1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  *  Driver for 8250/16550-type serial ports
4  *
5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6  *
7  *  Copyright (C) 2001 Russell King.
8  */
9 
10 #include <linux/bits.h>
11 #include <linux/serial_8250.h>
12 #include <linux/serial_reg.h>
13 #include <linux/dmaengine.h>
14 
15 #include "../serial_mctrl_gpio.h"
16 
17 struct uart_8250_dma {
18 	int (*tx_dma)(struct uart_8250_port *p);
19 	int (*rx_dma)(struct uart_8250_port *p);
20 
21 	/* Filter function */
22 	dma_filter_fn		fn;
23 	/* Parameter to the filter function */
24 	void			*rx_param;
25 	void			*tx_param;
26 
27 	struct dma_slave_config	rxconf;
28 	struct dma_slave_config	txconf;
29 
30 	struct dma_chan		*rxchan;
31 	struct dma_chan		*txchan;
32 
33 	/* Device address base for DMA operations */
34 	phys_addr_t		rx_dma_addr;
35 	phys_addr_t		tx_dma_addr;
36 
37 	/* DMA address of the buffer in memory */
38 	dma_addr_t		rx_addr;
39 	dma_addr_t		tx_addr;
40 
41 	dma_cookie_t		rx_cookie;
42 	dma_cookie_t		tx_cookie;
43 
44 	void			*rx_buf;
45 
46 	size_t			rx_size;
47 	size_t			tx_size;
48 
49 	unsigned char		tx_running;
50 	unsigned char		tx_err;
51 	unsigned char		rx_running;
52 };
53 
54 struct old_serial_port {
55 	unsigned int uart;
56 	unsigned int baud_base;
57 	unsigned int port;
58 	unsigned int irq;
59 	upf_t        flags;
60 	unsigned char io_type;
61 	unsigned char __iomem *iomem_base;
62 	unsigned short iomem_reg_shift;
63 };
64 
65 struct serial8250_config {
66 	const char	*name;
67 	unsigned short	fifo_size;
68 	unsigned short	tx_loadsz;
69 	unsigned char	fcr;
70 	unsigned char	rxtrig_bytes[UART_FCR_R_TRIG_MAX_STATE];
71 	unsigned int	flags;
72 };
73 
74 #define UART_CAP_FIFO	BIT(8)	/* UART has FIFO */
75 #define UART_CAP_EFR	BIT(9)	/* UART has EFR */
76 #define UART_CAP_SLEEP	BIT(10)	/* UART has IER sleep */
77 #define UART_CAP_AFE	BIT(11)	/* MCR-based hw flow control */
78 #define UART_CAP_UUE	BIT(12)	/* UART needs IER bit 6 set (Xscale) */
79 #define UART_CAP_RTOIE	BIT(13)	/* UART needs IER bit 4 set (Xscale, Tegra) */
80 #define UART_CAP_HFIFO	BIT(14)	/* UART has a "hidden" FIFO */
81 #define UART_CAP_RPM	BIT(15)	/* Runtime PM is active while idle */
82 #define UART_CAP_IRDA	BIT(16)	/* UART supports IrDA line discipline */
83 #define UART_CAP_MINI	BIT(17)	/* Mini UART on BCM283X family lacks:
84 					 * STOP PARITY EPAR SPAR WLEN5 WLEN6
85 					 */
86 
87 #define UART_BUG_QUOT	BIT(0)	/* UART has buggy quot LSB */
88 #define UART_BUG_TXEN	BIT(1)	/* UART has buggy TX IIR status */
89 #define UART_BUG_NOMSR	BIT(2)	/* UART has buggy MSR status bits (Au1x00) */
90 #define UART_BUG_THRE	BIT(3)	/* UART has buggy THRE reassertion */
91 #define UART_BUG_PARITY	BIT(4)	/* UART mishandles parity if FIFO enabled */
92 #define UART_BUG_TXRACE	BIT(5)	/* UART Tx fails to set remote DR */
93 
94 
95 #ifdef CONFIG_SERIAL_8250_SHARE_IRQ
96 #define SERIAL8250_SHARE_IRQS 1
97 #else
98 #define SERIAL8250_SHARE_IRQS 0
99 #endif
100 
101 #define SERIAL8250_PORT_FLAGS(_base, _irq, _flags)		\
102 	{							\
103 		.iobase		= _base,			\
104 		.irq		= _irq,				\
105 		.uartclk	= 1843200,			\
106 		.iotype		= UPIO_PORT,			\
107 		.flags		= UPF_BOOT_AUTOCONF | (_flags),	\
108 	}
109 
110 #define SERIAL8250_PORT(_base, _irq) SERIAL8250_PORT_FLAGS(_base, _irq, 0)
111 
112 
serial_in(struct uart_8250_port * up,int offset)113 static inline int serial_in(struct uart_8250_port *up, int offset)
114 {
115 	return up->port.serial_in(&up->port, offset);
116 }
117 
serial_out(struct uart_8250_port * up,int offset,int value)118 static inline void serial_out(struct uart_8250_port *up, int offset, int value)
119 {
120 	up->port.serial_out(&up->port, offset, value);
121 }
122 
123 void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p);
124 
serial_dl_read(struct uart_8250_port * up)125 static inline int serial_dl_read(struct uart_8250_port *up)
126 {
127 	return up->dl_read(up);
128 }
129 
serial_dl_write(struct uart_8250_port * up,int value)130 static inline void serial_dl_write(struct uart_8250_port *up, int value)
131 {
132 	up->dl_write(up, value);
133 }
134 
serial8250_set_THRI(struct uart_8250_port * up)135 static inline bool serial8250_set_THRI(struct uart_8250_port *up)
136 {
137 	if (up->ier & UART_IER_THRI)
138 		return false;
139 	up->ier |= UART_IER_THRI;
140 	serial_out(up, UART_IER, up->ier);
141 	return true;
142 }
143 
serial8250_clear_THRI(struct uart_8250_port * up)144 static inline bool serial8250_clear_THRI(struct uart_8250_port *up)
145 {
146 	if (!(up->ier & UART_IER_THRI))
147 		return false;
148 	up->ier &= ~UART_IER_THRI;
149 	serial_out(up, UART_IER, up->ier);
150 	return true;
151 }
152 
153 struct uart_8250_port *serial8250_get_port(int line);
154 
155 void serial8250_rpm_get(struct uart_8250_port *p);
156 void serial8250_rpm_put(struct uart_8250_port *p);
157 
158 void serial8250_rpm_get_tx(struct uart_8250_port *p);
159 void serial8250_rpm_put_tx(struct uart_8250_port *p);
160 
161 int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485);
162 void serial8250_em485_start_tx(struct uart_8250_port *p);
163 void serial8250_em485_stop_tx(struct uart_8250_port *p);
164 void serial8250_em485_destroy(struct uart_8250_port *p);
165 
166 /* MCR <-> TIOCM conversion */
serial8250_TIOCM_to_MCR(int tiocm)167 static inline int serial8250_TIOCM_to_MCR(int tiocm)
168 {
169 	int mcr = 0;
170 
171 	if (tiocm & TIOCM_RTS)
172 		mcr |= UART_MCR_RTS;
173 	if (tiocm & TIOCM_DTR)
174 		mcr |= UART_MCR_DTR;
175 	if (tiocm & TIOCM_OUT1)
176 		mcr |= UART_MCR_OUT1;
177 	if (tiocm & TIOCM_OUT2)
178 		mcr |= UART_MCR_OUT2;
179 	if (tiocm & TIOCM_LOOP)
180 		mcr |= UART_MCR_LOOP;
181 
182 	return mcr;
183 }
184 
serial8250_MCR_to_TIOCM(int mcr)185 static inline int serial8250_MCR_to_TIOCM(int mcr)
186 {
187 	int tiocm = 0;
188 
189 	if (mcr & UART_MCR_RTS)
190 		tiocm |= TIOCM_RTS;
191 	if (mcr & UART_MCR_DTR)
192 		tiocm |= TIOCM_DTR;
193 	if (mcr & UART_MCR_OUT1)
194 		tiocm |= TIOCM_OUT1;
195 	if (mcr & UART_MCR_OUT2)
196 		tiocm |= TIOCM_OUT2;
197 	if (mcr & UART_MCR_LOOP)
198 		tiocm |= TIOCM_LOOP;
199 
200 	return tiocm;
201 }
202 
203 /* MSR <-> TIOCM conversion */
serial8250_MSR_to_TIOCM(int msr)204 static inline int serial8250_MSR_to_TIOCM(int msr)
205 {
206 	int tiocm = 0;
207 
208 	if (msr & UART_MSR_DCD)
209 		tiocm |= TIOCM_CAR;
210 	if (msr & UART_MSR_RI)
211 		tiocm |= TIOCM_RNG;
212 	if (msr & UART_MSR_DSR)
213 		tiocm |= TIOCM_DSR;
214 	if (msr & UART_MSR_CTS)
215 		tiocm |= TIOCM_CTS;
216 
217 	return tiocm;
218 }
219 
serial8250_out_MCR(struct uart_8250_port * up,int value)220 static inline void serial8250_out_MCR(struct uart_8250_port *up, int value)
221 {
222 	serial_out(up, UART_MCR, value);
223 
224 	if (up->gpios)
225 		mctrl_gpio_set(up->gpios, serial8250_MCR_to_TIOCM(value));
226 }
227 
serial8250_in_MCR(struct uart_8250_port * up)228 static inline int serial8250_in_MCR(struct uart_8250_port *up)
229 {
230 	int mctrl;
231 
232 	mctrl = serial_in(up, UART_MCR);
233 
234 	if (up->gpios) {
235 		unsigned int mctrl_gpio = 0;
236 
237 		mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio);
238 		mctrl |= serial8250_TIOCM_to_MCR(mctrl_gpio);
239 	}
240 
241 	return mctrl;
242 }
243 
244 #if defined(__alpha__) && !defined(CONFIG_PCI)
245 /*
246  * Digital did something really horribly wrong with the OUT1 and OUT2
247  * lines on at least some ALPHA's.  The failure mode is that if either
248  * is cleared, the machine locks up with endless interrupts.
249  */
250 #define ALPHA_KLUDGE_MCR  (UART_MCR_OUT2 | UART_MCR_OUT1)
251 #else
252 #define ALPHA_KLUDGE_MCR 0
253 #endif
254 
255 #ifdef CONFIG_SERIAL_8250_PNP
256 int serial8250_pnp_init(void);
257 void serial8250_pnp_exit(void);
258 #else
serial8250_pnp_init(void)259 static inline int serial8250_pnp_init(void) { return 0; }
serial8250_pnp_exit(void)260 static inline void serial8250_pnp_exit(void) { }
261 #endif
262 
263 #ifdef CONFIG_SERIAL_8250_FINTEK
264 int fintek_8250_probe(struct uart_8250_port *uart);
265 #else
fintek_8250_probe(struct uart_8250_port * uart)266 static inline int fintek_8250_probe(struct uart_8250_port *uart) { return 0; }
267 #endif
268 
269 #ifdef CONFIG_ARCH_OMAP1
is_omap1_8250(struct uart_8250_port * pt)270 static inline int is_omap1_8250(struct uart_8250_port *pt)
271 {
272 	int res;
273 
274 	switch (pt->port.mapbase) {
275 	case OMAP1_UART1_BASE:
276 	case OMAP1_UART2_BASE:
277 	case OMAP1_UART3_BASE:
278 		res = 1;
279 		break;
280 	default:
281 		res = 0;
282 		break;
283 	}
284 
285 	return res;
286 }
287 
is_omap1510_8250(struct uart_8250_port * pt)288 static inline int is_omap1510_8250(struct uart_8250_port *pt)
289 {
290 	if (!cpu_is_omap1510())
291 		return 0;
292 
293 	return is_omap1_8250(pt);
294 }
295 #else
is_omap1_8250(struct uart_8250_port * pt)296 static inline int is_omap1_8250(struct uart_8250_port *pt)
297 {
298 	return 0;
299 }
is_omap1510_8250(struct uart_8250_port * pt)300 static inline int is_omap1510_8250(struct uart_8250_port *pt)
301 {
302 	return 0;
303 }
304 #endif
305 
306 #ifdef CONFIG_SERIAL_8250_DMA
307 extern int serial8250_tx_dma(struct uart_8250_port *);
308 extern int serial8250_rx_dma(struct uart_8250_port *);
309 extern void serial8250_rx_dma_flush(struct uart_8250_port *);
310 extern int serial8250_request_dma(struct uart_8250_port *);
311 extern void serial8250_release_dma(struct uart_8250_port *);
312 #else
serial8250_tx_dma(struct uart_8250_port * p)313 static inline int serial8250_tx_dma(struct uart_8250_port *p)
314 {
315 	return -1;
316 }
serial8250_rx_dma(struct uart_8250_port * p)317 static inline int serial8250_rx_dma(struct uart_8250_port *p)
318 {
319 	return -1;
320 }
serial8250_rx_dma_flush(struct uart_8250_port * p)321 static inline void serial8250_rx_dma_flush(struct uart_8250_port *p) { }
serial8250_request_dma(struct uart_8250_port * p)322 static inline int serial8250_request_dma(struct uart_8250_port *p)
323 {
324 	return -1;
325 }
serial8250_release_dma(struct uart_8250_port * p)326 static inline void serial8250_release_dma(struct uart_8250_port *p) { }
327 #endif
328 
ns16550a_goto_highspeed(struct uart_8250_port * up)329 static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
330 {
331 	unsigned char status;
332 
333 	status = serial_in(up, 0x04); /* EXCR2 */
334 #define PRESL(x) ((x) & 0x30)
335 	if (PRESL(status) == 0x10) {
336 		/* already in high speed mode */
337 		return 0;
338 	} else {
339 		status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
340 		status |= 0x10;  /* 1.625 divisor for baud_base --> 921600 */
341 		serial_out(up, 0x04, status);
342 	}
343 	return 1;
344 }
345 
serial_index(struct uart_port * port)346 static inline int serial_index(struct uart_port *port)
347 {
348 	return port->minor - 64;
349 }
350