drivers/input/joystick/n64joy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Support for the four N64 controllers.
   4  *
   5  * Copyright (c) 2021 Lauri Kasanen
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/errno.h>
  11 #include <linux/init.h>
  12 #include <linux/input.h>
  13 #include <linux/limits.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/mutex.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/slab.h>
  19 #include <linux/timer.h>
  20
  21 MODULE_AUTHOR("Lauri Kasanen <cand@gmx.com>");
  22 MODULE_DESCRIPTION("Driver for N64 controllers");
  23 MODULE_LICENSE("GPL");
  24
  25 #define PIF_RAM 0x1fc007c0
  26
  27 #define SI_DRAM_REG 0
  28 #define SI_READ_REG 1
  29 #define SI_WRITE_REG 4
  30 #define SI_STATUS_REG 6
  31
  32 #define SI_STATUS_DMA_BUSY  BIT(0)
  33 #define SI_STATUS_IO_BUSY   BIT(1)
  34
  35 #define N64_CONTROLLER_ID 0x0500
  36
  37 #define MAX_CONTROLLERS 4
  38
  39 static const char *n64joy_phys[MAX_CONTROLLERS] = {
  40         "n64joy/port0",
  41         "n64joy/port1",
  42         "n64joy/port2",
  43         "n64joy/port3",
  44 };
  45
  46 struct n64joy_priv {
  47         u64 si_buf[8] ____cacheline_aligned;
  48         struct timer_list timer;
  49         struct mutex n64joy_mutex;
  50         struct input_dev *n64joy_dev[MAX_CONTROLLERS];
  51         u32 __iomem *reg_base;
  52         u8 n64joy_opened;
  53 };
  54
  55 struct joydata {
  56         unsigned int: 16; /* unused */
  57         unsigned int err: 2;
  58         unsigned int: 14; /* unused */
  59
  60         union {
  61                 u32 data;
  62
  63                 struct {
  64                         unsigned int a: 1;
  65                         unsigned int b: 1;
  66                         unsigned int z: 1;
  67                         unsigned int start: 1;
  68                         unsigned int up: 1;
  69                         unsigned int down: 1;
  70                         unsigned int left: 1;
  71                         unsigned int right: 1;
  72                         unsigned int: 2; /* unused */
  73                         unsigned int l: 1;
  74                         unsigned int r: 1;
  75                         unsigned int c_up: 1;
  76                         unsigned int c_down: 1;
  77                         unsigned int c_left: 1;
  78                         unsigned int c_right: 1;
  79                         signed int x: 8;
  80                         signed int y: 8;
  81                 };
  82         };
  83 };
  84
  85 static void n64joy_write_reg(u32 __iomem *reg_base, const u8 reg, const u32 value)
  86 {
  87         writel(value, reg_base + reg);
  88 }
  89
  90 static u32 n64joy_read_reg(u32 __iomem *reg_base, const u8 reg)
  91 {
  92         return readl(reg_base + reg);
  93 }
  94
  95 static void n64joy_wait_si_dma(u32 __iomem *reg_base)
  96 {
  97         while (n64joy_read_reg(reg_base, SI_STATUS_REG) &
  98                (SI_STATUS_DMA_BUSY | SI_STATUS_IO_BUSY))
  99                 cpu_relax();
 100 }
 101
 102 static void n64joy_exec_pif(struct n64joy_priv *priv, const u64 in[8])
 103 {
 104         unsigned long flags;
 105
 106         dma_cache_wback_inv((unsigned long) in, 8 * 8);
 107         dma_cache_inv((unsigned long) priv->si_buf, 8 * 8);
 108
 109         local_irq_save(flags);
 110
 111         n64joy_wait_si_dma(priv->reg_base);
 112
 113         barrier();
 114         n64joy_write_reg(priv->reg_base, SI_DRAM_REG, virt_to_phys(in));
 115         barrier();
 116         n64joy_write_reg(priv->reg_base, SI_WRITE_REG, PIF_RAM);
 117         barrier();
 118
 119         n64joy_wait_si_dma(priv->reg_base);
 120
 121         barrier();
 122         n64joy_write_reg(priv->reg_base, SI_DRAM_REG, virt_to_phys(priv->si_buf));
 123         barrier();
 124         n64joy_write_reg(priv->reg_base, SI_READ_REG, PIF_RAM);
 125         barrier();
 126
 127         n64joy_wait_si_dma(priv->reg_base);
 128
 129         local_irq_restore(flags);
 130 }
 131
 132 static const u64 polldata[] ____cacheline_aligned = {
 133         0xff010401ffffffff,
 134         0xff010401ffffffff,
 135         0xff010401ffffffff,
 136         0xff010401ffffffff,
 137         0xfe00000000000000,
 138         0,
 139         0,
 140         1
 141 };
 142
 143 static void n64joy_poll(struct timer_list *t)
 144 {
 145         const struct joydata *data;
 146         struct n64joy_priv *priv = container_of(t, struct n64joy_priv, timer);
 147         struct input_dev *dev;
 148         u32 i;
 149
 150         n64joy_exec_pif(priv, polldata);
 151
 152         data = (struct joydata *) priv->si_buf;
 153
 154         for (i = 0; i < MAX_CONTROLLERS; i++) {
 155                 if (!priv->n64joy_dev[i])
 156                         continue;
 157
 158                 dev = priv->n64joy_dev[i];
 159
 160                 /* d-pad */
 161                 input_report_key(dev, BTN_DPAD_UP, data[i].up);
 162                 input_report_key(dev, BTN_DPAD_DOWN, data[i].down);
 163                 input_report_key(dev, BTN_DPAD_LEFT, data[i].left);
 164                 input_report_key(dev, BTN_DPAD_RIGHT, data[i].right);
 165
 166                 /* c buttons */
 167                 input_report_key(dev, BTN_FORWARD, data[i].c_up);
 168                 input_report_key(dev, BTN_BACK, data[i].c_down);
 169                 input_report_key(dev, BTN_LEFT, data[i].c_left);
 170                 input_report_key(dev, BTN_RIGHT, data[i].c_right);
 171
 172                 /* matching buttons */
 173                 input_report_key(dev, BTN_START, data[i].start);
 174                 input_report_key(dev, BTN_Z, data[i].z);
 175
 176                 /* remaining ones: a, b, l, r */
 177                 input_report_key(dev, BTN_0, data[i].a);
 178                 input_report_key(dev, BTN_1, data[i].b);
 179                 input_report_key(dev, BTN_2, data[i].l);
 180                 input_report_key(dev, BTN_3, data[i].r);
 181
 182                 input_report_abs(dev, ABS_X, data[i].x);
 183                 input_report_abs(dev, ABS_Y, data[i].y);
 184
 185                 input_sync(dev);
 186         }
 187
 188         mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
 189 }
 190
 191 static int n64joy_open(struct input_dev *dev)
 192 {
 193         struct n64joy_priv *priv = input_get_drvdata(dev);
 194
 195         scoped_guard(mutex_intr, &priv->n64joy_mutex) {
 196                 if (!priv->n64joy_opened) {
 197                         /*
 198                          * We could use the vblank irq, but it's not important
 199                          * if the poll point slightly changes.
 200                          */
 201                         timer_setup(&priv->timer, n64joy_poll, 0);
 202                         mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
 203                 }
 204
 205                 priv->n64joy_opened++;
 206                 return 0;
 207         }
 208
 209         return -EINTR;
 210 }
 211
 212 static void n64joy_close(struct input_dev *dev)
 213 {
 214         struct n64joy_priv *priv = input_get_drvdata(dev);
 215
 216         guard(mutex)(&priv->n64joy_mutex);
 217
 218         if (!--priv->n64joy_opened)
 219                 del_timer_sync(&priv->timer);
 220 }
 221
 222 static const u64 __initconst scandata[] ____cacheline_aligned = {
 223         0xff010300ffffffff,
 224         0xff010300ffffffff,
 225         0xff010300ffffffff,
 226         0xff010300ffffffff,
 227         0xfe00000000000000,
 228         0,
 229         0,
 230         1
 231 };
 232
 233 /*
 234  * The target device is embedded and RAM-constrained. We save RAM
 235  * by initializing in __init code that gets dropped late in boot.
 236  * For the same reason there is no module or unloading support.
 237  */
 238 static int __init n64joy_probe(struct platform_device *pdev)
 239 {
 240         const struct joydata *data;
 241         struct n64joy_priv *priv;
 242         struct input_dev *dev;
 243         int err = 0;
 244         u32 i, j, found = 0;
 245
 246         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 247         if (!priv)
 248                 return -ENOMEM;
 249         mutex_init(&priv->n64joy_mutex);
 250
 251         priv->reg_base = devm_platform_ioremap_resource(pdev, 0);
 252         if (IS_ERR(priv->reg_base)) {
 253                 err = PTR_ERR(priv->reg_base);
 254                 goto fail;
 255         }
 256
 257         /* The controllers are not hotpluggable, so we can scan in init */
 258         n64joy_exec_pif(priv, scandata);
 259
 260         data = (struct joydata *) priv->si_buf;
 261
 262         for (i = 0; i < MAX_CONTROLLERS; i++) {
 263                 if (!data[i].err && data[i].data >> 16 == N64_CONTROLLER_ID) {
 264                         found++;
 265
 266                         dev = priv->n64joy_dev[i] = input_allocate_device();
 267                         if (!priv->n64joy_dev[i]) {
 268                                 err = -ENOMEM;
 269                                 goto fail;
 270                         }
 271
 272                         input_set_drvdata(dev, priv);
 273
 274                         dev->name = "N64 controller";
 275                         dev->phys = n64joy_phys[i];
 276                         dev->id.bustype = BUS_HOST;
 277                         dev->id.vendor = 0;
 278                         dev->id.product = data[i].data >> 16;
 279                         dev->id.version = 0;
 280                         dev->dev.parent = &pdev->dev;
 281
 282                         dev->open = n64joy_open;
 283                         dev->close = n64joy_close;
 284
 285                         /* d-pad */
 286                         input_set_capability(dev, EV_KEY, BTN_DPAD_UP);
 287                         input_set_capability(dev, EV_KEY, BTN_DPAD_DOWN);
 288                         input_set_capability(dev, EV_KEY, BTN_DPAD_LEFT);
 289                         input_set_capability(dev, EV_KEY, BTN_DPAD_RIGHT);
 290                         /* c buttons */
 291                         input_set_capability(dev, EV_KEY, BTN_LEFT);
 292                         input_set_capability(dev, EV_KEY, BTN_RIGHT);
 293                         input_set_capability(dev, EV_KEY, BTN_FORWARD);
 294                         input_set_capability(dev, EV_KEY, BTN_BACK);
 295                         /* matching buttons */
 296                         input_set_capability(dev, EV_KEY, BTN_START);
 297                         input_set_capability(dev, EV_KEY, BTN_Z);
 298                         /* remaining ones: a, b, l, r */
 299                         input_set_capability(dev, EV_KEY, BTN_0);
 300                         input_set_capability(dev, EV_KEY, BTN_1);
 301                         input_set_capability(dev, EV_KEY, BTN_2);
 302                         input_set_capability(dev, EV_KEY, BTN_3);
 303
 304                         for (j = 0; j < 2; j++)
 305                                 input_set_abs_params(dev, ABS_X + j,
 306                                                      S8_MIN, S8_MAX, 0, 0);
 307
 308                         err = input_register_device(dev);
 309                         if (err) {
 310                                 input_free_device(dev);
 311                                 goto fail;
 312                         }
 313                 }
 314         }
 315
 316         pr_info("%u controller(s) connected\n", found);
 317
 318         if (!found)
 319                 return -ENODEV;
 320
 321         return 0;
 322 fail:
 323         for (i = 0; i < MAX_CONTROLLERS; i++) {
 324                 if (!priv->n64joy_dev[i])
 325                         continue;
 326                 input_unregister_device(priv->n64joy_dev[i]);
 327         }
 328         return err;
 329 }
 330
 331 static struct platform_driver n64joy_driver = {
 332         .driver = {
 333                 .name = "n64joy",
 334         },
 335 };
 336
 337 static int __init n64joy_init(void)
 338 {
 339         return platform_driver_probe(&n64joy_driver, n64joy_probe);
 340 }
 341
 342 module_init(n64joy_init);