/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2012 NetApp, Inc. * Copyright (c) 2013 Neel Natu * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ * */ /* * This file and its contents are supplied under the terms of the * Common Development and Distribution License ("CDDL"), version 1.0. * You may only use this file in accordance with the terms of version * 1.0 of the CDDL. * * A full copy of the text of the CDDL should have accompanied this * source. A copy of the CDDL is also available via the Internet at * http://www.illumos.org/license/CDDL. * * Copyright 2015 Pluribus Networks Inc. * Copyright 2018 Joyent, Inc. */ #include __FBSDID("$FreeBSD$"); #include #include #ifndef WITHOUT_CAPSICUM #include #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #ifndef __FreeBSD__ #include #endif #include "mevent.h" #include "uart_emul.h" #include "debug.h" #define COM1_BASE 0x3F8 #define COM1_IRQ 4 #define COM2_BASE 0x2F8 #define COM2_IRQ 3 #define COM3_BASE 0x3E8 #define COM3_IRQ 4 #define COM4_BASE 0x2E8 #define COM4_IRQ 3 #define DEFAULT_RCLK 1843200 #define DEFAULT_BAUD 9600 #define FCR_RX_MASK 0xC0 #define MCR_OUT1 0x04 #define MCR_OUT2 0x08 #define MSR_DELTA_MASK 0x0f #ifndef REG_SCR #define REG_SCR com_scr #endif #define FIFOSZ 16 static bool uart_stdio; /* stdio in use for i/o */ static struct termios tio_stdio_orig; static struct { int baseaddr; int irq; bool inuse; } uart_lres[] = { { COM1_BASE, COM1_IRQ, false}, { COM2_BASE, COM2_IRQ, false}, { COM3_BASE, COM3_IRQ, false}, { COM4_BASE, COM4_IRQ, false}, }; #define UART_NLDEVS (sizeof(uart_lres) / sizeof(uart_lres[0])) struct fifo { uint8_t buf[FIFOSZ]; int rindex; /* index to read from */ int windex; /* index to write to */ int num; /* number of characters in the fifo */ int size; /* size of the fifo */ }; struct ttyfd { bool opened; int rfd; /* fd for reading */ int wfd; /* fd for writing, may be == rfd */ }; struct uart_softc { pthread_mutex_t mtx; /* protects all softc elements */ uint8_t data; /* Data register (R/W) */ uint8_t ier; /* Interrupt enable register (R/W) */ uint8_t lcr; /* Line control register (R/W) */ uint8_t mcr; /* Modem control register (R/W) */ uint8_t lsr; /* Line status register (R/W) */ uint8_t msr; /* Modem status register (R/W) */ uint8_t fcr; /* FIFO control register (W) */ uint8_t scr; /* Scratch register (R/W) */ uint8_t dll; /* Baudrate divisor latch LSB */ uint8_t dlh; /* Baudrate divisor latch MSB */ struct fifo rxfifo; struct mevent *mev; struct ttyfd tty; #ifndef __FreeBSD__ bool sock; struct { int clifd; /* console client unix domain socket */ int servfd; /* console server unix domain socket */ struct mevent *servmev; /* mevent for server socket */ } usc_sock; #endif bool thre_int_pending; /* THRE interrupt pending */ void *arg; uart_intr_func_t intr_assert; uart_intr_func_t intr_deassert; }; static void uart_drain(int fd, enum ev_type ev, void *arg); static void ttyclose(void) { tcsetattr(STDIN_FILENO, TCSANOW, &tio_stdio_orig); } static void ttyopen(struct ttyfd *tf) { struct termios orig, new; tcgetattr(tf->rfd, &orig); new = orig; cfmakeraw(&new); new.c_cflag |= CLOCAL; tcsetattr(tf->rfd, TCSANOW, &new); if (uart_stdio) { tio_stdio_orig = orig; atexit(ttyclose); } raw_stdio = 1; } static int ttyread(struct ttyfd *tf) { unsigned char rb; if (read(tf->rfd, &rb, 1) == 1) return (rb); else return (-1); } static void ttywrite(struct ttyfd *tf, unsigned char wb) { (void)write(tf->wfd, &wb, 1); } #ifndef __FreeBSD__ static void sockwrite(struct uart_softc *sc, unsigned char wb) { (void) write(sc->usc_sock.clifd, &wb, 1); } #endif static void rxfifo_reset(struct uart_softc *sc, int size) { char flushbuf[32]; struct fifo *fifo; ssize_t nread; int error; fifo = &sc->rxfifo; bzero(fifo, sizeof(struct fifo)); fifo->size = size; if (sc->tty.opened) { /* * Flush any unread input from the tty buffer. */ while (1) { nread = read(sc->tty.rfd, flushbuf, sizeof(flushbuf)); if (nread != sizeof(flushbuf)) break; } /* * Enable mevent to trigger when new characters are available * on the tty fd. */ error = mevent_enable(sc->mev); assert(error == 0); } #ifndef __FreeBSD__ if (sc->sock && sc->usc_sock.clifd != -1) { /* Flush any unread input from the socket buffer. */ do { nread = read(sc->usc_sock.clifd, flushbuf, sizeof (flushbuf)); } while (nread == sizeof (flushbuf)); /* Enable mevent to trigger when new data available on sock */ error = mevent_enable(sc->mev); assert(error == 0); } #endif /* __FreeBSD__ */ } static int rxfifo_available(struct uart_softc *sc) { struct fifo *fifo; fifo = &sc->rxfifo; return (fifo->num < fifo->size); } static int rxfifo_putchar(struct uart_softc *sc, uint8_t ch) { struct fifo *fifo; int error; fifo = &sc->rxfifo; if (fifo->num < fifo->size) { fifo->buf[fifo->windex] = ch; fifo->windex = (fifo->windex + 1) % fifo->size; fifo->num++; if (!rxfifo_available(sc)) { if (sc->tty.opened) { /* * Disable mevent callback if the FIFO is full. */ error = mevent_disable(sc->mev); assert(error == 0); } #ifndef __FreeBSD__ if (sc->sock && sc->usc_sock.clifd != -1) { /* * Disable mevent callback if the FIFO is full. */ error = mevent_disable(sc->mev); assert(error == 0); } #endif /* __FreeBSD__ */ } return (0); } else return (-1); } static int rxfifo_getchar(struct uart_softc *sc) { struct fifo *fifo; int c, error, wasfull; wasfull = 0; fifo = &sc->rxfifo; if (fifo->num > 0) { if (!rxfifo_available(sc)) wasfull = 1; c = fifo->buf[fifo->rindex]; fifo->rindex = (fifo->rindex + 1) % fifo->size; fifo->num--; if (wasfull) { if (sc->tty.opened) { error = mevent_enable(sc->mev); assert(error == 0); } #ifndef __FreeBSD__ if (sc->sock && sc->usc_sock.clifd != -1) { error = mevent_enable(sc->mev); assert(error == 0); } #endif /* __FreeBSD__ */ } return (c); } else return (-1); } static int rxfifo_numchars(struct uart_softc *sc) { struct fifo *fifo = &sc->rxfifo; return (fifo->num); } static void uart_opentty(struct uart_softc *sc) { ttyopen(&sc->tty); sc->mev = mevent_add(sc->tty.rfd, EVF_READ, uart_drain, sc); assert(sc->mev != NULL); } static uint8_t modem_status(uint8_t mcr) { uint8_t msr; if (mcr & MCR_LOOPBACK) { /* * In the loopback mode certain bits from the MCR are * reflected back into MSR. */ msr = 0; if (mcr & MCR_RTS) msr |= MSR_CTS; if (mcr & MCR_DTR) msr |= MSR_DSR; if (mcr & MCR_OUT1) msr |= MSR_RI; if (mcr & MCR_OUT2) msr |= MSR_DCD; } else { /* * Always assert DCD and DSR so tty open doesn't block * even if CLOCAL is turned off. */ msr = MSR_DCD | MSR_DSR; } assert((msr & MSR_DELTA_MASK) == 0); return (msr); } /* * The IIR returns a prioritized interrupt reason: * - receive data available * - transmit holding register empty * - modem status change * * Return an interrupt reason if one is available. */ static int uart_intr_reason(struct uart_softc *sc) { if ((sc->lsr & LSR_OE) != 0 && (sc->ier & IER_ERLS) != 0) return (IIR_RLS); else if (rxfifo_numchars(sc) > 0 && (sc->ier & IER_ERXRDY) != 0) return (IIR_RXTOUT); else if (sc->thre_int_pending && (sc->ier & IER_ETXRDY) != 0) return (IIR_TXRDY); else if ((sc->msr & MSR_DELTA_MASK) != 0 && (sc->ier & IER_EMSC) != 0) return (IIR_MLSC); else return (IIR_NOPEND); } static void uart_reset(struct uart_softc *sc) { uint16_t divisor; divisor = DEFAULT_RCLK / DEFAULT_BAUD / 16; sc->dll = divisor; #ifndef __FreeBSD__ sc->dlh = 0; #else sc->dlh = divisor >> 16; #endif sc->msr = modem_status(sc->mcr); rxfifo_reset(sc, 1); /* no fifo until enabled by software */ } /* * Toggle the COM port's intr pin depending on whether or not we have an * interrupt condition to report to the processor. */ static void uart_toggle_intr(struct uart_softc *sc) { uint8_t intr_reason; intr_reason = uart_intr_reason(sc); if (intr_reason == IIR_NOPEND) (*sc->intr_deassert)(sc->arg); else (*sc->intr_assert)(sc->arg); } static void uart_drain(int fd, enum ev_type ev, void *arg) { struct uart_softc *sc; int ch; sc = arg; assert(fd == sc->tty.rfd); assert(ev == EVF_READ); /* * This routine is called in the context of the mevent thread * to take out the softc lock to protect against concurrent * access from a vCPU i/o exit */ pthread_mutex_lock(&sc->mtx); if ((sc->mcr & MCR_LOOPBACK) != 0) { (void) ttyread(&sc->tty); } else { while (rxfifo_available(sc) && ((ch = ttyread(&sc->tty)) != -1)) { rxfifo_putchar(sc, ch); } uart_toggle_intr(sc); } pthread_mutex_unlock(&sc->mtx); } void uart_write(struct uart_softc *sc, int offset, uint8_t value) { int fifosz; uint8_t msr; pthread_mutex_lock(&sc->mtx); /* * Take care of the special case DLAB accesses first */ if ((sc->lcr & LCR_DLAB) != 0) { if (offset == REG_DLL) { sc->dll = value; goto done; } if (offset == REG_DLH) { sc->dlh = value; goto done; } } switch (offset) { case REG_DATA: if (sc->mcr & MCR_LOOPBACK) { if (rxfifo_putchar(sc, value) != 0) sc->lsr |= LSR_OE; } else if (sc->tty.opened) { ttywrite(&sc->tty, value); #ifndef __FreeBSD__ } else if (sc->sock) { sockwrite(sc, value); #endif } /* else drop on floor */ sc->thre_int_pending = true; break; case REG_IER: /* Set pending when IER_ETXRDY is raised (edge-triggered). */ if ((sc->ier & IER_ETXRDY) == 0 && (value & IER_ETXRDY) != 0) sc->thre_int_pending = true; /* * Apply mask so that bits 4-7 are 0 * Also enables bits 0-3 only if they're 1 */ sc->ier = value & 0x0F; break; case REG_FCR: /* * When moving from FIFO and 16450 mode and vice versa, * the FIFO contents are reset. */ if ((sc->fcr & FCR_ENABLE) ^ (value & FCR_ENABLE)) { fifosz = (value & FCR_ENABLE) ? FIFOSZ : 1; rxfifo_reset(sc, fifosz); } /* * The FCR_ENABLE bit must be '1' for the programming * of other FCR bits to be effective. */ if ((value & FCR_ENABLE) == 0) { sc->fcr = 0; } else { if ((value & FCR_RCV_RST) != 0) rxfifo_reset(sc, FIFOSZ); sc->fcr = value & (FCR_ENABLE | FCR_DMA | FCR_RX_MASK); } break; case REG_LCR: sc->lcr = value; break; case REG_MCR: /* Apply mask so that bits 5-7 are 0 */ sc->mcr = value & 0x1F; msr = modem_status(sc->mcr); /* * Detect if there has been any change between the * previous and the new value of MSR. If there is * then assert the appropriate MSR delta bit. */ if ((msr & MSR_CTS) ^ (sc->msr & MSR_CTS)) sc->msr |= MSR_DCTS; if ((msr & MSR_DSR) ^ (sc->msr & MSR_DSR)) sc->msr |= MSR_DDSR; if ((msr & MSR_DCD) ^ (sc->msr & MSR_DCD)) sc->msr |= MSR_DDCD; if ((sc->msr & MSR_RI) != 0 && (msr & MSR_RI) == 0) sc->msr |= MSR_TERI; /* * Update the value of MSR while retaining the delta * bits. */ sc->msr &= MSR_DELTA_MASK; sc->msr |= msr; break; case REG_LSR: /* * Line status register is not meant to be written to * during normal operation. */ break; case REG_MSR: /* * As far as I can tell MSR is a read-only register. */ break; case REG_SCR: sc->scr = value; break; default: break; } done: uart_toggle_intr(sc); pthread_mutex_unlock(&sc->mtx); } uint8_t uart_read(struct uart_softc *sc, int offset) { uint8_t iir, intr_reason, reg; pthread_mutex_lock(&sc->mtx); /* * Take care of the special case DLAB accesses first */ if ((sc->lcr & LCR_DLAB) != 0) { if (offset == REG_DLL) { reg = sc->dll; goto done; } if (offset == REG_DLH) { reg = sc->dlh; goto done; } } switch (offset) { case REG_DATA: reg = rxfifo_getchar(sc); break; case REG_IER: reg = sc->ier; break; case REG_IIR: iir = (sc->fcr & FCR_ENABLE) ? IIR_FIFO_MASK : 0; intr_reason = uart_intr_reason(sc); /* * Deal with side effects of reading the IIR register */ if (intr_reason == IIR_TXRDY) sc->thre_int_pending = false; iir |= intr_reason; reg = iir; break; case REG_LCR: reg = sc->lcr; break; case REG_MCR: reg = sc->mcr; break; case REG_LSR: /* Transmitter is always ready for more data */ sc->lsr |= LSR_TEMT | LSR_THRE; /* Check for new receive data */ if (rxfifo_numchars(sc) > 0) sc->lsr |= LSR_RXRDY; else sc->lsr &= ~LSR_RXRDY; reg = sc->lsr; /* The LSR_OE bit is cleared on LSR read */ sc->lsr &= ~LSR_OE; break; case REG_MSR: /* * MSR delta bits are cleared on read */ reg = sc->msr; sc->msr &= ~MSR_DELTA_MASK; break; case REG_SCR: reg = sc->scr; break; default: reg = 0xFF; break; } done: uart_toggle_intr(sc); pthread_mutex_unlock(&sc->mtx); return (reg); } #ifndef __FreeBSD__ static void uart_sock_drain(int fd, enum ev_type ev, void *arg) { struct uart_softc *sc = arg; char ch; /* * Take the softc lock to protect against concurrent * access from a vCPU i/o exit */ pthread_mutex_lock(&sc->mtx); if ((sc->mcr & MCR_LOOPBACK) != 0) { (void) read(sc->usc_sock.clifd, &ch, 1); } else { bool err_close = false; while (rxfifo_available(sc)) { int res; res = read(sc->usc_sock.clifd, &ch, 1); if (res == 0) { err_close = true; break; } else if (res == -1) { if (errno != EAGAIN && errno != EINTR) { err_close = true; } break; } rxfifo_putchar(sc, ch); } uart_toggle_intr(sc); if (err_close) { (void) fprintf(stderr, "uart: closing client conn\n"); (void) shutdown(sc->usc_sock.clifd, SHUT_RDWR); mevent_delete_close(sc->mev); sc->mev = NULL; sc->usc_sock.clifd = -1; } } pthread_mutex_unlock(&sc->mtx); } static void uart_sock_accept(int fd, enum ev_type ev, void *arg) { struct uart_softc *sc = arg; int connfd; connfd = accept(sc->usc_sock.servfd, NULL, NULL); if (connfd == -1) { return; } /* * Do client connection management under protection of the softc lock * to avoid racing with concurrent UART events. */ pthread_mutex_lock(&sc->mtx); if (sc->usc_sock.clifd != -1) { /* we're already handling a client */ (void) fprintf(stderr, "uart: unexpected client conn\n"); (void) shutdown(connfd, SHUT_RDWR); (void) close(connfd); } else { if (fcntl(connfd, F_SETFL, O_NONBLOCK) < 0) { perror("uart: fcntl(O_NONBLOCK)"); (void) shutdown(connfd, SHUT_RDWR); (void) close(connfd); } else { sc->usc_sock.clifd = connfd; sc->mev = mevent_add(sc->usc_sock.clifd, EVF_READ, uart_sock_drain, sc); } } pthread_mutex_unlock(&sc->mtx); } static int init_sock(const char *path) { int servfd; struct sockaddr_un servaddr; bzero(&servaddr, sizeof (servaddr)); servaddr.sun_family = AF_UNIX; if (strlcpy(servaddr.sun_path, path, sizeof (servaddr.sun_path)) >= sizeof (servaddr.sun_path)) { (void) fprintf(stderr, "uart: path '%s' too long\n", path); return (-1); } if ((servfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) { (void) fprintf(stderr, "uart: socket() error - %s\n", strerror(errno)); return (-1); } (void) unlink(servaddr.sun_path); if (bind(servfd, (struct sockaddr *)&servaddr, sizeof (servaddr)) == -1) { (void) fprintf(stderr, "uart: bind() error - %s\n", strerror(errno)); goto out; } if (listen(servfd, 1) == -1) { (void) fprintf(stderr, "uart: listen() error - %s\n", strerror(errno)); goto out; } return (servfd); out: (void) unlink(servaddr.sun_path); (void) close(servfd); return (-1); } #endif /* not __FreeBSD__ */ int uart_legacy_alloc(int which, int *baseaddr, int *irq) { if (which < 0 || which >= UART_NLDEVS || uart_lres[which].inuse) return (-1); uart_lres[which].inuse = true; *baseaddr = uart_lres[which].baseaddr; *irq = uart_lres[which].irq; return (0); } struct uart_softc * uart_init(uart_intr_func_t intr_assert, uart_intr_func_t intr_deassert, void *arg) { struct uart_softc *sc; sc = calloc(1, sizeof(struct uart_softc)); sc->arg = arg; sc->intr_assert = intr_assert; sc->intr_deassert = intr_deassert; pthread_mutex_init(&sc->mtx, NULL); uart_reset(sc); return (sc); } #ifndef __FreeBSD__ static int uart_sock_backend(struct uart_softc *sc, const char *inopts) { char *opts, *tofree; char *opt; char *nextopt; char *path = NULL; if (strncmp(inopts, "socket,", 7) != 0) { return (-1); } if ((opts = strdup(inopts + 7)) == NULL) { return (-1); } tofree = nextopt = opts; for (opt = strsep(&nextopt, ","); opt != NULL; opt = strsep(&nextopt, ",")) { if (path == NULL && *opt == '/') { path = opt; continue; } /* * XXX check for server and client options here. For now, * everything is a server */ free(tofree); return (-1); } sc->usc_sock.clifd = -1; if ((sc->usc_sock.servfd = init_sock(path)) == -1) { free(tofree); return (-1); } sc->sock = true; sc->tty.rfd = sc->tty.wfd = -1; sc->usc_sock.servmev = mevent_add(sc->usc_sock.servfd, EVF_READ, uart_sock_accept, sc); assert(sc->usc_sock.servmev != NULL); free(tofree); return (0); } #endif /* not __FreeBSD__ */ static int uart_stdio_backend(struct uart_softc *sc) { #ifndef WITHOUT_CAPSICUM cap_rights_t rights; cap_ioctl_t cmds[] = { TIOCGETA, TIOCSETA, TIOCGWINSZ }; #endif if (uart_stdio) return (-1); sc->tty.rfd = STDIN_FILENO; sc->tty.wfd = STDOUT_FILENO; sc->tty.opened = true; if (fcntl(sc->tty.rfd, F_SETFL, O_NONBLOCK) != 0) return (-1); if (fcntl(sc->tty.wfd, F_SETFL, O_NONBLOCK) != 0) return (-1); #ifndef WITHOUT_CAPSICUM cap_rights_init(&rights, CAP_EVENT, CAP_IOCTL, CAP_READ); if (caph_rights_limit(sc->tty.rfd, &rights) == -1) errx(EX_OSERR, "Unable to apply rights for sandbox"); if (caph_ioctls_limit(sc->tty.rfd, cmds, nitems(cmds)) == -1) errx(EX_OSERR, "Unable to apply rights for sandbox"); #endif uart_stdio = true; return (0); } static int uart_tty_backend(struct uart_softc *sc, const char *path) { #ifndef WITHOUT_CAPSICUM cap_rights_t rights; cap_ioctl_t cmds[] = { TIOCGETA, TIOCSETA, TIOCGWINSZ }; #endif int fd; fd = open(path, O_RDWR | O_NONBLOCK); if (fd < 0) return (-1); if (!isatty(fd)) { close(fd); return (-1); } sc->tty.rfd = sc->tty.wfd = fd; sc->tty.opened = true; #ifndef WITHOUT_CAPSICUM cap_rights_init(&rights, CAP_EVENT, CAP_IOCTL, CAP_READ, CAP_WRITE); if (caph_rights_limit(fd, &rights) == -1) errx(EX_OSERR, "Unable to apply rights for sandbox"); if (caph_ioctls_limit(fd, cmds, nitems(cmds)) == -1) errx(EX_OSERR, "Unable to apply rights for sandbox"); #endif return (0); } int uart_set_backend(struct uart_softc *sc, const char *device) { int retval; if (device == NULL) return (0); #ifndef __FreeBSD__ if (strncmp("socket,", device, 7) == 0) return (uart_sock_backend(sc, device)); #endif if (strcmp("stdio", device) == 0) retval = uart_stdio_backend(sc); else retval = uart_tty_backend(sc, device); if (retval == 0) uart_opentty(sc); return (retval); }