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/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/tty.h>
  21 #include <linux/tty_flip.h>
  22 #include <linux/slab.h>
  23 #include <linux/io.h>
  24 #include <linux/module.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
  34         GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
  35         GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
  36         GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
  37         GOLDFISH_TTY_CMD_READ_BUFFER    = 3,
  38 };
  39
  40 struct goldfish_tty {
  41         struct tty_port port;
  42         spinlock_t lock;
  43         void __iomem *base;
  44         u32 irq;
  45         int opencount;
  46         struct console console;
  47 };
  48
  49 static DEFINE_MUTEX(goldfish_tty_lock);
  50 static struct tty_driver *goldfish_tty_driver;
  51 static u32 goldfish_tty_line_count = 8;
  52 static u32 goldfish_tty_current_line_count;
  53 static struct goldfish_tty *goldfish_ttys;
  54
  55 static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
  56 {
  57         unsigned long irq_flags;
  58         struct goldfish_tty *qtty = &goldfish_ttys[line];
  59         void __iomem *base = qtty->base;
  60         spin_lock_irqsave(&qtty->lock, irq_flags);
  61         writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
  62         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  63         writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
  64         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  65 }
  66
  67 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
  68 {
  69         struct platform_device *pdev = dev_id;
  70         struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
  71         void __iomem *base = qtty->base;
  72         unsigned long irq_flags;
  73         unsigned char *buf;
  74         u32 count;
  75         struct tty_struct *tty;
  76
  77         count = readl(base + GOLDFISH_TTY_BYTES_READY);
  78         if(count == 0)
  79                 return IRQ_NONE;
  80
  81         tty = tty_port_tty_get(&qtty->port);
  82         if (tty) {
  83                 count = tty_prepare_flip_string(tty, &buf, count);
  84                 spin_lock_irqsave(&qtty->lock, irq_flags);
  85                 writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
  86                 writel(count, base + GOLDFISH_TTY_DATA_LEN);
  87                 writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
  88                 spin_unlock_irqrestore(&qtty->lock, irq_flags);
  89                 tty_schedule_flip(tty);
  90                 tty_kref_put(tty);
  91         }
  92         return IRQ_HANDLED;
  93 }
  94
  95 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
  96 {
  97         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
  98         writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
  99         return 0;
 100 }
 101
 102 static void goldfish_tty_shutdown(struct tty_port *port)
 103 {
 104         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
 105         writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
 106 }
 107
 108 static int goldfish_tty_open(struct tty_struct * tty, struct file * filp)
 109 {
 110         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 111         return tty_port_open(&qtty->port, tty, filp);
 112 }
 113
 114 static void goldfish_tty_close(struct tty_struct * tty, struct file * filp)
 115 {
 116         tty_port_close(tty->port, tty, filp);
 117 }
 118
 119 static void goldfish_tty_hangup(struct tty_struct *tty)
 120 {
 121         tty_port_hangup(tty->port);
 122 }
 123
 124 static int goldfish_tty_write(struct tty_struct * tty, const unsigned char *buf, 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, unsigned count)
 143 {
 144         goldfish_tty_do_write(co->index, b, count);
 145 }
 146
 147 static struct tty_driver *goldfish_tty_console_device(struct console *c, int *index)
 148 {
 149         *index = c->index;
 150         return goldfish_tty_driver;
 151 }
 152
 153 static int goldfish_tty_console_setup(struct console *co, char *options)
 154 {
 155         if((unsigned)co->index > goldfish_tty_line_count)
 156                 return -ENODEV;
 157         if(goldfish_ttys[co->index].base == 0)
 158                 return -ENODEV;
 159         return 0;
 160 }
 161
 162 static struct tty_port_operations goldfish_port_ops = {
 163         .activate = goldfish_tty_activate,
 164         .shutdown = goldfish_tty_shutdown
 165 };
 166
 167 static struct tty_operations goldfish_tty_ops = {
 168         .open = goldfish_tty_open,
 169         .close = goldfish_tty_close,
 170         .hangup = goldfish_tty_hangup,
 171         .write = goldfish_tty_write,
 172         .write_room = goldfish_tty_write_room,
 173         .chars_in_buffer = goldfish_tty_chars_in_buffer,
 174 };
 175
 176 static int goldfish_tty_create_driver(void)
 177 {
 178         int ret;
 179         struct tty_driver *tty;
 180
 181         goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * goldfish_tty_line_count, GFP_KERNEL);
 182         if(goldfish_ttys == NULL) {
 183                 ret = -ENOMEM;
 184                 goto err_alloc_goldfish_ttys_failed;
 185         }
 186         tty = alloc_tty_driver(goldfish_tty_line_count);
 187         if(tty == NULL) {
 188                 ret = -ENOMEM;
 189                 goto err_alloc_tty_driver_failed;
 190         }
 191         tty->driver_name = "goldfish";
 192         tty->name = "ttyGF";
 193         tty->type = TTY_DRIVER_TYPE_SERIAL;
 194         tty->subtype = SERIAL_TYPE_NORMAL;
 195         tty->init_termios = tty_std_termios;
 196         tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 197         tty_set_operations(tty, &goldfish_tty_ops);
 198         ret = tty_register_driver(tty);
 199         if(ret)
 200                 goto err_tty_register_driver_failed;
 201
 202         goldfish_tty_driver = tty;
 203         return 0;
 204
 205 err_tty_register_driver_failed:
 206         put_tty_driver(tty);
 207 err_alloc_tty_driver_failed:
 208         kfree(goldfish_ttys);
 209         goldfish_ttys = NULL;
 210 err_alloc_goldfish_ttys_failed:
 211         return ret;
 212 }
 213
 214 static void goldfish_tty_delete_driver(void)
 215 {
 216         tty_unregister_driver(goldfish_tty_driver);
 217         put_tty_driver(goldfish_tty_driver);
 218         goldfish_tty_driver = NULL;
 219         kfree(goldfish_ttys);
 220         goldfish_ttys = NULL;
 221 }
 222
 223 static int goldfish_tty_probe(struct platform_device *pdev)
 224 {
 225         struct goldfish_tty *qtty;
 226         int ret = -EINVAL;
 227         int i;
 228         struct resource *r;
 229         struct device *ttydev;
 230         void __iomem *base;
 231         u32 irq;
 232
 233         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 234         if(r == NULL)
 235                 return -EINVAL;
 236
 237         base = ioremap(r->start, 0x1000);
 238         if (base == NULL)
 239                 pr_err("goldfish_tty: unable to remap base\n");
 240
 241         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 242         if(r == NULL)
 243                 goto err_unmap;
 244
 245         irq = r->start;
 246
 247         if(pdev->id >= goldfish_tty_line_count)
 248                 goto err_unmap;
 249
 250         mutex_lock(&goldfish_tty_lock);
 251         if(goldfish_tty_current_line_count == 0) {
 252                 ret = goldfish_tty_create_driver();
 253                 if(ret)
 254                         goto err_create_driver_failed;
 255         }
 256         goldfish_tty_current_line_count++;
 257
 258         qtty = &goldfish_ttys[pdev->id];
 259         spin_lock_init(&qtty->lock);
 260         tty_port_init(&qtty->port);
 261         qtty->port.ops = &goldfish_port_ops;
 262         qtty->base = base;
 263         qtty->irq = irq;
 264
 265         writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 266
 267         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, "goldfish_tty", pdev);
 268         if(ret)
 269                 goto err_request_irq_failed;
 270
 271
 272         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
 273                                                         pdev->id, &pdev->dev);
 274         if(IS_ERR(ttydev)) {
 275                 ret = PTR_ERR(ttydev);
 276                 goto err_tty_register_device_failed;
 277         }
 278
 279         strcpy(qtty->console.name, "ttyGF");
 280         qtty->console.write = goldfish_tty_console_write;
 281         qtty->console.device = goldfish_tty_console_device;
 282         qtty->console.setup = goldfish_tty_console_setup;
 283         qtty->console.flags = CON_PRINTBUFFER;
 284         qtty->console.index = pdev->id;
 285         register_console(&qtty->console);
 286
 287         mutex_unlock(&goldfish_tty_lock);
 288         return 0;
 289
 290         tty_unregister_device(goldfish_tty_driver, i);
 291 err_tty_register_device_failed:
 292         free_irq(irq, pdev);
 293 err_request_irq_failed:
 294         goldfish_tty_current_line_count--;
 295         if(goldfish_tty_current_line_count == 0)
 296                 goldfish_tty_delete_driver();
 297 err_create_driver_failed:
 298         mutex_unlock(&goldfish_tty_lock);
 299 err_unmap:
 300         iounmap(base);
 301         return ret;
 302 }
 303
 304 static int goldfish_tty_remove(struct platform_device *pdev)
 305 {
 306         struct goldfish_tty *qtty;
 307
 308         mutex_lock(&goldfish_tty_lock);
 309
 310         qtty = &goldfish_ttys[pdev->id];
 311         unregister_console(&qtty->console);
 312         tty_unregister_device(goldfish_tty_driver, pdev->id);
 313         iounmap(qtty->base);
 314         qtty->base = 0;
 315         free_irq(qtty->irq, pdev);
 316         goldfish_tty_current_line_count--;
 317         if(goldfish_tty_current_line_count == 0)
 318                 goldfish_tty_delete_driver();
 319         mutex_unlock(&goldfish_tty_lock);
 320         return 0;
 321 }
 322
 323 static struct platform_driver goldfish_tty_platform_driver = {
 324         .probe = goldfish_tty_probe,
 325         .remove = goldfish_tty_remove,
 326         .driver = {
 327                 .name = "goldfish_tty"
 328         }
 329 };
 330
 331 module_platform_driver(goldfish_tty_platform_driver);
 332
 333 MODULE_LICENSE("GPL v2");