2 * Copyright (c) 2018 Diane Bruce
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * Based on uart_dev_pl011.c
28 * Copyright (c) 2012 Semihalf.
29 * All rights reserved.
32 * The mini Uart has the following features:
33 * - 7 or 8 bit operation.
34 * - 1 start and 1 stop bit.
37 * - 8 symbols deep FIFOs for receive and transmit.
38 * - SW controlled RTS, SW readable CTS.
39 * - Auto flow control with programmable FIFO level.
40 * - 16550 like registers.
41 * - Baudrate derived from system clock.
42 * This is a mini UART and it does NOT have the following capabilities:
44 * - Framing errors detection.
46 * - Receive Time-out interrupt
47 * - DCD, DSR, DTR or RI signals.
48 * The implemented UART is not a 16650 compatible UART However as far
49 * as possible the first 8 control and status registers are laid out
50 * like a 16550 UART. All 16550 register bits which are not supported can
51 * be written but will be ignored and read back as 0. All control bits
52 * for simple UART receive/transmit operations are available.
56 #include "opt_platform.h"
58 #include <sys/param.h>
59 #include <sys/systm.h>
60 #include <sys/kernel.h>
63 #include <machine/bus.h>
64 #include <machine/machdep.h>
65 #include <machine/pcpu.h>
67 #include <dev/uart/uart.h>
68 #include <dev/uart/uart_cpu.h>
70 #include <dev/uart/uart_cpu_fdt.h>
71 #include <dev/ofw/ofw_bus.h>
73 #include <dev/uart/uart_bus.h>
76 /* BCM2835 Micro UART registers and masks*/
77 #define AUX_MU_IO_REG 0x00 /* I/O register */
80 * According to errata bits 1 and 2 are swapped,
81 * Also bits 2 and 3 are required to enable interrupts.
83 #define AUX_MU_IER_REG 0x01
84 #define IER_RXENABLE (1)
85 #define IER_TXENABLE (1<<1)
86 #define IER_REQUIRED (3<<2)
87 #define IER_MASK_ALL (IER_TXENABLE|IER_RXENABLE)
89 #define AUX_MU_IIR_REG 0x02
91 #define IIR_TXREADY (1<<1)
92 #define IIR_RXREADY (1<<2)
93 #define IIR_CLEAR (3<<1)
95 #define AUX_MU_LCR_REG 0x03
99 #define AUX_MU_MCR_REG 0x04
100 #define AUX_MCR_RTS (1<<1)
102 #define AUX_MU_LSR_REG 0x05
103 #define LSR_RXREADY (1)
104 #define LSR_OVRRUN (1<<1)
105 #define LSR_TXEMPTY (1<<5)
106 #define LSR_TXIDLE (1<<6)
108 #define AUX_MU_MSR_REG 0x06
109 #define MSR_CTS (1<<5)
111 #define AUX_MU_SCRATCH_REG 0x07
113 #define AUX_MU_CNTL_REG 0x08
114 #define CNTL_RXENAB (1)
115 #define CNTL_TXENAB (1<<1)
117 #define AUX_MU_STAT_REG 0x09
118 #define STAT_TX_SA (1<<1)
119 #define STAT_RX_SA (1)
121 #define AUX_MU_BAUD_REG 0x0a
124 * FIXME: actual register size is SoC-dependent, we need to handle it
126 #define __uart_getreg(bas, reg) \
127 bus_space_read_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg))
128 #define __uart_setreg(bas, reg, value) \
129 bus_space_write_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg), value)
132 * Low-level UART interface.
134 static int uart_mu_probe(struct uart_bas *bas);
135 static void uart_mu_init(struct uart_bas *bas, int, int, int, int);
136 static void uart_mu_term(struct uart_bas *bas);
137 static void uart_mu_putc(struct uart_bas *bas, int);
138 static int uart_mu_rxready(struct uart_bas *bas);
139 static int uart_mu_getc(struct uart_bas *bas, struct mtx *);
141 static struct uart_ops uart_mu_ops = {
142 .probe = uart_mu_probe,
143 .init = uart_mu_init,
144 .term = uart_mu_term,
145 .putc = uart_mu_putc,
146 .rxready = uart_mu_rxready,
147 .getc = uart_mu_getc,
151 uart_mu_probe(struct uart_bas *bas)
158 * According to the docs, the cpu clock is locked to 250Mhz when
159 * the micro-uart is used
161 #define CPU_CLOCK 250000000
164 uart_mu_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
171 * Zero all settings to make sure
172 * UART is disabled and not configured
175 __uart_setreg(bas, AUX_MU_CNTL_REG, line);
177 /* As I know UART is disabled I can setup the line */
189 __uart_setreg(bas, AUX_MU_LCR_REG, line);
191 /* See 2.2.1 BCM2835-ARM-Peripherals baudrate */
193 baud = CPU_CLOCK / (8 * baudrate);
195 * baud = cpu_clock() / (8 * baudrate);
197 __uart_setreg(bas, AUX_MU_BAUD_REG, ((uint32_t)(baud & 0xFFFF)));
201 __uart_setreg(bas, AUX_MU_CNTL_REG, CNTL_RXENAB|CNTL_TXENAB);
205 uart_mu_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
209 /* Mask all interrupts */
210 __uart_setreg(bas, AUX_MU_IER_REG, 0);
211 uart_mu_param(bas, baudrate, databits, stopbits, parity);
215 uart_mu_term(struct uart_bas *bas)
220 uart_mu_putc(struct uart_bas *bas, int c)
223 /* Wait when TX FIFO full. Push character otherwise. */
224 while ((__uart_getreg(bas, AUX_MU_LSR_REG) & LSR_TXEMPTY) == 0)
226 __uart_setreg(bas, AUX_MU_IO_REG, c & 0xff);
230 uart_mu_rxready(struct uart_bas *bas)
233 return ((__uart_getreg(bas, AUX_MU_LSR_REG) & LSR_RXREADY) != 0);
237 uart_mu_getc(struct uart_bas *bas, struct mtx *hwmtx)
241 while(!uart_mu_rxready(bas))
243 c = __uart_getreg(bas, AUX_MU_IO_REG) & 0xff;
248 * High-level UART interface.
250 struct uart_mu_softc {
251 struct uart_softc bas;
252 uint16_t aux_ier; /* Interrupt mask */
255 static int uart_mu_bus_attach(struct uart_softc *);
256 static int uart_mu_bus_detach(struct uart_softc *);
257 static int uart_mu_bus_flush(struct uart_softc *, int);
258 static int uart_mu_bus_getsig(struct uart_softc *);
259 static int uart_mu_bus_ioctl(struct uart_softc *, int, intptr_t);
260 static int uart_mu_bus_ipend(struct uart_softc *);
261 static int uart_mu_bus_param(struct uart_softc *, int, int, int, int);
262 static int uart_mu_bus_probe(struct uart_softc *);
263 static int uart_mu_bus_receive(struct uart_softc *);
264 static int uart_mu_bus_setsig(struct uart_softc *, int);
265 static int uart_mu_bus_transmit(struct uart_softc *);
266 static void uart_mu_bus_grab(struct uart_softc *);
267 static void uart_mu_bus_ungrab(struct uart_softc *);
269 static kobj_method_t uart_mu_methods[] = {
270 KOBJMETHOD(uart_attach, uart_mu_bus_attach),
271 KOBJMETHOD(uart_detach, uart_mu_bus_detach),
272 KOBJMETHOD(uart_flush, uart_mu_bus_flush),
273 KOBJMETHOD(uart_getsig, uart_mu_bus_getsig),
274 KOBJMETHOD(uart_ioctl, uart_mu_bus_ioctl),
275 KOBJMETHOD(uart_ipend, uart_mu_bus_ipend),
276 KOBJMETHOD(uart_param, uart_mu_bus_param),
277 KOBJMETHOD(uart_probe, uart_mu_bus_probe),
278 KOBJMETHOD(uart_receive, uart_mu_bus_receive),
279 KOBJMETHOD(uart_setsig, uart_mu_bus_setsig),
280 KOBJMETHOD(uart_transmit, uart_mu_bus_transmit),
281 KOBJMETHOD(uart_grab, uart_mu_bus_grab),
282 KOBJMETHOD(uart_ungrab, uart_mu_bus_ungrab),
286 static struct uart_class uart_mu_class = {
289 sizeof(struct uart_mu_softc),
290 .uc_ops = &uart_mu_ops,
297 static struct ofw_compat_data fdt_compat_data[] = {
298 {"brcm,bcm2835-aux-uart" , (uintptr_t)&uart_mu_class},
299 {NULL, (uintptr_t)NULL},
301 UART_FDT_CLASS_AND_DEVICE(fdt_compat_data);
305 uart_mu_bus_attach(struct uart_softc *sc)
307 struct uart_mu_softc *psc;
308 struct uart_bas *bas;
310 psc = (struct uart_mu_softc *)sc;
312 /* Clear interrupts */
313 __uart_setreg(bas, AUX_MU_IIR_REG, IIR_CLEAR);
314 /* Enable interrupts */
315 psc->aux_ier = (IER_RXENABLE|IER_TXENABLE|IER_REQUIRED);
316 __uart_setreg(bas, AUX_MU_IER_REG, psc->aux_ier);
323 uart_mu_bus_detach(struct uart_softc *sc)
330 uart_mu_bus_flush(struct uart_softc *sc, int what)
337 uart_mu_bus_getsig(struct uart_softc *sc)
344 uart_mu_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
349 uart_lock(sc->sc_hwmtx);
351 case UART_IOCTL_BREAK:
353 case UART_IOCTL_BAUD:
354 *(int*)data = 115200;
360 uart_unlock(sc->sc_hwmtx);
366 uart_mu_bus_ipend(struct uart_softc *sc)
368 struct uart_mu_softc *psc;
369 struct uart_bas *bas;
373 psc = (struct uart_mu_softc *)sc;
376 uart_lock(sc->sc_hwmtx);
377 ints = __uart_getreg(bas, AUX_MU_IIR_REG);
381 * According to docs only one of IIR_RXREADY
382 * or IIR_TXREADY are valid eg. Only one or the other.
384 if (ints & IIR_RXREADY) {
385 ipend |= SER_INT_RXREADY;
386 } else if (ints & IIR_TXREADY) {
387 if (__uart_getreg(bas, AUX_MU_LSR_REG) & LSR_TXIDLE) {
389 ipend |= SER_INT_TXIDLE;
391 /* Disable TX interrupt */
392 __uart_setreg(bas, AUX_MU_IER_REG,
393 psc->aux_ier & ~IER_TXENABLE);
397 uart_unlock(sc->sc_hwmtx);
403 uart_mu_bus_param(struct uart_softc *sc, int baudrate, int databits,
404 int stopbits, int parity)
407 uart_lock(sc->sc_hwmtx);
408 uart_mu_param(&sc->sc_bas, baudrate, databits, stopbits, parity);
409 uart_unlock(sc->sc_hwmtx);
415 uart_mu_bus_probe(struct uart_softc *sc)
418 /* MU always has 8 byte deep fifo */
421 device_set_desc(sc->sc_dev, "BCM2835 Mini-UART");
427 uart_mu_bus_receive(struct uart_softc *sc)
429 struct uart_bas *bas;
434 uart_lock(sc->sc_hwmtx);
436 lsr = __uart_getreg(bas, AUX_MU_LSR_REG);
437 while (lsr & LSR_RXREADY) {
438 xc = __uart_getreg(bas, AUX_MU_IO_REG);
440 if (uart_rx_full(sc)) {
441 sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
445 lsr = __uart_getreg(bas, AUX_MU_LSR_REG);
447 uart_unlock(sc->sc_hwmtx);
453 uart_mu_bus_setsig(struct uart_softc *sc, int sig)
460 uart_mu_bus_transmit(struct uart_softc *sc)
462 struct uart_mu_softc *psc;
463 struct uart_bas *bas;
466 psc = (struct uart_mu_softc *)sc;
468 uart_lock(sc->sc_hwmtx);
470 for (i = 0; i < sc->sc_txdatasz; i++) {
471 __uart_setreg(bas, AUX_MU_IO_REG, sc->sc_txbuf[i] & 0xff);
475 /* Mark busy and enable TX interrupt */
477 __uart_setreg(bas, AUX_MU_IER_REG, psc->aux_ier);
479 uart_unlock(sc->sc_hwmtx);
485 uart_mu_bus_grab(struct uart_softc *sc)
487 struct uart_mu_softc *psc;
488 struct uart_bas *bas;
490 psc = (struct uart_mu_softc *)sc;
493 /* Disable interrupts on switch to polling */
494 uart_lock(sc->sc_hwmtx);
495 __uart_setreg(bas, AUX_MU_IER_REG, psc->aux_ier &~IER_MASK_ALL);
496 uart_unlock(sc->sc_hwmtx);
500 uart_mu_bus_ungrab(struct uart_softc *sc)
502 struct uart_mu_softc *psc;
503 struct uart_bas *bas;
505 psc = (struct uart_mu_softc *)sc;
508 /* Switch to using interrupts while not grabbed */
509 uart_lock(sc->sc_hwmtx);
510 __uart_setreg(bas, AUX_MU_CNTL_REG, CNTL_RXENAB|CNTL_TXENAB);
511 __uart_setreg(bas, AUX_MU_IER_REG, psc->aux_ier);
512 uart_unlock(sc->sc_hwmtx);