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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Serial base bus layer for controllers4 *5 * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/6 * Author: Tony Lindgren <tony@atomide.com>7 *8 * The serial core bus manages the serial core controller instances.9 */10 11#include <linux/cleanup.h>12#include <linux/container_of.h>13#include <linux/device.h>14#include <linux/idr.h>15#include <linux/module.h>16#include <linux/serial_core.h>17#include <linux/slab.h>18#include <linux/spinlock.h>19 20#include "serial_base.h"21 22static bool serial_base_initialized;23 24static const struct device_type serial_ctrl_type = {25 .name = "ctrl",26};27 28static const struct device_type serial_port_type = {29 .name = "port",30};31 32static int serial_base_match(struct device *dev, const struct device_driver *drv)33{34 if (dev->type == &serial_ctrl_type &&35 str_has_prefix(drv->name, serial_ctrl_type.name))36 return 1;37 38 if (dev->type == &serial_port_type &&39 str_has_prefix(drv->name, serial_port_type.name))40 return 1;41 42 return 0;43}44 45static const struct bus_type serial_base_bus_type = {46 .name = "serial-base",47 .match = serial_base_match,48};49 50int serial_base_driver_register(struct device_driver *driver)51{52 driver->bus = &serial_base_bus_type;53 54 return driver_register(driver);55}56 57void serial_base_driver_unregister(struct device_driver *driver)58{59 driver_unregister(driver);60}61 62static int serial_base_device_init(struct uart_port *port,63 struct device *dev,64 struct device *parent_dev,65 const struct device_type *type,66 void (*release)(struct device *dev),67 unsigned int ctrl_id,68 unsigned int port_id)69{70 device_initialize(dev);71 dev->type = type;72 dev->parent = parent_dev;73 dev->bus = &serial_base_bus_type;74 dev->release = release;75 76 if (!serial_base_initialized) {77 dev_dbg(port->dev, "uart_add_one_port() called before arch_initcall()?\n");78 return -EPROBE_DEFER;79 }80 81 if (type == &serial_ctrl_type)82 return dev_set_name(dev, "%s:%d", dev_name(port->dev), ctrl_id);83 84 if (type == &serial_port_type)85 return dev_set_name(dev, "%s:%d.%d", dev_name(port->dev),86 ctrl_id, port_id);87 88 return -EINVAL;89}90 91static void serial_base_ctrl_release(struct device *dev)92{93 struct serial_ctrl_device *ctrl_dev = to_serial_base_ctrl_device(dev);94 95 kfree(ctrl_dev);96}97 98void serial_base_ctrl_device_remove(struct serial_ctrl_device *ctrl_dev)99{100 if (!ctrl_dev)101 return;102 103 device_del(&ctrl_dev->dev);104 put_device(&ctrl_dev->dev);105}106 107struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,108 struct device *parent)109{110 struct serial_ctrl_device *ctrl_dev;111 int err;112 113 ctrl_dev = kzalloc(sizeof(*ctrl_dev), GFP_KERNEL);114 if (!ctrl_dev)115 return ERR_PTR(-ENOMEM);116 117 ida_init(&ctrl_dev->port_ida);118 119 err = serial_base_device_init(port, &ctrl_dev->dev,120 parent, &serial_ctrl_type,121 serial_base_ctrl_release,122 port->ctrl_id, 0);123 if (err)124 goto err_put_device;125 126 err = device_add(&ctrl_dev->dev);127 if (err)128 goto err_put_device;129 130 return ctrl_dev;131 132err_put_device:133 put_device(&ctrl_dev->dev);134 135 return ERR_PTR(err);136}137 138static void serial_base_port_release(struct device *dev)139{140 struct serial_port_device *port_dev = to_serial_base_port_device(dev);141 142 kfree(port_dev);143}144 145struct serial_port_device *serial_base_port_add(struct uart_port *port,146 struct serial_ctrl_device *ctrl_dev)147{148 struct serial_port_device *port_dev;149 int min = 0, max = -1; /* Use -1 for max to apply IDA defaults */150 int err;151 152 port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);153 if (!port_dev)154 return ERR_PTR(-ENOMEM);155 156 /* Device driver specified port_id vs automatic assignment? */157 if (port->port_id) {158 min = port->port_id;159 max = port->port_id;160 }161 162 err = ida_alloc_range(&ctrl_dev->port_ida, min, max, GFP_KERNEL);163 if (err < 0) {164 kfree(port_dev);165 return ERR_PTR(err);166 }167 168 port->port_id = err;169 170 err = serial_base_device_init(port, &port_dev->dev,171 &ctrl_dev->dev, &serial_port_type,172 serial_base_port_release,173 port->ctrl_id, port->port_id);174 if (err)175 goto err_put_device;176 177 port_dev->port = port;178 179 err = device_add(&port_dev->dev);180 if (err)181 goto err_put_device;182 183 return port_dev;184 185err_put_device:186 put_device(&port_dev->dev);187 ida_free(&ctrl_dev->port_ida, port->port_id);188 189 return ERR_PTR(err);190}191 192void serial_base_port_device_remove(struct serial_port_device *port_dev)193{194 struct serial_ctrl_device *ctrl_dev;195 struct device *parent;196 197 if (!port_dev)198 return;199 200 parent = port_dev->dev.parent;201 ctrl_dev = to_serial_base_ctrl_device(parent);202 203 device_del(&port_dev->dev);204 ida_free(&ctrl_dev->port_ida, port_dev->port->port_id);205 put_device(&port_dev->dev);206}207 208#ifdef CONFIG_SERIAL_CORE_CONSOLE209 210/**211 * serial_base_match_and_update_preferred_console - Match and update a preferred console212 * @drv: Serial port device driver213 * @port: Serial port instance214 *215 * Tries to match and update the preferred console for a serial port for216 * the kernel command line option console=DEVNAME:0.0.217 *218 * Cannot be called early for ISA ports, depends on struct device.219 *220 * Return: 0 on success, negative error code on failure.221 */222int serial_base_match_and_update_preferred_console(struct uart_driver *drv,223 struct uart_port *port)224{225 const char *port_match __free(kfree) = NULL;226 int ret;227 228 port_match = kasprintf(GFP_KERNEL, "%s:%d.%d", dev_name(port->dev),229 port->ctrl_id, port->port_id);230 if (!port_match)231 return -ENOMEM;232 233 ret = match_devname_and_update_preferred_console(port_match,234 drv->dev_name,235 port->line);236 if (ret == -ENOENT)237 return 0;238 239 return ret;240}241 242#endif243 244static int serial_base_init(void)245{246 int ret;247 248 ret = bus_register(&serial_base_bus_type);249 if (ret)250 return ret;251 252 ret = serial_base_ctrl_init();253 if (ret)254 goto err_bus_unregister;255 256 ret = serial_base_port_init();257 if (ret)258 goto err_ctrl_exit;259 260 serial_base_initialized = true;261 262 return 0;263 264err_ctrl_exit:265 serial_base_ctrl_exit();266 267err_bus_unregister:268 bus_unregister(&serial_base_bus_type);269 270 return ret;271}272arch_initcall(serial_base_init);273 274static void serial_base_exit(void)275{276 serial_base_port_exit();277 serial_base_ctrl_exit();278 bus_unregister(&serial_base_bus_type);279}280module_exit(serial_base_exit);281 282MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");283MODULE_DESCRIPTION("Serial core bus");284MODULE_LICENSE("GPL");285