1 files changed, 482 insertions, 0 deletions

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
new file mode 100644
index 000000000..d02de3f03
--- /dev/null
+++ b/drivers/tty/goldfish.c
@@ -0,0 +1,482 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Google, Inc.
+ * Copyright (C) 2012 Intel, Inc.
+ * Copyright (C) 2017 Imagination Technologies Ltd.
+ */
+
+#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/mod_devicetable.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);
+	gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);
+
+	if (is_write)
+		gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,
+		       base + GOLDFISH_TTY_REG_CMD);
+	else
+		gf_iowrite32(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 = gf_ioread32(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_flip_buffer_push(&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);
+	gf_iowrite32(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);
+	gf_iowrite32(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 unsigned int goldfish_tty_write_room(struct tty_struct *tty)
+{
+	return 0x10000;
+}
+
+static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
+{
+	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
+	void __iomem *base = qtty->base;
+	return gf_ioread32(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 = kcalloc(goldfish_tty_line_count,
+				sizeof(*goldfish_ttys),
+				GFP_KERNEL);
+	if (goldfish_ttys == NULL) {
+		ret = -ENOMEM;
+		goto err_alloc_goldfish_ttys_failed;
+	}
+	tty = tty_alloc_driver(goldfish_tty_line_count,
+			TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
+			TTY_DRIVER_DYNAMIC_DEV);
+	if (IS_ERR(tty)) {
+		ret = PTR_ERR(tty);
+		goto err_tty_alloc_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_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:
+	tty_driver_kref_put(tty);
+err_tty_alloc_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);
+	tty_driver_kref_put(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;
+	int 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;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		goto err_unmap;
+	}
+
+	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 = gf_ioread32(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;
+		}
+	}
+
+	gf_iowrite32(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:
+	tty_port_destroy(&qtty->port);
+	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, qtty);
+	tty_port_destroy(&qtty->port);
+	goldfish_tty_current_line_count--;
+	if (goldfish_tty_current_line_count == 0)
+		goldfish_tty_delete_driver();
+	mutex_unlock(&goldfish_tty_lock);
+	return 0;
+}
+
+#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
+static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
+{
+	gf_iowrite32(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);
+#endif
+
+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");