1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Serial base bus layer for controllers
4 *
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(str: drv->name, prefix: serial_ctrl_type.name))
36 return 1;
37
38 if (dev->type == &serial_port_type &&
39 str_has_prefix(str: drv->name, prefix: 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(drv: driver);
55}
56
57void serial_base_driver_unregister(struct device_driver *driver)
58{
59 driver_unregister(drv: 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, name: "%s:%d", dev_name(dev: port->dev), ctrl_id);
83
84 if (type == &serial_port_type)
85 return dev_set_name(dev, name: "%s:%d.%d", dev_name(dev: 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(objp: 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(dev: &ctrl_dev->dev);
104 put_device(dev: &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(error: -ENOMEM);
116
117 ida_init(ida: &ctrl_dev->port_ida);
118
119 err = serial_base_device_init(port, dev: &ctrl_dev->dev,
120 parent_dev: parent, type: &serial_ctrl_type,
121 release: serial_base_ctrl_release,
122 ctrl_id: port->ctrl_id, port_id: 0);
123 if (err)
124 goto err_put_device;
125
126 err = device_add(dev: &ctrl_dev->dev);
127 if (err)
128 goto err_put_device;
129
130 return ctrl_dev;
131
132err_put_device:
133 put_device(dev: &ctrl_dev->dev);
134
135 return ERR_PTR(error: 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(objp: 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(error: -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(objp: port_dev);
165 return ERR_PTR(error: err);
166 }
167
168 port->port_id = err;
169
170 err = serial_base_device_init(port, dev: &port_dev->dev,
171 parent_dev: &ctrl_dev->dev, type: &serial_port_type,
172 release: serial_base_port_release,
173 ctrl_id: port->ctrl_id, port_id: port->port_id);
174 if (err)
175 goto err_put_device;
176
177 port_dev->port = port;
178
179 err = device_add(dev: &port_dev->dev);
180 if (err)
181 goto err_put_device;
182
183 return port_dev;
184
185err_put_device:
186 put_device(dev: &port_dev->dev);
187 ida_free(&ctrl_dev->port_ida, id: port->port_id);
188
189 return ERR_PTR(error: 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(dev: &port_dev->dev);
204 ida_free(&ctrl_dev->port_ida, id: port_dev->port->port_id);
205 put_device(dev: &port_dev->dev);
206}
207
208#ifdef CONFIG_SERIAL_CORE_CONSOLE
209
210/**
211 * serial_base_match_and_update_preferred_console - Match and update a preferred console
212 * @drv: Serial port device driver
213 * @port: Serial port instance
214 *
215 * Tries to match and update the preferred console for a serial port for
216 * 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, fmt: "%s:%d.%d", dev_name(dev: 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(match: port_match,
234 name: drv->dev_name,
235 idx: port->line);
236 if (ret == -ENOENT)
237 return 0;
238
239 return ret;
240}
241
242#endif
243
244static int serial_base_init(void)
245{
246 int ret;
247
248 ret = bus_register(bus: &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(bus: &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(bus: &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

source code of linux/drivers/tty/serial/serial_base_bus.c