[mirror_ubuntu-bionic-kernel.git] / drivers / tty / goldfish.c

/*
 * Copyright (C) 2007 Google, Inc.
 * Copyright (C) 2012 Intel, Inc.
 * Copyright (C) 2017 Imagination Technologies Ltd.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/goldfish.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/serial_core.h>

/* Goldfish tty register's offsets */
#define	GOLDFISH_TTY_REG_BYTES_READY	0x04
#define	GOLDFISH_TTY_REG_CMD		0x08
#define	GOLDFISH_TTY_REG_DATA_PTR	0x10
#define	GOLDFISH_TTY_REG_DATA_LEN	0x14
#define	GOLDFISH_TTY_REG_DATA_PTR_HIGH	0x18
#define	GOLDFISH_TTY_REG_VERSION	0x20

/* Goldfish tty commands */
#define	GOLDFISH_TTY_CMD_INT_DISABLE	0
#define	GOLDFISH_TTY_CMD_INT_ENABLE	1
#define	GOLDFISH_TTY_CMD_WRITE_BUFFER	2
#define	GOLDFISH_TTY_CMD_READ_BUFFER	3

struct goldfish_tty {
	struct tty_port port;
	spinlock_t lock;
	void __iomem *base;
	u32 irq;
	int opencount;
	struct console console;
	u32 version;
	struct device *dev;
};

static DEFINE_MUTEX(goldfish_tty_lock);
static struct tty_driver *goldfish_tty_driver;
static u32 goldfish_tty_line_count = 8;
static u32 goldfish_tty_current_line_count;
static struct goldfish_tty *goldfish_ttys;

static void do_rw_io(struct goldfish_tty *qtty,
		     unsigned long address,
		     unsigned int count,
		     int is_write)
{
	unsigned long irq_flags;
	void __iomem *base = qtty->base;

	spin_lock_irqsave(&qtty->lock, irq_flags);
	gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
		     base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
	writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);

	if (is_write)
		writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
		       base + GOLDFISH_TTY_REG_CMD);
	else
		writel(GOLDFISH_TTY_CMD_READ_BUFFER,
		       base + GOLDFISH_TTY_REG_CMD);

	spin_unlock_irqrestore(&qtty->lock, irq_flags);
}

static void goldfish_tty_rw(struct goldfish_tty *qtty,
			    unsigned long addr,
			    unsigned int count,
			    int is_write)
{
	dma_addr_t dma_handle;
	enum dma_data_direction dma_dir;

	dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	if (qtty->version > 0) {
		/*
		 * Goldfish TTY for Ranchu platform uses
		 * physical addresses and DMA for read/write operations
		 */
		unsigned long addr_end = addr + count;

		while (addr < addr_end) {
			unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
			unsigned long next =
					pg_end < addr_end ? pg_end : addr_end;
			unsigned long avail = next - addr;

			/*
			 * Map the buffer's virtual address to the DMA address
			 * so the buffer can be accessed by the device.
			 */
			dma_handle = dma_map_single(qtty->dev, (void *)addr,
						    avail, dma_dir);

			if (dma_mapping_error(qtty->dev, dma_handle)) {
				dev_err(qtty->dev, "tty: DMA mapping error.\n");
				return;
			}
			do_rw_io(qtty, dma_handle, avail, is_write);

			/*
			 * Unmap the previously mapped region after
			 * the completion of the read/write operation.
			 */
			dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);

			addr += avail;
		}
	} else {
		/*
		 * Old style Goldfish TTY used on the Goldfish platform
		 * uses virtual addresses.
		 */
		do_rw_io(qtty, addr, count, is_write);
	}
}

static void goldfish_tty_do_write(int line, const char *buf,
				  unsigned int count)
{
	struct goldfish_tty *qtty = &goldfish_ttys[line];
	unsigned long address = (unsigned long)(void *)buf;

	goldfish_tty_rw(qtty, address, count, 1);
}

static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
{
	struct goldfish_tty *qtty = dev_id;
	void __iomem *base = qtty->base;
	unsigned long address;
	unsigned char *buf;
	u32 count;

	count = readl(base + GOLDFISH_TTY_REG_BYTES_READY);
	if (count == 0)
		return IRQ_NONE;

	count = tty_prepare_flip_string(&qtty->port, &buf, count);

	address = (unsigned long)(void *)buf;
	goldfish_tty_rw(qtty, address, count, 0);

	tty_schedule_flip(&qtty->port);
	return IRQ_HANDLED;
}

static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
{
	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
									port);
	writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
	return 0;
}

static void goldfish_tty_shutdown(struct tty_port *port)
{
	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
									port);
	writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
}

static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
{
	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	return tty_port_open(&qtty->port, tty, filp);
}

static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)
{
	tty_port_close(tty->port, tty, filp);
}

static void goldfish_tty_hangup(struct tty_struct *tty)
{
	tty_port_hangup(tty->port);
}

static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf,
								int count)
{
	goldfish_tty_do_write(tty->index, buf, count);
	return count;
}

static int goldfish_tty_write_room(struct tty_struct *tty)
{
	return 0x10000;
}

static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
{
	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	void __iomem *base = qtty->base;
	return readl(base + GOLDFISH_TTY_REG_BYTES_READY);
}

static void goldfish_tty_console_write(struct console *co, const char *b,
								unsigned count)
{
	goldfish_tty_do_write(co->index, b, count);
}

static struct tty_driver *goldfish_tty_console_device(struct console *c,
								int *index)
{
	*index = c->index;
	return goldfish_tty_driver;
}

static int goldfish_tty_console_setup(struct console *co, char *options)
{
	if ((unsigned)co->index >= goldfish_tty_line_count)
		return -ENODEV;
	if (!goldfish_ttys[co->index].base)
		return -ENODEV;
	return 0;
}

static const struct tty_port_operations goldfish_port_ops = {
	.activate = goldfish_tty_activate,
	.shutdown = goldfish_tty_shutdown
};

static const struct tty_operations goldfish_tty_ops = {
	.open = goldfish_tty_open,
	.close = goldfish_tty_close,
	.hangup = goldfish_tty_hangup,
	.write = goldfish_tty_write,
	.write_room = goldfish_tty_write_room,
	.chars_in_buffer = goldfish_tty_chars_in_buffer,
};

static int goldfish_tty_create_driver(void)
{
	int ret;
	struct tty_driver *tty;

	goldfish_ttys = kzalloc(sizeof(*goldfish_ttys) *
				goldfish_tty_line_count, GFP_KERNEL);
	if (goldfish_ttys == NULL) {
		ret = -ENOMEM;
		goto err_alloc_goldfish_ttys_failed;
	}
	tty = alloc_tty_driver(goldfish_tty_line_count);
	if (tty == NULL) {
		ret = -ENOMEM;
		goto err_alloc_tty_driver_failed;
	}
	tty->driver_name = "goldfish";
	tty->name = "ttyGF";
	tty->type = TTY_DRIVER_TYPE_SERIAL;
	tty->subtype = SERIAL_TYPE_NORMAL;
	tty->init_termios = tty_std_termios;
	tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
						TTY_DRIVER_DYNAMIC_DEV;
	tty_set_operations(tty, &goldfish_tty_ops);
	ret = tty_register_driver(tty);
	if (ret)
		goto err_tty_register_driver_failed;

	goldfish_tty_driver = tty;
	return 0;

err_tty_register_driver_failed:
	put_tty_driver(tty);
err_alloc_tty_driver_failed:
	kfree(goldfish_ttys);
	goldfish_ttys = NULL;
err_alloc_goldfish_ttys_failed:
	return ret;
}

static void goldfish_tty_delete_driver(void)
{
	tty_unregister_driver(goldfish_tty_driver);
	put_tty_driver(goldfish_tty_driver);
	goldfish_tty_driver = NULL;
	kfree(goldfish_ttys);
	goldfish_ttys = NULL;
}

static int goldfish_tty_probe(struct platform_device *pdev)
{
	struct goldfish_tty *qtty;
	int ret = -ENODEV;
	struct resource *r;
	struct device *ttydev;
	void __iomem *base;
	u32 irq;
	unsigned int line;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		pr_err("goldfish_tty: No MEM resource available!\n");
		return -ENOMEM;
	}

	base = ioremap(r->start, 0x1000);
	if (!base) {
		pr_err("goldfish_tty: Unable to ioremap base!\n");
		return -ENOMEM;
	}

	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!r) {
		pr_err("goldfish_tty: No IRQ resource available!\n");
		goto err_unmap;
	}

	irq = r->start;

	mutex_lock(&goldfish_tty_lock);

	if (pdev->id == PLATFORM_DEVID_NONE)
		line = goldfish_tty_current_line_count;
	else
		line = pdev->id;

	if (line >= goldfish_tty_line_count) {
		pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
		       goldfish_tty_current_line_count);
		ret = -ENOMEM;
		goto err_unlock;
	}

	if (goldfish_tty_current_line_count == 0) {
		ret = goldfish_tty_create_driver();
		if (ret)
			goto err_unlock;
	}
	goldfish_tty_current_line_count++;

	qtty = &goldfish_ttys[line];
	spin_lock_init(&qtty->lock);
	tty_port_init(&qtty->port);
	qtty->port.ops = &goldfish_port_ops;
	qtty->base = base;
	qtty->irq = irq;
	qtty->dev = &pdev->dev;

	/*
	 * Goldfish TTY device used by the Goldfish emulator
	 * should identify itself with 0, forcing the driver
	 * to use virtual addresses. Goldfish TTY device
	 * on Ranchu emulator (qemu2) returns 1 here and
	 * driver will use physical addresses.
	 */
	qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION);

	/*
	 * Goldfish TTY device on Ranchu emulator (qemu2)
	 * will use DMA for read/write IO operations.
	 */
	if (qtty->version > 0) {
		/*
		 * Initialize dma_mask to 32-bits.
		 */
		if (!pdev->dev.dma_mask)
			pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
		ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
		if (ret) {
			dev_err(&pdev->dev, "No suitable DMA available.\n");
			goto err_dec_line_count;
		}
	}

	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);

	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
			  "goldfish_tty", qtty);
	if (ret) {
		pr_err("goldfish_tty: No IRQ available!\n");
		goto err_dec_line_count;
	}

	ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
					  line, &pdev->dev);
	if (IS_ERR(ttydev)) {
		ret = PTR_ERR(ttydev);
		goto err_tty_register_device_failed;
	}

	strcpy(qtty->console.name, "ttyGF");
	qtty->console.write = goldfish_tty_console_write;
	qtty->console.device = goldfish_tty_console_device;
	qtty->console.setup = goldfish_tty_console_setup;
	qtty->console.flags = CON_PRINTBUFFER;
	qtty->console.index = line;
	register_console(&qtty->console);
	platform_set_drvdata(pdev, qtty);

	mutex_unlock(&goldfish_tty_lock);
	return 0;

err_tty_register_device_failed:
	free_irq(irq, qtty);
err_dec_line_count:
	goldfish_tty_current_line_count--;
	if (goldfish_tty_current_line_count == 0)
		goldfish_tty_delete_driver();
err_unlock:
	mutex_unlock(&goldfish_tty_lock);
err_unmap:
	iounmap(base);
	return ret;
}

static int goldfish_tty_remove(struct platform_device *pdev)
{
	struct goldfish_tty *qtty = platform_get_drvdata(pdev);

	mutex_lock(&goldfish_tty_lock);

	unregister_console(&qtty->console);
	tty_unregister_device(goldfish_tty_driver, qtty->console.index);
	iounmap(qtty->base);
	qtty->base = NULL;
	free_irq(qtty->irq, pdev);
	goldfish_tty_current_line_count--;
	if (goldfish_tty_current_line_count == 0)
		goldfish_tty_delete_driver();
	mutex_unlock(&goldfish_tty_lock);
	return 0;
}

static void gf_early_console_putchar(struct uart_port *port, int ch)
{
	__raw_writel(ch, port->membase);
}

static void gf_early_write(struct console *con, const char *s, unsigned int n)
{
	struct earlycon_device *dev = con->data;

	uart_console_write(&dev->port, s, n, gf_early_console_putchar);
}

static int __init gf_earlycon_setup(struct earlycon_device *device,
				    const char *opt)
{
	if (!device->port.membase)
		return -ENODEV;

	device->con->write = gf_early_write;
	return 0;
}

OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);

static const struct of_device_id goldfish_tty_of_match[] = {
	{ .compatible = "google,goldfish-tty", },
	{},
};

MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);

static struct platform_driver goldfish_tty_platform_driver = {
	.probe = goldfish_tty_probe,
	.remove = goldfish_tty_remove,
	.driver = {
		.name = "goldfish_tty",
		.of_match_table = goldfish_tty_of_match,
	}
};

module_platform_driver(goldfish_tty_platform_driver);

MODULE_LICENSE("GPL v2");
Commit	Line	Data
666b7793 AH	1	/*
	2	* Copyright (C) 2007 Google, Inc.
	3	* Copyright (C) 2012 Intel, Inc.
3840ed95	4	* Copyright (C) 2017 Imagination Technologies Ltd.
666b7793 AH	5	*
	6	* This software is licensed under the terms of the GNU General Public
	7	* License version 2, as published by the Free Software Foundation, and
	8	* may be copied, distributed, and modified under those terms.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	*/
	16
	17	#include <linux/console.h>
666b7793 AH	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>
e0f682e0	25	#include <linux/goldfish.h>
7157d2be MD	26	#include <linux/mm.h>
7157d2be MD	27	#include <linux/dma-mapping.h>
3840ed95	28	#include <linux/serial_core.h>
666b7793	29
2296eee7 AM	30	/* Goldfish tty register's offsets */
	31	#define GOLDFISH_TTY_REG_BYTES_READY 0x04
	32	#define GOLDFISH_TTY_REG_CMD 0x08
	33	#define GOLDFISH_TTY_REG_DATA_PTR 0x10
	34	#define GOLDFISH_TTY_REG_DATA_LEN 0x14
	35	#define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x18
7157d2be	36	#define GOLDFISH_TTY_REG_VERSION 0x20
2296eee7 AM	37
	38	/* Goldfish tty commands */
	39	#define GOLDFISH_TTY_CMD_INT_DISABLE 0
	40	#define GOLDFISH_TTY_CMD_INT_ENABLE 1
	41	#define GOLDFISH_TTY_CMD_WRITE_BUFFER 2
	42	#define GOLDFISH_TTY_CMD_READ_BUFFER 3
666b7793 AH	43
	44	struct goldfish_tty {
	45	struct tty_port port;
	46	spinlock_t lock;
	47	void __iomem *base;
	48	u32 irq;
	49	int opencount;
	50	struct console console;
7157d2be MD	51	u32 version;
7157d2be MD	52	struct device *dev;
666b7793 AH	53	};
	54
	55	static DEFINE_MUTEX(goldfish_tty_lock);
	56	static struct tty_driver *goldfish_tty_driver;
	57	static u32 goldfish_tty_line_count = 8;
	58	static u32 goldfish_tty_current_line_count;
	59	static struct goldfish_tty *goldfish_ttys;
	60
7157d2be MD	61	static void do_rw_io(struct goldfish_tty *qtty,
	62	unsigned long address,
	63	unsigned int count,
	64	int is_write)
666b7793 AH	65	{
666b7793 AH	66	unsigned long irq_flags;
666b7793	67	void __iomem *base = qtty->base;
7157d2be	68
666b7793	69	spin_lock_irqsave(&qtty->lock, irq_flags);
7157d2be	70	gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
2296eee7 AM	71	base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
2296eee7 AM	72	writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);
7157d2be MD	73
	74	if (is_write)
	75	writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
	76	base + GOLDFISH_TTY_REG_CMD);
	77	else
	78	writel(GOLDFISH_TTY_CMD_READ_BUFFER,
	79	base + GOLDFISH_TTY_REG_CMD);
	80
666b7793 AH	81	spin_unlock_irqrestore(&qtty->lock, irq_flags);
	82	}
	83
7157d2be MD	84	static void goldfish_tty_rw(struct goldfish_tty *qtty,
	85	unsigned long addr,
	86	unsigned int count,
	87	int is_write)
	88	{
	89	dma_addr_t dma_handle;
	90	enum dma_data_direction dma_dir;
	91
	92	dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
	93	if (qtty->version > 0) {
	94	/*
	95	* Goldfish TTY for Ranchu platform uses
	96	* physical addresses and DMA for read/write operations
	97	*/
	98	unsigned long addr_end = addr + count;
	99
	100	while (addr < addr_end) {
	101	unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
	102	unsigned long next =
	103	pg_end < addr_end ? pg_end : addr_end;
	104	unsigned long avail = next - addr;
	105
	106	/*
	107	* Map the buffer's virtual address to the DMA address
	108	* so the buffer can be accessed by the device.
	109	*/
	110	dma_handle = dma_map_single(qtty->dev, (void *)addr,
	111	avail, dma_dir);
	112
	113	if (dma_mapping_error(qtty->dev, dma_handle)) {
	114	dev_err(qtty->dev, "tty: DMA mapping error.\n");
	115	return;
	116	}
	117	do_rw_io(qtty, dma_handle, avail, is_write);
	118
	119	/*
	120	* Unmap the previously mapped region after
	121	* the completion of the read/write operation.
	122	*/
	123	dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);
	124
	125	addr += avail;
	126	}
	127	} else {
	128	/*
	129	* Old style Goldfish TTY used on the Goldfish platform
	130	* uses virtual addresses.
	131	*/
	132	do_rw_io(qtty, addr, count, is_write);
	133	}
	134	}
	135
	136	static void goldfish_tty_do_write(int line, const char *buf,
	137	unsigned int count)
	138	{
	139	struct goldfish_tty *qtty = &goldfish_ttys[line];
	140	unsigned long address = (unsigned long)(void *)buf;
	141
	142	goldfish_tty_rw(qtty, address, count, 1);
	143	}
	144
666b7793 AH	145	static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
666b7793 AH	146	{
465893e1	147	struct goldfish_tty *qtty = dev_id;
666b7793	148	void __iomem *base = qtty->base;
7157d2be	149	unsigned long address;
666b7793 AH	150	unsigned char *buf;
666b7793 AH	151	u32 count;
666b7793	152
2296eee7	153	count = readl(base + GOLDFISH_TTY_REG_BYTES_READY);
d78055dc	154	if (count == 0)
666b7793 AH	155	return IRQ_NONE;
666b7793 AH	156
ebcf0981	157	count = tty_prepare_flip_string(&qtty->port, &buf, count);
7157d2be MD	158
	159	address = (unsigned long)(void *)buf;
	160	goldfish_tty_rw(qtty, address, count, 0);
	161
ebcf0981	162	tty_schedule_flip(&qtty->port);
666b7793 AH	163	return IRQ_HANDLED;
	164	}
	165
	166	static int goldfish_tty_activate(struct tty_port port, struct tty_struct tty)
	167	{
d78055dc A	168	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
d78055dc A	169	port);
2296eee7	170	writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
666b7793 AH	171	return 0;
	172	}
	173
	174	static void goldfish_tty_shutdown(struct tty_port *port)
	175	{
d78055dc A	176	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
d78055dc A	177	port);
2296eee7	178	writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
666b7793 AH	179	}
666b7793 AH	180
d78055dc	181	static int goldfish_tty_open(struct tty_struct tty, struct file filp)
666b7793 AH	182	{
	183	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	184	return tty_port_open(&qtty->port, tty, filp);
	185	}
	186
d78055dc	187	static void goldfish_tty_close(struct tty_struct tty, struct file filp)
666b7793 AH	188	{
	189	tty_port_close(tty->port, tty, filp);
	190	}
	191
	192	static void goldfish_tty_hangup(struct tty_struct *tty)
	193	{
	194	tty_port_hangup(tty->port);
	195	}
	196
d78055dc A	197	static int goldfish_tty_write(struct tty_struct tty, const unsigned char buf,
d78055dc A	198	int count)
666b7793 AH	199	{
	200	goldfish_tty_do_write(tty->index, buf, count);
	201	return count;
	202	}
	203
	204	static int goldfish_tty_write_room(struct tty_struct *tty)
	205	{
	206	return 0x10000;
	207	}
	208
	209	static int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
	210	{
	211	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
	212	void __iomem *base = qtty->base;
2296eee7	213	return readl(base + GOLDFISH_TTY_REG_BYTES_READY);
666b7793 AH	214	}
666b7793 AH	215
d78055dc A	216	static void goldfish_tty_console_write(struct console co, const char b,
d78055dc A	217	unsigned count)
666b7793 AH	218	{
	219	goldfish_tty_do_write(co->index, b, count);
	220	}
	221
d78055dc A	222	static struct tty_driver goldfish_tty_console_device(struct console c,
d78055dc A	223	int *index)
666b7793 AH	224	{
	225	*index = c->index;
	226	return goldfish_tty_driver;
	227	}
	228
	229	static int goldfish_tty_console_setup(struct console co, char options)
	230	{
fda2b418	231	if ((unsigned)co->index >= goldfish_tty_line_count)
666b7793	232	return -ENODEV;
a4dc9236	233	if (!goldfish_ttys[co->index].base)
666b7793 AH	234	return -ENODEV;
	235	return 0;
	236	}
	237
04b757df	238	static const struct tty_port_operations goldfish_port_ops = {
666b7793 AH	239	.activate = goldfish_tty_activate,
	240	.shutdown = goldfish_tty_shutdown
	241	};
	242
d78055dc	243	static const struct tty_operations goldfish_tty_ops = {
666b7793 AH	244	.open = goldfish_tty_open,
	245	.close = goldfish_tty_close,
	246	.hangup = goldfish_tty_hangup,
	247	.write = goldfish_tty_write,
	248	.write_room = goldfish_tty_write_room,
	249	.chars_in_buffer = goldfish_tty_chars_in_buffer,
	250	};
	251
	252	static int goldfish_tty_create_driver(void)
	253	{
	254	int ret;
	255	struct tty_driver *tty;
	256
d78055dc A	257	goldfish_ttys = kzalloc(sizeof(goldfish_ttys)
	258	goldfish_tty_line_count, GFP_KERNEL);
	259	if (goldfish_ttys == NULL) {
666b7793 AH	260	ret = -ENOMEM;
	261	goto err_alloc_goldfish_ttys_failed;
	262	}
	263	tty = alloc_tty_driver(goldfish_tty_line_count);
d78055dc	264	if (tty == NULL) {
666b7793 AH	265	ret = -ENOMEM;
	266	goto err_alloc_tty_driver_failed;
	267	}
	268	tty->driver_name = "goldfish";
	269	tty->name = "ttyGF";
	270	tty->type = TTY_DRIVER_TYPE_SERIAL;
	271	tty->subtype = SERIAL_TYPE_NORMAL;
	272	tty->init_termios = tty_std_termios;
d78055dc A	273	tty->flags = TTY_DRIVER_RESET_TERMIOS \| TTY_DRIVER_REAL_RAW \|
d78055dc A	274	TTY_DRIVER_DYNAMIC_DEV;
666b7793 AH	275	tty_set_operations(tty, &goldfish_tty_ops);
666b7793 AH	276	ret = tty_register_driver(tty);
d78055dc	277	if (ret)
666b7793 AH	278	goto err_tty_register_driver_failed;
	279
	280	goldfish_tty_driver = tty;
	281	return 0;
	282
	283	err_tty_register_driver_failed:
	284	put_tty_driver(tty);
	285	err_alloc_tty_driver_failed:
	286	kfree(goldfish_ttys);
	287	goldfish_ttys = NULL;
	288	err_alloc_goldfish_ttys_failed:
	289	return ret;
	290	}
	291
	292	static void goldfish_tty_delete_driver(void)
	293	{
	294	tty_unregister_driver(goldfish_tty_driver);
	295	put_tty_driver(goldfish_tty_driver);
	296	goldfish_tty_driver = NULL;
	297	kfree(goldfish_ttys);
	298	goldfish_ttys = NULL;
	299	}
	300
	301	static int goldfish_tty_probe(struct platform_device *pdev)
	302	{
	303	struct goldfish_tty *qtty;
7157d2be	304	int ret = -ENODEV;
666b7793 AH	305	struct resource *r;
	306	struct device *ttydev;
	307	void __iomem *base;
	308	u32 irq;
465893e1	309	unsigned int line;
666b7793 AH	310
666b7793 AH	311	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
7157d2be MD	312	if (!r) {
	313	pr_err("goldfish_tty: No MEM resource available!\n");
	314	return -ENOMEM;
	315	}
666b7793 AH	316
666b7793 AH	317	base = ioremap(r->start, 0x1000);
7157d2be MD	318	if (!base) {
	319	pr_err("goldfish_tty: Unable to ioremap base!\n");
	320	return -ENOMEM;
	321	}
666b7793 AH	322
666b7793 AH	323	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
7157d2be MD	324	if (!r) {
7157d2be MD	325	pr_err("goldfish_tty: No IRQ resource available!\n");
666b7793	326	goto err_unmap;
7157d2be	327	}
666b7793 AH	328
	329	irq = r->start;
	330
666b7793	331	mutex_lock(&goldfish_tty_lock);
465893e1 GH	332
	333	if (pdev->id == PLATFORM_DEVID_NONE)
	334	line = goldfish_tty_current_line_count;
	335	else
	336	line = pdev->id;
	337
7157d2be MD	338	if (line >= goldfish_tty_line_count) {
	339	pr_err("goldfish_tty: Reached maximum tty number of %d.\n",
	340	goldfish_tty_current_line_count);
	341	ret = -ENOMEM;
	342	goto err_unlock;
	343	}
465893e1	344
d78055dc	345	if (goldfish_tty_current_line_count == 0) {
666b7793	346	ret = goldfish_tty_create_driver();
d78055dc	347	if (ret)
7157d2be	348	goto err_unlock;
666b7793 AH	349	}
	350	goldfish_tty_current_line_count++;
	351
465893e1	352	qtty = &goldfish_ttys[line];
666b7793 AH	353	spin_lock_init(&qtty->lock);
	354	tty_port_init(&qtty->port);
	355	qtty->port.ops = &goldfish_port_ops;
	356	qtty->base = base;
	357	qtty->irq = irq;
7157d2be MD	358	qtty->dev = &pdev->dev;
	359
	360	/*
	361	* Goldfish TTY device used by the Goldfish emulator
	362	* should identify itself with 0, forcing the driver
	363	* to use virtual addresses. Goldfish TTY device
	364	* on Ranchu emulator (qemu2) returns 1 here and
	365	* driver will use physical addresses.
	366	*/
	367	qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION);
	368
	369	/*
	370	* Goldfish TTY device on Ranchu emulator (qemu2)
	371	* will use DMA for read/write IO operations.
	372	*/
	373	if (qtty->version > 0) {
	374	/*
	375	* Initialize dma_mask to 32-bits.
	376	*/
	377	if (!pdev->dev.dma_mask)
	378	pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
	379	ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
	380	if (ret) {
	381	dev_err(&pdev->dev, "No suitable DMA available.\n");
	382	goto err_dec_line_count;
	383	}
	384	}
666b7793	385
2296eee7	386	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
666b7793	387
d78055dc	388	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
7157d2be MD	389	"goldfish_tty", qtty);
	390	if (ret) {
	391	pr_err("goldfish_tty: No IRQ available!\n");
	392	goto err_dec_line_count;
	393	}
666b7793 AH	394
666b7793 AH	395	ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,
7157d2be	396	line, &pdev->dev);
d78055dc	397	if (IS_ERR(ttydev)) {
666b7793 AH	398	ret = PTR_ERR(ttydev);
	399	goto err_tty_register_device_failed;
	400	}
	401
	402	strcpy(qtty->console.name, "ttyGF");
	403	qtty->console.write = goldfish_tty_console_write;
	404	qtty->console.device = goldfish_tty_console_device;
	405	qtty->console.setup = goldfish_tty_console_setup;
	406	qtty->console.flags = CON_PRINTBUFFER;
465893e1	407	qtty->console.index = line;
666b7793	408	register_console(&qtty->console);
465893e1	409	platform_set_drvdata(pdev, qtty);
666b7793 AH	410
	411	mutex_unlock(&goldfish_tty_lock);
	412	return 0;
	413
666b7793	414	err_tty_register_device_failed:
1a5c2d1d	415	free_irq(irq, qtty);
7157d2be	416	err_dec_line_count:
666b7793	417	goldfish_tty_current_line_count--;
d78055dc	418	if (goldfish_tty_current_line_count == 0)
666b7793	419	goldfish_tty_delete_driver();
7157d2be	420	err_unlock:
666b7793 AH	421	mutex_unlock(&goldfish_tty_lock);
	422	err_unmap:
	423	iounmap(base);
	424	return ret;
	425	}
	426
	427	static int goldfish_tty_remove(struct platform_device *pdev)
	428	{
465893e1	429	struct goldfish_tty *qtty = platform_get_drvdata(pdev);
666b7793 AH	430
	431	mutex_lock(&goldfish_tty_lock);
	432
666b7793	433	unregister_console(&qtty->console);
465893e1	434	tty_unregister_device(goldfish_tty_driver, qtty->console.index);
666b7793	435	iounmap(qtty->base);
a4dc9236	436	qtty->base = NULL;
666b7793 AH	437	free_irq(qtty->irq, pdev);
666b7793 AH	438	goldfish_tty_current_line_count--;
d78055dc	439	if (goldfish_tty_current_line_count == 0)
666b7793 AH	440	goldfish_tty_delete_driver();
	441	mutex_unlock(&goldfish_tty_lock);
	442	return 0;
	443	}
	444
3840ed95 MD	445	static void gf_early_console_putchar(struct uart_port *port, int ch)
	446	{
	447	__raw_writel(ch, port->membase);
	448	}
	449
	450	static void gf_early_write(struct console con, const char s, unsigned int n)
	451	{
	452	struct earlycon_device *dev = con->data;
	453
	454	uart_console_write(&dev->port, s, n, gf_early_console_putchar);
	455	}
	456
	457	static int __init gf_earlycon_setup(struct earlycon_device *device,
	458	const char *opt)
	459	{
	460	if (!device->port.membase)
	461	return -ENODEV;
	462
	463	device->con->write = gf_early_write;
	464	return 0;
	465	}
	466
	467	OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
	468
9b883eea MD	469	static const struct of_device_id goldfish_tty_of_match[] = {
	470	{ .compatible = "google,goldfish-tty", },
	471	{},
	472	};
	473
	474	MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);
	475
666b7793 AH	476	static struct platform_driver goldfish_tty_platform_driver = {
	477	.probe = goldfish_tty_probe,
	478	.remove = goldfish_tty_remove,
	479	.driver = {
9b883eea MD	480	.name = "goldfish_tty",
9b883eea MD	481	.of_match_table = goldfish_tty_of_match,
666b7793 AH	482	}
	483	};
	484
	485	module_platform_driver(goldfish_tty_platform_driver);
	486
	487	MODULE_LICENSE("GPL v2");