// SPDX-License-Identifier: GPL-2.0
/*
* Support for the four N64 controllers.
*
* Copyright (c) 2021 Lauri Kasanen
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/limits.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/timer.h>
MODULE_AUTHOR("Lauri Kasanen <[email protected]>");
MODULE_DESCRIPTION("Driver for N64 controllers");
MODULE_LICENSE("GPL");
#define PIF_RAM 0x1fc007c0
#define SI_DRAM_REG 0
#define SI_READ_REG 1
#define SI_WRITE_REG 4
#define SI_STATUS_REG 6
#define SI_STATUS_DMA_BUSY BIT(0)
#define SI_STATUS_IO_BUSY BIT(1)
#define N64_CONTROLLER_ID 0x0500
#define MAX_CONTROLLERS 4
static const char *n64joy_phys[MAX_CONTROLLERS] = {
"n64joy/port0",
"n64joy/port1",
"n64joy/port2",
"n64joy/port3",
};
struct n64joy_priv {
u64 si_buf[8] ____cacheline_aligned;
struct timer_list timer;
struct mutex n64joy_mutex;
struct input_dev *n64joy_dev[MAX_CONTROLLERS];
u32 __iomem *reg_base;
u8 n64joy_opened;
};
struct joydata {
unsigned int: 16; /* unused */
unsigned int err: 2;
unsigned int: 14; /* unused */
union {
u32 data;
struct {
unsigned int a: 1;
unsigned int b: 1;
unsigned int z: 1;
unsigned int start: 1;
unsigned int up: 1;
unsigned int down: 1;
unsigned int left: 1;
unsigned int right: 1;
unsigned int: 2; /* unused */
unsigned int l: 1;
unsigned int r: 1;
unsigned int c_up: 1;
unsigned int c_down: 1;
unsigned int c_left: 1;
unsigned int c_right: 1;
signed int x: 8;
signed int y: 8;
};
};
};
static void n64joy_write_reg(u32 __iomem *reg_base, const u8 reg, const u32 value)
{
writel(value, reg_base + reg);
}
static u32 n64joy_read_reg(u32 __iomem *reg_base, const u8 reg)
{
return readl(reg_base + reg);
}
static void n64joy_wait_si_dma(u32 __iomem *reg_base)
{
while (n64joy_read_reg(reg_base, SI_STATUS_REG) &
(SI_STATUS_DMA_BUSY | SI_STATUS_IO_BUSY))
cpu_relax();
}
static void n64joy_exec_pif(struct n64joy_priv *priv, const u64 in[8])
{
unsigned long flags;
dma_cache_wback_inv((unsigned long) in, 8 * 8);
dma_cache_inv((unsigned long) priv->si_buf, 8 * 8);
local_irq_save(flags);
n64joy_wait_si_dma(priv->reg_base);
barrier();
n64joy_write_reg(priv->reg_base, SI_DRAM_REG, virt_to_phys(in));
barrier();
n64joy_write_reg(priv->reg_base, SI_WRITE_REG, PIF_RAM);
barrier();
n64joy_wait_si_dma(priv->reg_base);
barrier();
n64joy_write_reg(priv->reg_base, SI_DRAM_REG, virt_to_phys(priv->si_buf));
barrier();
n64joy_write_reg(priv->reg_base, SI_READ_REG, PIF_RAM);
barrier();
n64joy_wait_si_dma(priv->reg_base);
local_irq_restore(flags);
}
static const u64 polldata[] ____cacheline_aligned = {
0xff010401ffffffff,
0xff010401ffffffff,
0xff010401ffffffff,
0xff010401ffffffff,
0xfe00000000000000,
0,
0,
1
};
static void n64joy_poll(struct timer_list *t)
{
const struct joydata *data;
struct n64joy_priv *priv = container_of(t, struct n64joy_priv, timer);
struct input_dev *dev;
u32 i;
n64joy_exec_pif(priv, polldata);
data = (struct joydata *) priv->si_buf;
for (i = 0; i < MAX_CONTROLLERS; i++) {
if (!priv->n64joy_dev[i])
continue;
dev = priv->n64joy_dev[i];
/* d-pad */
input_report_key(dev, BTN_DPAD_UP, data[i].up);
input_report_key(dev, BTN_DPAD_DOWN, data[i].down);
input_report_key(dev, BTN_DPAD_LEFT, data[i].left);
input_report_key(dev, BTN_DPAD_RIGHT, data[i].right);
/* c buttons */
input_report_key(dev, BTN_FORWARD, data[i].c_up);
input_report_key(dev, BTN_BACK, data[i].c_down);
input_report_key(dev, BTN_LEFT, data[i].c_left);
input_report_key(dev, BTN_RIGHT, data[i].c_right);
/* matching buttons */
input_report_key(dev, BTN_START, data[i].start);
input_report_key(dev, BTN_Z, data[i].z);
/* remaining ones: a, b, l, r */
input_report_key(dev, BTN_0, data[i].a);
input_report_key(dev, BTN_1, data[i].b);
input_report_key(dev, BTN_2, data[i].l);
input_report_key(dev, BTN_3, data[i].r);
input_report_abs(dev, ABS_X, data[i].x);
input_report_abs(dev, ABS_Y, data[i].y);
input_sync(dev);
}
mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
}
static int n64joy_open(struct input_dev *dev)
{
struct n64joy_priv *priv = input_get_drvdata(dev);
int err;
err = mutex_lock_interruptible(&priv->n64joy_mutex);
if (err)
return err;
if (!priv->n64joy_opened) {
/*
* We could use the vblank irq, but it's not important if
* the poll point slightly changes.
*/
timer_setup(&priv->timer, n64joy_poll, 0);
mod_timer(&priv->timer, jiffies + msecs_to_jiffies(16));
}
priv->n64joy_opened++;
mutex_unlock(&priv->n64joy_mutex);
return err;
}
static void n64joy_close(struct input_dev *dev)
{
struct n64joy_priv *priv = input_get_drvdata(dev);
mutex_lock(&priv->n64joy_mutex);
if (!--priv->n64joy_opened)
del_timer_sync(&priv->timer);
mutex_unlock(&priv->n64joy_mutex);
}
static const u64 __initconst scandata[] ____cacheline_aligned = {
0xff010300ffffffff,
0xff010300ffffffff,
0xff010300ffffffff,
0xff010300ffffffff,
0xfe00000000000000,
0,
0,
1
};
/*
* The target device is embedded and RAM-constrained. We save RAM
* by initializing in __init code that gets dropped late in boot.
* For the same reason there is no module or unloading support.
*/
static int __init n64joy_probe(struct platform_device *pdev)
{
const struct joydata *data;
struct n64joy_priv *priv;
struct input_dev *dev;
int err = 0;
u32 i, j, found = 0;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
mutex_init(&priv->n64joy_mutex);
priv->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->reg_base)) {
err = PTR_ERR(priv->reg_base);
goto fail;
}
/* The controllers are not hotpluggable, so we can scan in init */
n64joy_exec_pif(priv, scandata);
data = (struct joydata *) priv->si_buf;
for (i = 0; i < MAX_CONTROLLERS; i++) {
if (!data[i].err && data[i].data >> 16 == N64_CONTROLLER_ID) {
found++;
dev = priv->n64joy_dev[i] = input_allocate_device();
if (!priv->n64joy_dev[i]) {
err = -ENOMEM;
goto fail;
}
input_set_drvdata(dev, priv);
dev->name = "N64 controller";
dev->phys = n64joy_phys[i];
dev->id.bustype = BUS_HOST;
dev->id.vendor = 0;
dev->id.product = data[i].data >> 16;
dev->id.version = 0;
dev->dev.parent = &pdev->dev;
dev->open = n64joy_open;
dev->close = n64joy_close;
/* d-pad */
input_set_capability(dev, EV_KEY, BTN_DPAD_UP);
input_set_capability(dev, EV_KEY, BTN_DPAD_DOWN);
input_set_capability(dev, EV_KEY, BTN_DPAD_LEFT);
input_set_capability(dev, EV_KEY, BTN_DPAD_RIGHT);
/* c buttons */
input_set_capability(dev, EV_KEY, BTN_LEFT);
input_set_capability(dev, EV_KEY, BTN_RIGHT);
input_set_capability(dev, EV_KEY, BTN_FORWARD);
input_set_capability(dev, EV_KEY, BTN_BACK);
/* matching buttons */
input_set_capability(dev, EV_KEY, BTN_START);
input_set_capability(dev, EV_KEY, BTN_Z);
/* remaining ones: a, b, l, r */
input_set_capability(dev, EV_KEY, BTN_0);
input_set_capability(dev, EV_KEY, BTN_1);
input_set_capability(dev, EV_KEY, BTN_2);
input_set_capability(dev, EV_KEY, BTN_3);
for (j = 0; j < 2; j++)
input_set_abs_params(dev, ABS_X + j,
S8_MIN, S8_MAX, 0, 0);
err = input_register_device(dev);
if (err) {
input_free_device(dev);
goto fail;
}
}
}
pr_info("%u controller(s) connected\n", found);
if (!found)
return -ENODEV;
return 0;
fail:
for (i = 0; i < MAX_CONTROLLERS; i++) {
if (!priv->n64joy_dev[i])
continue;
input_unregister_device(priv->n64joy_dev[i]);
}
return err;
}
static struct platform_driver n64joy_driver = {
.driver = {
.name = "n64joy",
},
};
static int __init n64joy_init(void)
{
return platform_driver_probe(&n64joy_driver, n64joy_probe);
}
module_init(n64joy_init);
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