1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Serial Port driver for Open Firmware platform devices
4 *
5 * Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
6 */
7
8#include <linux/bits.h>
9#include <linux/console.h>
10#include <linux/math.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/serial_core.h>
14#include <linux/serial_reg.h>
15#include <linux/of_address.h>
16#include <linux/of_irq.h>
17#include <linux/of_platform.h>
18#include <linux/pm_runtime.h>
19#include <linux/clk.h>
20#include <linux/reset.h>
21
22#include "8250.h"
23
24struct of_serial_info {
25 struct clk *clk;
26 struct reset_control *rst;
27 int type;
28 int line;
29};
30
31/* Nuvoton NPCM timeout register */
32#define UART_NPCM_TOR 7
33#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
34
35static int npcm_startup(struct uart_port *port)
36{
37 /*
38 * Nuvoton calls the scratch register 'UART_TOR' (timeout
39 * register). Enable it, and set TIOC (timeout interrupt
40 * comparator) to be 0x20 for correct operation.
41 */
42 serial_port_out(up: port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
43
44 return serial8250_do_startup(port);
45}
46
47/* Nuvoton NPCM UARTs have a custom divisor calculation */
48static unsigned int npcm_get_divisor(struct uart_port *port, unsigned int baud,
49 unsigned int *frac)
50{
51 return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
52}
53
54static int npcm_setup(struct uart_port *port)
55{
56 port->get_divisor = npcm_get_divisor;
57 port->startup = npcm_startup;
58 return 0;
59}
60
61/*
62 * Fill a struct uart_port for a given device node
63 */
64static int of_platform_serial_setup(struct platform_device *ofdev,
65 int type, struct uart_8250_port *up,
66 struct of_serial_info *info)
67{
68 struct resource resource;
69 struct device *dev = &ofdev->dev;
70 struct device_node *np = dev->of_node;
71 struct uart_port *port = &up->port;
72 u32 spd;
73 int ret;
74
75 memset(port, 0, sizeof *port);
76
77 pm_runtime_enable(dev: &ofdev->dev);
78 pm_runtime_get_sync(dev: &ofdev->dev);
79
80 ret = of_address_to_resource(dev: np, index: 0, r: &resource);
81 if (ret) {
82 dev_err_probe(dev, err: ret, fmt: "invalid address\n");
83 goto err_pmruntime;
84 }
85
86 port->dev = &ofdev->dev;
87 port->flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE;
88 spin_lock_init(&port->lock);
89
90 if (resource_type(res: &resource) == IORESOURCE_IO) {
91 port->iotype = UPIO_PORT;
92 port->iobase = resource.start;
93 } else {
94 port->mapbase = resource.start;
95 port->mapsize = resource_size(res: &resource);
96 port->flags |= UPF_IOREMAP;
97 }
98
99 ret = uart_read_and_validate_port_properties(port);
100 if (ret)
101 goto err_pmruntime;
102
103 /* Get clk rate through clk driver if present */
104 if (!port->uartclk) {
105 info->clk = devm_clk_get_enabled(dev, NULL);
106 if (IS_ERR(ptr: info->clk)) {
107 ret = dev_err_probe(dev, err: PTR_ERR(ptr: info->clk), fmt: "failed to get clock\n");
108 goto err_pmruntime;
109 }
110
111 port->uartclk = clk_get_rate(clk: info->clk);
112 }
113 /* If current-speed was set, then try not to change it. */
114 if (of_property_read_u32(np, propname: "current-speed", out_value: &spd) == 0)
115 port->custom_divisor = port->uartclk / (16 * spd);
116
117 /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
118 if (of_device_is_compatible(device: np, "mrvl,mmp-uart"))
119 port->regshift = 2;
120
121 info->rst = devm_reset_control_get_optional_shared(dev: &ofdev->dev, NULL);
122 if (IS_ERR(ptr: info->rst)) {
123 ret = PTR_ERR(ptr: info->rst);
124 goto err_pmruntime;
125 }
126
127 ret = reset_control_deassert(rstc: info->rst);
128 if (ret)
129 goto err_pmruntime;
130
131 port->type = type;
132 port->rs485_config = serial8250_em485_config;
133 port->rs485_supported = serial8250_em485_supported;
134 up->rs485_start_tx = serial8250_em485_start_tx;
135 up->rs485_stop_tx = serial8250_em485_stop_tx;
136
137 switch (type) {
138 case PORT_RT2880:
139 ret = rt288x_setup(p: port);
140 break;
141 case PORT_NPCM:
142 ret = npcm_setup(port);
143 break;
144 default:
145 /* Nothing to do */
146 ret = 0;
147 break;
148 }
149 if (ret)
150 goto err_pmruntime;
151
152 if (IS_REACHABLE(CONFIG_SERIAL_8250_FSL) &&
153 (of_device_is_compatible(device: np, "fsl,ns16550") ||
154 of_device_is_compatible(device: np, "fsl,16550-FIFO64"))) {
155 port->handle_irq = fsl8250_handle_irq;
156 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
157 }
158
159 return 0;
160err_pmruntime:
161 pm_runtime_put_sync(dev: &ofdev->dev);
162 pm_runtime_disable(dev: &ofdev->dev);
163 return ret;
164}
165
166/*
167 * Try to register a serial port
168 */
169static int of_platform_serial_probe(struct platform_device *ofdev)
170{
171 struct of_serial_info *info;
172 struct uart_8250_port port8250;
173 unsigned int port_type;
174 u32 tx_threshold;
175 int ret;
176
177 if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) &&
178 of_device_is_compatible(device: ofdev->dev.of_node, "brcm,bcm7271-uart"))
179 return -ENODEV;
180
181 port_type = (unsigned long)of_device_get_match_data(dev: &ofdev->dev);
182 if (port_type == PORT_UNKNOWN)
183 return -EINVAL;
184
185 if (of_property_read_bool(np: ofdev->dev.of_node, propname: "used-by-rtas"))
186 return -EBUSY;
187
188 info = kzalloc(size: sizeof(*info), GFP_KERNEL);
189 if (info == NULL)
190 return -ENOMEM;
191
192 memset(&port8250, 0, sizeof(port8250));
193 ret = of_platform_serial_setup(ofdev, type: port_type, up: &port8250, info);
194 if (ret)
195 goto err_free;
196
197 if (port8250.port.fifosize)
198 port8250.capabilities = UART_CAP_FIFO;
199
200 /* Check for TX FIFO threshold & set tx_loadsz */
201 if ((of_property_read_u32(np: ofdev->dev.of_node, propname: "tx-threshold",
202 out_value: &tx_threshold) == 0) &&
203 (tx_threshold < port8250.port.fifosize))
204 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
205
206 if (of_property_read_bool(np: ofdev->dev.of_node, propname: "auto-flow-control"))
207 port8250.capabilities |= UART_CAP_AFE;
208
209 if (of_property_read_u32(np: ofdev->dev.of_node,
210 propname: "overrun-throttle-ms",
211 out_value: &port8250.overrun_backoff_time_ms) != 0)
212 port8250.overrun_backoff_time_ms = 0;
213
214 ret = serial8250_register_8250_port(&port8250);
215 if (ret < 0)
216 goto err_dispose;
217
218 info->type = port_type;
219 info->line = ret;
220 platform_set_drvdata(pdev: ofdev, data: info);
221 return 0;
222err_dispose:
223 pm_runtime_put_sync(dev: &ofdev->dev);
224 pm_runtime_disable(dev: &ofdev->dev);
225err_free:
226 kfree(objp: info);
227 return ret;
228}
229
230/*
231 * Release a line
232 */
233static void of_platform_serial_remove(struct platform_device *ofdev)
234{
235 struct of_serial_info *info = platform_get_drvdata(pdev: ofdev);
236
237 serial8250_unregister_port(line: info->line);
238
239 reset_control_assert(rstc: info->rst);
240 pm_runtime_put_sync(dev: &ofdev->dev);
241 pm_runtime_disable(dev: &ofdev->dev);
242 kfree(objp: info);
243}
244
245#ifdef CONFIG_PM_SLEEP
246static int of_serial_suspend(struct device *dev)
247{
248 struct of_serial_info *info = dev_get_drvdata(dev);
249 struct uart_8250_port *port8250 = serial8250_get_port(line: info->line);
250 struct uart_port *port = &port8250->port;
251
252 serial8250_suspend_port(line: info->line);
253
254 if (!uart_console(port) || console_suspend_enabled) {
255 pm_runtime_put_sync(dev);
256 clk_disable_unprepare(clk: info->clk);
257 }
258 return 0;
259}
260
261static int of_serial_resume(struct device *dev)
262{
263 struct of_serial_info *info = dev_get_drvdata(dev);
264 struct uart_8250_port *port8250 = serial8250_get_port(line: info->line);
265 struct uart_port *port = &port8250->port;
266
267 if (!uart_console(port) || console_suspend_enabled) {
268 pm_runtime_get_sync(dev);
269 clk_prepare_enable(clk: info->clk);
270 }
271
272 serial8250_resume_port(line: info->line);
273
274 return 0;
275}
276#endif
277static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
278
279/*
280 * A few common types, add more as needed.
281 */
282static const struct of_device_id of_platform_serial_table[] = {
283 { .compatible = "ns8250", .data = (void *)PORT_8250, },
284 { .compatible = "ns16450", .data = (void *)PORT_16450, },
285 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
286 { .compatible = "ns16550", .data = (void *)PORT_16550, },
287 { .compatible = "ns16750", .data = (void *)PORT_16750, },
288 { .compatible = "ns16850", .data = (void *)PORT_16850, },
289 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
290 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
291 { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
292 { .compatible = "altr,16550-FIFO32",
293 .data = (void *)PORT_ALTR_16550_F32, },
294 { .compatible = "altr,16550-FIFO64",
295 .data = (void *)PORT_ALTR_16550_F64, },
296 { .compatible = "altr,16550-FIFO128",
297 .data = (void *)PORT_ALTR_16550_F128, },
298 { .compatible = "fsl,16550-FIFO64",
299 .data = (void *)PORT_16550A_FSL64, },
300 { .compatible = "mediatek,mtk-btif",
301 .data = (void *)PORT_MTK_BTIF, },
302 { .compatible = "mrvl,mmp-uart",
303 .data = (void *)PORT_XSCALE, },
304 { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
305 { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, },
306 { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
307 { /* end of list */ },
308};
309MODULE_DEVICE_TABLE(of, of_platform_serial_table);
310
311static struct platform_driver of_platform_serial_driver = {
312 .driver = {
313 .name = "of_serial",
314 .of_match_table = of_platform_serial_table,
315 .pm = &of_serial_pm_ops,
316 },
317 .probe = of_platform_serial_probe,
318 .remove_new = of_platform_serial_remove,
319};
320
321module_platform_driver(of_platform_serial_driver);
322
323MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
324MODULE_LICENSE("GPL");
325MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
326

source code of linux/drivers/tty/serial/8250/8250_of.c