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
  25 enum {
  26         GOLDFISH_TTY_PUT_CHAR       = 0x00,
  27         GOLDFISH_TTY_BYTES_READY    = 0x04,
  28         GOLDFISH_TTY_CMD            = 0x08,
  29
  30         GOLDFISH_TTY_DATA_PTR       = 0x10,
  31         GOLDFISH_TTY_DATA_LEN       = 0x14,
  32
  33         GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
  34         GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
  35         GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
  36         GOLDFISH_TTY_CMD_READ_BUFFER    = 3,
  37 };
  38
  39 struct goldfish_tty {
  40         struct tty_port port;
  41         spinlock_t lock;
  42         void __iomem *base;
  43         u32 irq;
  44         int opencount;
  45         struct console console;
  46 };
  47
  48 static DEFINE_MUTEX(goldfish_tty_lock);
  49 static struct tty_driver *goldfish_tty_driver;
  50 static u32 goldfish_tty_line_count = 8;
  51 static u32 goldfish_tty_current_line_count;
  52 static struct goldfish_tty *goldfish_ttys;
  53
  54 static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
  55 {
  56         unsigned long irq_flags;
  57         struct goldfish_tty *qtty = &goldfish_ttys[line];
  58         void __iomem *base = qtty->base;
  59         spin_lock_irqsave(&qtty->lock, irq_flags);
  60         writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
  61         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  62         writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
  63         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  64 }
  65
  66 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
  67 {
  68         struct platform_device *pdev = dev_id;
  69         struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
  70         void __iomem *base = qtty->base;
  71         unsigned long irq_flags;
  72         unsigned char *buf;
  73         u32 count;
  74
  75         count = readl(base + GOLDFISH_TTY_BYTES_READY);
  76         if(count == 0)
  77                 return IRQ_NONE;
  78
  79         count = tty_prepare_flip_string(&qtty->port, &buf, count);
  80         spin_lock_irqsave(&qtty->lock, irq_flags);
  81         writel((u32)buf, base + GOLDFISH_TTY_DATA_PTR);
  82         writel(count, base + GOLDFISH_TTY_DATA_LEN);
  83         writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
  84         spin_unlock_irqrestore(&qtty->lock, irq_flags);
  85         tty_schedule_flip(&qtty->port);
  86         return IRQ_HANDLED;
  87 }
  88
  89 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
  90 {
  91         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
  92         writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
  93         return 0;
  94 }
  95
  96 static void goldfish_tty_shutdown(struct tty_port *port)
  97 {
  98         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, port);
  99         writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_CMD);
 100 }
 101
 102 static int goldfish_tty_open(struct tty_struct * tty, struct file * filp)
 103 {
 104         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 105         return tty_port_open(&qtty->port, tty, filp);
 106 }
 107
 108 static void goldfish_tty_close(struct tty_struct * tty, struct file * filp)
 109 {
 110         tty_port_close(tty->port, tty, filp);
 111 }
 112
 113 static void goldfish_tty_hangup(struct tty_struct *tty)
 114 {
 115         tty_port_hangup(tty->port);
 116 }
 117
 118 static int goldfish_tty_write(struct tty_struct * tty, const unsigned char *buf, int count)
 119 {
 120         goldfish_tty_do_write(tty->index, buf, count);
 121         return count;
 122 }
 123
 124 static int goldfish_tty_write_room(struct tty_struct *tty)
 125 {
 126         return 0x10000;
 127 }
 128
 129 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
 130 {
 131         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 132         void __iomem *base = qtty->base;
 133         return readl(base + GOLDFISH_TTY_BYTES_READY);
 134 }
 135
 136 static void goldfish_tty_console_write(struct console *co, const char *b, unsigned count)
 137 {
 138         goldfish_tty_do_write(co->index, b, count);
 139 }
 140
 141 static struct tty_driver *goldfish_tty_console_device(struct console *c, int *index)
 142 {
 143         *index = c->index;
 144         return goldfish_tty_driver;
 145 }
 146
 147 static int goldfish_tty_console_setup(struct console *co, char *options)
 148 {
 149         if((unsigned)co->index > goldfish_tty_line_count)
 150                 return -ENODEV;
 151         if(goldfish_ttys[co->index].base == 0)
 152                 return -ENODEV;
 153         return 0;
 154 }
 155
 156 static struct tty_port_operations goldfish_port_ops = {
 157         .activate = goldfish_tty_activate,
 158         .shutdown = goldfish_tty_shutdown
 159 };
 160
 161 static struct tty_operations goldfish_tty_ops = {
 162         .open = goldfish_tty_open,
 163         .close = goldfish_tty_close,
 164         .hangup = goldfish_tty_hangup,
 165         .write = goldfish_tty_write,
 166         .write_room = goldfish_tty_write_room,
 167         .chars_in_buffer = goldfish_tty_chars_in_buffer,
 168 };
 169
 170 static int goldfish_tty_create_driver(void)
 171 {
 172         int ret;
 173         struct tty_driver *tty;
 174
 175         goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) * goldfish_tty_line_count, GFP_KERNEL);
 176         if(goldfish_ttys == NULL) {
 177                 ret = -ENOMEM;
 178                 goto err_alloc_goldfish_ttys_failed;
 179         }
 180         tty = alloc_tty_driver(goldfish_tty_line_count);
 181         if(tty == NULL) {
 182                 ret = -ENOMEM;
 183                 goto err_alloc_tty_driver_failed;
 184         }
 185         tty->driver_name = "goldfish";
 186         tty->name = "ttyGF";
 187         tty->type = TTY_DRIVER_TYPE_SERIAL;
 188         tty->subtype = SERIAL_TYPE_NORMAL;
 189         tty->init_termios = tty_std_termios;
 190         tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 191         tty_set_operations(tty, &goldfish_tty_ops);
 192         ret = tty_register_driver(tty);
 193         if(ret)
 194                 goto err_tty_register_driver_failed;
 195
 196         goldfish_tty_driver = tty;
 197         return 0;
 198
 199 err_tty_register_driver_failed:
 200         put_tty_driver(tty);
 201 err_alloc_tty_driver_failed:
 202         kfree(goldfish_ttys);
 203         goldfish_ttys = NULL;
 204 err_alloc_goldfish_ttys_failed:
 205         return ret;
 206 }
 207
 208 static void goldfish_tty_delete_driver(void)
 209 {
 210         tty_unregister_driver(goldfish_tty_driver);
 211         put_tty_driver(goldfish_tty_driver);
 212         goldfish_tty_driver = NULL;
 213         kfree(goldfish_ttys);
 214         goldfish_ttys = NULL;
 215 }
 216
 217 static int goldfish_tty_probe(struct platform_device *pdev)
 218 {
 219         struct goldfish_tty *qtty;
 220         int ret = -EINVAL;
 221         int i;
 222         struct resource *r;
 223         struct device *ttydev;
 224         void __iomem *base;
 225         u32 irq;
 226
 227         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 228         if(r == NULL)
 229                 return -EINVAL;
 230
 231         base = ioremap(r->start, 0x1000);
 232         if (base == NULL)
 233                 pr_err("goldfish_tty: unable to remap base\n");
 234
 235         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 236         if(r == NULL)
 237                 goto err_unmap;
 238
 239         irq = r->start;
 240
 241         if(pdev->id >= goldfish_tty_line_count)
 242                 goto err_unmap;
 243
 244         mutex_lock(&goldfish_tty_lock);
 245         if(goldfish_tty_current_line_count == 0) {
 246                 ret = goldfish_tty_create_driver();
 247                 if(ret)
 248                         goto err_create_driver_failed;
 249         }
 250         goldfish_tty_current_line_count++;
 251
 252         qtty = &goldfish_ttys[pdev->id];
 253         spin_lock_init(&qtty->lock);
 254         tty_port_init(&qtty->port);
 255         qtty->port.ops = &goldfish_port_ops;
 256         qtty->base = base;
 257         qtty->irq = irq;
 258
 259         writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 260
 261         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, "goldfish_tty", pdev);
 262         if(ret)
 263                 goto err_request_irq_failed;
 264
 265
 266         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
 267                                                         pdev->id, &pdev->dev);
 268         if(IS_ERR(ttydev)) {
 269                 ret = PTR_ERR(ttydev);
 270                 goto err_tty_register_device_failed;
 271         }
 272
 273         strcpy(qtty->console.name, "ttyGF");
 274         qtty->console.write = goldfish_tty_console_write;
 275         qtty->console.device = goldfish_tty_console_device;
 276         qtty->console.setup = goldfish_tty_console_setup;
 277         qtty->console.flags = CON_PRINTBUFFER;
 278         qtty->console.index = pdev->id;
 279         register_console(&qtty->console);
 280
 281         mutex_unlock(&goldfish_tty_lock);
 282         return 0;
 283
 284         tty_unregister_device(goldfish_tty_driver, i);
 285 err_tty_register_device_failed:
 286         free_irq(irq, pdev);
 287 err_request_irq_failed:
 288         goldfish_tty_current_line_count--;
 289         if(goldfish_tty_current_line_count == 0)
 290                 goldfish_tty_delete_driver();
 291 err_create_driver_failed:
 292         mutex_unlock(&goldfish_tty_lock);
 293 err_unmap:
 294         iounmap(base);
 295         return ret;
 296 }
 297
 298 static int goldfish_tty_remove(struct platform_device *pdev)
 299 {
 300         struct goldfish_tty *qtty;
 301
 302         mutex_lock(&goldfish_tty_lock);
 303
 304         qtty = &goldfish_ttys[pdev->id];
 305         unregister_console(&qtty->console);
 306         tty_unregister_device(goldfish_tty_driver, pdev->id);
 307         iounmap(qtty->base);
 308         qtty->base = 0;
 309         free_irq(qtty->irq, pdev);
 310         goldfish_tty_current_line_count--;
 311         if(goldfish_tty_current_line_count == 0)
 312                 goldfish_tty_delete_driver();
 313         mutex_unlock(&goldfish_tty_lock);
 314         return 0;
 315 }
 316
 317 static struct platform_driver goldfish_tty_platform_driver = {
 318         .probe = goldfish_tty_probe,
 319         .remove = goldfish_tty_remove,
 320         .driver = {
 321                 .name = "goldfish_tty"
 322         }
 323 };
 324
 325 module_platform_driver(goldfish_tty_platform_driver);
 326
 327 MODULE_LICENSE("GPL v2");