1 files changed, 402 insertions, 195 deletions

diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 911e9e0711d2..9a0160f6dc3d 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -1,43 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Simple synchronous userspace interface to SPI devices
  *
  * Copyright (C) 2006 SWAPP
  *	Andrea Paterniani <a.paterniani@swapp-eng.it>
  * Copyright (C) 2007 David Brownell (simplification, cleanup)
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * 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.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/ioctl.h>
 #include <linux/fs.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/list.h>
 #include <linux/errno.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/compat.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spidev.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 
 
 /*
@@ -58,6 +45,7 @@
 
 static DECLARE_BITMAP(minors, N_SPI_MINORS);
 
+static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256);
 
 /* Bit masks for spi_device.mode management.  Note that incorrect
  * settings for some settings can cause *lots* of trouble for other
@@ -71,20 +59,26 @@ static DECLARE_BITMAP(minors, N_SPI_MINORS);
  *
  * REVISIT should changing those flags be privileged?
  */
-#define SPI_MODE_MASK		(SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \
+#define SPI_MODE_MASK		(SPI_MODE_X_MASK | SPI_CS_HIGH \
 				| SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \
-				| SPI_NO_CS | SPI_READY)
+				| SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
+				| SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \
+				| SPI_RX_QUAD | SPI_RX_OCTAL \
+				| SPI_RX_CPHA_FLIP | SPI_3WIRE_HIZ \
+				| SPI_MOSI_IDLE_LOW)
 
 struct spidev_data {
 	dev_t			devt;
-	spinlock_t		spi_lock;
+	struct mutex		spi_lock;
 	struct spi_device	*spi;
 	struct list_head	device_entry;
 
-	/* buffer is NULL unless this device is open (users > 0) */
+	/* TX/RX buffers are NULL unless this device is open (users > 0) */
 	struct mutex		buf_lock;
 	unsigned		users;
-	u8			*buffer;
+	u8			*tx_buffer;
+	u8			*rx_buffer;
+	u32			speed_hz;
 };
 
 static LIST_HEAD(device_list);
@@ -96,37 +90,33 @@ MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
 
 /*-------------------------------------------------------------------------*/
 
-/*
- * We can't use the standard synchronous wrappers for file I/O; we
- * need to protect against async removal of the underlying spi_device.
- */
-static void spidev_complete(void *arg)
+static ssize_t
+spidev_sync_unlocked(struct spi_device *spi, struct spi_message *message)
 {
-	complete(arg);
+	ssize_t status;
+
+	status = spi_sync(spi, message);
+	if (status == 0)
+		status = message->actual_length;
+
+	return status;
 }
 
 static ssize_t
 spidev_sync(struct spidev_data *spidev, struct spi_message *message)
 {
-	DECLARE_COMPLETION_ONSTACK(done);
-	int status;
+	ssize_t status;
+	struct spi_device *spi;
 
-	message->complete = spidev_complete;
-	message->context = &done;
+	mutex_lock(&spidev->spi_lock);
+	spi = spidev->spi;
 
-	spin_lock_irq(&spidev->spi_lock);
-	if (spidev->spi == NULL)
+	if (spi == NULL)
 		status = -ESHUTDOWN;
 	else
-		status = spi_async(spidev->spi, message);
-	spin_unlock_irq(&spidev->spi_lock);
+		status = spidev_sync_unlocked(spi, message);
 
-	if (status == 0) {
-		wait_for_completion(&done);
-		status = message->status;
-		if (status == 0)
-			status = message->actual_length;
-	}
+	mutex_unlock(&spidev->spi_lock);
 	return status;
 }
 
@@ -134,8 +124,9 @@ static inline ssize_t
 spidev_sync_write(struct spidev_data *spidev, size_t len)
 {
 	struct spi_transfer	t = {
-			.tx_buf		= spidev->buffer,
+			.tx_buf		= spidev->tx_buffer,
 			.len		= len,
+			.speed_hz	= spidev->speed_hz,
 		};
 	struct spi_message	m;
 
@@ -148,8 +139,9 @@ static inline ssize_t
 spidev_sync_read(struct spidev_data *spidev, size_t len)
 {
 	struct spi_transfer	t = {
-			.rx_buf		= spidev->buffer,
+			.rx_buf		= spidev->rx_buffer,
 			.len		= len,
+			.speed_hz	= spidev->speed_hz,
 		};
 	struct spi_message	m;
 
@@ -165,7 +157,7 @@ static ssize_t
 spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
 {
 	struct spidev_data	*spidev;
-	ssize_t			status = 0;
+	ssize_t			status;
 
 	/* chipselect only toggles at start or end of operation */
 	if (count > bufsiz)
@@ -178,7 +170,7 @@ spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
 	if (status > 0) {
 		unsigned long	missing;
 
-		missing = copy_to_user(buf, spidev->buffer, status);
+		missing = copy_to_user(buf, spidev->rx_buffer, status);
 		if (missing == status)
 			status = -EFAULT;
 		else
@@ -195,7 +187,7 @@ spidev_write(struct file *filp, const char __user *buf,
 		size_t count, loff_t *f_pos)
 {
 	struct spidev_data	*spidev;
-	ssize_t			status = 0;
+	ssize_t			status;
 	unsigned long		missing;
 
 	/* chipselect only toggles at start or end of operation */
@@ -205,10 +197,10 @@ spidev_write(struct file *filp, const char __user *buf,
 	spidev = filp->private_data;
 
 	mutex_lock(&spidev->buf_lock);
-	missing = copy_from_user(spidev->buffer, buf, count);
-	if (missing == 0) {
+	missing = copy_from_user(spidev->tx_buffer, buf, count);
+	if (missing == 0)
 		status = spidev_sync_write(spidev, count);
-	} else
+	else
 		status = -EFAULT;
 	mutex_unlock(&spidev->buf_lock);
 
@@ -222,8 +214,8 @@ static int spidev_message(struct spidev_data *spidev,
 	struct spi_transfer	*k_xfers;
 	struct spi_transfer	*k_tmp;
 	struct spi_ioc_transfer *u_tmp;
-	unsigned		n, total;
-	u8			*buf;
+	unsigned		n, total, tx_total, rx_total;
+	u8			*tx_buf, *rx_buf;
 	int			status = -EFAULT;
 
 	spi_message_init(&msg);
@@ -235,69 +227,99 @@ static int spidev_message(struct spidev_data *spidev,
 	 * We walk the array of user-provided transfers, using each one
 	 * to initialize a kernel version of the same transfer.
 	 */
-	buf = spidev->buffer;
+	tx_buf = spidev->tx_buffer;
+	rx_buf = spidev->rx_buffer;
 	total = 0;
+	tx_total = 0;
+	rx_total = 0;
 	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
 			n;
 			n--, k_tmp++, u_tmp++) {
+		/* Ensure that also following allocations from rx_buf/tx_buf will meet
+		 * DMA alignment requirements.
+		 */
+		unsigned int len_aligned = ALIGN(u_tmp->len, ARCH_DMA_MINALIGN);
+
 		k_tmp->len = u_tmp->len;
 
 		total += k_tmp->len;
-		if (total > bufsiz) {
+		/* Since the function returns the total length of transfers
+		 * on success, restrict the total to positive int values to
+		 * avoid the return value looking like an error.  Also check
+		 * each transfer length to avoid arithmetic overflow.
+		 */
+		if (total > INT_MAX || k_tmp->len > INT_MAX) {
 			status = -EMSGSIZE;
 			goto done;
 		}
 
 		if (u_tmp->rx_buf) {
-			k_tmp->rx_buf = buf;
-			if (!access_ok(VERIFY_WRITE, (u8 __user *)
-						(uintptr_t) u_tmp->rx_buf,
-						u_tmp->len))
+			/* this transfer needs space in RX bounce buffer */
+			rx_total += len_aligned;
+			if (rx_total > bufsiz) {
+				status = -EMSGSIZE;
 				goto done;
+			}
+			k_tmp->rx_buf = rx_buf;
+			rx_buf += len_aligned;
 		}
 		if (u_tmp->tx_buf) {
-			k_tmp->tx_buf = buf;
-			if (copy_from_user(buf, (const u8 __user *)
+			/* this transfer needs space in TX bounce buffer */
+			tx_total += len_aligned;
+			if (tx_total > bufsiz) {
+				status = -EMSGSIZE;
+				goto done;
+			}
+			k_tmp->tx_buf = tx_buf;
+			if (copy_from_user(tx_buf, (const u8 __user *)
 						(uintptr_t) u_tmp->tx_buf,
 					u_tmp->len))
 				goto done;
+			tx_buf += len_aligned;
 		}
-		buf += k_tmp->len;
 
 		k_tmp->cs_change = !!u_tmp->cs_change;
+		k_tmp->tx_nbits = u_tmp->tx_nbits;
+		k_tmp->rx_nbits = u_tmp->rx_nbits;
 		k_tmp->bits_per_word = u_tmp->bits_per_word;
-		k_tmp->delay_usecs = u_tmp->delay_usecs;
+		k_tmp->delay.value = u_tmp->delay_usecs;
+		k_tmp->delay.unit = SPI_DELAY_UNIT_USECS;
 		k_tmp->speed_hz = u_tmp->speed_hz;
+		k_tmp->word_delay.value = u_tmp->word_delay_usecs;
+		k_tmp->word_delay.unit = SPI_DELAY_UNIT_USECS;
+		if (!k_tmp->speed_hz)
+			k_tmp->speed_hz = spidev->speed_hz;
 #ifdef VERBOSE
 		dev_dbg(&spidev->spi->dev,
-			"  xfer len %zd %s%s%s%dbits %u usec %uHz\n",
-			u_tmp->len,
-			u_tmp->rx_buf ? "rx " : "",
-			u_tmp->tx_buf ? "tx " : "",
-			u_tmp->cs_change ? "cs " : "",
-			u_tmp->bits_per_word ? : spidev->spi->bits_per_word,
-			u_tmp->delay_usecs,
-			u_tmp->speed_hz ? : spidev->spi->max_speed_hz);
+			"  xfer len %u %s%s%s%dbits %u usec %u usec %uHz\n",
+			k_tmp->len,
+			k_tmp->rx_buf ? "rx " : "",
+			k_tmp->tx_buf ? "tx " : "",
+			k_tmp->cs_change ? "cs " : "",
+			k_tmp->bits_per_word ? : spidev->spi->bits_per_word,
+			k_tmp->delay.value,
+			k_tmp->word_delay.value,
+			k_tmp->speed_hz ? : spidev->spi->max_speed_hz);
 #endif
 		spi_message_add_tail(k_tmp, &msg);
 	}
 
-	status = spidev_sync(spidev, &msg);
+	status = spidev_sync_unlocked(spidev->spi, &msg);
 	if (status < 0)
 		goto done;
 
 	/* copy any rx data out of bounce buffer */
-	buf = spidev->buffer;
-	for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) {
+	for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers;
+			n;
+			n--, k_tmp++, u_tmp++) {
 		if (u_tmp->rx_buf) {
-			if (__copy_to_user((u8 __user *)
-					(uintptr_t) u_tmp->rx_buf, buf,
+			if (copy_to_user((u8 __user *)
+					(uintptr_t) u_tmp->rx_buf, k_tmp->rx_buf,
 					u_tmp->len)) {
 				status = -EFAULT;
 				goto done;
 			}
 		}
-		buf += u_tmp->len;
 	}
 	status = total;
 
@@ -306,13 +328,36 @@ done:
 	return status;
 }
 
+static struct spi_ioc_transfer *
+spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
+		unsigned *n_ioc)
+{
+	u32	tmp;
+
+	/* Check type, command number and direction */
+	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC
+			|| _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
+			|| _IOC_DIR(cmd) != _IOC_WRITE)
+		return ERR_PTR(-ENOTTY);
+
+	tmp = _IOC_SIZE(cmd);
+	if ((tmp % sizeof(struct spi_ioc_transfer)) != 0)
+		return ERR_PTR(-EINVAL);
+	*n_ioc = tmp / sizeof(struct spi_ioc_transfer);
+	if (*n_ioc == 0)
+		return NULL;
+
+	/* copy into scratch area */
+	return memdup_user(u_ioc, tmp);
+}
+
 static long
 spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	int			err = 0;
 	int			retval = 0;
 	struct spidev_data	*spidev;
 	struct spi_device	*spi;
+	struct spi_controller	*ctlr;
 	u32			tmp;
 	unsigned		n_ioc;
 	struct spi_ioc_transfer	*ioc;
@@ -321,29 +366,18 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC)
 		return -ENOTTY;
 
-	/* Check access direction once here; don't repeat below.
-	 * IOC_DIR is from the user perspective, while access_ok is
-	 * from the kernel perspective; so they look reversed.
-	 */
-	if (_IOC_DIR(cmd) & _IOC_READ)
-		err = !access_ok(VERIFY_WRITE,
-				(void __user *)arg, _IOC_SIZE(cmd));
-	if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE)
-		err = !access_ok(VERIFY_READ,
-				(void __user *)arg, _IOC_SIZE(cmd));
-	if (err)
-		return -EFAULT;
-
 	/* guard against device removal before, or while,
 	 * we issue this ioctl.
 	 */
 	spidev = filp->private_data;
-	spin_lock_irq(&spidev->spi_lock);
+	mutex_lock(&spidev->spi_lock);
 	spi = spi_dev_get(spidev->spi);
-	spin_unlock_irq(&spidev->spi_lock);
-
-	if (spi == NULL)
+	if (spi == NULL) {
+		mutex_unlock(&spidev->spi_lock);
 		return -ESHUTDOWN;
+	}
+
+	ctlr = spi->controller;
 
 	/* use the buffer lock here for triple duty:
 	 *  - prevent I/O (from us) so calling spi_setup() is safe;
@@ -356,44 +390,59 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	switch (cmd) {
 	/* read requests */
 	case SPI_IOC_RD_MODE:
-		retval = __put_user(spi->mode & SPI_MODE_MASK,
-					(__u8 __user *)arg);
+	case SPI_IOC_RD_MODE32:
+		tmp = spi->mode & SPI_MODE_MASK;
+
+		if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
+			tmp &= ~SPI_CS_HIGH;
+
+		if (cmd == SPI_IOC_RD_MODE)
+			retval = put_user(tmp, (__u8 __user *)arg);
+		else
+			retval = put_user(tmp, (__u32 __user *)arg);
 		break;
 	case SPI_IOC_RD_LSB_FIRST:
-		retval = __put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
+		retval = put_user((spi->mode & SPI_LSB_FIRST) ?  1 : 0,
 					(__u8 __user *)arg);
 		break;
 	case SPI_IOC_RD_BITS_PER_WORD:
-		retval = __put_user(spi->bits_per_word, (__u8 __user *)arg);
+		retval = put_user(spi->bits_per_word, (__u8 __user *)arg);
 		break;
 	case SPI_IOC_RD_MAX_SPEED_HZ:
-		retval = __put_user(spi->max_speed_hz, (__u32 __user *)arg);
+		retval = put_user(spidev->speed_hz, (__u32 __user *)arg);
 		break;
 
 	/* write requests */
 	case SPI_IOC_WR_MODE:
-		retval = __get_user(tmp, (u8 __user *)arg);
+	case SPI_IOC_WR_MODE32:
+		if (cmd == SPI_IOC_WR_MODE)
+			retval = get_user(tmp, (u8 __user *)arg);
+		else
+			retval = get_user(tmp, (u32 __user *)arg);
 		if (retval == 0) {
-			u8	save = spi->mode;
+			u32	save = spi->mode;
 
 			if (tmp & ~SPI_MODE_MASK) {
 				retval = -EINVAL;
 				break;
 			}
 
+			if (ctlr->use_gpio_descriptors && spi_get_csgpiod(spi, 0))
+				tmp |= SPI_CS_HIGH;
+
 			tmp |= spi->mode & ~SPI_MODE_MASK;
-			spi->mode = (u8)tmp;
+			spi->mode = tmp & SPI_MODE_USER_MASK;
 			retval = spi_setup(spi);
 			if (retval < 0)
 				spi->mode = save;
 			else
-				dev_dbg(&spi->dev, "spi mode %02x\n", tmp);
+				dev_dbg(&spi->dev, "spi mode %x\n", tmp);
 		}
 		break;
 	case SPI_IOC_WR_LSB_FIRST:
-		retval = __get_user(tmp, (__u8 __user *)arg);
+		retval = get_user(tmp, (__u8 __user *)arg);
 		if (retval == 0) {
-			u8	save = spi->mode;
+			u32	save = spi->mode;
 
 			if (tmp)
 				spi->mode |= SPI_LSB_FIRST;
@@ -408,7 +457,7 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	case SPI_IOC_WR_BITS_PER_WORD:
-		retval = __get_user(tmp, (__u8 __user *)arg);
+		retval = get_user(tmp, (__u8 __user *)arg);
 		if (retval == 0) {
 			u8	save = spi->bits_per_word;
 
@@ -420,48 +469,40 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 				dev_dbg(&spi->dev, "%d bits per word\n", tmp);
 		}
 		break;
-	case SPI_IOC_WR_MAX_SPEED_HZ:
-		retval = __get_user(tmp, (__u32 __user *)arg);
-		if (retval == 0) {
-			u32	save = spi->max_speed_hz;
-
-			spi->max_speed_hz = tmp;
-			retval = spi_setup(spi);
-			if (retval < 0)
-				spi->max_speed_hz = save;
-			else
-				dev_dbg(&spi->dev, "%d Hz (max)\n", tmp);
-		}
-		break;
+	case SPI_IOC_WR_MAX_SPEED_HZ: {
+		u32 save;
 
-	default:
-		/* segmented and/or full-duplex I/O request */
-		if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0))
-				|| _IOC_DIR(cmd) != _IOC_WRITE) {
-			retval = -ENOTTY;
+		retval = get_user(tmp, (__u32 __user *)arg);
+		if (retval)
 			break;
-		}
-
-		tmp = _IOC_SIZE(cmd);
-		if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) {
+		if (tmp == 0) {
 			retval = -EINVAL;
 			break;
 		}
-		n_ioc = tmp / sizeof(struct spi_ioc_transfer);
-		if (n_ioc == 0)
-			break;
 
-		/* copy into scratch area */
-		ioc = kmalloc(tmp, GFP_KERNEL);
-		if (!ioc) {
-			retval = -ENOMEM;
-			break;
+		save = spi->max_speed_hz;
+
+		spi->max_speed_hz = tmp;
+		retval = spi_setup(spi);
+		if (retval == 0) {
+			spidev->speed_hz = tmp;
+			dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz);
 		}
-		if (__copy_from_user(ioc, (void __user *)arg, tmp)) {
-			kfree(ioc);
-			retval = -EFAULT;
+
+		spi->max_speed_hz = save;
+		break;
+	}
+	default:
+		/* segmented and/or full-duplex I/O request */
+		/* Check message and copy into scratch area */
+		ioc = spidev_get_ioc_message(cmd,
+				(struct spi_ioc_transfer __user *)arg, &n_ioc);
+		if (IS_ERR(ioc)) {
+			retval = PTR_ERR(ioc);
 			break;
 		}
+		if (!ioc)
+			break;	/* n_ioc is also 0 */
 
 		/* translate to spi_message, execute */
 		retval = spidev_message(spidev, ioc, n_ioc);
@@ -471,13 +512,72 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 	mutex_unlock(&spidev->buf_lock);
 	spi_dev_put(spi);
+	mutex_unlock(&spidev->spi_lock);
 	return retval;
 }
 
 #ifdef CONFIG_COMPAT
 static long
+spidev_compat_ioc_message(struct file *filp, unsigned int cmd,
+		unsigned long arg)
+{
+	struct spi_ioc_transfer __user	*u_ioc;
+	int				retval = 0;
+	struct spidev_data		*spidev;
+	struct spi_device		*spi;
+	unsigned			n_ioc, n;
+	struct spi_ioc_transfer		*ioc;
+
+	u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg);
+
+	/* guard against device removal before, or while,
+	 * we issue this ioctl.
+	 */
+	spidev = filp->private_data;
+	mutex_lock(&spidev->spi_lock);
+	spi = spi_dev_get(spidev->spi);
+	if (spi == NULL) {
+		mutex_unlock(&spidev->spi_lock);
+		return -ESHUTDOWN;
+	}
+
+	/* SPI_IOC_MESSAGE needs the buffer locked "normally" */
+	mutex_lock(&spidev->buf_lock);
+
+	/* Check message and copy into scratch area */
+	ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc);
+	if (IS_ERR(ioc)) {
+		retval = PTR_ERR(ioc);
+		goto done;
+	}
+	if (!ioc)
+		goto done;	/* n_ioc is also 0 */
+
+	/* Convert buffer pointers */
+	for (n = 0; n < n_ioc; n++) {
+		ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf);
+		ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf);
+	}
+
+	/* translate to spi_message, execute */
+	retval = spidev_message(spidev, ioc, n_ioc);
+	kfree(ioc);
+
+done:
+	mutex_unlock(&spidev->buf_lock);
+	spi_dev_put(spi);
+	mutex_unlock(&spidev->spi_lock);
+	return retval;
+}
+
+static long
 spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
+	if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC
+			&& _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0))
+			&& _IOC_DIR(cmd) == _IOC_WRITE)
+		return spidev_compat_ioc_message(filp, cmd, arg);
+
 	return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg));
 }
 #else
@@ -486,65 +586,91 @@ spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 static int spidev_open(struct inode *inode, struct file *filp)
 {
-	struct spidev_data	*spidev;
+	struct spidev_data	*spidev = NULL, *iter;
 	int			status = -ENXIO;
 
 	mutex_lock(&device_list_lock);
 
-	list_for_each_entry(spidev, &device_list, device_entry) {
-		if (spidev->devt == inode->i_rdev) {
+	list_for_each_entry(iter, &device_list, device_entry) {
+		if (iter->devt == inode->i_rdev) {
 			status = 0;
+			spidev = iter;
 			break;
 		}
 	}
-	if (status == 0) {
-		if (!spidev->buffer) {
-			spidev->buffer = kmalloc(bufsiz, GFP_KERNEL);
-			if (!spidev->buffer) {
-				dev_dbg(&spidev->spi->dev, "open/ENOMEM\n");
-				status = -ENOMEM;
-			}
+
+	if (!spidev) {
+		pr_debug("spidev: nothing for minor %d\n", iminor(inode));
+		goto err_find_dev;
+	}
+
+	if (!spidev->tx_buffer) {
+		spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL);
+		if (!spidev->tx_buffer) {
+			status = -ENOMEM;
+			goto err_find_dev;
 		}
-		if (status == 0) {
-			spidev->users++;
-			filp->private_data = spidev;
-			nonseekable_open(inode, filp);
+	}
+
+	if (!spidev->rx_buffer) {
+		spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL);
+		if (!spidev->rx_buffer) {
+			status = -ENOMEM;
+			goto err_alloc_rx_buf;
 		}
-	} else
-		pr_debug("spidev: nothing for minor %d\n", iminor(inode));
+	}
+
+	spidev->users++;
+	filp->private_data = spidev;
+	stream_open(inode, filp);
 
 	mutex_unlock(&device_list_lock);
+	return 0;
+
+err_alloc_rx_buf:
+	kfree(spidev->tx_buffer);
+	spidev->tx_buffer = NULL;
+err_find_dev:
+	mutex_unlock(&device_list_lock);
 	return status;
 }
 
 static int spidev_release(struct inode *inode, struct file *filp)
 {
 	struct spidev_data	*spidev;
-	int			status = 0;
+	int			dofree;
 
 	mutex_lock(&device_list_lock);
 	spidev = filp->private_data;
 	filp->private_data = NULL;
 
+	mutex_lock(&spidev->spi_lock);
+	/* ... after we unbound from the underlying device? */
+	dofree = (spidev->spi == NULL);
+	mutex_unlock(&spidev->spi_lock);
+
 	/* last close? */
 	spidev->users--;
 	if (!spidev->users) {
-		int		dofree;
 
-		kfree(spidev->buffer);
-		spidev->buffer = NULL;
+		kfree(spidev->tx_buffer);
+		spidev->tx_buffer = NULL;
 
-		/* ... after we unbound from the underlying device? */
-		spin_lock_irq(&spidev->spi_lock);
-		dofree = (spidev->spi == NULL);
-		spin_unlock_irq(&spidev->spi_lock);
+		kfree(spidev->rx_buffer);
+		spidev->rx_buffer = NULL;
 
 		if (dofree)
 			kfree(spidev);
+		else
+			spidev->speed_hz = spidev->spi->max_speed_hz;
 	}
+#ifdef CONFIG_SPI_SLAVE
+	if (!dofree)
+		spi_target_abort(spidev->spi);
+#endif
 	mutex_unlock(&device_list_lock);
 
-	return status;
+	return 0;
 }
 
 static const struct file_operations spidev_fops = {
@@ -559,7 +685,6 @@ static const struct file_operations spidev_fops = {
 	.compat_ioctl = spidev_compat_ioctl,
 	.open =		spidev_open,
 	.release =	spidev_release,
-	.llseek =	no_llseek,
 };
 
 /*-------------------------------------------------------------------------*/
@@ -569,16 +694,106 @@ static const struct file_operations spidev_fops = {
  * It also simplifies memory management.
  */
 
-static struct class *spidev_class;
+static const struct class spidev_class = {
+	.name = "spidev",
+};
+
+/*
+ * The spi device ids are expected to match the device names of the
+ * spidev_dt_ids array below. Both arrays are kept in the same ordering.
+ */
+static const struct spi_device_id spidev_spi_ids[] = {
+	{ .name = /* abb */ "spi-sensor" },
+	{ .name = /* arduino */ "unoq-mcu" },
+	{ .name = /* cisco */ "spi-petra" },
+	{ .name = /* dh */ "dhcom-board" },
+	{ .name = /* elgin */ "jg10309-01" },
+	{ .name = /* gocontroll */ "moduline-module-slot"},
+	{ .name = /* lineartechnology */ "ltc2488" },
+	{ .name = /* lwn */ "bk4" },
+	{ .name = /* lwn */ "bk4-spi" },
+	{ .name = /* menlo */ "m53cpld" },
+	{ .name = /* micron */ "spi-authenta" },
+	{ .name = /* rohm */ "bh2228fv" },
+	{ .name = /* rohm */ "dh2228fv" },
+	{ .name = /* semtech */ "sx1301" },
+	{ .name = /* silabs */ "em3581" },
+	{ .name = /* silabs */ "si3210" },
+	{},
+};
+MODULE_DEVICE_TABLE(spi, spidev_spi_ids);
+
+/*
+ * spidev should never be referenced in DT without a specific compatible string,
+ * it is a Linux implementation thing rather than a description of the hardware.
+ */
+static int spidev_of_check(struct device *dev)
+{
+	if (device_property_match_string(dev, "compatible", "spidev") < 0)
+		return 0;
+
+	dev_err(dev, "spidev listed directly in DT is not supported\n");
+	return -EINVAL;
+}
+
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "abb,spi-sensor", .data = &spidev_of_check },
+	{ .compatible = "arduino,unoq-mcu", .data = &spidev_of_check },
+	{ .compatible = "cisco,spi-petra", .data = &spidev_of_check },
+	{ .compatible = "dh,dhcom-board", .data = &spidev_of_check },
+	{ .compatible = "elgin,jg10309-01", .data = &spidev_of_check },
+	{ .compatible = "gocontroll,moduline-module-slot", .data = &spidev_of_check},
+	{ .compatible = "lineartechnology,ltc2488", .data = &spidev_of_check },
+	{ .compatible = "lwn,bk4", .data = &spidev_of_check },
+	{ .compatible = "lwn,bk4-spi", .data = &spidev_of_check },
+	{ .compatible = "menlo,m53cpld", .data = &spidev_of_check },
+	{ .compatible = "micron,spi-authenta", .data = &spidev_of_check },
+	{ .compatible = "rohm,bh2228fv", .data = &spidev_of_check },
+	{ .compatible = "rohm,dh2228fv", .data = &spidev_of_check },
+	{ .compatible = "semtech,sx1301", .data = &spidev_of_check },
+	{ .compatible = "silabs,em3581", .data = &spidev_of_check },
+	{ .compatible = "silabs,si3210", .data = &spidev_of_check },
+	{},
+};
+MODULE_DEVICE_TABLE(of, spidev_dt_ids);
+
+/* Dummy SPI devices not to be used in production systems */
+static int spidev_acpi_check(struct device *dev)
+{
+	dev_warn(dev, "do not use this driver in production systems!\n");
+	return 0;
+}
+
+static const struct acpi_device_id spidev_acpi_ids[] = {
+	/*
+	 * The ACPI SPT000* devices are only meant for development and
+	 * testing. Systems used in production should have a proper ACPI
+	 * description of the connected peripheral and they should also use
+	 * a proper driver instead of poking directly to the SPI bus.
+	 */
+	{ "SPT0001", (kernel_ulong_t)&spidev_acpi_check },
+	{ "SPT0002", (kernel_ulong_t)&spidev_acpi_check },
+	{ "SPT0003", (kernel_ulong_t)&spidev_acpi_check },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, spidev_acpi_ids);
 
 /*-------------------------------------------------------------------------*/
 
 static int spidev_probe(struct spi_device *spi)
 {
+	int (*match)(struct device *dev);
 	struct spidev_data	*spidev;
 	int			status;
 	unsigned long		minor;
 
+	match = device_get_match_data(&spi->dev);
+	if (match) {
+		status = match(&spi->dev);
+		if (status)
+			return status;
+	}
+
 	/* Allocate driver data */
 	spidev = kzalloc(sizeof(*spidev), GFP_KERNEL);
 	if (!spidev)
@@ -586,7 +801,7 @@ static int spidev_probe(struct spi_device *spi)
 
 	/* Initialize the driver data */
 	spidev->spi = spi;
-	spin_lock_init(&spidev->spi_lock);
+	mutex_init(&spidev->spi_lock);
 	mutex_init(&spidev->buf_lock);
 
 	INIT_LIST_HEAD(&spidev->device_entry);
@@ -600,10 +815,10 @@ static int spidev_probe(struct spi_device *spi)
 		struct device *dev;
 
 		spidev->devt = MKDEV(SPIDEV_MAJOR, minor);
-		dev = device_create(spidev_class, &spi->dev, spidev->devt,
+		dev = device_create(&spidev_class, &spi->dev, spidev->devt,
 				    spidev, "spidev%d.%d",
-				    spi->master->bus_num, spi->chip_select);
-		status = PTR_RET(dev);
+				    spi->controller->bus_num, spi_get_chipselect(spi, 0));
+		status = PTR_ERR_OR_ZERO(dev);
 	} else {
 		dev_dbg(&spi->dev, "no minor number available!\n");
 		status = -ENODEV;
@@ -614,6 +829,8 @@ static int spidev_probe(struct spi_device *spi)
 	}
 	mutex_unlock(&device_list_lock);
 
+	spidev->speed_hz = spi->max_speed_hz;
+
 	if (status == 0)
 		spi_set_drvdata(spi, spidev);
 	else
@@ -622,43 +839,34 @@ static int spidev_probe(struct spi_device *spi)
 	return status;
 }
 
-static int spidev_remove(struct spi_device *spi)
+static void spidev_remove(struct spi_device *spi)
 {
 	struct spidev_data	*spidev = spi_get_drvdata(spi);
 
+	/* prevent new opens */
+	mutex_lock(&device_list_lock);
 	/* make sure ops on existing fds can abort cleanly */
-	spin_lock_irq(&spidev->spi_lock);
+	mutex_lock(&spidev->spi_lock);
 	spidev->spi = NULL;
-	spi_set_drvdata(spi, NULL);
-	spin_unlock_irq(&spidev->spi_lock);
+	mutex_unlock(&spidev->spi_lock);
 
-	/* prevent new opens */
-	mutex_lock(&device_list_lock);
 	list_del(&spidev->device_entry);
-	device_destroy(spidev_class, spidev->devt);
+	device_destroy(&spidev_class, spidev->devt);
 	clear_bit(MINOR(spidev->devt), minors);
 	if (spidev->users == 0)
 		kfree(spidev);
 	mutex_unlock(&device_list_lock);
-
-	return 0;
 }
 
-static const struct of_device_id spidev_dt_ids[] = {
-	{ .compatible = "rohm,dh2228fv" },
-	{},
-};
-
-MODULE_DEVICE_TABLE(of, spidev_dt_ids);
-
 static struct spi_driver spidev_spi_driver = {
 	.driver = {
 		.name =		"spidev",
-		.owner =	THIS_MODULE,
-		.of_match_table = of_match_ptr(spidev_dt_ids),
+		.of_match_table = spidev_dt_ids,
+		.acpi_match_table = spidev_acpi_ids,
 	},
 	.probe =	spidev_probe,
 	.remove =	spidev_remove,
+	.id_table =	spidev_spi_ids,
 
 	/* NOTE:  suspend/resume methods are not necessary here.
 	 * We don't do anything except pass the requests to/from
@@ -677,20 +885,19 @@ static int __init spidev_init(void)
 	 * that will key udev/mdev to add/remove /dev nodes.  Last, register
 	 * the driver which manages those device numbers.
 	 */
-	BUILD_BUG_ON(N_SPI_MINORS > 256);
 	status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
 	if (status < 0)
 		return status;
 
-	spidev_class = class_create(THIS_MODULE, "spidev");
-	if (IS_ERR(spidev_class)) {
+	status = class_register(&spidev_class);
+	if (status) {
 		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
-		return PTR_ERR(spidev_class);
+		return status;
 	}
 
 	status = spi_register_driver(&spidev_spi_driver);
 	if (status < 0) {
-		class_destroy(spidev_class);
+		class_unregister(&spidev_class);
 		unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
 	}
 	return status;
@@ -700,7 +907,7 @@ module_init(spidev_init);
 static void __exit spidev_exit(void)
 {
 	spi_unregister_driver(&spidev_spi_driver);
-	class_destroy(spidev_class);
+	class_unregister(&spidev_class);
 	unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name);
 }
 module_exit(spidev_exit);