GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / tty / goldfish.c
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
53 static void do_rw_io(struct goldfish_tty *qtty,
54                      unsigned long address,
55                      unsigned int count,
56                      int is_write)
57 {
58         unsigned long irq_flags;
59         void __iomem *base = qtty->base;
60
61         spin_lock_irqsave(&qtty->lock, irq_flags);
62         gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
63                      base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
64         gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);
65
66         if (is_write)
67                 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,
68                        base + GOLDFISH_TTY_REG_CMD);
69         else
70                 gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER,
71                        base + GOLDFISH_TTY_REG_CMD);
72
73         spin_unlock_irqrestore(&qtty->lock, irq_flags);
74 }
75
76 static void goldfish_tty_rw(struct goldfish_tty *qtty,
77                             unsigned long addr,
78                             unsigned int count,
79                             int is_write)
80 {
81         dma_addr_t dma_handle;
82         enum dma_data_direction dma_dir;
83
84         dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
85         if (qtty->version > 0) {
86                 /*
87                  * Goldfish TTY for Ranchu platform uses
88                  * physical addresses and DMA for read/write operations
89                  */
90                 unsigned long addr_end = addr + count;
91
92                 while (addr < addr_end) {
93                         unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
94                         unsigned long next =
95                                         pg_end < addr_end ? pg_end : addr_end;
96                         unsigned long avail = next - addr;
97
98                         /*
99                          * Map the buffer's virtual address to the DMA address
100                          * so the buffer can be accessed by the device.
101                          */
102                         dma_handle = dma_map_single(qtty->dev, (void *)addr,
103                                                     avail, dma_dir);
104
105                         if (dma_mapping_error(qtty->dev, dma_handle)) {
106                                 dev_err(qtty->dev, "tty: DMA mapping error.\n");
107                                 return;
108                         }
109                         do_rw_io(qtty, dma_handle, avail, is_write);
110
111                         /*
112                          * Unmap the previously mapped region after
113                          * the completion of the read/write operation.
114                          */
115                         dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);
116
117                         addr += avail;
118                 }
119         } else {
120                 /*
121                  * Old style Goldfish TTY used on the Goldfish platform
122                  * uses virtual addresses.
123                  */
124                 do_rw_io(qtty, addr, count, is_write);
125         }
126 }
127
128 static void goldfish_tty_do_write(int line, const char *buf,
129                                   unsigned int count)
130 {
131         struct goldfish_tty *qtty = &goldfish_ttys[line];
132         unsigned long address = (unsigned long)(void *)buf;
133
134         goldfish_tty_rw(qtty, address, count, 1);
135 }
136
137 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
138 {
139         struct goldfish_tty *qtty = dev_id;
140         void __iomem *base = qtty->base;
141         unsigned long address;
142         unsigned char *buf;
143         u32 count;
144
145         count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
146         if (count == 0)
147                 return IRQ_NONE;
148
149         count = tty_prepare_flip_string(&qtty->port, &buf, count);
150
151         address = (unsigned long)(void *)buf;
152         goldfish_tty_rw(qtty, address, count, 0);
153
154         tty_flip_buffer_push(&qtty->port);
155         return IRQ_HANDLED;
156 }
157
158 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
159 {
160         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
161                                                                         port);
162         gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
163         return 0;
164 }
165
166 static void goldfish_tty_shutdown(struct tty_port *port)
167 {
168         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
169                                                                         port);
170         gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
171 }
172
173 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
174 {
175         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
176         return tty_port_open(&qtty->port, tty, filp);
177 }
178
179 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
180 {
181         tty_port_close(tty->port, tty, filp);
182 }
183
184 static void goldfish_tty_hangup(struct tty_struct *tty)
185 {
186         tty_port_hangup(tty->port);
187 }
188
189 static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf,
190                                                                 int count)
191 {
192         goldfish_tty_do_write(tty->index, buf, count);
193         return count;
194 }
195
196 static unsigned int goldfish_tty_write_room(struct tty_struct *tty)
197 {
198         return 0x10000;
199 }
200
201 static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
202 {
203         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
204         void __iomem *base = qtty->base;
205         return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
206 }
207
208 static void goldfish_tty_console_write(struct console *co, const char *b,
209                                                                 unsigned count)
210 {
211         goldfish_tty_do_write(co->index, b, count);
212 }
213
214 static struct tty_driver *goldfish_tty_console_device(struct console *c,
215                                                                 int *index)
216 {
217         *index = c->index;
218         return goldfish_tty_driver;
219 }
220
221 static int goldfish_tty_console_setup(struct console *co, char *options)
222 {
223         if ((unsigned)co->index >= goldfish_tty_line_count)
224                 return -ENODEV;
225         if (!goldfish_ttys[co->index].base)
226                 return -ENODEV;
227         return 0;
228 }
229
230 static const struct tty_port_operations goldfish_port_ops = {
231         .activate = goldfish_tty_activate,
232         .shutdown = goldfish_tty_shutdown
233 };
234
235 static const struct tty_operations goldfish_tty_ops = {
236         .open = goldfish_tty_open,
237         .close = goldfish_tty_close,
238         .hangup = goldfish_tty_hangup,
239         .write = goldfish_tty_write,
240         .write_room = goldfish_tty_write_room,
241         .chars_in_buffer = goldfish_tty_chars_in_buffer,
242 };
243
244 static int goldfish_tty_create_driver(void)
245 {
246         int ret;
247         struct tty_driver *tty;
248
249         goldfish_ttys = kcalloc(goldfish_tty_line_count,
250                                 sizeof(*goldfish_ttys),
251                                 GFP_KERNEL);
252         if (goldfish_ttys == NULL) {
253                 ret = -ENOMEM;
254                 goto err_alloc_goldfish_ttys_failed;
255         }
256         tty = tty_alloc_driver(goldfish_tty_line_count,
257                         TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
258                         TTY_DRIVER_DYNAMIC_DEV);
259         if (IS_ERR(tty)) {
260                 ret = PTR_ERR(tty);
261                 goto err_tty_alloc_driver_failed;
262         }
263         tty->driver_name = "goldfish";
264         tty->name = "ttyGF";
265         tty->type = TTY_DRIVER_TYPE_SERIAL;
266         tty->subtype = SERIAL_TYPE_NORMAL;
267         tty->init_termios = tty_std_termios;
268         tty_set_operations(tty, &goldfish_tty_ops);
269         ret = tty_register_driver(tty);
270         if (ret)
271                 goto err_tty_register_driver_failed;
272
273         goldfish_tty_driver = tty;
274         return 0;
275
276 err_tty_register_driver_failed:
277         tty_driver_kref_put(tty);
278 err_tty_alloc_driver_failed:
279         kfree(goldfish_ttys);
280         goldfish_ttys = NULL;
281 err_alloc_goldfish_ttys_failed:
282         return ret;
283 }
284
285 static void goldfish_tty_delete_driver(void)
286 {
287         tty_unregister_driver(goldfish_tty_driver);
288         tty_driver_kref_put(goldfish_tty_driver);
289         goldfish_tty_driver = NULL;
290         kfree(goldfish_ttys);
291         goldfish_ttys = NULL;
292 }
293
294 static int goldfish_tty_probe(struct platform_device *pdev)
295 {
296         struct goldfish_tty *qtty;
297         int ret = -ENODEV;
298         struct resource *r;
299         struct device *ttydev;
300         void __iomem *base;
301         int irq;
302         unsigned int line;
303
304         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
305         if (!r) {
306                 pr_err("goldfish_tty: No MEM resource available!\n");
307                 return -ENOMEM;
308         }
309
310         base = ioremap(r->start, 0x1000);
311         if (!base) {
312                 pr_err("goldfish_tty: Unable to ioremap base!\n");
313                 return -ENOMEM;
314         }
315
316         irq = platform_get_irq(pdev, 0);
317         if (irq < 0) {
318                 ret = irq;
319                 goto err_unmap;
320         }
321
322         mutex_lock(&goldfish_tty_lock);
323
324         if (pdev->id == PLATFORM_DEVID_NONE)
325                 line = goldfish_tty_current_line_count;
326         else
327                 line = pdev->id;
328
329         if (line >= goldfish_tty_line_count) {
330                 pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
331                        goldfish_tty_current_line_count);
332                 ret = -ENOMEM;
333                 goto err_unlock;
334         }
335
336         if (goldfish_tty_current_line_count == 0) {
337                 ret = goldfish_tty_create_driver();
338                 if (ret)
339                         goto err_unlock;
340         }
341         goldfish_tty_current_line_count++;
342
343         qtty = &goldfish_ttys[line];
344         spin_lock_init(&qtty->lock);
345         tty_port_init(&qtty->port);
346         qtty->port.ops = &goldfish_port_ops;
347         qtty->base = base;
348         qtty->irq = irq;
349         qtty->dev = &pdev->dev;
350
351         /*
352          * Goldfish TTY device used by the Goldfish emulator
353          * should identify itself with 0, forcing the driver
354          * to use virtual addresses. Goldfish TTY device
355          * on Ranchu emulator (qemu2) returns 1 here and
356          * driver will use physical addresses.
357          */
358         qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);
359
360         /*
361          * Goldfish TTY device on Ranchu emulator (qemu2)
362          * will use DMA for read/write IO operations.
363          */
364         if (qtty->version > 0) {
365                 /*
366                  * Initialize dma_mask to 32-bits.
367                  */
368                 if (!pdev->dev.dma_mask)
369                         pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
370                 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
371                 if (ret) {
372                         dev_err(&pdev->dev, "No suitable DMA available.\n");
373                         goto err_dec_line_count;
374                 }
375         }
376
377         gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
378
379         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
380                           "goldfish_tty", qtty);
381         if (ret) {
382                 pr_err("goldfish_tty: No IRQ available!\n");
383                 goto err_dec_line_count;
384         }
385
386         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
387                                           line, &pdev->dev);
388         if (IS_ERR(ttydev)) {
389                 ret = PTR_ERR(ttydev);
390                 goto err_tty_register_device_failed;
391         }
392
393         strcpy(qtty->console.name, "ttyGF");
394         qtty->console.write = goldfish_tty_console_write;
395         qtty->console.device = goldfish_tty_console_device;
396         qtty->console.setup = goldfish_tty_console_setup;
397         qtty->console.flags = CON_PRINTBUFFER;
398         qtty->console.index = line;
399         register_console(&qtty->console);
400         platform_set_drvdata(pdev, qtty);
401
402         mutex_unlock(&goldfish_tty_lock);
403         return 0;
404
405 err_tty_register_device_failed:
406         free_irq(irq, qtty);
407 err_dec_line_count:
408         tty_port_destroy(&qtty->port);
409         goldfish_tty_current_line_count--;
410         if (goldfish_tty_current_line_count == 0)
411                 goldfish_tty_delete_driver();
412 err_unlock:
413         mutex_unlock(&goldfish_tty_lock);
414 err_unmap:
415         iounmap(base);
416         return ret;
417 }
418
419 static int goldfish_tty_remove(struct platform_device *pdev)
420 {
421         struct goldfish_tty *qtty = platform_get_drvdata(pdev);
422
423         mutex_lock(&goldfish_tty_lock);
424
425         unregister_console(&qtty->console);
426         tty_unregister_device(goldfish_tty_driver, qtty->console.index);
427         iounmap(qtty->base);
428         qtty->base = NULL;
429         free_irq(qtty->irq, qtty);
430         tty_port_destroy(&qtty->port);
431         goldfish_tty_current_line_count--;
432         if (goldfish_tty_current_line_count == 0)
433                 goldfish_tty_delete_driver();
434         mutex_unlock(&goldfish_tty_lock);
435         return 0;
436 }
437
438 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
439 static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
440 {
441         gf_iowrite32(ch, port->membase);
442 }
443
444 static void gf_early_write(struct console *con, const char *s, unsigned int n)
445 {
446         struct earlycon_device *dev = con->data;
447
448         uart_console_write(&dev->port, s, n, gf_early_console_putchar);
449 }
450
451 static int __init gf_earlycon_setup(struct earlycon_device *device,
452                                     const char *opt)
453 {
454         if (!device->port.membase)
455                 return -ENODEV;
456
457         device->con->write = gf_early_write;
458         return 0;
459 }
460
461 OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
462 #endif
463
464 static const struct of_device_id goldfish_tty_of_match[] = {
465         { .compatible = "google,goldfish-tty", },
466         {},
467 };
468
469 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
470
471 static struct platform_driver goldfish_tty_platform_driver = {
472         .probe = goldfish_tty_probe,
473         .remove = goldfish_tty_remove,
474         .driver = {
475                 .name = "goldfish_tty",
476                 .of_match_table = goldfish_tty_of_match,
477         }
478 };
479
480 module_platform_driver(goldfish_tty_platform_driver);
481
482 MODULE_LICENSE("GPL v2");