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
  76         count = readl(base + GOLDFISH_TTY_BYTES_READY);
  77         if(count == 0)
  78                 return IRQ_NONE;
  79
  80         count = tty_prepare_flip_string(&qtty->port, &buf, count);
  81         spin_lock_irqsave(&qtty->lock, irq_flags);
  82         writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
  83         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  84         writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
  85         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  86         tty_schedule_flip(&qtty->port);
  87         return IRQ_HANDLED;
  88 }
  89
  90 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
  91 {
  92         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
  93         writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
  94         return 0;
  95 }
  96
  97 static void goldfish_tty_shutdown(struct tty_port *port)
  98 {
  99         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
 100         writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
 101 }
 102
 103 static int goldfish_tty_open(struct tty_struct * tty, struct file * filp)
 104 {
 105         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 106         return tty_port_open(&qtty->port, tty, filp);
 107 }
 108
 109 static void goldfish_tty_close(struct tty_struct * tty, struct file * filp)
 110 {
 111         tty_port_close(tty->port, tty, filp);
 112 }
 113
 114 static void goldfish_tty_hangup(struct tty_struct *tty)
 115 {
 116         tty_port_hangup(tty->port);
 117 }
 118
 119 static int goldfish_tty_write(struct tty_struct * tty, const unsigned char *buf, int count)
 120 {
 121         goldfish_tty_do_write(tty->index, buf, count);
 122         return count;
 123 }
 124
 125 static int goldfish_tty_write_room(struct tty_struct *tty)
 126 {
 127         return 0x10000;
 128 }
 129
 130 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
 131 {
 132         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 133         void __iomem *base = qtty->base;
 134         return readl(base + GOLDFISH_TTY_BYTES_READY);
 135 }
 136
 137 static void goldfish_tty_console_write(struct console *co, const char *b, unsigned count)
 138 {
 139         goldfish_tty_do_write(co->index, b, count);
 140 }
 141
 142 static struct tty_driver *goldfish_tty_console_device(struct console *c, int *index)
 143 {
 144         *index = c->index;
 145         return goldfish_tty_driver;
 146 }
 147
 148 static int goldfish_tty_console_setup(struct console *co, char *options)
 149 {
 150         if((unsigned)co->index > goldfish_tty_line_count)
 151                 return -ENODEV;
 152         if(goldfish_ttys[co->index].base == 0)
 153                 return -ENODEV;
 154         return 0;
 155 }
 156
 157 static struct tty_port_operations goldfish_port_ops = {
 158         .activate = goldfish_tty_activate,
 159         .shutdown = goldfish_tty_shutdown
 160 };
 161
 162 static struct tty_operations goldfish_tty_ops = {
 163         .open = goldfish_tty_open,
 164         .close = goldfish_tty_close,
 165         .hangup = goldfish_tty_hangup,
 166         .write = goldfish_tty_write,
 167         .write_room = goldfish_tty_write_room,
 168         .chars_in_buffer = goldfish_tty_chars_in_buffer,
 169 };
 170
 171 static int goldfish_tty_create_driver(void)
 172 {
 173         int ret;
 174         struct tty_driver *tty;
 175
 176         goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * goldfish_tty_line_count, GFP_KERNEL);
 177         if(goldfish_ttys == NULL) {
 178                 ret = -ENOMEM;
 179                 goto err_alloc_goldfish_ttys_failed;
 180         }
 181         tty = alloc_tty_driver(goldfish_tty_line_count);
 182         if(tty == NULL) {
 183                 ret = -ENOMEM;
 184                 goto err_alloc_tty_driver_failed;
 185         }
 186         tty->driver_name = "goldfish";
 187         tty->name = "ttyGF";
 188         tty->type = TTY_DRIVER_TYPE_SERIAL;
 189         tty->subtype = SERIAL_TYPE_NORMAL;
 190         tty->init_termios = tty_std_termios;
 191         tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 192         tty_set_operations(tty, &goldfish_tty_ops);
 193         ret = tty_register_driver(tty);
 194         if(ret)
 195                 goto err_tty_register_driver_failed;
 196
 197         goldfish_tty_driver = tty;
 198         return 0;
 199
 200 err_tty_register_driver_failed:
 201         put_tty_driver(tty);
 202 err_alloc_tty_driver_failed:
 203         kfree(goldfish_ttys);
 204         goldfish_ttys = NULL;
 205 err_alloc_goldfish_ttys_failed:
 206         return ret;
 207 }
 208
 209 static void goldfish_tty_delete_driver(void)
 210 {
 211         tty_unregister_driver(goldfish_tty_driver);
 212         put_tty_driver(goldfish_tty_driver);
 213         goldfish_tty_driver = NULL;
 214         kfree(goldfish_ttys);
 215         goldfish_ttys = NULL;
 216 }
 217
 218 static int goldfish_tty_probe(struct platform_device *pdev)
 219 {
 220         struct goldfish_tty *qtty;
 221         int ret = -EINVAL;
 222         int i;
 223         struct resource *r;
 224         struct device *ttydev;
 225         void __iomem *base;
 226         u32 irq;
 227
 228         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 229         if(r == NULL)
 230                 return -EINVAL;
 231
 232         base = ioremap(r->start, 0x1000);
 233         if (base == NULL)
 234                 pr_err("goldfish_tty: unable to remap base\n");
 235
 236         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 237         if(r == NULL)
 238                 goto err_unmap;
 239
 240         irq = r->start;
 241
 242         if(pdev->id >= goldfish_tty_line_count)
 243                 goto err_unmap;
 244
 245         mutex_lock(&goldfish_tty_lock);
 246         if(goldfish_tty_current_line_count == 0) {
 247                 ret = goldfish_tty_create_driver();
 248                 if(ret)
 249                         goto err_create_driver_failed;
 250         }
 251         goldfish_tty_current_line_count++;
 252
 253         qtty = &goldfish_ttys[pdev->id];
 254         spin_lock_init(&qtty->lock);
 255         tty_port_init(&qtty->port);
 256         qtty->port.ops = &goldfish_port_ops;
 257         qtty->base = base;
 258         qtty->irq = irq;
 259
 260         writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 261
 262         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, "goldfish_tty", pdev);
 263         if(ret)
 264                 goto err_request_irq_failed;
 265
 266
 267         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
 268                                                         pdev->id, &pdev->dev);
 269         if(IS_ERR(ttydev)) {
 270                 ret = PTR_ERR(ttydev);
 271                 goto err_tty_register_device_failed;
 272         }
 273
 274         strcpy(qtty->console.name, "ttyGF");
 275         qtty->console.write = goldfish_tty_console_write;
 276         qtty->console.device = goldfish_tty_console_device;
 277         qtty->console.setup = goldfish_tty_console_setup;
 278         qtty->console.flags = CON_PRINTBUFFER;
 279         qtty->console.index = pdev->id;
 280         register_console(&qtty->console);
 281
 282         mutex_unlock(&goldfish_tty_lock);
 283         return 0;
 284
 285         tty_unregister_device(goldfish_tty_driver, i);
 286 err_tty_register_device_failed:
 287         free_irq(irq, pdev);
 288 err_request_irq_failed:
 289         goldfish_tty_current_line_count--;
 290         if(goldfish_tty_current_line_count == 0)
 291                 goldfish_tty_delete_driver();
 292 err_create_driver_failed:
 293         mutex_unlock(&goldfish_tty_lock);
 294 err_unmap:
 295         iounmap(base);
 296         return ret;
 297 }
 298
 299 static int goldfish_tty_remove(struct platform_device *pdev)
 300 {
 301         struct goldfish_tty *qtty;
 302
 303         mutex_lock(&goldfish_tty_lock);
 304
 305         qtty = &goldfish_ttys[pdev->id];
 306         unregister_console(&qtty->console);
 307         tty_unregister_device(goldfish_tty_driver, pdev->id);
 308         iounmap(qtty->base);
 309         qtty->base = 0;
 310         free_irq(qtty->irq, pdev);
 311         goldfish_tty_current_line_count--;
 312         if(goldfish_tty_current_line_count == 0)
 313                 goldfish_tty_delete_driver();
 314         mutex_unlock(&goldfish_tty_lock);
 315         return 0;
 316 }
 317
 318 static struct platform_driver goldfish_tty_platform_driver = {
 319         .probe = goldfish_tty_probe,
 320         .remove = goldfish_tty_remove,
 321         .driver = {
 322                 .name = "goldfish_tty"
 323         }
 324 };
 325
 326 module_platform_driver(goldfish_tty_platform_driver);
 327
 328 MODULE_LICENSE("GPL v2");