/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2003 Marcel Moolenaar * 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 THE AUTHOR ``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 THE AUTHOR 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. */ #include "opt_acpi.h" #include "opt_platform.h" #include "opt_uart.h" #include #include #include #include #include #include #include #ifdef FDT #include #include #include #endif #include #include #ifdef FDT #include #endif #include #include #include #ifdef DEV_ACPI #include #include #endif #include #include "uart_if.h" #define DEFAULT_RCLK 1843200 /* * Set the default baudrate tolerance to 3.0%. * * Some embedded boards have odd reference clocks (eg 25MHz) * and we need to handle higher variances in the target baud rate. */ #ifndef UART_DEV_TOLERANCE_PCT #define UART_DEV_TOLERANCE_PCT 30 #endif /* UART_DEV_TOLERANCE_PCT */ static int broken_txfifo = 0; SYSCTL_INT(_hw, OID_AUTO, broken_txfifo, CTLFLAG_RWTUN, &broken_txfifo, 0, "UART FIFO has QEMU emulation bug"); static int uart_noise_threshold = 0; SYSCTL_INT(_hw, OID_AUTO, uart_noise_threshold, CTLFLAG_RWTUN, &uart_noise_threshold, 0, "Number of UART RX interrupts where TX is not ready, before data is discarded"); /* * To use early printf on x86, add the following to your kernel config: * * options UART_NS8250_EARLY_PORT=0x3f8 * options EARLY_PRINTF=ns8250 */ #if CHECK_EARLY_PRINTF(ns8250) #if !(defined(__amd64__) || defined(__i386__)) #error ns8250 early putc is x86 specific as it uses inb/outb #endif static void uart_ns8250_early_putc(int c) { u_int stat = UART_NS8250_EARLY_PORT + REG_LSR; u_int tx = UART_NS8250_EARLY_PORT + REG_DATA; int limit = 10000; /* 10ms is plenty of time */ while ((inb(stat) & LSR_THRE) == 0 && --limit > 0) continue; outb(tx, c); } early_putc_t *early_putc = uart_ns8250_early_putc; #endif /* EARLY_PRINTF */ /* * Clear pending interrupts. THRE is cleared by reading IIR. Data * that may have been received gets lost here. */ static void ns8250_clrint(struct uart_bas *bas) { uint8_t iir, lsr; iir = uart_getreg(bas, REG_IIR); while ((iir & IIR_NOPEND) == 0) { iir &= IIR_IMASK; if (iir == IIR_RLS) { lsr = uart_getreg(bas, REG_LSR); if (lsr & (LSR_BI|LSR_FE|LSR_PE)) (void)uart_getreg(bas, REG_DATA); } else if (iir == IIR_RXRDY || iir == IIR_RXTOUT) (void)uart_getreg(bas, REG_DATA); else if (iir == IIR_MLSC) (void)uart_getreg(bas, REG_MSR); uart_barrier(bas); iir = uart_getreg(bas, REG_IIR); } } static uint32_t ns8250_get_divisor(struct uart_bas *bas) { uint32_t divisor; uint8_t lcr; lcr = uart_getreg(bas, REG_LCR); uart_setreg(bas, REG_LCR, lcr | LCR_DLAB); uart_barrier(bas); divisor = uart_getreg(bas, REG_DLL) | (uart_getreg(bas, REG_DLH) << 8); uart_barrier(bas); uart_setreg(bas, REG_LCR, lcr); uart_barrier(bas); return (divisor); } static int ns8250_delay(struct uart_bas *bas) { int divisor; divisor = ns8250_get_divisor(bas); /* 1/10th the time to transmit 1 character (estimate). */ if (divisor <= 134) return (16000000 * divisor / bas->rclk); return (16000 * divisor / (bas->rclk / 1000)); } static int ns8250_divisor(int rclk, int baudrate) { int actual_baud, divisor; int error; if (baudrate == 0) return (0); divisor = (rclk / (baudrate << 3) + 1) >> 1; if (divisor == 0 || divisor >= 65536) return (0); actual_baud = rclk / (divisor << 4); /* 10 times error in percent: */ error = ((actual_baud - baudrate) * 2000 / baudrate + 1) / 2; /* enforce maximum error tolerance: */ if (error < -UART_DEV_TOLERANCE_PCT || error > UART_DEV_TOLERANCE_PCT) return (0); return (divisor); } static int ns8250_drain(struct uart_bas *bas, int what) { int delay, limit; delay = ns8250_delay(bas); if (what & UART_DRAIN_TRANSMITTER) { /* * Pick an arbitrary high limit to avoid getting stuck in * an infinite loop when the hardware is broken. Make the * limit high enough to handle large FIFOs. */ limit = 10*1024; while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0 && --limit) DELAY(delay); if (limit == 0) { /* printf("uart: ns8250: transmitter appears stuck... "); */ return (EIO); } } if (what & UART_DRAIN_RECEIVER) { /* * Pick an arbitrary high limit to avoid getting stuck in * an infinite loop when the hardware is broken. Make the * limit high enough to handle large FIFOs and integrated * UARTs. The HP rx2600 for example has 3 UARTs on the * management board that tend to get a lot of data send * to it when the UART is first activated. Assume that we * have finished draining if LSR_RXRDY is not asserted both * prior to and after a DELAY; but as long as LSR_RXRDY is * asserted, read (and discard) characters as quickly as * possible. */ limit=10*4096; while (limit && (uart_getreg(bas, REG_LSR) & LSR_RXRDY) && --limit) { do { (void)uart_getreg(bas, REG_DATA); uart_barrier(bas); } while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) && --limit); uart_barrier(bas); DELAY(delay << 2); } if (limit == 0) { /* printf("uart: ns8250: receiver appears broken... "); */ return (EIO); } } return (0); } /* * We can only flush UARTs with FIFOs. UARTs without FIFOs should be * drained. WARNING: this function clobbers the FIFO setting! */ static void ns8250_flush(struct uart_bas *bas, int what) { uint8_t fcr; uint8_t lsr; int drain = 0; fcr = FCR_ENABLE; if (what & UART_FLUSH_TRANSMITTER) fcr |= FCR_XMT_RST; if (what & UART_FLUSH_RECEIVER) fcr |= FCR_RCV_RST; uart_setreg(bas, REG_FCR, fcr); uart_barrier(bas); /* * Detect and work around emulated UARTs which don't implement the * FCR register; on these systems we need to drain the FIFO since * the flush we request doesn't happen. One such system is the * Firecracker VMM, aka. the rust-vmm/vm-superio emulation code: * https://github.com/rust-vmm/vm-superio/issues/83 */ lsr = uart_getreg(bas, REG_LSR); if (((lsr & LSR_TEMT) == 0) && (what & UART_FLUSH_TRANSMITTER)) drain |= UART_DRAIN_TRANSMITTER; if ((lsr & LSR_RXRDY) && (what & UART_FLUSH_RECEIVER)) drain |= UART_DRAIN_RECEIVER; if (drain != 0) { printf("uart: ns8250: UART FCR is broken\n"); ns8250_drain(bas, drain); } } static int ns8250_param(struct uart_bas *bas, int baudrate, int databits, int stopbits, int parity) { int divisor; uint8_t lcr; /* Don't change settings when running on Hyper-V */ if (vm_guest == VM_GUEST_HV) return (0); lcr = 0; if (databits >= 8) lcr |= LCR_8BITS; else if (databits == 7) lcr |= LCR_7BITS; else if (databits == 6) lcr |= LCR_6BITS; else lcr |= LCR_5BITS; if (stopbits > 1) lcr |= LCR_STOPB; lcr |= parity << 3; /* Set baudrate if we know a rclk and both are not 0. */ if (baudrate > 0 && bas->rclk > 0) { divisor = ns8250_divisor(bas->rclk, baudrate); if (divisor == 0) return (EINVAL); uart_setreg(bas, REG_LCR, lcr | LCR_DLAB); uart_barrier(bas); uart_setreg(bas, REG_DLL, divisor & 0xff); uart_setreg(bas, REG_DLH, (divisor >> 8) & 0xff); uart_barrier(bas); } /* Set LCR and clear DLAB. */ uart_setreg(bas, REG_LCR, lcr); uart_barrier(bas); return (0); } /* * Low-level UART interface. */ static int ns8250_probe(struct uart_bas *bas); static void ns8250_init(struct uart_bas *bas, int, int, int, int); static void ns8250_term(struct uart_bas *bas); static void ns8250_putc(struct uart_bas *bas, int); static int ns8250_rxready(struct uart_bas *bas); static int ns8250_getc(struct uart_bas *bas, struct mtx *); struct uart_ops uart_ns8250_ops = { .probe = ns8250_probe, .init = ns8250_init, .term = ns8250_term, .putc = ns8250_putc, .rxready = ns8250_rxready, .getc = ns8250_getc, }; static int ns8250_probe(struct uart_bas *bas) { u_char val; /* Check known 0 bits that don't depend on DLAB. */ val = uart_getreg(bas, REG_IIR); if (val & 0x30) return (ENXIO); /* * Bit 6 of the MCR (= 0x40) appears to be 1 for the Sun1699 * chip, but otherwise doesn't seem to have a function. In * other words, uart(4) works regardless. Ignore that bit so * the probe succeeds. */ val = uart_getreg(bas, REG_MCR); if (val & 0xa0) return (ENXIO); return (0); } static void ns8250_init(struct uart_bas *bas, int baudrate, int databits, int stopbits, int parity) { u_char ier; /* Disable all interrupt sources. */ /* * We use 0xe0 instead of 0xf0 as the mask because the XScale PXA * UARTs split the receive time-out interrupt bit out separately as * 0x10. This gets handled by ier_mask and ier_rxbits below. */ ier = uart_getreg(bas, REG_IER) & 0xe0; uart_setreg(bas, REG_IER, ier); uart_barrier(bas); /* * Loader tells us to infer the rclk when it sets xo to 0 in * hw.uart.console. We know the baudrate was set by the firmware, so * calculate rclk from baudrate and the divisor register. If 'div' is * actually 0, the resulting 0 value will have us fall back to other * rclk methods. */ if (bas->rclk_guess && bas->rclk == 0 && baudrate != 0) { uint32_t div; div = ns8250_get_divisor(bas); bas->rclk = baudrate * div * 16; } /* * Pick a default because we just don't know. This likely needs future * refinement, but that's hard outside of consoles to know what to use. * But defer as long as possible if there's no defined baud rate. */ if (bas->rclk == 0 && baudrate != 0) bas->rclk = DEFAULT_RCLK; ns8250_param(bas, baudrate, databits, stopbits, parity); /* Disable the FIFO (if present). */ uart_setreg(bas, REG_FCR, 0); uart_barrier(bas); /* Set RTS & DTR. */ uart_setreg(bas, REG_MCR, MCR_IE | MCR_RTS | MCR_DTR); uart_barrier(bas); ns8250_clrint(bas); } static void ns8250_term(struct uart_bas *bas) { /* Clear RTS & DTR. */ uart_setreg(bas, REG_MCR, MCR_IE); uart_barrier(bas); } static void ns8250_putc(struct uart_bas *bas, int c) { int limit; if (vm_guest != VM_GUEST_HV) { limit = 250000; while ((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0 && --limit) DELAY(4); } uart_setreg(bas, REG_DATA, c); uart_barrier(bas); } static int ns8250_rxready(struct uart_bas *bas) { return ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) != 0 ? 1 : 0); } static int ns8250_getc(struct uart_bas *bas, struct mtx *hwmtx) { int c; uart_lock(hwmtx); while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0) { uart_unlock(hwmtx); DELAY(4); uart_lock(hwmtx); } c = uart_getreg(bas, REG_DATA); uart_unlock(hwmtx); return (c); } static kobj_method_t ns8250_methods[] = { KOBJMETHOD(uart_attach, ns8250_bus_attach), KOBJMETHOD(uart_detach, ns8250_bus_detach), KOBJMETHOD(uart_flush, ns8250_bus_flush), KOBJMETHOD(uart_getsig, ns8250_bus_getsig), KOBJMETHOD(uart_ioctl, ns8250_bus_ioctl), KOBJMETHOD(uart_ipend, ns8250_bus_ipend), KOBJMETHOD(uart_param, ns8250_bus_param), KOBJMETHOD(uart_probe, ns8250_bus_probe), KOBJMETHOD(uart_receive, ns8250_bus_receive), KOBJMETHOD(uart_setsig, ns8250_bus_setsig), KOBJMETHOD(uart_transmit, ns8250_bus_transmit), KOBJMETHOD(uart_txbusy, ns8250_bus_txbusy), KOBJMETHOD(uart_grab, ns8250_bus_grab), KOBJMETHOD(uart_ungrab, ns8250_bus_ungrab), KOBJMETHOD_END }; struct uart_class uart_ns8250_class = { "ns8250", ns8250_methods, sizeof(struct ns8250_softc), .uc_ops = &uart_ns8250_ops, .uc_range = 8, .uc_rclk = DEFAULT_RCLK, .uc_rshift = 0 }; UART_CLASS(uart_ns8250_class); /* * XXX -- refactor out ACPI and FDT ifdefs */ #ifdef DEV_ACPI static struct acpi_uart_compat_data acpi_compat_data[] = { {"AMD0020", &uart_ns8250_class, 0, 2, 0, 48000000, UART_F_BUSY_DETECT, "AMD / Synopsys Designware UART"}, {"AMDI0020", &uart_ns8250_class, 0, 2, 0, 48000000, UART_F_BUSY_DETECT, "AMD / Synopsys Designware UART"}, {"APMC0D08", &uart_ns8250_class, ACPI_DBG2_16550_COMPATIBLE, 2, 4, 0, 0, "APM compatible UART"}, {"MRVL0001", &uart_ns8250_class, ACPI_DBG2_16550_SUBSET, 2, 0, 200000000, UART_F_BUSY_DETECT, "Marvell / Synopsys Designware UART"}, {"SCX0006", &uart_ns8250_class, 0, 2, 0, 62500000, UART_F_BUSY_DETECT, "SynQuacer / Synopsys Designware UART"}, {"HISI0031", &uart_ns8250_class, 0, 2, 0, 200000000, UART_F_BUSY_DETECT, "HiSilicon / Synopsys Designware UART"}, {"INTC1006", &uart_ns8250_class, 0, 2, 0, 25000000, 0, "Intel ARM64 UART"}, {"NXP0018", &uart_ns8250_class, 0, 0, 0, 350000000, UART_F_BUSY_DETECT, "NXP / Synopsys Designware UART"}, {"PNP0500", &uart_ns8250_class, 0, 0, 0, 0, 0, "Standard PC COM port"}, {"PNP0501", &uart_ns8250_class, 0, 0, 0, 0, 0, "16550A-compatible COM port"}, {"PNP0502", &uart_ns8250_class, 0, 0, 0, 0, 0, "Multiport serial device (non-intelligent 16550)"}, {"PNP0510", &uart_ns8250_class, 0, 0, 0, 0, 0, "Generic IRDA-compatible device"}, {"PNP0511", &uart_ns8250_class, 0, 0, 0, 0, 0, "Generic IRDA-compatible device"}, {"WACF004", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet PC Screen"}, {"WACF00E", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet PC Screen 00e"}, {"FUJ02E5", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet at FuS Lifebook T"}, {NULL, NULL, 0, 0 , 0, 0, 0, NULL}, }; UART_ACPI_CLASS_AND_DEVICE(acpi_compat_data); #endif #ifdef FDT static struct ofw_compat_data compat_data[] = { {"ns16550", (uintptr_t)&uart_ns8250_class}, {"ns16550a", (uintptr_t)&uart_ns8250_class}, {NULL, (uintptr_t)NULL}, }; UART_FDT_CLASS_AND_DEVICE(compat_data); #endif /* Use token-pasting to form SER_ and MSR_ named constants. */ #define SER(sig) SER_##sig #define SERD(sig) SER_D##sig #define MSR(sig) MSR_##sig #define MSRD(sig) MSR_D##sig /* * Detect signal changes using software delta detection. The previous state of * the signals is in 'var' the new hardware state is in 'msr', and 'sig' is the * short name (DCD, CTS, etc) of the signal bit being processed; 'var' gets the * new state of both the signal and the delta bits. */ #define SIGCHGSW(var, msr, sig) \ if ((msr) & MSR(sig)) { \ if ((var & SER(sig)) == 0) \ var |= SERD(sig) | SER(sig); \ } else { \ if ((var & SER(sig)) != 0) \ var = SERD(sig) | (var & ~SER(sig)); \ } /* * Detect signal changes using the hardware msr delta bits. This is currently * used only when PPS timing information is being captured using the "narrow * pulse" option. With a narrow PPS pulse the signal may not still be asserted * by time the interrupt handler is invoked. The hardware will latch the fact * that it changed in the delta bits. */ #define SIGCHGHW(var, msr, sig) \ if ((msr) & MSRD(sig)) { \ if (((msr) & MSR(sig)) != 0) \ var |= SERD(sig) | SER(sig); \ else \ var = SERD(sig) | (var & ~SER(sig)); \ } int ns8250_bus_attach(struct uart_softc *sc) { struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; struct uart_bas *bas; unsigned int ivar; #ifdef FDT phandle_t node; pcell_t cell; #endif #ifdef FDT /* Check whether uart has a broken txfifo. */ node = ofw_bus_get_node(sc->sc_dev); if ((OF_getencprop(node, "broken-txfifo", &cell, sizeof(cell))) > 0) broken_txfifo = cell ? 1 : 0; #endif bas = &sc->sc_bas; ns8250->busy_detect = bas->busy_detect; ns8250->mcr = uart_getreg(bas, REG_MCR); ns8250->fcr = FCR_ENABLE; if (!resource_int_value("uart", device_get_unit(sc->sc_dev), "flags", &ivar)) { if (UART_FLAGS_FCR_RX_LOW(ivar)) ns8250->fcr |= FCR_RX_LOW; else if (UART_FLAGS_FCR_RX_MEDL(ivar)) ns8250->fcr |= FCR_RX_MEDL; else if (UART_FLAGS_FCR_RX_HIGH(ivar)) ns8250->fcr |= FCR_RX_HIGH; else ns8250->fcr |= FCR_RX_MEDH; } else ns8250->fcr |= FCR_RX_MEDH; /* Get IER mask */ ivar = 0xf0; resource_int_value("uart", device_get_unit(sc->sc_dev), "ier_mask", &ivar); ns8250->ier_mask = (uint8_t)(ivar & 0xff); /* Get IER RX interrupt bits */ ivar = IER_EMSC | IER_ERLS | IER_ERXRDY; resource_int_value("uart", device_get_unit(sc->sc_dev), "ier_rxbits", &ivar); ns8250->ier_rxbits = (uint8_t)(ivar & 0xff); uart_setreg(bas, REG_FCR, ns8250->fcr); uart_barrier(bas); ns8250_bus_flush(sc, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER); if (ns8250->mcr & MCR_DTR) sc->sc_hwsig |= SER_DTR; if (ns8250->mcr & MCR_RTS) sc->sc_hwsig |= SER_RTS; ns8250_bus_getsig(sc); ns8250_clrint(bas); ns8250->ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask; ns8250->ier |= ns8250->ier_rxbits; uart_setreg(bas, REG_IER, ns8250->ier); uart_barrier(bas); /* * Timing of the H/W access was changed with r253161 of uart_core.c * It has been observed that an ITE IT8513E would signal a break * condition with pretty much every character it received, unless * it had enough time to settle between ns8250_bus_attach() and * ns8250_bus_ipend() -- which it accidentally had before r253161. * It's not understood why the UART chip behaves this way and it * could very well be that the DELAY make the H/W work in the same * accidental manner as before. More analysis is warranted, but * at least now we fixed a known regression. */ DELAY(200); return (0); } int ns8250_bus_detach(struct uart_softc *sc) { struct ns8250_softc *ns8250; struct uart_bas *bas; u_char ier; ns8250 = (struct ns8250_softc *)sc; bas = &sc->sc_bas; ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask; uart_setreg(bas, REG_IER, ier); uart_barrier(bas); ns8250_clrint(bas); return (0); } int ns8250_bus_flush(struct uart_softc *sc, int what) { struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; struct uart_bas *bas; int error; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); if (sc->sc_rxfifosz > 1) { ns8250_flush(bas, what); uart_setreg(bas, REG_FCR, ns8250->fcr); uart_barrier(bas); error = 0; } else error = ns8250_drain(bas, what); uart_unlock(sc->sc_hwmtx); return (error); } int ns8250_bus_getsig(struct uart_softc *sc) { uint32_t old, sig; uint8_t msr; /* * The delta bits are reputed to be broken on some hardware, so use * software delta detection by default. Use the hardware delta bits * when capturing PPS pulses which are too narrow for software detection * to see the edges. Hardware delta for RI doesn't work like the * others, so always use software for it. Other threads may be changing * other (non-MSR) bits in sc_hwsig, so loop until it can successfully * update without other changes happening. Note that the SIGCHGxx() * macros carefully preserve the delta bits when we have to loop several * times and a signal transitions between iterations. */ do { old = sc->sc_hwsig; sig = old; uart_lock(sc->sc_hwmtx); msr = uart_getreg(&sc->sc_bas, REG_MSR); uart_unlock(sc->sc_hwmtx); if (sc->sc_pps_mode & UART_PPS_NARROW_PULSE) { SIGCHGHW(sig, msr, DSR); SIGCHGHW(sig, msr, CTS); SIGCHGHW(sig, msr, DCD); } else { SIGCHGSW(sig, msr, DSR); SIGCHGSW(sig, msr, CTS); SIGCHGSW(sig, msr, DCD); } SIGCHGSW(sig, msr, RI); } while (!atomic_cmpset_32(&sc->sc_hwsig, old, sig & ~SER_MASK_DELTA)); return (sig); } int ns8250_bus_ioctl(struct uart_softc *sc, int request, intptr_t data) { struct uart_bas *bas; int baudrate, divisor, error; uint8_t efr, lcr; bas = &sc->sc_bas; error = 0; uart_lock(sc->sc_hwmtx); switch (request) { case UART_IOCTL_BREAK: lcr = uart_getreg(bas, REG_LCR); if (data) lcr |= LCR_SBREAK; else lcr &= ~LCR_SBREAK; uart_setreg(bas, REG_LCR, lcr); uart_barrier(bas); break; case UART_IOCTL_IFLOW: lcr = uart_getreg(bas, REG_LCR); uart_barrier(bas); uart_setreg(bas, REG_LCR, 0xbf); uart_barrier(bas); efr = uart_getreg(bas, REG_EFR); if (data) efr |= EFR_RTS; else efr &= ~EFR_RTS; uart_setreg(bas, REG_EFR, efr); uart_barrier(bas); uart_setreg(bas, REG_LCR, lcr); uart_barrier(bas); break; case UART_IOCTL_OFLOW: lcr = uart_getreg(bas, REG_LCR); uart_barrier(bas); uart_setreg(bas, REG_LCR, 0xbf); uart_barrier(bas); efr = uart_getreg(bas, REG_EFR); if (data) efr |= EFR_CTS; else efr &= ~EFR_CTS; uart_setreg(bas, REG_EFR, efr); uart_barrier(bas); uart_setreg(bas, REG_LCR, lcr); uart_barrier(bas); break; case UART_IOCTL_BAUD: divisor = ns8250_get_divisor(bas); baudrate = (divisor > 0) ? bas->rclk / divisor / 16 : 0; if (baudrate > 0) *(int*)data = baudrate; else error = ENXIO; break; default: error = EINVAL; break; } uart_unlock(sc->sc_hwmtx); return (error); } int ns8250_bus_ipend(struct uart_softc *sc) { struct uart_bas *bas; struct ns8250_softc *ns8250; int ipend; uint8_t iir, lsr; ns8250 = (struct ns8250_softc *)sc; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); iir = uart_getreg(bas, REG_IIR); if (ns8250->busy_detect && (iir & IIR_BUSY) == IIR_BUSY) { (void)uart_getreg(bas, DW_REG_USR); uart_unlock(sc->sc_hwmtx); return (0); } if (iir & IIR_NOPEND) { uart_unlock(sc->sc_hwmtx); return (0); } ipend = 0; if (iir & IIR_RXRDY) { lsr = uart_getreg(bas, REG_LSR); if (lsr & LSR_OE) ipend |= SER_INT_OVERRUN; if (lsr & LSR_BI) ipend |= SER_INT_BREAK; if (lsr & LSR_RXRDY) ipend |= SER_INT_RXREADY; } else { if (iir & IIR_TXRDY) { ipend |= SER_INT_TXIDLE; ns8250->ier &= ~IER_ETXRDY; uart_setreg(bas, REG_IER, ns8250->ier); uart_barrier(bas); } else ipend |= SER_INT_SIGCHG; } if (ipend == 0) ns8250_clrint(bas); uart_unlock(sc->sc_hwmtx); return (ipend); } int ns8250_bus_param(struct uart_softc *sc, int baudrate, int databits, int stopbits, int parity) { struct ns8250_softc *ns8250; struct uart_bas *bas; int error, limit; ns8250 = (struct ns8250_softc*)sc; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); /* * When using DW UART with BUSY detection it is necessary to wait * until all serial transfers are finished before manipulating the * line control. LCR will not be affected when UART is busy. */ if (ns8250->busy_detect != 0) { /* * Pick an arbitrary high limit to avoid getting stuck in * an infinite loop in case when the hardware is broken. */ limit = 10 * 1024; while (((uart_getreg(bas, DW_REG_USR) & USR_BUSY) != 0) && --limit) DELAY(4); if (limit <= 0) { /* UART appears to be stuck */ uart_unlock(sc->sc_hwmtx); return (EIO); } } error = ns8250_param(bas, baudrate, databits, stopbits, parity); uart_unlock(sc->sc_hwmtx); return (error); } int ns8250_bus_probe(struct uart_softc *sc) { struct uart_bas *bas; int count, delay, error, limit; uint8_t lsr, mcr, ier; bas = &sc->sc_bas; error = ns8250_probe(bas); if (error) return (error); mcr = MCR_IE; if (sc->sc_sysdev == NULL) { /* By using ns8250_init() we also set DTR and RTS. */ ns8250_init(bas, 115200, 8, 1, UART_PARITY_NONE); } else mcr |= MCR_DTR | MCR_RTS; error = ns8250_drain(bas, UART_DRAIN_TRANSMITTER); if (error) return (error); /* * Set loopback mode. This avoids having garbage on the wire and * also allows us send and receive data. We set DTR and RTS to * avoid the possibility that automatic flow-control prevents * any data from being sent. */ uart_setreg(bas, REG_MCR, MCR_LOOPBACK | MCR_IE | MCR_DTR | MCR_RTS); uart_barrier(bas); /* * Enable FIFOs. And check that the UART has them. If not, we're * done. Since this is the first time we enable the FIFOs, we reset * them. */ uart_setreg(bas, REG_FCR, FCR_ENABLE); uart_barrier(bas); if (!(uart_getreg(bas, REG_IIR) & IIR_FIFO_MASK)) { /* * NS16450 or INS8250. We don't bother to differentiate * between them. They're too old to be interesting. */ uart_setreg(bas, REG_MCR, mcr); uart_barrier(bas); sc->sc_rxfifosz = sc->sc_txfifosz = 1; device_set_desc(sc->sc_dev, "8250 or 16450 or compatible"); return (0); } uart_setreg(bas, REG_FCR, FCR_ENABLE | FCR_XMT_RST | FCR_RCV_RST); uart_barrier(bas); count = 0; delay = ns8250_delay(bas); /* We have FIFOs. Drain the transmitter and receiver. */ error = ns8250_drain(bas, UART_DRAIN_RECEIVER|UART_DRAIN_TRANSMITTER); if (error) { uart_setreg(bas, REG_MCR, mcr); uart_setreg(bas, REG_FCR, 0); uart_barrier(bas); goto describe; } /* * We should have a sufficiently clean "pipe" to determine the * size of the FIFOs. We send as much characters as is reasonable * and wait for the overflow bit in the LSR register to be * asserted, counting the characters as we send them. Based on * that count we know the FIFO size. */ do { uart_setreg(bas, REG_DATA, 0); uart_barrier(bas); count++; limit = 30; lsr = 0; /* * LSR bits are cleared upon read, so we must accumulate * them to be able to test LSR_OE below. */ while (((lsr |= uart_getreg(bas, REG_LSR)) & LSR_TEMT) == 0 && --limit) DELAY(delay); if (limit == 0) { /* See the comment in ns8250_init(). */ ier = uart_getreg(bas, REG_IER) & 0xe0; uart_setreg(bas, REG_IER, ier); uart_setreg(bas, REG_MCR, mcr); uart_setreg(bas, REG_FCR, 0); uart_barrier(bas); count = 0; goto describe; } } while ((lsr & LSR_OE) == 0 && count < 260); count--; uart_setreg(bas, REG_MCR, mcr); /* Reset FIFOs. */ ns8250_flush(bas, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER); describe: if (count >= 14 && count <= 16) { sc->sc_rxfifosz = 16; device_set_desc(sc->sc_dev, "16550 or compatible"); } else if (count >= 28 && count <= 32) { sc->sc_rxfifosz = 32; device_set_desc(sc->sc_dev, "16650 or compatible"); } else if (count >= 56 && count <= 64) { sc->sc_rxfifosz = 64; device_set_desc(sc->sc_dev, "16750 or compatible"); } else if (count >= 112 && count <= 128) { sc->sc_rxfifosz = 128; device_set_desc(sc->sc_dev, "16950 or compatible"); } else if (count >= 224 && count <= 256) { sc->sc_rxfifosz = 256; device_set_desc(sc->sc_dev, "16x50 with 256 byte FIFO"); } else { sc->sc_rxfifosz = 16; device_set_desc(sc->sc_dev, "Non-standard ns8250 class UART with FIFOs"); } /* * Force the Tx FIFO size to 16 bytes for now. We don't program the * Tx trigger. Also, we assume that all data has been sent when the * interrupt happens. */ sc->sc_txfifosz = 16; #if 0 /* * XXX there are some issues related to hardware flow control and * it's likely that uart(4) is the cause. This basically needs more * investigation, but we avoid using for hardware flow control * until then. */ /* 16650s or higher have automatic flow control. */ if (sc->sc_rxfifosz > 16) { sc->sc_hwiflow = 1; sc->sc_hwoflow = 1; } #endif return (0); } int ns8250_bus_receive(struct uart_softc *sc) { struct uart_bas *bas; struct ns8250_softc *ns8250 = (struct ns8250_softc *)sc; int xc; uint8_t lsr; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); lsr = uart_getreg(bas, REG_LSR); while (lsr & LSR_RXRDY) { if (uart_rx_full(sc)) { sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN; break; } /* Filter out possible noise on the line. * Expect that the device should be able to transmit as well as * receive, so if we receive too many characters before transmit * is ready, it's probably noise. */ if ((lsr & (LSR_TXRDY | LSR_TEMT)) == 0 && uart_noise_threshold > 0) { if (++ns8250->noise_count >= uart_noise_threshold) break; } else ns8250->noise_count = 0; xc = uart_getreg(bas, REG_DATA); if (lsr & LSR_FE) xc |= UART_STAT_FRAMERR; if (lsr & LSR_PE) xc |= UART_STAT_PARERR; uart_rx_put(sc, xc); lsr = uart_getreg(bas, REG_LSR); } /* Discard everything left in the Rx FIFO. */ while (lsr & LSR_RXRDY) { (void)uart_getreg(bas, REG_DATA); uart_barrier(bas); lsr = uart_getreg(bas, REG_LSR); } uart_unlock(sc->sc_hwmtx); return (0); } int ns8250_bus_setsig(struct uart_softc *sc, int sig) { struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; struct uart_bas *bas; uint32_t new, old; bas = &sc->sc_bas; do { old = sc->sc_hwsig; new = old; if (sig & SER_DDTR) { new = (new & ~SER_DTR) | (sig & (SER_DTR | SER_DDTR)); } if (sig & SER_DRTS) { new = (new & ~SER_RTS) | (sig & (SER_RTS | SER_DRTS)); } } while (!atomic_cmpset_32(&sc->sc_hwsig, old, new)); uart_lock(sc->sc_hwmtx); ns8250->mcr &= ~(MCR_DTR|MCR_RTS); if (new & SER_DTR) ns8250->mcr |= MCR_DTR; if (new & SER_RTS) ns8250->mcr |= MCR_RTS; uart_setreg(bas, REG_MCR, ns8250->mcr); uart_barrier(bas); uart_unlock(sc->sc_hwmtx); return (0); } int ns8250_bus_transmit(struct uart_softc *sc) { struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; struct uart_bas *bas; int i; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); while ((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0) DELAY(4); for (i = 0; i < sc->sc_txdatasz; i++) { uart_setreg(bas, REG_DATA, sc->sc_txbuf[i]); uart_barrier(bas); } if (!broken_txfifo) ns8250->ier |= IER_ETXRDY; uart_setreg(bas, REG_IER, ns8250->ier); uart_barrier(bas); if (broken_txfifo) ns8250_drain(bas, UART_DRAIN_TRANSMITTER); else sc->sc_txbusy = 1; uart_unlock(sc->sc_hwmtx); if (broken_txfifo) uart_sched_softih(sc, SER_INT_TXIDLE); return (0); } bool ns8250_bus_txbusy(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; if ((uart_getreg(bas, REG_LSR) & (LSR_TEMT | LSR_THRE)) != (LSR_TEMT | LSR_THRE)) return (true); return (false); } void ns8250_bus_grab(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; u_char ier; /* * turn off all interrupts to enter polling mode. Leave the * saved mask alone. We'll restore whatever it was in ungrab. * All pending interrupt signals are reset when IER is set to 0. */ uart_lock(sc->sc_hwmtx); ier = uart_getreg(bas, REG_IER); uart_setreg(bas, REG_IER, ier & ns8250->ier_mask); uart_barrier(bas); uart_unlock(sc->sc_hwmtx); } void ns8250_bus_ungrab(struct uart_softc *sc) { struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; struct uart_bas *bas = &sc->sc_bas; /* * Restore previous interrupt mask */ uart_lock(sc->sc_hwmtx); uart_setreg(bas, REG_IER, ns8250->ier); uart_barrier(bas); uart_unlock(sc->sc_hwmtx); }