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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Serial core port device driver
4 *
5 * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
6 * Author: Tony Lindgren <tony@atomide.com>
7 */
8
9#include <linux/device.h>
10#include <linux/module.h>
11#include <linux/pm_runtime.h>
12#include <linux/serial_core.h>
13#include <linux/spinlock.h>
14
15#include "serial_base.h"
16
17#define SERIAL_PORT_AUTOSUSPEND_DELAY_MS 500
18
19/* Only considers pending TX for now. Caller must take care of locking */
20static int __serial_port_busy(struct uart_port *port)
21{
22 return !uart_tx_stopped(port) &&
23 uart_circ_chars_pending(&port->state->xmit);
24}
25
26static int serial_port_runtime_resume(struct device *dev)
27{
28 struct serial_port_device *port_dev = to_serial_base_port_device(dev);
29 struct uart_port *port;
30 unsigned long flags;
31
32 port = port_dev->port;
33
34 if (port->flags & UPF_DEAD)
35 goto out;
36
37 /* Flush any pending TX for the port */
38 uart_port_lock_irqsave(port, &flags);
39 if (__serial_port_busy(port))
40 port->ops->start_tx(port);
41 uart_port_unlock_irqrestore(port, flags);
42
43out:
44 pm_runtime_mark_last_busy(dev);
45
46 return 0;
47}
48
49static int serial_port_runtime_suspend(struct device *dev)
50{
51 struct serial_port_device *port_dev = to_serial_base_port_device(dev);
52 struct uart_port *port = port_dev->port;
53 unsigned long flags;
54 bool busy;
55
56 if (port->flags & UPF_DEAD)
57 return 0;
58
59 uart_port_lock_irqsave(port, &flags);
60 busy = __serial_port_busy(port);
61 if (busy)
62 port->ops->start_tx(port);
63 uart_port_unlock_irqrestore(port, flags);
64
65 if (busy)
66 pm_runtime_mark_last_busy(dev);
67
68 return busy ? -EBUSY : 0;
69}
70
71static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm,
72 serial_port_runtime_suspend,
73 serial_port_runtime_resume, NULL);
74
75static int serial_port_probe(struct device *dev)
76{
77 pm_runtime_enable(dev);
78 pm_runtime_set_autosuspend_delay(dev, SERIAL_PORT_AUTOSUSPEND_DELAY_MS);
79 pm_runtime_use_autosuspend(dev);
80
81 return 0;
82}
83
84static int serial_port_remove(struct device *dev)
85{
86 pm_runtime_dont_use_autosuspend(dev);
87 pm_runtime_disable(dev);
88
89 return 0;
90}
91
92/*
93 * Serial core port device init functions. Note that the physical serial
94 * port device driver may not have completed probe at this point.
95 */
96int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
97{
98 return serial_ctrl_register_port(drv, port);
99}
100EXPORT_SYMBOL(uart_add_one_port);
101
102void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
103{
104 serial_ctrl_unregister_port(drv, port);
105}
106EXPORT_SYMBOL(uart_remove_one_port);
107
108static struct device_driver serial_port_driver = {
109 .name = "port",
110 .suppress_bind_attrs = true,
111 .probe = serial_port_probe,
112 .remove = serial_port_remove,
113 .pm = pm_ptr(&serial_port_pm),
114};
115
116int serial_base_port_init(void)
117{
118 return serial_base_driver_register(&serial_port_driver);
119}
120
121void serial_base_port_exit(void)
122{
123 serial_base_driver_unregister(&serial_port_driver);
124}
125
126MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
127MODULE_DESCRIPTION("Serial controller port driver");
128MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Serial core port device driver
4 *
5 * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
6 * Author: Tony Lindgren <tony@atomide.com>
7 */
8
9#include <linux/device.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/pm_runtime.h>
14#include <linux/property.h>
15#include <linux/serial_core.h>
16#include <linux/spinlock.h>
17
18#include "serial_base.h"
19
20#define SERIAL_PORT_AUTOSUSPEND_DELAY_MS 500
21
22/* Only considers pending TX for now. Caller must take care of locking */
23static int __serial_port_busy(struct uart_port *port)
24{
25 return !uart_tx_stopped(port) &&
26 uart_circ_chars_pending(&port->state->xmit);
27}
28
29static int serial_port_runtime_resume(struct device *dev)
30{
31 struct serial_port_device *port_dev = to_serial_base_port_device(dev);
32 struct uart_port *port;
33 unsigned long flags;
34
35 port = port_dev->port;
36
37 if (port->flags & UPF_DEAD)
38 goto out;
39
40 /* Flush any pending TX for the port */
41 uart_port_lock_irqsave(port, &flags);
42 if (!port_dev->tx_enabled)
43 goto unlock;
44 if (__serial_port_busy(port))
45 port->ops->start_tx(port);
46
47unlock:
48 uart_port_unlock_irqrestore(port, flags);
49
50out:
51 pm_runtime_mark_last_busy(dev);
52
53 return 0;
54}
55
56static int serial_port_runtime_suspend(struct device *dev)
57{
58 struct serial_port_device *port_dev = to_serial_base_port_device(dev);
59 struct uart_port *port = port_dev->port;
60 unsigned long flags;
61 bool busy;
62
63 if (port->flags & UPF_DEAD)
64 return 0;
65
66 uart_port_lock_irqsave(port, &flags);
67 if (!port_dev->tx_enabled) {
68 uart_port_unlock_irqrestore(port, flags);
69 return 0;
70 }
71
72 busy = __serial_port_busy(port);
73 if (busy)
74 port->ops->start_tx(port);
75 uart_port_unlock_irqrestore(port, flags);
76
77 if (busy)
78 pm_runtime_mark_last_busy(dev);
79
80 return busy ? -EBUSY : 0;
81}
82
83static void serial_base_port_set_tx(struct uart_port *port,
84 struct serial_port_device *port_dev,
85 bool enabled)
86{
87 unsigned long flags;
88
89 uart_port_lock_irqsave(port, &flags);
90 port_dev->tx_enabled = enabled;
91 uart_port_unlock_irqrestore(port, flags);
92}
93
94void serial_base_port_startup(struct uart_port *port)
95{
96 struct serial_port_device *port_dev = port->port_dev;
97
98 serial_base_port_set_tx(port, port_dev, true);
99}
100
101void serial_base_port_shutdown(struct uart_port *port)
102{
103 struct serial_port_device *port_dev = port->port_dev;
104
105 serial_base_port_set_tx(port, port_dev, false);
106}
107
108static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm,
109 serial_port_runtime_suspend,
110 serial_port_runtime_resume, NULL);
111
112static int serial_port_probe(struct device *dev)
113{
114 pm_runtime_enable(dev);
115 pm_runtime_set_autosuspend_delay(dev, SERIAL_PORT_AUTOSUSPEND_DELAY_MS);
116 pm_runtime_use_autosuspend(dev);
117
118 return 0;
119}
120
121static int serial_port_remove(struct device *dev)
122{
123 pm_runtime_dont_use_autosuspend(dev);
124 pm_runtime_disable(dev);
125
126 return 0;
127}
128
129/*
130 * Serial core port device init functions. Note that the physical serial
131 * port device driver may not have completed probe at this point.
132 */
133int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
134{
135 return serial_ctrl_register_port(drv, port);
136}
137EXPORT_SYMBOL(uart_add_one_port);
138
139void uart_remove_one_port(struct uart_driver *drv, struct uart_port *port)
140{
141 serial_ctrl_unregister_port(drv, port);
142}
143EXPORT_SYMBOL(uart_remove_one_port);
144
145/**
146 * __uart_read_properties - read firmware properties of the given UART port
147 * @port: corresponding port
148 * @use_defaults: apply defaults (when %true) or validate the values (when %false)
149 *
150 * The following device properties are supported:
151 * - clock-frequency (optional)
152 * - fifo-size (optional)
153 * - no-loopback-test (optional)
154 * - reg-shift (defaults may apply)
155 * - reg-offset (value may be validated)
156 * - reg-io-width (defaults may apply or value may be validated)
157 * - interrupts (OF only)
158 * - serial [alias ID] (OF only)
159 *
160 * If the port->dev is of struct platform_device type the interrupt line
161 * will be retrieved via platform_get_irq() call against that device.
162 * Otherwise it will be assigned by fwnode_irq_get() call. In both cases
163 * the index 0 of the resource is used.
164 *
165 * The caller is responsible to initialize the following fields of the @port
166 * ->dev (must be valid)
167 * ->flags
168 * ->mapbase
169 * ->mapsize
170 * ->regshift (if @use_defaults is false)
171 * before calling this function. Alternatively the above mentioned fields
172 * may be zeroed, in such case the only ones, that have associated properties
173 * found, will be set to the respective values.
174 *
175 * If no error happened, the ->irq, ->mapbase, ->mapsize will be altered.
176 * The ->iotype is always altered.
177 *
178 * When @use_defaults is true and the respective property is not found
179 * the following values will be applied:
180 * ->regshift = 0
181 * In this case IRQ must be provided, otherwise an error will be returned.
182 *
183 * When @use_defaults is false and the respective property is found
184 * the following values will be validated:
185 * - reg-io-width (->iotype)
186 * - reg-offset (->mapsize against ->mapbase)
187 *
188 * Returns: 0 on success or negative errno on failure
189 */
190static int __uart_read_properties(struct uart_port *port, bool use_defaults)
191{
192 struct device *dev = port->dev;
193 u32 value;
194 int ret;
195
196 /* Read optional UART functional clock frequency */
197 device_property_read_u32(dev, "clock-frequency", &port->uartclk);
198
199 /* Read the registers alignment (default: 8-bit) */
200 ret = device_property_read_u32(dev, "reg-shift", &value);
201 if (ret)
202 port->regshift = use_defaults ? 0 : port->regshift;
203 else
204 port->regshift = value;
205
206 /* Read the registers I/O access type (default: MMIO 8-bit) */
207 ret = device_property_read_u32(dev, "reg-io-width", &value);
208 if (ret) {
209 port->iotype = UPIO_MEM;
210 } else {
211 switch (value) {
212 case 1:
213 port->iotype = UPIO_MEM;
214 break;
215 case 2:
216 port->iotype = UPIO_MEM16;
217 break;
218 case 4:
219 port->iotype = device_is_big_endian(dev) ? UPIO_MEM32BE : UPIO_MEM32;
220 break;
221 default:
222 if (!use_defaults) {
223 dev_err(dev, "Unsupported reg-io-width (%u)\n", value);
224 return -EINVAL;
225 }
226 port->iotype = UPIO_UNKNOWN;
227 break;
228 }
229 }
230
231 /* Read the address mapping base offset (default: no offset) */
232 ret = device_property_read_u32(dev, "reg-offset", &value);
233 if (ret)
234 value = 0;
235
236 /* Check for shifted address mapping overflow */
237 if (!use_defaults && port->mapsize < value) {
238 dev_err(dev, "reg-offset %u exceeds region size %pa\n", value, &port->mapsize);
239 return -EINVAL;
240 }
241
242 port->mapbase += value;
243 port->mapsize -= value;
244
245 /* Read optional FIFO size */
246 device_property_read_u32(dev, "fifo-size", &port->fifosize);
247
248 if (device_property_read_bool(dev, "no-loopback-test"))
249 port->flags |= UPF_SKIP_TEST;
250
251 /* Get index of serial line, if found in DT aliases */
252 ret = of_alias_get_id(dev_of_node(dev), "serial");
253 if (ret >= 0)
254 port->line = ret;
255
256 if (dev_is_platform(dev))
257 ret = platform_get_irq(to_platform_device(dev), 0);
258 else
259 ret = fwnode_irq_get(dev_fwnode(dev), 0);
260 if (ret == -EPROBE_DEFER)
261 return ret;
262 if (ret > 0)
263 port->irq = ret;
264 else if (use_defaults)
265 /* By default IRQ support is mandatory */
266 return ret;
267 else
268 port->irq = 0;
269
270 port->flags |= UPF_SHARE_IRQ;
271
272 return 0;
273}
274
275int uart_read_port_properties(struct uart_port *port)
276{
277 return __uart_read_properties(port, true);
278}
279EXPORT_SYMBOL_GPL(uart_read_port_properties);
280
281int uart_read_and_validate_port_properties(struct uart_port *port)
282{
283 return __uart_read_properties(port, false);
284}
285EXPORT_SYMBOL_GPL(uart_read_and_validate_port_properties);
286
287static struct device_driver serial_port_driver = {
288 .name = "port",
289 .suppress_bind_attrs = true,
290 .probe = serial_port_probe,
291 .remove = serial_port_remove,
292 .pm = pm_ptr(&serial_port_pm),
293};
294
295int serial_base_port_init(void)
296{
297 return serial_base_driver_register(&serial_port_driver);
298}
299
300void serial_base_port_exit(void)
301{
302 serial_base_driver_unregister(&serial_port_driver);
303}
304
305MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
306MODULE_DESCRIPTION("Serial controller port driver");
307MODULE_LICENSE("GPL");