Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/arm/nvidia/tegra_uart.c
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1 /*- 2 * Copyright (c) 2016 Michal Meloun <mmel@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 /* 31 * UART driver for Tegra SoCs. 32 */ 33 #include "opt_platform.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/bus.h> 38 #include <sys/conf.h> 39 #include <sys/kernel.h> 40 #include <sys/module.h> 41 #include <sys/sysctl.h> 42 #include <machine/bus.h> 43 44 #include <dev/extres/clk/clk.h> 45 #include <dev/extres/hwreset/hwreset.h> 46 #include <dev/ofw/ofw_bus.h> 47 #include <dev/ofw/ofw_bus_subr.h> 48 #include <dev/uart/uart.h> 49 #include <dev/uart/uart_cpu.h> 50 #include <dev/uart/uart_cpu_fdt.h> 51 #include <dev/uart/uart_bus.h> 52 #include <dev/uart/uart_dev_ns8250.h> 53 #include <dev/ic/ns16550.h> 54 55 #include "uart_if.h" 56 57 /* 58 * High-level UART interface. 59 */ 60 struct tegra_softc { 61 struct ns8250_softc ns8250_base; 62 clk_t clk; 63 hwreset_t reset; 64 }; 65 66 /* 67 * UART class interface. 68 */ 69 static int 70 tegra_uart_attach(struct uart_softc *sc) 71 { 72 int rv; 73 struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; 74 struct uart_bas *bas = &sc->sc_bas; 75 76 rv = ns8250_bus_attach(sc); 77 if (rv != 0) 78 return (rv); 79 80 ns8250->ier_rxbits = 0x1d; 81 ns8250->ier_mask = 0xc0; 82 ns8250->ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask; 83 ns8250->ier |= ns8250->ier_rxbits; 84 uart_setreg(bas, REG_IER, ns8250->ier); 85 uart_barrier(bas); 86 return (0); 87 } 88 89 static void 90 tegra_uart_grab(struct uart_softc *sc) 91 { 92 struct uart_bas *bas = &sc->sc_bas; 93 struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; 94 u_char ier; 95 96 /* 97 * turn off all interrupts to enter polling mode. Leave the 98 * saved mask alone. We'll restore whatever it was in ungrab. 99 * All pending interrupt signals are reset when IER is set to 0. 100 */ 101 uart_lock(sc->sc_hwmtx); 102 ier = uart_getreg(bas, REG_IER); 103 uart_setreg(bas, REG_IER, ier & ns8250->ier_mask); 104 105 while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0) 106 ; 107 108 uart_setreg(bas, REG_FCR, 0); 109 uart_barrier(bas); 110 uart_unlock(sc->sc_hwmtx); 111 } 112 113 static void 114 tegra_uart_ungrab(struct uart_softc *sc) 115 { 116 struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc; 117 struct uart_bas *bas = &sc->sc_bas; 118 119 /* 120 * Restore previous interrupt mask 121 */ 122 uart_lock(sc->sc_hwmtx); 123 uart_setreg(bas, REG_FCR, ns8250->fcr); 124 uart_setreg(bas, REG_IER, ns8250->ier); 125 uart_barrier(bas); 126 uart_unlock(sc->sc_hwmtx); 127 } 128 129 static kobj_method_t tegra_methods[] = { 130 KOBJMETHOD(uart_probe, ns8250_bus_probe), 131 KOBJMETHOD(uart_attach, tegra_uart_attach), 132 KOBJMETHOD(uart_detach, ns8250_bus_detach), 133 KOBJMETHOD(uart_flush, ns8250_bus_flush), 134 KOBJMETHOD(uart_getsig, ns8250_bus_getsig), 135 KOBJMETHOD(uart_ioctl, ns8250_bus_ioctl), 136 KOBJMETHOD(uart_ipend, ns8250_bus_ipend), 137 KOBJMETHOD(uart_param, ns8250_bus_param), 138 KOBJMETHOD(uart_receive, ns8250_bus_receive), 139 KOBJMETHOD(uart_setsig, ns8250_bus_setsig), 140 KOBJMETHOD(uart_transmit, ns8250_bus_transmit), 141 KOBJMETHOD(uart_grab, tegra_uart_grab), 142 KOBJMETHOD(uart_ungrab, tegra_uart_ungrab), 143 KOBJMETHOD_END 144 }; 145 146 static struct uart_class tegra_uart_class = { 147 "tegra class", 148 tegra_methods, 149 sizeof(struct tegra_softc), 150 .uc_ops = &uart_ns8250_ops, 151 .uc_range = 8, 152 .uc_rclk = 0, 153 }; 154 155 /* Compatible devices. */ 156 static struct ofw_compat_data compat_data[] = { 157 {"nvidia,tegra124-uart", (uintptr_t)&tegra_uart_class}, 158 {"nvidia,tegra210-uart", (uintptr_t)&tegra_uart_class}, 159 {NULL, (uintptr_t)NULL}, 160 }; 161 162 UART_FDT_CLASS(compat_data); 163 164 /* 165 * UART Driver interface. 166 */ 167 static int 168 uart_fdt_get_shift1(phandle_t node) 169 { 170 pcell_t shift; 171 172 if ((OF_getencprop(node, "reg-shift", &shift, sizeof(shift))) <= 0) 173 shift = 2; 174 return ((int)shift); 175 } 176 177 static int 178 tegra_uart_probe(device_t dev) 179 { 180 struct tegra_softc *sc; 181 phandle_t node; 182 uint64_t freq; 183 int shift; 184 int rv; 185 const struct ofw_compat_data *cd; 186 187 sc = device_get_softc(dev); 188 if (!ofw_bus_status_okay(dev)) 189 return (ENXIO); 190 cd = ofw_bus_search_compatible(dev, compat_data); 191 if (cd->ocd_data == 0) 192 return (ENXIO); 193 sc->ns8250_base.base.sc_class = (struct uart_class *)cd->ocd_data; 194 rv = hwreset_get_by_ofw_name(dev, 0, "serial", &sc->reset); 195 if (rv != 0) { 196 device_printf(dev, "Cannot get 'serial' reset\n"); 197 return (ENXIO); 198 } 199 rv = hwreset_deassert(sc->reset); 200 if (rv != 0) { 201 device_printf(dev, "Cannot unreset 'serial' reset\n"); 202 return (ENXIO); 203 } 204 node = ofw_bus_get_node(dev); 205 shift = uart_fdt_get_shift1(node); 206 rv = clk_get_by_ofw_index(dev, 0, 0, &sc->clk); 207 if (rv != 0) { 208 device_printf(dev, "Cannot get UART clock: %d\n", rv); 209 return (ENXIO); 210 } 211 rv = clk_enable(sc->clk); 212 if (rv != 0) { 213 device_printf(dev, "Cannot enable UART clock: %d\n", rv); 214 return (ENXIO); 215 } 216 rv = clk_get_freq(sc->clk, &freq); 217 if (rv != 0) { 218 device_printf(dev, "Cannot enable UART clock: %d\n", rv); 219 return (ENXIO); 220 } 221 return (uart_bus_probe(dev, shift, 0, (int)freq, 0, 0, 0)); 222 } 223 224 static int 225 tegra_uart_detach(device_t dev) 226 { 227 struct tegra_softc *sc; 228 229 sc = device_get_softc(dev); 230 if (sc->clk != NULL) { 231 clk_release(sc->clk); 232 } 233 234 return (uart_bus_detach(dev)); 235 } 236 237 static device_method_t tegra_uart_bus_methods[] = { 238 /* Device interface */ 239 DEVMETHOD(device_probe, tegra_uart_probe), 240 DEVMETHOD(device_attach, uart_bus_attach), 241 DEVMETHOD(device_detach, tegra_uart_detach), 242 { 0, 0 } 243 }; 244 245 static driver_t tegra_uart_driver = { 246 uart_driver_name, 247 tegra_uart_bus_methods, 248 sizeof(struct tegra_softc), 249 }; 250 251 DRIVER_MODULE(tegra_uart, simplebus, tegra_uart_driver, uart_devclass, 252 0, 0);
Cache object: 1a78d109edb3ca403af460e636cc7da2
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