Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
36struct 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
47static DEFINE_MUTEX(goldfish_tty_lock);
48static struct tty_driver *goldfish_tty_driver;
49static u32 goldfish_tty_line_count = 8;
50static u32 goldfish_tty_current_line_count;
51static struct goldfish_tty *goldfish_ttys;
52
53static 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
74static 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
124static 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
131static 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
150static 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
158static 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
165static 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
171static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
172{
173 tty_port_close(tty->port, tty, filp);
174}
175
176static void goldfish_tty_hangup(struct tty_struct *tty)
177{
178 tty_port_hangup(tty->port);
179}
180
181static 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
188static unsigned int goldfish_tty_write_room(struct tty_struct *tty)
189{
190 return 0x10000;
191}
192
193static 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
200static 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
206static 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
213static 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
222static const struct tty_port_operations goldfish_port_ops = {
223 .activate = goldfish_tty_activate,
224 .shutdown = goldfish_tty_shutdown
225};
226
227static 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
236static int goldfish_tty_create_driver(void)
237{
238 int ret;
239 struct tty_driver *tty;
240
241 goldfish_ttys = kzalloc_objs(*goldfish_ttys, goldfish_tty_line_count);
242 if (goldfish_ttys == NULL) {
243 ret = -ENOMEM;
244 goto err_alloc_goldfish_ttys_failed;
245 }
246 tty = tty_alloc_driver(goldfish_tty_line_count,
247 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
248 TTY_DRIVER_DYNAMIC_DEV);
249 if (IS_ERR(tty)) {
250 ret = PTR_ERR(tty);
251 goto err_tty_alloc_driver_failed;
252 }
253 tty->driver_name = "goldfish";
254 tty->name = "ttyGF";
255 tty->type = TTY_DRIVER_TYPE_SERIAL;
256 tty->subtype = SERIAL_TYPE_NORMAL;
257 tty->init_termios = tty_std_termios;
258 tty_set_operations(tty, &goldfish_tty_ops);
259 ret = tty_register_driver(tty);
260 if (ret)
261 goto err_tty_register_driver_failed;
262
263 goldfish_tty_driver = tty;
264 return 0;
265
266err_tty_register_driver_failed:
267 tty_driver_kref_put(tty);
268err_tty_alloc_driver_failed:
269 kfree(goldfish_ttys);
270 goldfish_ttys = NULL;
271err_alloc_goldfish_ttys_failed:
272 return ret;
273}
274
275static void goldfish_tty_delete_driver(void)
276{
277 tty_unregister_driver(goldfish_tty_driver);
278 tty_driver_kref_put(goldfish_tty_driver);
279 goldfish_tty_driver = NULL;
280 kfree(goldfish_ttys);
281 goldfish_ttys = NULL;
282}
283
284static int goldfish_tty_probe(struct platform_device *pdev)
285{
286 struct goldfish_tty *qtty;
287 int ret = -ENODEV;
288 struct resource *r;
289 struct device *ttydev;
290 void __iomem *base;
291 int irq;
292 unsigned int line;
293
294 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
295 if (!r) {
296 pr_err("goldfish_tty: No MEM resource available!\n");
297 return -ENOMEM;
298 }
299
300 base = ioremap(r->start, 0x1000);
301 if (!base) {
302 pr_err("goldfish_tty: Unable to ioremap base!\n");
303 return -ENOMEM;
304 }
305
306 irq = platform_get_irq(pdev, 0);
307 if (irq < 0) {
308 ret = irq;
309 goto err_unmap;
310 }
311
312 mutex_lock(&goldfish_tty_lock);
313
314 if (pdev->id == PLATFORM_DEVID_NONE)
315 line = goldfish_tty_current_line_count;
316 else
317 line = pdev->id;
318
319 if (line >= goldfish_tty_line_count) {
320 pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
321 goldfish_tty_current_line_count);
322 ret = -ENOMEM;
323 goto err_unlock;
324 }
325
326 if (goldfish_tty_current_line_count == 0) {
327 ret = goldfish_tty_create_driver();
328 if (ret)
329 goto err_unlock;
330 }
331 goldfish_tty_current_line_count++;
332
333 qtty = &goldfish_ttys[line];
334 spin_lock_init(&qtty->lock);
335 tty_port_init(&qtty->port);
336 qtty->port.ops = &goldfish_port_ops;
337 qtty->base = base;
338 qtty->irq = irq;
339 qtty->dev = &pdev->dev;
340
341 /*
342 * Goldfish TTY device used by the Goldfish emulator
343 * should identify itself with 0, forcing the driver
344 * to use virtual addresses. Goldfish TTY device
345 * on Ranchu emulator (qemu2) returns 1 here and
346 * driver will use physical addresses.
347 */
348 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);
349
350 /*
351 * Goldfish TTY device on Ranchu emulator (qemu2)
352 * will use DMA for read/write IO operations.
353 */
354 if (qtty->version > 0) {
355 /*
356 * Initialize dma_mask to 32-bits.
357 */
358 if (!pdev->dev.dma_mask)
359 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
360 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
361 if (ret) {
362 dev_err(&pdev->dev, "No suitable DMA available.\n");
363 goto err_dec_line_count;
364 }
365 }
366
367 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
368
369 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
370 "goldfish_tty", qtty);
371 if (ret) {
372 pr_err("goldfish_tty: No IRQ available!\n");
373 goto err_dec_line_count;
374 }
375
376 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
377 line, &pdev->dev);
378 if (IS_ERR(ttydev)) {
379 ret = PTR_ERR(ttydev);
380 goto err_tty_register_device_failed;
381 }
382
383 strcpy(qtty->console.name, "ttyGF");
384 qtty->console.write = goldfish_tty_console_write;
385 qtty->console.device = goldfish_tty_console_device;
386 qtty->console.setup = goldfish_tty_console_setup;
387 qtty->console.flags = CON_PRINTBUFFER;
388 qtty->console.index = line;
389 register_console(&qtty->console);
390 platform_set_drvdata(pdev, qtty);
391
392 mutex_unlock(&goldfish_tty_lock);
393 return 0;
394
395err_tty_register_device_failed:
396 free_irq(irq, qtty);
397err_dec_line_count:
398 tty_port_destroy(&qtty->port);
399 goldfish_tty_current_line_count--;
400 if (goldfish_tty_current_line_count == 0)
401 goldfish_tty_delete_driver();
402err_unlock:
403 mutex_unlock(&goldfish_tty_lock);
404err_unmap:
405 iounmap(base);
406 return ret;
407}
408
409static void goldfish_tty_remove(struct platform_device *pdev)
410{
411 struct goldfish_tty *qtty = platform_get_drvdata(pdev);
412
413 mutex_lock(&goldfish_tty_lock);
414
415 unregister_console(&qtty->console);
416 tty_unregister_device(goldfish_tty_driver, qtty->console.index);
417 iounmap(qtty->base);
418 qtty->base = NULL;
419 free_irq(qtty->irq, qtty);
420 tty_port_destroy(&qtty->port);
421 goldfish_tty_current_line_count--;
422 if (goldfish_tty_current_line_count == 0)
423 goldfish_tty_delete_driver();
424 mutex_unlock(&goldfish_tty_lock);
425}
426
427#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
428static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
429{
430 gf_iowrite32(ch, port->membase);
431}
432
433static void gf_early_write(struct console *con, const char *s, unsigned int n)
434{
435 struct earlycon_device *dev = con->data;
436
437 uart_console_write(&dev->port, s, n, gf_early_console_putchar);
438}
439
440static int __init gf_earlycon_setup(struct earlycon_device *device,
441 const char *opt)
442{
443 if (!device->port.membase)
444 return -ENODEV;
445
446 device->con->write = gf_early_write;
447 return 0;
448}
449
450OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
451#endif
452
453static const struct of_device_id goldfish_tty_of_match[] = {
454 { .compatible = "google,goldfish-tty", },
455 {},
456};
457
458MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
459
460static struct platform_driver goldfish_tty_platform_driver = {
461 .probe = goldfish_tty_probe,
462 .remove = goldfish_tty_remove,
463 .driver = {
464 .name = "goldfish_tty",
465 .of_match_table = goldfish_tty_of_match,
466 }
467};
468
469module_platform_driver(goldfish_tty_platform_driver);
470
471MODULE_DESCRIPTION("Goldfish TTY Driver");
472MODULE_LICENSE("GPL v2");