drivers/tty/goldfish.c

   1 /*
   2  * Copyright (C) 2007 Google, Inc.
   3  * Copyright (C) 2012 Intel, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/console.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/tty.h>
  20 #include <linux/tty_flip.h>
  21 #include <linux/slab.h>
  22 #include <linux/io.h>
  23 #include <linux/module.h>
  24 #include <linux/goldfish.h>
  25
  26 enum {
  27         GOLDFISH_TTY_PUT_CHAR       = 0x00,
  28         GOLDFISH_TTY_BYTES_READY    = 0x04,
  29         GOLDFISH_TTY_CMD            = 0x08,
  30
  31         GOLDFISH_TTY_DATA_PTR       = 0x10,
  32         GOLDFISH_TTY_DATA_LEN       = 0x14,
  33         GOLDFISH_TTY_DATA_PTR_HIGH  = 0x18,
  34
  35         GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
  36         GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
  37         GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
  38         GOLDFISH_TTY_CMD_READ_BUFFER    = 3,
  39 };
  40
  41 struct goldfish_tty {
  42         struct tty_port port;
  43         spinlock_t lock;
  44         void __iomem *base;
  45         u32 irq;
  46         int opencount;
  47         struct console console;
  48 };
  49
  50 static DEFINE_MUTEX(goldfish_tty_lock);
  51 static struct tty_driver *goldfish_tty_driver;
  52 static u32 goldfish_tty_line_count = 8;
  53 static u32 goldfish_tty_current_line_count;
  54 static struct goldfish_tty *goldfish_ttys;
  55
  56 static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
  57 {
  58         unsigned long irq_flags;
  59         struct goldfish_tty *qtty = &goldfish_ttys[line];
  60         void __iomem *base = qtty->base;
  61         spin_lock_irqsave(&qtty->lock, irq_flags);
  62         gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
  63                                 base + GOLDFISH_TTY_DATA_PTR_HIGH);
  64         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  65         writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
  66         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  67 }
  68
  69 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
  70 {
  71         struct goldfish_tty *qtty = dev_id;
  72         void __iomem *base = qtty->base;
  73         unsigned long irq_flags;
  74         unsigned char *buf;
  75         u32 count;
  76
  77         count = readl(base + GOLDFISH_TTY_BYTES_READY);
  78         if (count == 0)
  79                 return IRQ_NONE;
  80
  81         count = tty_prepare_flip_string(&qtty->port, &buf, count);
  82         spin_lock_irqsave(&qtty->lock, irq_flags);
  83         gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
  84                                 base + GOLDFISH_TTY_DATA_PTR_HIGH);
  85         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  86         writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
  87         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  88         tty_schedule_flip(&qtty->port);
  89         return IRQ_HANDLED;
  90 }
  91
  92 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
  93 {
  94         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
  95                                                                         port);
  96         writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
  97         return 0;
  98 }
  99
 100 static void goldfish_tty_shutdown(struct tty_port *port)
 101 {
 102         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 103                                                                         port);
 104         writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
 105 }
 106
 107 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
 108 {
 109         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 110         return tty_port_open(&qtty->port, tty, filp);
 111 }
 112
 113 static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
 114 {
 115         tty_port_close(tty->port, tty, filp);
 116 }
 117
 118 static void goldfish_tty_hangup(struct tty_struct *tty)
 119 {
 120         tty_port_hangup(tty->port);
 121 }
 122
 123 static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf,
 124                                                                 int count)
 125 {
 126         goldfish_tty_do_write(tty->index, buf, count);
 127         return count;
 128 }
 129
 130 static int goldfish_tty_write_room(struct tty_struct *tty)
 131 {
 132         return 0x10000;
 133 }
 134
 135 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
 136 {
 137         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 138         void __iomem *base = qtty->base;
 139         return readl(base + GOLDFISH_TTY_BYTES_READY);
 140 }
 141
 142 static void goldfish_tty_console_write(struct console *co, const char *b,
 143                                                                 unsigned count)
 144 {
 145         goldfish_tty_do_write(co->index, b, count);
 146 }
 147
 148 static struct tty_driver *goldfish_tty_console_device(struct console *c,
 149                                                                 int *index)
 150 {
 151         *index = c->index;
 152         return goldfish_tty_driver;
 153 }
 154
 155 static int goldfish_tty_console_setup(struct console *co, char *options)
 156 {
 157         if ((unsigned)co->index >= goldfish_tty_line_count)
 158                 return -ENODEV;
 159         if (!goldfish_ttys[co->index].base)
 160                 return -ENODEV;
 161         return 0;
 162 }
 163
 164 static const struct tty_port_operations goldfish_port_ops = {
 165         .activate = goldfish_tty_activate,
 166         .shutdown = goldfish_tty_shutdown
 167 };
 168
 169 static const struct tty_operations goldfish_tty_ops = {
 170         .open = goldfish_tty_open,
 171         .close = goldfish_tty_close,
 172         .hangup = goldfish_tty_hangup,
 173         .write = goldfish_tty_write,
 174         .write_room = goldfish_tty_write_room,
 175         .chars_in_buffer = goldfish_tty_chars_in_buffer,
 176 };
 177
 178 static int goldfish_tty_create_driver(void)
 179 {
 180         int ret;
 181         struct tty_driver *tty;
 182
 183         goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) *
 184                                 goldfish_tty_line_count, GFP_KERNEL);
 185         if (goldfish_ttys == NULL) {
 186                 ret = -ENOMEM;
 187                 goto err_alloc_goldfish_ttys_failed;
 188         }
 189         tty = alloc_tty_driver(goldfish_tty_line_count);
 190         if (tty == NULL) {
 191                 ret = -ENOMEM;
 192                 goto err_alloc_tty_driver_failed;
 193         }
 194         tty->driver_name = "goldfish";
 195         tty->name = "ttyGF";
 196         tty->type = TTY_DRIVER_TYPE_SERIAL;
 197         tty->subtype = SERIAL_TYPE_NORMAL;
 198         tty->init_termios = tty_std_termios;
 199         tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 200                                                 TTY_DRIVER_DYNAMIC_DEV;
 201         tty_set_operations(tty, &goldfish_tty_ops);
 202         ret = tty_register_driver(tty);
 203         if (ret)
 204                 goto err_tty_register_driver_failed;
 205
 206         goldfish_tty_driver = tty;
 207         return 0;
 208
 209 err_tty_register_driver_failed:
 210         put_tty_driver(tty);
 211 err_alloc_tty_driver_failed:
 212         kfree(goldfish_ttys);
 213         goldfish_ttys = NULL;
 214 err_alloc_goldfish_ttys_failed:
 215         return ret;
 216 }
 217
 218 static void goldfish_tty_delete_driver(void)
 219 {
 220         tty_unregister_driver(goldfish_tty_driver);
 221         put_tty_driver(goldfish_tty_driver);
 222         goldfish_tty_driver = NULL;
 223         kfree(goldfish_ttys);
 224         goldfish_ttys = NULL;
 225 }
 226
 227 static int goldfish_tty_probe(struct platform_device *pdev)
 228 {
 229         struct goldfish_tty *qtty;
 230         int ret = -EINVAL;
 231         struct resource *r;
 232         struct device *ttydev;
 233         void __iomem *base;
 234         u32 irq;
 235         unsigned int line;
 236
 237         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 238         if (r == NULL)
 239                 return -EINVAL;
 240
 241         base = ioremap(r->start, 0x1000);
 242         if (base == NULL)
 243                 pr_err("goldfish_tty: unable to remap base\n");
 244
 245         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 246         if (r == NULL)
 247                 goto err_unmap;
 248
 249         irq = r->start;
 250
 251         mutex_lock(&goldfish_tty_lock);
 252
 253         if (pdev->id == PLATFORM_DEVID_NONE)
 254                 line = goldfish_tty_current_line_count;
 255         else
 256                 line = pdev->id;
 257
 258         if (line >= goldfish_tty_line_count)
 259                 goto err_create_driver_failed;
 260
 261         if (goldfish_tty_current_line_count == 0) {
 262                 ret = goldfish_tty_create_driver();
 263                 if (ret)
 264                         goto err_create_driver_failed;
 265         }
 266         goldfish_tty_current_line_count++;
 267
 268         qtty = &goldfish_ttys[line];
 269         spin_lock_init(&qtty->lock);
 270         tty_port_init(&qtty->port);
 271         qtty->port.ops = &goldfish_port_ops;
 272         qtty->base = base;
 273         qtty->irq = irq;
 274
 275         writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 276
 277         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
 278                                                 "goldfish_tty", qtty);
 279         if (ret)
 280                 goto err_request_irq_failed;
 281
 282
 283         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
 284                                                         line, &pdev->dev);
 285         if (IS_ERR(ttydev)) {
 286                 ret = PTR_ERR(ttydev);
 287                 goto err_tty_register_device_failed;
 288         }
 289
 290         strcpy(qtty->console.name, "ttyGF");
 291         qtty->console.write = goldfish_tty_console_write;
 292         qtty->console.device = goldfish_tty_console_device;
 293         qtty->console.setup = goldfish_tty_console_setup;
 294         qtty->console.flags = CON_PRINTBUFFER;
 295         qtty->console.index = line;
 296         register_console(&qtty->console);
 297         platform_set_drvdata(pdev, qtty);
 298
 299         mutex_unlock(&goldfish_tty_lock);
 300         return 0;
 301
 302 err_tty_register_device_failed:
 303         free_irq(irq, pdev);
 304 err_request_irq_failed:
 305         goldfish_tty_current_line_count--;
 306         if (goldfish_tty_current_line_count == 0)
 307                 goldfish_tty_delete_driver();
 308 err_create_driver_failed:
 309         mutex_unlock(&goldfish_tty_lock);
 310 err_unmap:
 311         iounmap(base);
 312         return ret;
 313 }
 314
 315 static int goldfish_tty_remove(struct platform_device *pdev)
 316 {
 317         struct goldfish_tty *qtty = platform_get_drvdata(pdev);
 318
 319         mutex_lock(&goldfish_tty_lock);
 320
 321         unregister_console(&qtty->console);
 322         tty_unregister_device(goldfish_tty_driver, qtty->console.index);
 323         iounmap(qtty->base);
 324         qtty->base = NULL;
 325         free_irq(qtty->irq, pdev);
 326         goldfish_tty_current_line_count--;
 327         if (goldfish_tty_current_line_count == 0)
 328                 goldfish_tty_delete_driver();
 329         mutex_unlock(&goldfish_tty_lock);
 330         return 0;
 331 }
 332
 333 static const struct of_device_id goldfish_tty_of_match[] = {
 334         { .compatible = "google,goldfish-tty", },
 335         {},
 336 };
 337
 338 MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
 339
 340 static struct platform_driver goldfish_tty_platform_driver = {
 341         .probe = goldfish_tty_probe,
 342         .remove = goldfish_tty_remove,
 343         .driver = {
 344                 .name = "goldfish_tty",
 345                 .of_match_table = goldfish_tty_of_match,
 346         }
 347 };
 348
 349 module_platform_driver(goldfish_tty_platform_driver);
 350
 351 MODULE_LICENSE("GPL v2");