1 files changed, 73 insertions, 126 deletions

diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index 9bffcec5ad82..69508d7a4135 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -1,13 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
 /* ePAPR hypervisor byte channel device driver
  *
  * Copyright 2009-2011 Freescale Semiconductor, Inc.
  *
  * Author: Timur Tabi <timur@freescale.com>
  *
- * This file is licensed under the terms of the GNU General Public License
- * version 2.  This program is licensed "as is" without any warranty of any
- * kind, whether express or implied.
- *
  * This driver support three distinct interfaces, all of which are related to
  * ePAPR hypervisor byte channels.
  *
@@ -23,7 +20,6 @@
  * byte channel used for the console is designated as the default tty.
  */
 
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/err.h>
@@ -32,6 +28,7 @@
 #include <linux/poll.h>
 #include <asm/epapr_hcalls.h>
 #include <linux/of.h>
+#include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/cdev.h>
 #include <linux/console.h>
@@ -52,7 +49,7 @@ struct ehv_bc_data {
 	unsigned int tx_irq;
 
 	spinlock_t lock;	/* lock for transmit buffer */
-	unsigned char buf[BUF_SIZE];	/* transmit circular buffer */
+	u8 buf[BUF_SIZE];	/* transmit circular buffer */
 	unsigned int head;	/* circular buffer head */
 	unsigned int tail;	/* circular buffer tail */
 
@@ -107,55 +104,22 @@ static void disable_tx_interrupt(struct ehv_bc_data *bc)
  *
  * The byte channel to be used for the console is specified via a "stdout"
  * property in the /chosen node.
- *
- * For compatible with legacy device trees, we also look for a "stdout" alias.
  */
 static int find_console_handle(void)
 {
-	struct device_node *np, *np2;
-	const char *sprop = NULL;
+	struct device_node *np = of_stdout;
 	const uint32_t *iprop;
 
-	np = of_find_node_by_path("/chosen");
-	if (np)
-		sprop = of_get_property(np, "stdout-path", NULL);
-
-	if (!np || !sprop) {
-		of_node_put(np);
-		np = of_find_node_by_name(NULL, "aliases");
-		if (np)
-			sprop = of_get_property(np, "stdout", NULL);
-	}
-
-	if (!sprop) {
-		of_node_put(np);
-		return 0;
-	}
-
 	/* We don't care what the aliased node is actually called.  We only
 	 * care if it's compatible with "epapr,hv-byte-channel", because that
-	 * indicates that it's a byte channel node.  We use a temporary
-	 * variable, 'np2', because we can't release 'np' until we're done with
-	 * 'sprop'.
+	 * indicates that it's a byte channel node.
 	 */
-	np2 = of_find_node_by_path(sprop);
-	of_node_put(np);
-	np = np2;
-	if (!np) {
-		pr_warning("ehv-bc: stdout node '%s' does not exist\n", sprop);
-		return 0;
-	}
-
-	/* Is it a byte channel? */
-	if (!of_device_is_compatible(np, "epapr,hv-byte-channel")) {
-		of_node_put(np);
+	if (!np || !of_device_is_compatible(np, "epapr,hv-byte-channel"))
 		return 0;
-	}
 
 	stdout_irq = irq_of_parse_and_map(np, 0);
-	if (stdout_irq == NO_IRQ) {
-		pr_err("ehv-bc: no 'interrupts' property in %s node\n", sprop);
-		of_node_put(np);
+	if (!stdout_irq) {
+		pr_err("ehv-bc: no 'interrupts' property in %pOF node\n", np);
 		return 0;
 	}
 
@@ -164,17 +128,32 @@ static int find_console_handle(void)
 	 */
 	iprop = of_get_property(np, "hv-handle", NULL);
 	if (!iprop) {
-		pr_err("ehv-bc: no 'hv-handle' property in %s node\n",
-		       np->name);
-		of_node_put(np);
+		pr_err("ehv-bc: no 'hv-handle' property in %pOFn node\n",
+		       np);
 		return 0;
 	}
 	stdout_bc = be32_to_cpu(*iprop);
-
-	of_node_put(np);
 	return 1;
 }
 
+static unsigned int local_ev_byte_channel_send(unsigned int handle,
+					       unsigned int *count,
+					       const u8 *p)
+{
+	u8 buffer[EV_BYTE_CHANNEL_MAX_BYTES];
+	unsigned int c = *count;
+
+	/*
+	 * ev_byte_channel_send() expects at least EV_BYTE_CHANNEL_MAX_BYTES
+	 * (16 B) in the buffer. Fake it using a local buffer if needed.
+	 */
+	if (c < sizeof(buffer)) {
+		memcpy_and_pad(buffer, sizeof(buffer), p, c, 0);
+		p = buffer;
+	}
+	return ev_byte_channel_send(handle, count, p);
+}
+
 /*************************** EARLY CONSOLE DRIVER ***************************/
 
 #ifdef CONFIG_PPC_EARLY_DEBUG_EHV_BC
@@ -187,13 +166,13 @@ static int find_console_handle(void)
  * has been sent, or if some error has occurred.
  *
  */
-static void byte_channel_spin_send(const char data)
+static void byte_channel_spin_send(const u8 data)
 {
 	int ret, count;
 
 	do {
 		count = 1;
-		ret = ev_byte_channel_send(CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE,
+		ret = local_ev_byte_channel_send(CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE,
 					   &count, &data);
 	} while (ret == EV_EAGAIN);
 }
@@ -260,7 +239,7 @@ static int ehv_bc_console_byte_channel_send(unsigned int handle, const char *s,
 	while (count) {
 		len = min_t(unsigned int, count, EV_BYTE_CHANNEL_MAX_BYTES);
 		do {
-			ret = ev_byte_channel_send(handle, &len, s);
+			ret = local_ev_byte_channel_send(handle, &len, s);
 		} while (ret == EV_EAGAIN);
 		count -= len;
 		s += len;
@@ -343,8 +322,8 @@ static int __init ehv_bc_console_init(void)
 	 * handle for udbg.
 	 */
 	if (stdout_bc != CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE)
-		pr_warning("ehv-bc: udbg handle %u is not the stdout handle\n",
-			   CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE);
+		pr_warn("ehv-bc: udbg handle %u is not the stdout handle\n",
+			CONFIG_PPC_EARLY_DEBUG_EHV_BC_HANDLE);
 #endif
 
 	/* add_preferred_console() must be called before register_console(),
@@ -364,7 +343,7 @@ console_initcall(ehv_bc_console_init);
 /******************************** TTY DRIVER ********************************/
 
 /*
- * byte channel receive interupt handler
+ * byte channel receive interrupt handler
  *
  * This ISR is called whenever data is available on a byte channel.
  */
@@ -440,7 +419,7 @@ static void ehv_bc_tx_dequeue(struct ehv_bc_data *bc)
 			    CIRC_CNT_TO_END(bc->head, bc->tail, BUF_SIZE),
 			    EV_BYTE_CHANNEL_MAX_BYTES);
 
-		ret = ev_byte_channel_send(bc->handle, &len, bc->buf + bc->tail);
+		ret = local_ev_byte_channel_send(bc->handle, &len, bc->buf + bc->tail);
 
 		/* 'len' is valid only if the return code is 0 or EV_EAGAIN */
 		if (!ret || (ret == EV_EAGAIN))
@@ -464,7 +443,7 @@ static void ehv_bc_tx_dequeue(struct ehv_bc_data *bc)
 }
 
 /*
- * byte channel transmit interupt handler
+ * byte channel transmit interrupt handler
  *
  * This ISR is called whenever space becomes available for transmitting
  * characters on a byte channel.
@@ -490,13 +469,12 @@ static irqreturn_t ehv_bc_tty_tx_isr(int irq, void *data)
  * ehv_bc_tty_write_room() will never lie, so the tty layer will never send us
  * too much data.
  */
-static int ehv_bc_tty_write(struct tty_struct *ttys, const unsigned char *s,
-			    int count)
+static ssize_t ehv_bc_tty_write(struct tty_struct *ttys, const u8 *s,
+				size_t count)
 {
 	struct ehv_bc_data *bc = ttys->driver_data;
 	unsigned long flags;
-	unsigned int len;
-	unsigned int written = 0;
+	size_t len, written = 0;
 
 	while (1) {
 		spin_lock_irqsave(&bc->lock, flags);
@@ -560,11 +538,11 @@ static void ehv_bc_tty_close(struct tty_struct *ttys, struct file *filp)
  * how much write room the driver can guarantee will be sent OR BUFFERED.  This
  * driver MUST honor the return value.
  */
-static int ehv_bc_tty_write_room(struct tty_struct *ttys)
+static unsigned int ehv_bc_tty_write_room(struct tty_struct *ttys)
 {
 	struct ehv_bc_data *bc = ttys->driver_data;
 	unsigned long flags;
-	int count;
+	unsigned int count;
 
 	spin_lock_irqsave(&bc->lock, flags);
 	count = CIRC_SPACE(bc->head, bc->tail, BUF_SIZE);
@@ -700,8 +678,8 @@ static int ehv_bc_tty_probe(struct platform_device *pdev)
 
 	iprop = of_get_property(np, "hv-handle", NULL);
 	if (!iprop) {
-		dev_err(&pdev->dev, "no 'hv-handle' property in %s node\n",
-			np->name);
+		dev_err(&pdev->dev, "no 'hv-handle' property in %pOFn node\n",
+			np);
 		return -ENODEV;
 	}
 
@@ -720,9 +698,9 @@ static int ehv_bc_tty_probe(struct platform_device *pdev)
 
 	bc->rx_irq = irq_of_parse_and_map(np, 0);
 	bc->tx_irq = irq_of_parse_and_map(np, 1);
-	if ((bc->rx_irq == NO_IRQ) || (bc->tx_irq == NO_IRQ)) {
-		dev_err(&pdev->dev, "no 'interrupts' property in %s node\n",
-			np->name);
+	if (!bc->rx_irq || !bc->tx_irq) {
+		dev_err(&pdev->dev, "no 'interrupts' property in %pOFn node\n",
+			np);
 		ret = -ENODEV;
 		goto error;
 	}
@@ -754,19 +732,6 @@ error:
 	return ret;
 }
 
-static int ehv_bc_tty_remove(struct platform_device *pdev)
-{
-	struct ehv_bc_data *bc = dev_get_drvdata(&pdev->dev);
-
-	tty_unregister_device(ehv_bc_driver, bc - bcs);
-
-	tty_port_destroy(&bc->port);
-	irq_dispose_mapping(bc->tx_irq);
-	irq_dispose_mapping(bc->rx_irq);
-
-	return 0;
-}
-
 static const struct of_device_id ehv_bc_tty_of_ids[] = {
 	{ .compatible = "epapr,hv-byte-channel" },
 	{}
@@ -774,21 +739,21 @@ static const struct of_device_id ehv_bc_tty_of_ids[] = {
 
 static struct platform_driver ehv_bc_tty_driver = {
 	.driver = {
-		.owner = THIS_MODULE,
 		.name = "ehv-bc",
 		.of_match_table = ehv_bc_tty_of_ids,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= ehv_bc_tty_probe,
-	.remove		= ehv_bc_tty_remove,
 };
 
 /**
  * ehv_bc_init - ePAPR hypervisor byte channel driver initialization
  *
- * This function is called when this module is loaded.
+ * This function is called when this driver is loaded.
  */
 static int __init ehv_bc_init(void)
 {
+	struct tty_driver *driver;
 	struct device_node *np;
 	unsigned int count = 0; /* Number of elements in bcs[] */
 	int ret;
@@ -807,67 +772,49 @@ static int __init ehv_bc_init(void)
 	 * array, then you can use pointer math (e.g. "bc - bcs") to get its
 	 * tty index.
 	 */
-	bcs = kzalloc(count * sizeof(struct ehv_bc_data), GFP_KERNEL);
+	bcs = kcalloc(count, sizeof(struct ehv_bc_data), GFP_KERNEL);
 	if (!bcs)
 		return -ENOMEM;
 
-	ehv_bc_driver = alloc_tty_driver(count);
-	if (!ehv_bc_driver) {
-		ret = -ENOMEM;
-		goto error;
+	driver = tty_alloc_driver(count, TTY_DRIVER_REAL_RAW |
+			TTY_DRIVER_DYNAMIC_DEV);
+	if (IS_ERR(driver)) {
+		ret = PTR_ERR(driver);
+		goto err_free_bcs;
 	}
 
-	ehv_bc_driver->driver_name = "ehv-bc";
-	ehv_bc_driver->name = ehv_bc_console.name;
-	ehv_bc_driver->type = TTY_DRIVER_TYPE_CONSOLE;
-	ehv_bc_driver->subtype = SYSTEM_TYPE_CONSOLE;
-	ehv_bc_driver->init_termios = tty_std_termios;
-	ehv_bc_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
-	tty_set_operations(ehv_bc_driver, &ehv_bc_ops);
+	driver->driver_name = "ehv-bc";
+	driver->name = ehv_bc_console.name;
+	driver->type = TTY_DRIVER_TYPE_CONSOLE;
+	driver->subtype = SYSTEM_TYPE_CONSOLE;
+	driver->init_termios = tty_std_termios;
+	tty_set_operations(driver, &ehv_bc_ops);
 
-	ret = tty_register_driver(ehv_bc_driver);
+	ret = tty_register_driver(driver);
 	if (ret) {
 		pr_err("ehv-bc: could not register tty driver (ret=%i)\n", ret);
-		goto error;
+		goto err_tty_driver_kref_put;
 	}
 
+	ehv_bc_driver = driver;
+
 	ret = platform_driver_register(&ehv_bc_tty_driver);
 	if (ret) {
 		pr_err("ehv-bc: could not register platform driver (ret=%i)\n",
 		       ret);
-		goto error;
+		goto err_deregister_tty_driver;
 	}
 
 	return 0;
 
-error:
-	if (ehv_bc_driver) {
-		tty_unregister_driver(ehv_bc_driver);
-		put_tty_driver(ehv_bc_driver);
-	}
-
+err_deregister_tty_driver:
+	ehv_bc_driver = NULL;
+	tty_unregister_driver(driver);
+err_tty_driver_kref_put:
+	tty_driver_kref_put(driver);
+err_free_bcs:
 	kfree(bcs);
 
 	return ret;
 }
-
-
-/**
- * ehv_bc_exit - ePAPR hypervisor byte channel driver termination
- *
- * This function is called when this driver is unloaded.
- */
-static void __exit ehv_bc_exit(void)
-{
-	platform_driver_unregister(&ehv_bc_tty_driver);
-	tty_unregister_driver(ehv_bc_driver);
-	put_tty_driver(ehv_bc_driver);
-	kfree(bcs);
-}
-
-module_init(ehv_bc_init);
-module_exit(ehv_bc_exit);
-
-MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
-MODULE_DESCRIPTION("ePAPR hypervisor byte channel driver");
-MODULE_LICENSE("GPL v2");
+device_initcall(ehv_bc_init);