1 files changed, 185 insertions, 49 deletions

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 996bd473dd03..381e981dee06 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -1,6 +1,7 @@
 /*
  * 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
@@ -22,21 +23,23 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/goldfish.h>
-
-enum {
-	GOLDFISH_TTY_PUT_CHAR       = 0x00,
-	GOLDFISH_TTY_BYTES_READY    = 0x04,
-	GOLDFISH_TTY_CMD            = 0x08,
-
-	GOLDFISH_TTY_DATA_PTR       = 0x10,
-	GOLDFISH_TTY_DATA_LEN       = 0x14,
-	GOLDFISH_TTY_DATA_PTR_HIGH  = 0x18,
-
-	GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
-	GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
-	GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
-	GOLDFISH_TTY_CMD_READ_BUFFER    = 3,
-};
+#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;
@@ -45,6 +48,8 @@ struct goldfish_tty {
 	u32 irq;
 	int opencount;
 	struct console console;
+	u32 version;
+	struct device *dev;
 };
 
 static DEFINE_MUTEX(goldfish_tty_lock);
@@ -53,38 +58,107 @@ static u32 goldfish_tty_line_count = 8;
 static u32 goldfish_tty_current_line_count;
 static struct goldfish_tty *goldfish_ttys;
 
-static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
+static void do_rw_io(struct goldfish_tty *qtty,
+		     unsigned long address,
+		     unsigned int count,
+		     int is_write)
 {
 	unsigned long irq_flags;
-	struct goldfish_tty *qtty = &goldfish_ttys[line];
 	void __iomem *base = qtty->base;
+
 	spin_lock_irqsave(&qtty->lock, irq_flags);
-	gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
-				base + GOLDFISH_TTY_DATA_PTR_HIGH);
-	writel(count, base + GOLDFISH_TTY_DATA_LEN);
-	writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
+	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 irq_flags;
+	unsigned long address;
 	unsigned char *buf;
 	u32 count;
 
-	count = readl(base + GOLDFISH_TTY_BYTES_READY);
+	count = readl(base + GOLDFISH_TTY_REG_BYTES_READY);
 	if (count == 0)
 		return IRQ_NONE;
 
 	count = tty_prepare_flip_string(&qtty->port, &buf, count);
-	spin_lock_irqsave(&qtty->lock, irq_flags);
-	gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
-				base + GOLDFISH_TTY_DATA_PTR_HIGH);
-	writel(count, base + GOLDFISH_TTY_DATA_LEN);
-	writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
-	spin_unlock_irqrestore(&qtty->lock, irq_flags);
+
+	address = (unsigned long)(void *)buf;
+	goldfish_tty_rw(qtty, address, count, 0);
+
 	tty_schedule_flip(&qtty->port);
 	return IRQ_HANDLED;
 }
@@ -93,7 +167,7 @@ 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_CMD);
+	writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
 	return 0;
 }
 
@@ -101,7 +175,7 @@ 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_CMD);
+	writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
 }
 
 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
@@ -136,7 +210,7 @@ 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_BYTES_READY);
+	return readl(base + GOLDFISH_TTY_REG_BYTES_READY);
 }
 
 static void goldfish_tty_console_write(struct console *co, const char *b,
@@ -227,7 +301,7 @@ static void goldfish_tty_delete_driver(void)
 static int goldfish_tty_probe(struct platform_device *pdev)
 {
 	struct goldfish_tty *qtty;
-	int ret = -EINVAL;
+	int ret = -ENODEV;
 	struct resource *r;
 	struct device *ttydev;
 	void __iomem *base;
@@ -235,16 +309,22 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	unsigned int line;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (r == NULL)
-		return -EINVAL;
+	if (!r) {
+		pr_err("goldfish_tty: No MEM resource available!\n");
+		return -ENOMEM;
+	}
 
 	base = ioremap(r->start, 0x1000);
-	if (base == NULL)
-		pr_err("goldfish_tty: unable to remap base\n");
+	if (!base) {
+		pr_err("goldfish_tty: Unable to ioremap base!\n");
+		return -ENOMEM;
+	}
 
 	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (r == NULL)
+	if (!r) {
+		pr_err("goldfish_tty: No IRQ resource available!\n");
 		goto err_unmap;
+	}
 
 	irq = r->start;
 
@@ -255,13 +335,17 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	else
 		line = pdev->id;
 
-	if (line >= goldfish_tty_line_count)
-		goto err_create_driver_failed;
+	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_create_driver_failed;
+			goto err_unlock;
 	}
 	goldfish_tty_current_line_count++;
 
@@ -271,17 +355,45 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	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_CMD);
+	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)
-		goto err_request_irq_failed;
-
+			  "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);
+					  line, &pdev->dev);
 	if (IS_ERR(ttydev)) {
 		ret = PTR_ERR(ttydev);
 		goto err_tty_register_device_failed;
@@ -301,11 +413,11 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 
 err_tty_register_device_failed:
 	free_irq(irq, qtty);
-err_request_irq_failed:
+err_dec_line_count:
 	goldfish_tty_current_line_count--;
 	if (goldfish_tty_current_line_count == 0)
 		goldfish_tty_delete_driver();
-err_create_driver_failed:
+err_unlock:
 	mutex_unlock(&goldfish_tty_lock);
 err_unmap:
 	iounmap(base);
@@ -330,6 +442,30 @@ static int goldfish_tty_remove(struct platform_device *pdev)
 	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", },
 	{},