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 platform_device *pdev = dev_id;
  72         struct goldfish_tty *qtty = &goldfish_ttys[pdev->id];
  73         void __iomem *base = qtty->base;
  74         unsigned long irq_flags;
  75         unsigned char *buf;
  76         u32 count;
  77
  78         count = readl(base + GOLDFISH_TTY_BYTES_READY);
  79         if (count == 0)
  80                 return IRQ_NONE;
  81
  82         count = tty_prepare_flip_string(&qtty->port, &buf, count);
  83         spin_lock_irqsave(&qtty->lock, irq_flags);
  84         gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
  85                                 base + GOLDFISH_TTY_DATA_PTR_HIGH);
  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(&qtty->port);
  90         return IRQ_HANDLED;
  91 }
  92
  93 static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
  94 {
  95         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
  96                                                                         port);
  97         writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_CMD);
  98         return 0;
  99 }
 100
 101 static void goldfish_tty_shutdown(struct tty_port *port)
 102 {
 103         struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 104                                                                         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,
 125                                                                 int count)
 126 {
 127         goldfish_tty_do_write(tty->index, buf, count);
 128         return count;
 129 }
 130
 131 static int goldfish_tty_write_room(struct tty_struct *tty)
 132 {
 133         return 0x10000;
 134 }
 135
 136 static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
 137 {
 138         struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 139         void __iomem *base = qtty->base;
 140         return readl(base + GOLDFISH_TTY_BYTES_READY);
 141 }
 142
 143 static void goldfish_tty_console_write(struct console *co, const char *b,
 144                                                                 unsigned count)
 145 {
 146         goldfish_tty_do_write(co->index, b, count);
 147 }
 148
 149 static struct tty_driver *goldfish_tty_console_device(struct console *c,
 150                                                                 int *index)
 151 {
 152         *index = c->index;
 153         return goldfish_tty_driver;
 154 }
 155
 156 static int goldfish_tty_console_setup(struct console *co, char *options)
 157 {
 158         if ((unsigned)co->index >= goldfish_tty_line_count)
 159                 return -ENODEV;
 160         if (!goldfish_ttys[co->index].base)
 161                 return -ENODEV;
 162         return 0;
 163 }
 164
 165 static struct tty_port_operations goldfish_port_ops = {
 166         .activate = goldfish_tty_activate,
 167         .shutdown = goldfish_tty_shutdown
 168 };
 169
 170 static const struct tty_operations goldfish_tty_ops = {
 171         .open = goldfish_tty_open,
 172         .close = goldfish_tty_close,
 173         .hangup = goldfish_tty_hangup,
 174         .write = goldfish_tty_write,
 175         .write_room = goldfish_tty_write_room,
 176         .chars_in_buffer = goldfish_tty_chars_in_buffer,
 177 };
 178
 179 static int goldfish_tty_create_driver(void)
 180 {
 181         int ret;
 182         struct tty_driver *tty;
 183
 184         goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) *
 185                                 goldfish_tty_line_count, GFP_KERNEL);
 186         if (goldfish_ttys == NULL) {
 187                 ret = -ENOMEM;
 188                 goto err_alloc_goldfish_ttys_failed;
 189         }
 190         tty = alloc_tty_driver(goldfish_tty_line_count);
 191         if (tty == NULL) {
 192                 ret = -ENOMEM;
 193                 goto err_alloc_tty_driver_failed;
 194         }
 195         tty->driver_name = "goldfish";
 196         tty->name = "ttyGF";
 197         tty->type = TTY_DRIVER_TYPE_SERIAL;
 198         tty->subtype = SERIAL_TYPE_NORMAL;
 199         tty->init_termios = tty_std_termios;
 200         tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 201                                                 TTY_DRIVER_DYNAMIC_DEV;
 202         tty_set_operations(tty, &goldfish_tty_ops);
 203         ret = tty_register_driver(tty);
 204         if (ret)
 205                 goto err_tty_register_driver_failed;
 206
 207         goldfish_tty_driver = tty;
 208         return 0;
 209
 210 err_tty_register_driver_failed:
 211         put_tty_driver(tty);
 212 err_alloc_tty_driver_failed:
 213         kfree(goldfish_ttys);
 214         goldfish_ttys = NULL;
 215 err_alloc_goldfish_ttys_failed:
 216         return ret;
 217 }
 218
 219 static void goldfish_tty_delete_driver(void)
 220 {
 221         tty_unregister_driver(goldfish_tty_driver);
 222         put_tty_driver(goldfish_tty_driver);
 223         goldfish_tty_driver = NULL;
 224         kfree(goldfish_ttys);
 225         goldfish_ttys = NULL;
 226 }
 227
 228 static int goldfish_tty_probe(struct platform_device *pdev)
 229 {
 230         struct goldfish_tty *qtty;
 231         int ret = -EINVAL;
 232         struct resource *r;
 233         struct device *ttydev;
 234         void __iomem *base;
 235         u32 irq;
 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         if (pdev->id >= goldfish_tty_line_count)
 252                 goto err_unmap;
 253
 254         mutex_lock(&goldfish_tty_lock);
 255         if (goldfish_tty_current_line_count == 0) {
 256                 ret = goldfish_tty_create_driver();
 257                 if (ret)
 258                         goto err_create_driver_failed;
 259         }
 260         goldfish_tty_current_line_count++;
 261
 262         qtty = &goldfish_ttys[pdev->id];
 263         spin_lock_init(&qtty->lock);
 264         tty_port_init(&qtty->port);
 265         qtty->port.ops = &goldfish_port_ops;
 266         qtty->base = base;
 267         qtty->irq = irq;
 268
 269         writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 270
 271         ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
 272                                                 "goldfish_tty", pdev);
 273         if (ret)
 274                 goto err_request_irq_failed;
 275
 276
 277         ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
 278                                                         pdev->id, &pdev->dev);
 279         if (IS_ERR(ttydev)) {
 280                 ret = PTR_ERR(ttydev);
 281                 goto err_tty_register_device_failed;
 282         }
 283
 284         strcpy(qtty->console.name, "ttyGF");
 285         qtty->console.write = goldfish_tty_console_write;
 286         qtty->console.device = goldfish_tty_console_device;
 287         qtty->console.setup = goldfish_tty_console_setup;
 288         qtty->console.flags = CON_PRINTBUFFER;
 289         qtty->console.index = pdev->id;
 290         register_console(&qtty->console);
 291
 292         mutex_unlock(&goldfish_tty_lock);
 293         return 0;
 294
 295 err_tty_register_device_failed:
 296         free_irq(irq, pdev);
 297 err_request_irq_failed:
 298         goldfish_tty_current_line_count--;
 299         if (goldfish_tty_current_line_count == 0)
 300                 goldfish_tty_delete_driver();
 301 err_create_driver_failed:
 302         mutex_unlock(&goldfish_tty_lock);
 303 err_unmap:
 304         iounmap(base);
 305         return ret;
 306 }
 307
 308 static int goldfish_tty_remove(struct platform_device *pdev)
 309 {
 310         struct goldfish_tty *qtty;
 311
 312         mutex_lock(&goldfish_tty_lock);
 313
 314         qtty = &goldfish_ttys[pdev->id];
 315         unregister_console(&qtty->console);
 316         tty_unregister_device(goldfish_tty_driver, pdev->id);
 317         iounmap(qtty->base);
 318         qtty->base = NULL;
 319         free_irq(qtty->irq, pdev);
 320         goldfish_tty_current_line_count--;
 321         if (goldfish_tty_current_line_count == 0)
 322                 goldfish_tty_delete_driver();
 323         mutex_unlock(&goldfish_tty_lock);
 324         return 0;
 325 }
 326
 327 static struct platform_driver goldfish_tty_platform_driver = {
 328         .probe = goldfish_tty_probe,
 329         .remove = goldfish_tty_remove,
 330         .driver = {
 331                 .name = "goldfish_tty"
 332         }
 333 };
 334
 335 module_platform_driver(goldfish_tty_platform_driver);
 336
 337 MODULE_LICENSE("GPL v2");