (struct xlx_uartlite), |
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xilinx_uartlite_init); |
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} |
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device_init(xilinx_uart_register) |