/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2013 Adrian Chadd * 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 #include #include #include #include #include #include #include #include #include #include "uart_if.h" /* * Default system clock is 25MHz; see ar933x_chip.c for how * the startup process determines whether it's 25MHz or 40MHz. */ #define DEFAULT_RCLK (25 * 1000 * 1000) #define ar933x_getreg(bas, reg) \ bus_space_read_4((bas)->bst, (bas)->bsh, reg) #define ar933x_setreg(bas, reg, value) \ bus_space_write_4((bas)->bst, (bas)->bsh, reg, value) static int ar933x_drain(struct uart_bas *bas, int what) { int limit; if (what & UART_DRAIN_TRANSMITTER) { limit = 10*1024; /* Loop over until the TX FIFO shows entirely clear */ while (--limit) { if ((ar933x_getreg(bas, AR933X_UART_CS_REG) & AR933X_UART_CS_TX_BUSY) == 0) break; } if (limit == 0) { return (EIO); } } if (what & UART_DRAIN_RECEIVER) { limit=10*4096; while (--limit) { /* XXX duplicated from ar933x_getc() */ /* XXX TODO: refactor! */ /* If there's nothing to read, stop! */ if ((ar933x_getreg(bas, AR933X_UART_DATA_REG) & AR933X_UART_DATA_RX_CSR) == 0) { break; } /* Read the top of the RX FIFO */ (void) ar933x_getreg(bas, AR933X_UART_DATA_REG); /* Remove that entry from said RX FIFO */ ar933x_setreg(bas, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR); uart_barrier(bas); DELAY(2); } if (limit == 0) { return (EIO); } } return (0); } /* * Calculate the baud from the given chip configuration parameters. */ static unsigned long ar933x_uart_get_baud(unsigned int clk, unsigned int scale, unsigned int step) { uint64_t t; uint32_t div; div = (2 << 16) * (scale + 1); t = clk; t *= step; t += (div / 2); t = t / div; return (t); } /* * Calculate the scale/step with the lowest possible deviation from * the target baudrate. */ static void ar933x_uart_get_scale_step(struct uart_bas *bas, unsigned int baud, unsigned int *scale, unsigned int *step) { unsigned int tscale; uint32_t clk; long min_diff; clk = bas->rclk; *scale = 0; *step = 0; min_diff = baud; for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) { uint64_t tstep; int diff; tstep = baud * (tscale + 1); tstep *= (2 << 16); tstep = tstep / clk; if (tstep > AR933X_UART_MAX_STEP) break; diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud); if (diff < min_diff) { min_diff = diff; *scale = tscale; *step = tstep; } } } static int ar933x_param(struct uart_bas *bas, int baudrate, int databits, int stopbits, int parity) { /* UART always 8 bits */ /* UART always 1 stop bit */ /* UART parity is controllable by bits 0:1, ignore for now */ /* Set baudrate if required. */ if (baudrate > 0) { uint32_t clock_scale, clock_step; /* Find the best fit for the given baud rate */ ar933x_uart_get_scale_step(bas, baudrate, &clock_scale, &clock_step); /* * Program the clock register in its entirety - no need * for Read-Modify-Write. */ ar933x_setreg(bas, AR933X_UART_CLOCK_REG, ((clock_scale & AR933X_UART_CLOCK_SCALE_M) << AR933X_UART_CLOCK_SCALE_S) | (clock_step & AR933X_UART_CLOCK_STEP_M)); } uart_barrier(bas); return (0); } /* * Low-level UART interface. */ static int ar933x_probe(struct uart_bas *bas); static void ar933x_init(struct uart_bas *bas, int, int, int, int); static void ar933x_term(struct uart_bas *bas); static void ar933x_putc(struct uart_bas *bas, int); static int ar933x_rxready(struct uart_bas *bas); static int ar933x_getc(struct uart_bas *bas, struct mtx *); static struct uart_ops uart_ar933x_ops = { .probe = ar933x_probe, .init = ar933x_init, .term = ar933x_term, .putc = ar933x_putc, .rxready = ar933x_rxready, .getc = ar933x_getc, }; static int ar933x_probe(struct uart_bas *bas) { /* We always know this will be here */ return (0); } static void ar933x_init(struct uart_bas *bas, int baudrate, int databits, int stopbits, int parity) { uint32_t reg; /* Setup default parameters */ ar933x_param(bas, baudrate, databits, stopbits, parity); /* XXX Force enable UART in case it was disabled */ /* Disable all interrupts */ ar933x_setreg(bas, AR933X_UART_INT_EN_REG, 0x00000000); /* Disable the host interrupt */ reg = ar933x_getreg(bas, AR933X_UART_CS_REG); reg &= ~AR933X_UART_CS_HOST_INT_EN; ar933x_setreg(bas, AR933X_UART_CS_REG, reg); uart_barrier(bas); /* XXX Set RTS/DTR? */ } /* * Detach from console. */ static void ar933x_term(struct uart_bas *bas) { /* XXX TODO */ } static void ar933x_putc(struct uart_bas *bas, int c) { int limit; limit = 250000; /* Wait for space in the TX FIFO */ while ( ((ar933x_getreg(bas, AR933X_UART_DATA_REG) & AR933X_UART_DATA_TX_CSR) == 0) && --limit) DELAY(4); /* Write the actual byte */ ar933x_setreg(bas, AR933X_UART_DATA_REG, (c & 0xff) | AR933X_UART_DATA_TX_CSR); } static int ar933x_rxready(struct uart_bas *bas) { /* Wait for a character to come ready */ return (!!(ar933x_getreg(bas, AR933X_UART_DATA_REG) & AR933X_UART_DATA_RX_CSR)); } static int ar933x_getc(struct uart_bas *bas, struct mtx *hwmtx) { int c; uart_lock(hwmtx); /* Wait for a character to come ready */ while ((ar933x_getreg(bas, AR933X_UART_DATA_REG) & AR933X_UART_DATA_RX_CSR) == 0) { uart_unlock(hwmtx); DELAY(4); uart_lock(hwmtx); } /* Read the top of the RX FIFO */ c = ar933x_getreg(bas, AR933X_UART_DATA_REG) & 0xff; /* Remove that entry from said RX FIFO */ ar933x_setreg(bas, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR); uart_unlock(hwmtx); return (c); } /* * High-level UART interface. */ struct ar933x_softc { struct uart_softc base; uint32_t u_ier; }; static int ar933x_bus_attach(struct uart_softc *); static int ar933x_bus_detach(struct uart_softc *); static int ar933x_bus_flush(struct uart_softc *, int); static int ar933x_bus_getsig(struct uart_softc *); static int ar933x_bus_ioctl(struct uart_softc *, int, intptr_t); static int ar933x_bus_ipend(struct uart_softc *); static int ar933x_bus_param(struct uart_softc *, int, int, int, int); static int ar933x_bus_probe(struct uart_softc *); static int ar933x_bus_receive(struct uart_softc *); static int ar933x_bus_setsig(struct uart_softc *, int); static int ar933x_bus_transmit(struct uart_softc *); static void ar933x_bus_grab(struct uart_softc *); static void ar933x_bus_ungrab(struct uart_softc *); static kobj_method_t ar933x_methods[] = { KOBJMETHOD(uart_attach, ar933x_bus_attach), KOBJMETHOD(uart_detach, ar933x_bus_detach), KOBJMETHOD(uart_flush, ar933x_bus_flush), KOBJMETHOD(uart_getsig, ar933x_bus_getsig), KOBJMETHOD(uart_ioctl, ar933x_bus_ioctl), KOBJMETHOD(uart_ipend, ar933x_bus_ipend), KOBJMETHOD(uart_param, ar933x_bus_param), KOBJMETHOD(uart_probe, ar933x_bus_probe), KOBJMETHOD(uart_receive, ar933x_bus_receive), KOBJMETHOD(uart_setsig, ar933x_bus_setsig), KOBJMETHOD(uart_transmit, ar933x_bus_transmit), KOBJMETHOD(uart_grab, ar933x_bus_grab), KOBJMETHOD(uart_ungrab, ar933x_bus_ungrab), { 0, 0 } }; struct uart_class uart_ar933x_class = { "ar933x", ar933x_methods, sizeof(struct ar933x_softc), .uc_ops = &uart_ar933x_ops, .uc_range = 8, .uc_rclk = DEFAULT_RCLK, .uc_rshift = 0 }; #define SIGCHG(c, i, s, d) \ if (c) { \ i |= (i & s) ? s : s | d; \ } else { \ i = (i & s) ? (i & ~s) | d : i; \ } static int ar933x_bus_attach(struct uart_softc *sc) { struct ar933x_softc *u = (struct ar933x_softc *)sc; struct uart_bas *bas = &sc->sc_bas; uint32_t reg; /* XXX TODO: flush transmitter */ /* * Setup initial interrupt notifications. * * XXX for now, just RX FIFO valid. * Later on (when they're handled), also handle * RX errors/overflow. */ u->u_ier = AR933X_UART_INT_RX_VALID; /* Enable RX interrupts to kick-start things */ ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier); /* Enable the host interrupt now */ reg = ar933x_getreg(bas, AR933X_UART_CS_REG); reg |= AR933X_UART_CS_HOST_INT_EN; ar933x_setreg(bas, AR933X_UART_CS_REG, reg); return (0); } static int ar933x_bus_detach(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; uint32_t reg; /* Disable all interrupts */ ar933x_setreg(bas, AR933X_UART_INT_EN_REG, 0x00000000); /* Disable the host interrupt */ reg = ar933x_getreg(bas, AR933X_UART_CS_REG); reg &= ~AR933X_UART_CS_HOST_INT_EN; ar933x_setreg(bas, AR933X_UART_CS_REG, reg); uart_barrier(bas); return (0); } static int ar933x_bus_flush(struct uart_softc *sc, int what) { struct uart_bas *bas; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); ar933x_drain(bas, what); uart_unlock(sc->sc_hwmtx); return (0); } static int ar933x_bus_getsig(struct uart_softc *sc) { uint32_t sig = sc->sc_hwsig; /* * For now, let's just return that DSR/DCD/CTS is asserted. */ SIGCHG(1, sig, SER_DSR, SER_DDSR); SIGCHG(1, sig, SER_CTS, SER_DCTS); SIGCHG(1, sig, SER_DCD, SER_DDCD); SIGCHG(1, sig, SER_RI, SER_DRI); sc->sc_hwsig = sig & ~SER_MASK_DELTA; return (sig); } /* * XXX TODO: actually implement the rest of this! */ static int ar933x_bus_ioctl(struct uart_softc *sc, int request, intptr_t data) { int error = 0; /* XXX lock */ switch (request) { case UART_IOCTL_BREAK: case UART_IOCTL_IFLOW: case UART_IOCTL_OFLOW: break; case UART_IOCTL_BAUD: *(int*)data = 115200; break; default: error = EINVAL; break; } /* XXX unlock */ return (error); } /* * Bus interrupt handler. * * For now, system interrupts are disabled. * So this is just called from a callout in uart_core.c * to poll various state. */ static int ar933x_bus_ipend(struct uart_softc *sc) { struct ar933x_softc *u = (struct ar933x_softc *)sc; struct uart_bas *bas = &sc->sc_bas; int ipend = 0; uint32_t isr; uart_lock(sc->sc_hwmtx); /* * Fetch/ACK the ISR status. */ isr = ar933x_getreg(bas, AR933X_UART_INT_REG); ar933x_setreg(bas, AR933X_UART_INT_REG, isr); uart_barrier(bas); /* * RX ready - notify upper layer. */ if (isr & AR933X_UART_INT_RX_VALID) { ipend |= SER_INT_RXREADY; } /* * If we get this interrupt, we should disable * it from the interrupt mask and inform the uart * driver appropriately. * * We can't keep setting SER_INT_TXIDLE or SER_INT_SIGCHG * all the time or IO stops working. So we will always * clear this interrupt if we get it, then we only signal * the upper layer if we were doing active TX in the * first place. * * Also, the name is misleading. This actually means * "the FIFO is almost empty." So if we just write some * more data to the FIFO without checking whether it can * take said data, we'll overflow the thing. * * Unfortunately the FreeBSD uart device has no concept of * partial UART writes - it expects that the whole buffer * is written to the hardware. Thus for now, ar933x_bus_transmit() * will wait for the FIFO to finish draining before it pushes * more frames into it. */ if (isr & AR933X_UART_INT_TX_EMPTY) { /* * Update u_ier to disable TX notifications; update hardware */ u->u_ier &= ~AR933X_UART_INT_TX_EMPTY; ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier); uart_barrier(bas); } /* * Only signal TX idle if we're not busy transmitting. * * XXX I never get _out_ of txbusy? Debug that! */ if (sc->sc_txbusy) { if (isr & AR933X_UART_INT_TX_EMPTY) { ipend |= SER_INT_TXIDLE; } else { ipend |= SER_INT_SIGCHG; } } uart_unlock(sc->sc_hwmtx); return (ipend); } static int ar933x_bus_param(struct uart_softc *sc, int baudrate, int databits, int stopbits, int parity) { struct uart_bas *bas; int error; bas = &sc->sc_bas; uart_lock(sc->sc_hwmtx); error = ar933x_param(bas, baudrate, databits, stopbits, parity); uart_unlock(sc->sc_hwmtx); return (error); } static int ar933x_bus_probe(struct uart_softc *sc) { struct uart_bas *bas; int error; bas = &sc->sc_bas; error = ar933x_probe(bas); if (error) return (error); /* Reset FIFOs. */ ar933x_drain(bas, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER); /* XXX TODO: actually find out what the FIFO depth is! */ sc->sc_rxfifosz = 16; sc->sc_txfifosz = 16; return (0); } static int ar933x_bus_receive(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; int xc; uart_lock(sc->sc_hwmtx); /* Loop over until we are full, or no data is available */ while (ar933x_rxready(bas)) { if (uart_rx_full(sc)) { sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN; break; } /* Read the top of the RX FIFO */ xc = ar933x_getreg(bas, AR933X_UART_DATA_REG) & 0xff; /* Remove that entry from said RX FIFO */ ar933x_setreg(bas, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR); uart_barrier(bas); /* XXX frame, parity error */ uart_rx_put(sc, xc); } /* * XXX TODO: Discard everything left in the Rx FIFO? * XXX only if we've hit an overrun condition? */ uart_unlock(sc->sc_hwmtx); return (0); } static int ar933x_bus_setsig(struct uart_softc *sc, int sig) { #if 0 struct ar933x_softc *ns8250 = (struct ar933x_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) { SIGCHG(sig & SER_DTR, new, SER_DTR, SER_DDTR); } if (sig & SER_DRTS) { SIGCHG(sig & SER_RTS, new, 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); #endif return (0); } /* * Write the current transmit buffer to the TX FIFO. * * Unfortunately the FreeBSD uart device has no concept of * partial UART writes - it expects that the whole buffer * is written to the hardware. Thus for now, this will wait for * the FIFO to finish draining before it pushes more frames into it. * * If non-blocking operation is truely needed here, either * the FreeBSD uart device will need to handle partial writes * in xxx_bus_transmit(), or we'll need to do TX FIFO buffering * of our own here. */ static int ar933x_bus_transmit(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; struct ar933x_softc *u = (struct ar933x_softc *)sc; int i; uart_lock(sc->sc_hwmtx); /* Wait for the FIFO to be clear - see above */ while (ar933x_getreg(bas, AR933X_UART_CS_REG) & AR933X_UART_CS_TX_BUSY) ; /* * Write some data! */ for (i = 0; i < sc->sc_txdatasz; i++) { /* Write the TX data */ ar933x_setreg(bas, AR933X_UART_DATA_REG, (sc->sc_txbuf[i] & 0xff) | AR933X_UART_DATA_TX_CSR); uart_barrier(bas); } /* * Now that we're transmitting, get interrupt notification * when the FIFO is (almost) empty - see above. */ u->u_ier |= AR933X_UART_INT_TX_EMPTY; ar933x_setreg(bas, AR933X_UART_INT_EN_REG, u->u_ier); uart_barrier(bas); /* * Inform the upper layer that we are presently transmitting * data to the hardware; this will be cleared when the * TXIDLE interrupt occurs. */ sc->sc_txbusy = 1; uart_unlock(sc->sc_hwmtx); return (0); } static void ar933x_bus_grab(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; uint32_t reg; /* Disable the host interrupt now */ uart_lock(sc->sc_hwmtx); reg = ar933x_getreg(bas, AR933X_UART_CS_REG); reg &= ~AR933X_UART_CS_HOST_INT_EN; ar933x_setreg(bas, AR933X_UART_CS_REG, reg); uart_unlock(sc->sc_hwmtx); } static void ar933x_bus_ungrab(struct uart_softc *sc) { struct uart_bas *bas = &sc->sc_bas; uint32_t reg; /* Enable the host interrupt now */ uart_lock(sc->sc_hwmtx); reg = ar933x_getreg(bas, AR933X_UART_CS_REG); reg |= AR933X_UART_CS_HOST_INT_EN; ar933x_setreg(bas, AR933X_UART_CS_REG, reg); uart_unlock(sc->sc_hwmtx); }