1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2007 Google, Inc.
4 * Copyright (C) 2012 Intel, Inc.
5 * Copyright (C) 2017 Imagination Technologies Ltd.
6 */
7
8 #include <linux/console.h>
9 #include <linux/interrupt.h>
10 #include <linux/platform_device.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/io.h>
15 #include <linux/module.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/goldfish.h>
18 #include <linux/mm.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/serial_core.h>
21
22 /* Goldfish tty register's offsets */
23 #define GOLDFISH_TTY_REG_BYTES_READY 0x04
24 #define GOLDFISH_TTY_REG_CMD 0x08
25 #define GOLDFISH_TTY_REG_DATA_PTR 0x10
26 #define GOLDFISH_TTY_REG_DATA_LEN 0x14
27 #define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x18
28 #define GOLDFISH_TTY_REG_VERSION 0x20
29
30 /* Goldfish tty commands */
31 #define GOLDFISH_TTY_CMD_INT_DISABLE 0
32 #define GOLDFISH_TTY_CMD_INT_ENABLE 1
33 #define GOLDFISH_TTY_CMD_WRITE_BUFFER 2
34 #define GOLDFISH_TTY_CMD_READ_BUFFER 3
35
36 struct goldfish_tty {
37 struct tty_port port;
38 spinlock_t lock;
39 void __iomem *base;
40 u32 irq;
41 int opencount;
42 struct console console;
43 u32 version;
44 struct device *dev;
45 };
46
47 static DEFINE_MUTEX(goldfish_tty_lock);
48 static struct tty_driver *goldfish_tty_driver;
49 static u32 goldfish_tty_line_count = 8;
50 static u32 goldfish_tty_current_line_count;
51 static struct goldfish_tty *goldfish_ttys;
52
do_rw_io(struct goldfish_tty * qtty,unsigned long address,size_t count,bool is_write)53 static void do_rw_io(struct goldfish_tty *qtty, unsigned long address,
54 size_t count, bool is_write)
55 {
56 unsigned long irq_flags;
57 void __iomem *base = qtty->base;
58
59 spin_lock_irqsave(&qtty->lock, irq_flags);
60 gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
61 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
62 gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);
63
64 if (is_write)
65 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,
66 base + GOLDFISH_TTY_REG_CMD);
67 else
68 gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER,
69 base + GOLDFISH_TTY_REG_CMD);
70
71 spin_unlock_irqrestore(&qtty->lock, irq_flags);
72 }
73
goldfish_tty_rw(struct goldfish_tty * qtty,unsigned long addr,size_t count,bool is_write)74 static void goldfish_tty_rw(struct goldfish_tty *qtty, unsigned long addr,
75 size_t count, bool is_write)
76 {
77 dma_addr_t dma_handle;
78 enum dma_data_direction dma_dir;
79
80 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
81 if (qtty->version > 0) {
82 /*
83 * Goldfish TTY for Ranchu platform uses
84 * physical addresses and DMA for read/write operations
85 */
86 unsigned long addr_end = addr + count;
87
88 while (addr < addr_end) {
89 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
90 unsigned long next =
91 pg_end < addr_end ? pg_end : addr_end;
92 unsigned long avail = next - addr;
93
94 /*
95 * Map the buffer's virtual address to the DMA address
96 * so the buffer can be accessed by the device.
97 */
98 dma_handle = dma_map_single(qtty->dev, (void *)addr,
99 avail, dma_dir);
100
101 if (dma_mapping_error(qtty->dev, dma_handle)) {
102 dev_err(qtty->dev, "tty: DMA mapping error.\n");
103 return;
104 }
105 do_rw_io(qtty, dma_handle, avail, is_write);
106
107 /*
108 * Unmap the previously mapped region after
109 * the completion of the read/write operation.
110 */
111 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);
112
113 addr += avail;
114 }
115 } else {
116 /*
117 * Old style Goldfish TTY used on the Goldfish platform
118 * uses virtual addresses.
119 */
120 do_rw_io(qtty, addr, count, is_write);
121 }
122 }
123
goldfish_tty_do_write(int line,const u8 * buf,size_t count)124 static void goldfish_tty_do_write(int line, const u8 *buf, size_t count)
125 {
126 struct goldfish_tty *qtty = &goldfish_ttys[line];
127
128 goldfish_tty_rw(qtty, (unsigned long)buf, count, true);
129 }
130
goldfish_tty_interrupt(int irq,void * dev_id)131 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
132 {
133 struct goldfish_tty *qtty = dev_id;
134 void __iomem *base = qtty->base;
135 u8 *buf;
136 u32 count;
137
138 count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
139 if (count == 0)
140 return IRQ_NONE;
141
142 count = tty_prepare_flip_string(&qtty->port, &buf, count);
143
144 goldfish_tty_rw(qtty, (unsigned long)buf, count, false);
145
146 tty_flip_buffer_push(&qtty->port);
147 return IRQ_HANDLED;
148 }
149
goldfish_tty_activate(struct tty_port * port,struct tty_struct * tty)150 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
151 {
152 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
153 port);
154 gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
155 return 0;
156 }
157
goldfish_tty_shutdown(struct tty_port * port)158 static void goldfish_tty_shutdown(struct tty_port *port)
159 {
160 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
161 port);
162 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
163 }
164
goldfish_tty_open(struct tty_struct * tty,struct file * filp)165 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
166 {
167 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
168 return tty_port_open(&qtty->port, tty, filp);
169 }
170
goldfish_tty_close(struct tty_struct * tty,struct file * filp)171 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
172 {
173 tty_port_close(tty->port, tty, filp);
174 }
175
goldfish_tty_hangup(struct tty_struct * tty)176 static void goldfish_tty_hangup(struct tty_struct *tty)
177 {
178 tty_port_hangup(tty->port);
179 }
180
goldfish_tty_write(struct tty_struct * tty,const u8 * buf,size_t count)181 static ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf,
182 size_t count)
183 {
184 goldfish_tty_do_write(tty->index, buf, count);
185 return count;
186 }
187
goldfish_tty_write_room(struct tty_struct * tty)188 static unsigned int goldfish_tty_write_room(struct tty_struct *tty)
189 {
190 return 0x10000;
191 }
192
goldfish_tty_chars_in_buffer(struct tty_struct * tty)193 static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
194 {
195 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
196 void __iomem *base = qtty->base;
197 return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
198 }
199
goldfish_tty_console_write(struct console * co,const char * b,unsigned count)200 static void goldfish_tty_console_write(struct console *co, const char *b,
201 unsigned count)
202 {
203 goldfish_tty_do_write(co->index, b, count);
204 }
205
goldfish_tty_console_device(struct console * c,int * index)206 static struct tty_driver *goldfish_tty_console_device(struct console *c,
207 int *index)
208 {
209 *index = c->index;
210 return goldfish_tty_driver;
211 }
212
goldfish_tty_console_setup(struct console * co,char * options)213 static int goldfish_tty_console_setup(struct console *co, char *options)
214 {
215 if ((unsigned)co->index >= goldfish_tty_line_count)
216 return -ENODEV;
217 if (!goldfish_ttys[co->index].base)
218 return -ENODEV;
219 return 0;
220 }
221
222 static const struct tty_port_operations goldfish_port_ops = {
223 .activate = goldfish_tty_activate,
224 .shutdown = goldfish_tty_shutdown
225 };
226
227 static const struct tty_operations goldfish_tty_ops = {
228 .open = goldfish_tty_open,
229 .close = goldfish_tty_close,
230 .hangup = goldfish_tty_hangup,
231 .write = goldfish_tty_write,
232 .write_room = goldfish_tty_write_room,
233 .chars_in_buffer = goldfish_tty_chars_in_buffer,
234 };
235
goldfish_tty_create_driver(void)236 static int goldfish_tty_create_driver(void)
237 {
238 int ret;
239 struct tty_driver *tty;
240
241 goldfish_ttys = kcalloc(goldfish_tty_line_count,
242 sizeof(*goldfish_ttys),
243 GFP_KERNEL);
244 if (goldfish_ttys == NULL) {
245 ret = -ENOMEM;
246 goto err_alloc_goldfish_ttys_failed;
247 }
248 tty = tty_alloc_driver(goldfish_tty_line_count,
249 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
250 TTY_DRIVER_DYNAMIC_DEV);
251 if (IS_ERR(tty)) {
252 ret = PTR_ERR(tty);
253 goto err_tty_alloc_driver_failed;
254 }
255 tty->driver_name = "goldfish";
256 tty->name = "ttyGF";
257 tty->type = TTY_DRIVER_TYPE_SERIAL;
258 tty->subtype = SERIAL_TYPE_NORMAL;
259 tty->init_termios = tty_std_termios;
260 tty_set_operations(tty, &goldfish_tty_ops);
261 ret = tty_register_driver(tty);
262 if (ret)
263 goto err_tty_register_driver_failed;
264
265 goldfish_tty_driver = tty;
266 return 0;
267
268 err_tty_register_driver_failed:
269 tty_driver_kref_put(tty);
270 err_tty_alloc_driver_failed:
271 kfree(goldfish_ttys);
272 goldfish_ttys = NULL;
273 err_alloc_goldfish_ttys_failed:
274 return ret;
275 }
276
goldfish_tty_delete_driver(void)277 static void goldfish_tty_delete_driver(void)
278 {
279 tty_unregister_driver(goldfish_tty_driver);
280 tty_driver_kref_put(goldfish_tty_driver);
281 goldfish_tty_driver = NULL;
282 kfree(goldfish_ttys);
283 goldfish_ttys = NULL;
284 }
285
goldfish_tty_probe(struct platform_device * pdev)286 static int goldfish_tty_probe(struct platform_device *pdev)
287 {
288 struct goldfish_tty *qtty;
289 int ret = -ENODEV;
290 struct resource *r;
291 struct device *ttydev;
292 void __iomem *base;
293 int irq;
294 unsigned int line;
295
296 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
297 if (!r) {
298 pr_err("goldfish_tty: No MEM resource available!\n");
299 return -ENOMEM;
300 }
301
302 base = ioremap(r->start, 0x1000);
303 if (!base) {
304 pr_err("goldfish_tty: Unable to ioremap base!\n");
305 return -ENOMEM;
306 }
307
308 irq = platform_get_irq(pdev, 0);
309 if (irq < 0) {
310 ret = irq;
311 goto err_unmap;
312 }
313
314 mutex_lock(&goldfish_tty_lock);
315
316 if (pdev->id == PLATFORM_DEVID_NONE)
317 line = goldfish_tty_current_line_count;
318 else
319 line = pdev->id;
320
321 if (line >= goldfish_tty_line_count) {
322 pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
323 goldfish_tty_current_line_count);
324 ret = -ENOMEM;
325 goto err_unlock;
326 }
327
328 if (goldfish_tty_current_line_count == 0) {
329 ret = goldfish_tty_create_driver();
330 if (ret)
331 goto err_unlock;
332 }
333 goldfish_tty_current_line_count++;
334
335 qtty = &goldfish_ttys[line];
336 spin_lock_init(&qtty->lock);
337 tty_port_init(&qtty->port);
338 qtty->port.ops = &goldfish_port_ops;
339 qtty->base = base;
340 qtty->irq = irq;
341 qtty->dev = &pdev->dev;
342
343 /*
344 * Goldfish TTY device used by the Goldfish emulator
345 * should identify itself with 0, forcing the driver
346 * to use virtual addresses. Goldfish TTY device
347 * on Ranchu emulator (qemu2) returns 1 here and
348 * driver will use physical addresses.
349 */
350 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);
351
352 /*
353 * Goldfish TTY device on Ranchu emulator (qemu2)
354 * will use DMA for read/write IO operations.
355 */
356 if (qtty->version > 0) {
357 /*
358 * Initialize dma_mask to 32-bits.
359 */
360 if (!pdev->dev.dma_mask)
361 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
362 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
363 if (ret) {
364 dev_err(&pdev->dev, "No suitable DMA available.\n");
365 goto err_dec_line_count;
366 }
367 }
368
369 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
370
371 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
372 "goldfish_tty", qtty);
373 if (ret) {
374 pr_err("goldfish_tty: No IRQ available!\n");
375 goto err_dec_line_count;
376 }
377
378 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
379 line, &pdev->dev);
380 if (IS_ERR(ttydev)) {
381 ret = PTR_ERR(ttydev);
382 goto err_tty_register_device_failed;
383 }
384
385 strcpy(qtty->console.name, "ttyGF");
386 qtty->console.write = goldfish_tty_console_write;
387 qtty->console.device = goldfish_tty_console_device;
388 qtty->console.setup = goldfish_tty_console_setup;
389 qtty->console.flags = CON_PRINTBUFFER;
390 qtty->console.index = line;
391 register_console(&qtty->console);
392 platform_set_drvdata(pdev, qtty);
393
394 mutex_unlock(&goldfish_tty_lock);
395 return 0;
396
397 err_tty_register_device_failed:
398 free_irq(irq, qtty);
399 err_dec_line_count:
400 tty_port_destroy(&qtty->port);
401 goldfish_tty_current_line_count--;
402 if (goldfish_tty_current_line_count == 0)
403 goldfish_tty_delete_driver();
404 err_unlock:
405 mutex_unlock(&goldfish_tty_lock);
406 err_unmap:
407 iounmap(base);
408 return ret;
409 }
410
goldfish_tty_remove(struct platform_device * pdev)411 static void goldfish_tty_remove(struct platform_device *pdev)
412 {
413 struct goldfish_tty *qtty = platform_get_drvdata(pdev);
414
415 mutex_lock(&goldfish_tty_lock);
416
417 unregister_console(&qtty->console);
418 tty_unregister_device(goldfish_tty_driver, qtty->console.index);
419 iounmap(qtty->base);
420 qtty->base = NULL;
421 free_irq(qtty->irq, qtty);
422 tty_port_destroy(&qtty->port);
423 goldfish_tty_current_line_count--;
424 if (goldfish_tty_current_line_count == 0)
425 goldfish_tty_delete_driver();
426 mutex_unlock(&goldfish_tty_lock);
427 }
428
429 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
gf_early_console_putchar(struct uart_port * port,unsigned char ch)430 static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
431 {
432 gf_iowrite32(ch, port->membase);
433 }
434
gf_early_write(struct console * con,const char * s,unsigned int n)435 static void gf_early_write(struct console *con, const char *s, unsigned int n)
436 {
437 struct earlycon_device *dev = con->data;
438
439 uart_console_write(&dev->port, s, n, gf_early_console_putchar);
440 }
441
gf_earlycon_setup(struct earlycon_device * device,const char * opt)442 static int __init gf_earlycon_setup(struct earlycon_device *device,
443 const char *opt)
444 {
445 if (!device->port.membase)
446 return -ENODEV;
447
448 device->con->write = gf_early_write;
449 return 0;
450 }
451
452 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
453 #endif
454
455 static const struct of_device_id goldfish_tty_of_match[] = {
456 { .compatible = "google,goldfish-tty", },
457 {},
458 };
459
460 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
461
462 static struct platform_driver goldfish_tty_platform_driver = {
463 .probe = goldfish_tty_probe,
464 .remove_new = goldfish_tty_remove,
465 .driver = {
466 .name = "goldfish_tty",
467 .of_match_table = goldfish_tty_of_match,
468 }
469 };
470
471 module_platform_driver(goldfish_tty_platform_driver);
472
473 MODULE_DESCRIPTION("Goldfish TTY Driver");
474 MODULE_LICENSE("GPL v2");
475