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tegra_rtc.c revision 1.2 
      1 /* $NetBSD: tegra_rtc.c,v 1.2 2015/12/13 17:39:19 jmcneill Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: tegra_rtc.c,v 1.2 2015/12/13 17:39:19 jmcneill Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/device.h>
     35 #include <sys/intr.h>
     36 #include <sys/systm.h>
     37 #include <sys/kernel.h>
     38 #include <sys/kmem.h>
     39 
     40 #include <dev/clock_subr.h>
     41 
     42 #include <arm/nvidia/tegra_reg.h>
     43 #include <arm/nvidia/tegra_rtcreg.h>
     44 #include <arm/nvidia/tegra_var.h>
     45 
     46 #include <dev/fdt/fdtvar.h>
     47 
     48 static int	tegra_rtc_match(device_t, cfdata_t, void *);
     49 static void	tegra_rtc_attach(device_t, device_t, void *);
     50 
     51 struct tegra_rtc_softc {
     52 	device_t		sc_dev;
     53 	bus_space_tag_t		sc_bst;
     54 	bus_space_handle_t	sc_bsh;
     55 
     56 	struct todr_chip_handle	sc_todr;
     57 };
     58 
     59 static int	tegra_rtc_gettime(todr_chip_handle_t, struct timeval *);
     60 static int	tegra_rtc_settime(todr_chip_handle_t, struct timeval *);
     61 
     62 CFATTACH_DECL_NEW(tegra_rtc, sizeof(struct tegra_rtc_softc),
     63 	tegra_rtc_match, tegra_rtc_attach, NULL, NULL);
     64 
     65 #define RTC_READ(sc, reg)	\
     66 	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
     67 #define RTC_WRITE(sc, reg, val)	\
     68 	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
     69 
     70 static int
     71 tegra_rtc_match(device_t parent, cfdata_t cf, void *aux)
     72 {
     73 	const char * const compatible[] = { "nvidia,tegra124-rtc", NULL };
     74 	struct fdt_attach_args * const faa = aux;
     75 
     76 	return of_match_compatible(faa->faa_phandle, compatible);
     77 }
     78 
     79 static void
     80 tegra_rtc_attach(device_t parent, device_t self, void *aux)
     81 {
     82 	struct tegra_rtc_softc * const sc = device_private(self);
     83 	struct fdt_attach_args * const faa = aux;
     84 	bus_addr_t addr;
     85 	bus_size_t size;
     86 	int error;
     87 
     88 	if (fdtbus_get_reg(faa->faa_phandle, 0, &addr, &size) != 0) {
     89 		aprint_error(": couldn't get registers\n");
     90 		return;
     91 	}
     92 
     93 	sc->sc_dev = self;
     94 	sc->sc_bst = faa->faa_bst;
     95 	error = bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh);
     96 	if (error) {
     97 		aprint_error(": couldn't map %#llx: %d", (uint64_t)addr, error);
     98 		return;
     99 	}
    100 
    101 	aprint_naive("\n");
    102 	aprint_normal(": RTC\n");
    103 
    104 	sc->sc_todr.todr_gettime = tegra_rtc_gettime;
    105 	sc->sc_todr.todr_settime = tegra_rtc_settime;
    106 	sc->sc_todr.cookie = sc;
    107 	todr_attach(&sc->sc_todr);
    108 }
    109 
    110 static int
    111 tegra_rtc_gettime(todr_chip_handle_t tch, struct timeval *tv)
    112 {
    113 	struct tegra_rtc_softc * const sc = tch->cookie;
    114 
    115 	tv->tv_sec = RTC_READ(sc, RTC_SECONDS_REG);
    116 	tv->tv_usec = 0;
    117 
    118 	return 0;
    119 }
    120 
    121 static int
    122 tegra_rtc_settime(todr_chip_handle_t tch, struct timeval *tv)
    123 {
    124 	struct tegra_rtc_softc * const sc = tch->cookie;
    125 	int retry = 500;
    126 
    127 	while (--retry > 0) {
    128 		if ((RTC_READ(sc, RTC_BUSY_REG) & RTC_BUSY_STATUS) == 0)
    129 			break;
    130 		delay(1);
    131 	}
    132 	if (retry == 0) {
    133 		device_printf(sc->sc_dev, "RTC write failed (BUSY)\n");
    134 		return ETIMEDOUT;
    135 	}
    136 
    137 	RTC_WRITE(sc, RTC_SECONDS_REG, tv->tv_sec);
    138 
    139 	return 0;
    140 }
    141