3 files changed, 192 insertions, 289 deletions

diff --git a/drivers/staging/axis-fifo/Kconfig b/drivers/staging/axis-fifo/Kconfig
index 3fffe4d6f327..f180a8e9f58a 100644
--- a/drivers/staging/axis-fifo/Kconfig
+++ b/drivers/staging/axis-fifo/Kconfig
@@ -4,7 +4,7 @@
 #
 config XIL_AXIS_FIFO
 	tristate "Xilinx AXI-Stream FIFO IP core driver"
-	depends on OF
+	depends on OF && HAS_IOMEM
 	help
 	  This adds support for the Xilinx AXI-Stream FIFO IP core driver.
 	  The AXI Streaming FIFO allows memory mapped access to a AXI Streaming
diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index 805437fa249a..5801067e7c1b 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -16,7 +16,7 @@
 
 #include <linux/kernel.h>
 #include <linux/wait.h>
-#include <linux/spinlock_types.h>
+#include <linux/mutex.h>
 #include <linux/device.h>
 #include <linux/cdev.h>
 #include <linux/init.h>
@@ -125,7 +125,6 @@ MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing out;
 
 struct axis_fifo {
 	int irq; /* interrupt */
-	struct resource *mem; /* physical memory */
 	void __iomem *base_addr; /* kernel space memory */
 
 	unsigned int rx_fifo_depth; /* max words in the receive fifo */
@@ -134,9 +133,9 @@ struct axis_fifo {
 	int has_tx_fifo; /* whether the IP has the tx fifo enabled */
 
 	wait_queue_head_t read_queue; /* wait queue for asynchronos read */
-	spinlock_t read_queue_lock; /* lock for reading waitqueue */
+	struct mutex read_lock; /* lock for reading */
 	wait_queue_head_t write_queue; /* wait queue for asynchronos write */
-	spinlock_t write_queue_lock; /* lock for writing waitqueue */
+	struct mutex write_lock; /* lock for writing */
 	unsigned int write_flags; /* write file flags */
 	unsigned int read_flags; /* read file flags */
 
@@ -337,7 +336,21 @@ static void reset_ip_core(struct axis_fifo *fifo)
 	iowrite32(XLLF_INT_ALL_MASK, fifo->base_addr + XLLF_ISR_OFFSET);
 }
 
-/* reads a single packet from the fifo as dictated by the tlast signal */
+/**
+ * axis_fifo_write() - Read a packet from AXIS-FIFO character device.
+ * @f Open file.
+ * @buf User space buffer to read to.
+ * @len User space buffer length.
+ * @off Buffer offset.
+ *
+ * As defined by the device's documentation, we need to check the device's
+ * occupancy before reading the length register and then the data. All these
+ * operations must be executed atomically, in order and one after the other
+ * without missing any.
+ *
+ * Returns the number of bytes read from the device or negative error code
+ *	on failure.
+ */
 static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 			      size_t len, loff_t *off)
 {
@@ -351,36 +364,37 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 	u32 tmp_buf[READ_BUF_SIZE];
 
 	if (fifo->read_flags & O_NONBLOCK) {
-		/* opened in non-blocking mode
-		 * return if there are no packets available
+		/*
+		 * Device opened in non-blocking mode. Try to lock it and then
+		 * check if any packet is available.
 		 */
-		if (!ioread32(fifo->base_addr + XLLF_RDFO_OFFSET))
+		if (!mutex_trylock(&fifo->read_lock))
 			return -EAGAIN;
+
+		if (!ioread32(fifo->base_addr + XLLF_RDFO_OFFSET)) {
+			ret = -EAGAIN;
+			goto end_unlock;
+		}
 	} else {
 		/* opened in blocking mode
 		 * wait for a packet available interrupt (or timeout)
 		 * if nothing is currently available
 		 */
-		spin_lock_irq(&fifo->read_queue_lock);
-		ret = wait_event_interruptible_lock_irq_timeout
-			(fifo->read_queue,
-			 ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
-			 fifo->read_queue_lock,
-			 (read_timeout >= 0) ? msecs_to_jiffies(read_timeout) :
+		mutex_lock(&fifo->read_lock);
+		ret = wait_event_interruptible_timeout(fifo->read_queue,
+			ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
+			(read_timeout >= 0) ? msecs_to_jiffies(read_timeout) :
 				MAX_SCHEDULE_TIMEOUT);
-		spin_unlock_irq(&fifo->read_queue_lock);
 
-		if (ret == 0) {
-			/* timeout occurred */
-			dev_dbg(fifo->dt_device, "read timeout");
-			return -EAGAIN;
-		} else if (ret == -ERESTARTSYS) {
-			/* signal received */
-			return -ERESTARTSYS;
-		} else if (ret < 0) {
-			dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in read (ret=%i)\n",
-				ret);
-			return ret;
+		if (ret <= 0) {
+			if (ret == 0) {
+				ret = -EAGAIN;
+			} else if (ret != -ERESTARTSYS) {
+				dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in read (ret=%i)\n",
+					ret);
+			}
+
+			goto end_unlock;
 		}
 	}
 
@@ -388,14 +402,16 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 	if (!bytes_available) {
 		dev_err(fifo->dt_device, "received a packet of length 0 - fifo core will be reset\n");
 		reset_ip_core(fifo);
-		return -EIO;
+		ret = -EIO;
+		goto end_unlock;
 	}
 
 	if (bytes_available > len) {
 		dev_err(fifo->dt_device, "user read buffer too small (available bytes=%zu user buffer bytes=%zu) - fifo core will be reset\n",
 			bytes_available, len);
 		reset_ip_core(fifo);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto end_unlock;
 	}
 
 	if (bytes_available % sizeof(u32)) {
@@ -404,7 +420,8 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 		 */
 		dev_err(fifo->dt_device, "received a packet that isn't word-aligned - fifo core will be reset\n");
 		reset_ip_core(fifo);
-		return -EIO;
+		ret = -EIO;
+		goto end_unlock;
 	}
 
 	words_available = bytes_available / sizeof(u32);
@@ -424,16 +441,37 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
 		if (copy_to_user(buf + copied * sizeof(u32), tmp_buf,
 				 copy * sizeof(u32))) {
 			reset_ip_core(fifo);
-			return -EFAULT;
+			ret = -EFAULT;
+			goto end_unlock;
 		}
 
 		copied += copy;
 		words_available -= copy;
 	}
 
-	return bytes_available;
+	ret = bytes_available;
+
+end_unlock:
+	mutex_unlock(&fifo->read_lock);
+
+	return ret;
 }
 
+/**
+ * axis_fifo_write() - Write buffer to AXIS-FIFO character device.
+ * @f Open file.
+ * @buf User space buffer to write to the device.
+ * @len User space buffer length.
+ * @off Buffer offset.
+ *
+ * As defined by the device's documentation, we need to write to the device's
+ * data buffer then to the device's packet length register atomically. Also,
+ * we need to lock before checking if the device has available space to avoid
+ * any concurrency issue.
+ *
+ * Returns the number of bytes written to the device or negative error code
+ *	on failure.
+ */
 static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 			       size_t len, loff_t *off)
 {
@@ -466,12 +504,17 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 	}
 
 	if (fifo->write_flags & O_NONBLOCK) {
-		/* opened in non-blocking mode
-		 * return if there is not enough room available in the fifo
+		/*
+		 * Device opened in non-blocking mode. Try to lock it and then
+		 * check if there is any room to write the given buffer.
 		 */
+		if (!mutex_trylock(&fifo->write_lock))
+			return -EAGAIN;
+
 		if (words_to_write > ioread32(fifo->base_addr +
 					      XLLF_TDFV_OFFSET)) {
-			return -EAGAIN;
+			ret = -EAGAIN;
+			goto end_unlock;
 		}
 	} else {
 		/* opened in blocking mode */
@@ -479,30 +522,22 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 		/* wait for an interrupt (or timeout) if there isn't
 		 * currently enough room in the fifo
 		 */
-		spin_lock_irq(&fifo->write_queue_lock);
-		ret = wait_event_interruptible_lock_irq_timeout
-			(fifo->write_queue,
-			 ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
+		mutex_lock(&fifo->write_lock);
+		ret = wait_event_interruptible_timeout(fifo->write_queue,
+			ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
 				>= words_to_write,
-			 fifo->write_queue_lock,
-			 (write_timeout >= 0) ?
-				msecs_to_jiffies(write_timeout) :
+			(write_timeout >= 0) ? msecs_to_jiffies(write_timeout) :
 				MAX_SCHEDULE_TIMEOUT);
-		spin_unlock_irq(&fifo->write_queue_lock);
 
-		if (ret == 0) {
-			/* timeout occurred */
-			dev_dbg(fifo->dt_device, "write timeout\n");
-			return -EAGAIN;
-		} else if (ret == -ERESTARTSYS) {
-			/* signal received */
-			return -ERESTARTSYS;
-		} else if (ret < 0) {
-			/* unknown error */
-			dev_err(fifo->dt_device,
-				"wait_event_interruptible_timeout() error in write (ret=%i)\n",
-				ret);
-			return ret;
+		if (ret <= 0) {
+			if (ret == 0) {
+				ret = -EAGAIN;
+			} else if (ret != -ERESTARTSYS) {
+				dev_err(fifo->dt_device, "wait_event_interruptible_timeout() error in write (ret=%i)\n",
+					ret);
+			}
+
+			goto end_unlock;
 		}
 	}
 
@@ -516,7 +551,8 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 		if (copy_from_user(tmp_buf, buf + copied * sizeof(u32),
 				   copy * sizeof(u32))) {
 			reset_ip_core(fifo);
-			return -EFAULT;
+			ret = -EFAULT;
+			goto end_unlock;
 		}
 
 		for (i = 0; i < copy; i++)
@@ -527,10 +563,15 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
 		words_to_write -= copy;
 	}
 
+	ret = copied * sizeof(u32);
+
 	/* write packet size to fifo */
-	iowrite32(copied * sizeof(u32), fifo->base_addr + XLLF_TLR_OFFSET);
+	iowrite32(ret, fifo->base_addr + XLLF_TLR_OFFSET);
 
-	return (ssize_t)copied * sizeof(u32);
+end_unlock:
+	mutex_unlock(&fifo->write_lock);
+
+	return ret;
 }
 
 static irqreturn_t axis_fifo_irq(int irq, void *dw)
@@ -701,6 +742,68 @@ static int get_dts_property(struct axis_fifo *fifo,
 	return 0;
 }
 
+static int axis_fifo_parse_dt(struct axis_fifo *fifo)
+{
+	int ret;
+	unsigned int value;
+
+	ret = get_dts_property(fifo, "xlnx,axi-str-rxd-tdata-width", &value);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,axi-str-rxd-tdata-width property\n");
+		goto end;
+	} else if (value != 32) {
+		dev_err(fifo->dt_device, "xlnx,axi-str-rxd-tdata-width only supports 32 bits\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,axi-str-txd-tdata-width", &value);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,axi-str-txd-tdata-width property\n");
+		goto end;
+	} else if (value != 32) {
+		dev_err(fifo->dt_device, "xlnx,axi-str-txd-tdata-width only supports 32 bits\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,rx-fifo-depth",
+			       &fifo->rx_fifo_depth);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,rx-fifo-depth property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,tx-fifo-depth",
+			       &fifo->tx_fifo_depth);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,tx-fifo-depth property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	/* IP sets TDFV to fifo depth - 4 so we will do the same */
+	fifo->tx_fifo_depth -= 4;
+
+	ret = get_dts_property(fifo, "xlnx,use-rx-data", &fifo->has_rx_fifo);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,use-rx-data property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+	ret = get_dts_property(fifo, "xlnx,use-tx-data", &fifo->has_tx_fifo);
+	if (ret) {
+		dev_err(fifo->dt_device, "missing xlnx,use-tx-data property\n");
+		ret = -EIO;
+		goto end;
+	}
+
+end:
+	return ret;
+}
+
 static int axis_fifo_probe(struct platform_device *pdev)
 {
 	struct resource *r_irq; /* interrupt resources */
@@ -712,34 +815,6 @@ static int axis_fifo_probe(struct platform_device *pdev)
 
 	int rc = 0; /* error return value */
 
-	/* IP properties from device tree */
-	unsigned int rxd_tdata_width;
-	unsigned int txc_tdata_width;
-	unsigned int txd_tdata_width;
-	unsigned int tdest_width;
-	unsigned int tid_width;
-	unsigned int tuser_width;
-	unsigned int data_interface_type;
-	unsigned int has_tdest;
-	unsigned int has_tid;
-	unsigned int has_tkeep;
-	unsigned int has_tstrb;
-	unsigned int has_tuser;
-	unsigned int rx_fifo_depth;
-	unsigned int rx_programmable_empty_threshold;
-	unsigned int rx_programmable_full_threshold;
-	unsigned int axi_id_width;
-	unsigned int axi4_data_width;
-	unsigned int select_xpm;
-	unsigned int tx_fifo_depth;
-	unsigned int tx_programmable_empty_threshold;
-	unsigned int tx_programmable_full_threshold;
-	unsigned int use_rx_cut_through;
-	unsigned int use_rx_data;
-	unsigned int use_tx_control;
-	unsigned int use_tx_cut_through;
-	unsigned int use_tx_data;
-
 	/* ----------------------------
 	 *     init wrapper device
 	 * ----------------------------
@@ -756,8 +831,8 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	init_waitqueue_head(&fifo->read_queue);
 	init_waitqueue_head(&fifo->write_queue);
 
-	spin_lock_init(&fifo->read_queue_lock);
-	spin_lock_init(&fifo->write_queue_lock);
+	mutex_init(&fifo->read_lock);
+	mutex_init(&fifo->write_lock);
 
 	/* ----------------------------
 	 *   init device memory space
@@ -772,32 +847,19 @@ static int axis_fifo_probe(struct platform_device *pdev)
 		goto err_initial;
 	}
 
-	fifo->mem = r_mem;
-
 	/* request physical memory */
-	if (!request_mem_region(fifo->mem->start, resource_size(fifo->mem),
-				DRIVER_NAME)) {
-		dev_err(fifo->dt_device,
-			"couldn't lock memory region at 0x%pa\n",
-			&fifo->mem->start);
-		rc = -EBUSY;
+	fifo->base_addr = devm_ioremap_resource(fifo->dt_device, r_mem);
+	if (IS_ERR(fifo->base_addr)) {
+		rc = PTR_ERR(fifo->base_addr);
+		dev_err(fifo->dt_device, "can't remap IO resource (%d)\n", rc);
 		goto err_initial;
 	}
-	dev_dbg(fifo->dt_device, "got memory location [0x%pa - 0x%pa]\n",
-		&fifo->mem->start, &fifo->mem->end);
-
-	/* map physical memory to kernel virtual address space */
-	fifo->base_addr = ioremap(fifo->mem->start, resource_size(fifo->mem));
-	if (!fifo->base_addr) {
-		dev_err(fifo->dt_device, "couldn't map physical memory\n");
-		rc = -ENOMEM;
-		goto err_mem;
-	}
+
 	dev_dbg(fifo->dt_device, "remapped memory to 0x%p\n", fifo->base_addr);
 
 	/* create unique device name */
 	snprintf(device_name, sizeof(device_name), "%s_%pa",
-		 DRIVER_NAME, &fifo->mem->start);
+		 DRIVER_NAME, &r_mem->start);
 
 	dev_dbg(fifo->dt_device, "device name [%s]\n", device_name);
 
@@ -806,164 +868,9 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	 * ----------------------------
 	 */
 
-	/* retrieve device tree properties */
-	rc = get_dts_property(fifo, "xlnx,axi-str-rxd-tdata-width",
-			      &rxd_tdata_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,axi-str-txc-tdata-width",
-			      &txc_tdata_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,axi-str-txd-tdata-width",
-			      &txd_tdata_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,axis-tdest-width", &tdest_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,axis-tid-width", &tid_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,axis-tuser-width", &tuser_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,data-interface-type",
-			      &data_interface_type);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,has-axis-tdest", &has_tdest);
+	rc = axis_fifo_parse_dt(fifo);
 	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,has-axis-tid", &has_tid);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,has-axis-tkeep", &has_tkeep);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,has-axis-tstrb", &has_tstrb);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,has-axis-tuser", &has_tuser);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,rx-fifo-depth", &rx_fifo_depth);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,rx-fifo-pe-threshold",
-			      &rx_programmable_empty_threshold);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,rx-fifo-pf-threshold",
-			      &rx_programmable_full_threshold);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,s-axi-id-width", &axi_id_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,s-axi4-data-width", &axi4_data_width);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,select-xpm", &select_xpm);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,tx-fifo-depth", &tx_fifo_depth);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,tx-fifo-pe-threshold",
-			      &tx_programmable_empty_threshold);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,tx-fifo-pf-threshold",
-			      &tx_programmable_full_threshold);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,use-rx-cut-through",
-			      &use_rx_cut_through);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,use-rx-data", &use_rx_data);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,use-tx-ctrl", &use_tx_control);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,use-tx-cut-through",
-			      &use_tx_cut_through);
-	if (rc)
-		goto err_unmap;
-	rc = get_dts_property(fifo, "xlnx,use-tx-data", &use_tx_data);
-	if (rc)
-		goto err_unmap;
-
-	/* check validity of device tree properties */
-	if (rxd_tdata_width != 32) {
-		dev_err(fifo->dt_device,
-			"rxd_tdata_width width [%u] unsupported\n",
-			rxd_tdata_width);
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (txd_tdata_width != 32) {
-		dev_err(fifo->dt_device,
-			"txd_tdata_width width [%u] unsupported\n",
-			txd_tdata_width);
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (has_tdest) {
-		dev_err(fifo->dt_device, "tdest not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (has_tid) {
-		dev_err(fifo->dt_device, "tid not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (has_tkeep) {
-		dev_err(fifo->dt_device, "tkeep not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (has_tstrb) {
-		dev_err(fifo->dt_device, "tstrb not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (has_tuser) {
-		dev_err(fifo->dt_device, "tuser not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (use_rx_cut_through) {
-		dev_err(fifo->dt_device, "rx cut-through not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (use_tx_cut_through) {
-		dev_err(fifo->dt_device, "tx cut-through not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-	if (use_tx_control) {
-		dev_err(fifo->dt_device, "tx control not supported\n");
-		rc = -EIO;
-		goto err_unmap;
-	}
-
-	/* TODO
-	 * these exist in the device tree but it's unclear what they do
-	 * - select-xpm
-	 * - data-interface-type
-	 */
-
-	/* set device wrapper properties based on IP config */
-	fifo->rx_fifo_depth = rx_fifo_depth;
-	/* IP sets TDFV to fifo depth - 4 so we will do the same */
-	fifo->tx_fifo_depth = tx_fifo_depth - 4;
-	fifo->has_rx_fifo = use_rx_data;
-	fifo->has_tx_fifo = use_tx_data;
+		goto err_initial;
 
 	reset_ip_core(fifo);
 
@@ -976,18 +883,19 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	r_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (!r_irq) {
 		dev_err(fifo->dt_device, "no IRQ found for 0x%pa\n",
-			&fifo->mem->start);
+			&r_mem->start);
 		rc = -EIO;
-		goto err_unmap;
+		goto err_initial;
 	}
 
 	/* request IRQ */
 	fifo->irq = r_irq->start;
-	rc = request_irq(fifo->irq, &axis_fifo_irq, 0, DRIVER_NAME, fifo);
+	rc = devm_request_irq(fifo->dt_device, fifo->irq, &axis_fifo_irq, 0,
+			      DRIVER_NAME, fifo);
 	if (rc) {
 		dev_err(fifo->dt_device, "couldn't allocate interrupt %i\n",
 			fifo->irq);
-		goto err_unmap;
+		goto err_initial;
 	}
 
 	/* ----------------------------
@@ -998,7 +906,7 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	/* allocate device number */
 	rc = alloc_chrdev_region(&fifo->devt, 0, 1, DRIVER_NAME);
 	if (rc < 0)
-		goto err_irq;
+		goto err_initial;
 	dev_dbg(fifo->dt_device, "allocated device number major %i minor %i\n",
 		MAJOR(fifo->devt), MINOR(fifo->devt));
 
@@ -1022,14 +930,14 @@ static int axis_fifo_probe(struct platform_device *pdev)
 	}
 
 	/* create sysfs entries */
-	rc = sysfs_create_group(&fifo->device->kobj, &axis_fifo_attrs_group);
+	rc = devm_device_add_group(fifo->device, &axis_fifo_attrs_group);
 	if (rc < 0) {
 		dev_err(fifo->dt_device, "couldn't register sysfs group\n");
 		goto err_cdev;
 	}
 
 	dev_info(fifo->dt_device, "axis-fifo created at %pa mapped to 0x%pa, irq=%i, major=%i, minor=%i\n",
-		 &fifo->mem->start, &fifo->base_addr, fifo->irq,
+		 &r_mem->start, &fifo->base_addr, fifo->irq,
 		 MAJOR(fifo->devt), MINOR(fifo->devt));
 
 	return 0;
@@ -1040,12 +948,6 @@ err_dev:
 	device_destroy(axis_fifo_driver_class, fifo->devt);
 err_chrdev_region:
 	unregister_chrdev_region(fifo->devt, 1);
-err_irq:
-	free_irq(fifo->irq, fifo);
-err_unmap:
-	iounmap(fifo->base_addr);
-err_mem:
-	release_mem_region(fifo->mem->start, resource_size(fifo->mem));
 err_initial:
 	dev_set_drvdata(dev, NULL);
 	return rc;
@@ -1056,15 +958,12 @@ static int axis_fifo_remove(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct axis_fifo *fifo = dev_get_drvdata(dev);
 
-	sysfs_remove_group(&fifo->device->kobj, &axis_fifo_attrs_group);
 	cdev_del(&fifo->char_device);
 	dev_set_drvdata(fifo->device, NULL);
 	device_destroy(axis_fifo_driver_class, fifo->devt);
 	unregister_chrdev_region(fifo->devt, 1);
-	free_irq(fifo->irq, fifo);
-	iounmap(fifo->base_addr);
-	release_mem_region(fifo->mem->start, resource_size(fifo->mem));
 	dev_set_drvdata(dev, NULL);
+
 	return 0;
 }
 
diff --git a/drivers/staging/axis-fifo/axis-fifo.txt b/drivers/staging/axis-fifo/axis-fifo.txt
index 85d88c010e72..5828e1b8e822 100644
--- a/drivers/staging/axis-fifo/axis-fifo.txt
+++ b/drivers/staging/axis-fifo/axis-fifo.txt
@@ -25,10 +25,10 @@ Required properties:
 - xlnx,axi-str-txc-tdata-width: Should be <0x20>
 - xlnx,axi-str-txd-protocol: Should be "XIL_AXI_STREAM_ETH_DATA"
 - xlnx,axi-str-txd-tdata-width: Should be <0x20>
-- xlnx,axis-tdest-width: AXI-Stream TDEST width
-- xlnx,axis-tid-width: AXI-Stream TID width
-- xlnx,axis-tuser-width: AXI-Stream TUSER width
-- xlnx,data-interface-type: Should be <0x0>
+- xlnx,axis-tdest-width: AXI-Stream TDEST width (ignored by the driver)
+- xlnx,axis-tid-width: AXI-Stream TID width (ignored by the driver)
+- xlnx,axis-tuser-width: AXI-Stream TUSER width (ignored by the driver)
+- xlnx,data-interface-type: Should be <0x0> (ignored by the driver)
 - xlnx,has-axis-tdest: Should be <0x0> (this feature isn't supported)
 - xlnx,has-axis-tid: Should be <0x0> (this feature isn't supported)
 - xlnx,has-axis-tkeep: Should be <0x0> (this feature isn't supported)
@@ -36,13 +36,17 @@ Required properties:
 - xlnx,has-axis-tuser: Should be <0x0> (this feature isn't supported)
 - xlnx,rx-fifo-depth: Depth of RX FIFO in words
 - xlnx,rx-fifo-pe-threshold: RX programmable empty interrupt threshold
+	(ignored by the driver)
 - xlnx,rx-fifo-pf-threshold: RX programmable full interrupt threshold
-- xlnx,s-axi-id-width: Should be <0x4>
-- xlnx,s-axi4-data-width: Should be <0x20>
-- xlnx,select-xpm: Should be <0x0>
+	(ignored by the driver)
+- xlnx,s-axi-id-width: Should be <0x4> (ignored by the driver)
+- xlnx,s-axi4-data-width: Should be <0x20> (ignored by the driver)
+- xlnx,select-xpm: Should be <0x0> (ignored by the driver)
 - xlnx,tx-fifo-depth: Depth of TX FIFO in words
 - xlnx,tx-fifo-pe-threshold: TX programmable empty interrupt threshold
+	(ignored by the driver)
 - xlnx,tx-fifo-pf-threshold: TX programmable full interrupt threshold
+	(ignored by the driver)
 - xlnx,use-rx-cut-through: Should be <0x0> (this feature isn't supported)
 - xlnx,use-rx-data: <0x1> if RX FIFO is enabled, <0x0> otherwise
 - xlnx,use-tx-ctrl: Should be <0x0> (this feature isn't supported)