1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/char/broadcom/bcm2835_smi_dev.c b/drivers/char/broadcom/bcm2835_smi_dev.c
new file mode 100644
index 000000000000..9db8f1e3db0f
--- /dev/null
+++ b/drivers/char/broadcom/bcm2835_smi_dev.c
@@ -0,0 +1,402 @@
+/**
+ * Character device driver for Broadcom Secondary Memory Interface
+ *
+ * Written by Luke Wren <luke@raspberrypi.org>
+ * Copyright (c) 2015, Raspberry Pi (Trading) Ltd.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2, as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+
+#include <linux/broadcom/bcm2835_smi.h>
+
+#define DEVICE_NAME "bcm2835-smi-dev"
+#define DRIVER_NAME "smi-dev-bcm2835"
+#define DEVICE_MINOR 0
+
+static struct cdev bcm2835_smi_cdev;
+static dev_t bcm2835_smi_devid;
+static struct class *bcm2835_smi_class;
+static struct device *bcm2835_smi_dev;
+
+struct bcm2835_smi_dev_instance {
+	struct device *dev;
+};
+
+static struct bcm2835_smi_instance *smi_inst;
+static struct bcm2835_smi_dev_instance *inst;
+
+static const char *const ioctl_names[] = {
+	"READ_SETTINGS",
+	"WRITE_SETTINGS",
+	"ADDRESS"
+};
+
+/****************************************************************************
+*
+*   SMI chardev file ops
+*
+***************************************************************************/
+static long
+bcm2835_smi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	long ret = 0;
+
+	dev_info(inst->dev, "serving ioctl...");
+
+	switch (cmd) {
+	case BCM2835_SMI_IOC_GET_SETTINGS:{
+		struct smi_settings *settings;
+
+		dev_info(inst->dev, "Reading SMI settings to user.");
+		settings = bcm2835_smi_get_settings_from_regs(smi_inst);
+		if (copy_to_user((void *)arg, settings,
+				 sizeof(struct smi_settings)))
+			dev_err(inst->dev, "settings copy failed.");
+		break;
+	}
+	case BCM2835_SMI_IOC_WRITE_SETTINGS:{
+		struct smi_settings *settings;
+
+		dev_info(inst->dev, "Setting user's SMI settings.");
+		settings = bcm2835_smi_get_settings_from_regs(smi_inst);
+		if (copy_from_user(settings, (void *)arg,
+				   sizeof(struct smi_settings)))
+			dev_err(inst->dev, "settings copy failed.");
+		else
+			bcm2835_smi_set_regs_from_settings(smi_inst);
+		break;
+	}
+	case BCM2835_SMI_IOC_ADDRESS:
+		dev_info(inst->dev, "SMI address set: 0x%02x", (int)arg);
+		bcm2835_smi_set_address(smi_inst, arg);
+		break;
+	default:
+		dev_err(inst->dev, "invalid ioctl cmd: %d", cmd);
+		ret = -ENOTTY;
+		break;
+	}
+
+	return ret;
+}
+
+static int bcm2835_smi_open(struct inode *inode, struct file *file)
+{
+	int dev = iminor(inode);
+
+	dev_dbg(inst->dev, "SMI device opened.");
+
+	if (dev != DEVICE_MINOR) {
+		dev_err(inst->dev,
+			"bcm2835_smi_release: Unknown minor device: %d",
+			dev);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static int bcm2835_smi_release(struct inode *inode, struct file *file)
+{
+	int dev = iminor(inode);
+
+	if (dev != DEVICE_MINOR) {
+		dev_err(inst->dev,
+			"bcm2835_smi_release: Unknown minor device %d", dev);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static ssize_t dma_bounce_user(
+	enum dma_transfer_direction dma_dir,
+	char __user *user_ptr,
+	size_t count,
+	struct bcm2835_smi_bounce_info *bounce)
+{
+	int chunk_size;
+	int chunk_no = 0;
+	int count_left = count;
+
+	while (count_left) {
+		int rv;
+		void *buf;
+
+		/* Wait for current chunk to complete: */
+		if (down_timeout(&bounce->callback_sem,
+			msecs_to_jiffies(1000))) {
+			dev_err(inst->dev, "DMA bounce timed out");
+			count -= (count_left);
+			break;
+		}
+
+		if (bounce->callback_sem.count >= DMA_BOUNCE_BUFFER_COUNT - 1)
+			dev_err(inst->dev, "WARNING: Ring buffer overflow");
+		chunk_size = count_left > DMA_BOUNCE_BUFFER_SIZE ?
+			DMA_BOUNCE_BUFFER_SIZE : count_left;
+		buf = bounce->buffer[chunk_no % DMA_BOUNCE_BUFFER_COUNT];
+		if (dma_dir == DMA_DEV_TO_MEM)
+			rv = copy_to_user(user_ptr, buf, chunk_size);
+		else
+			rv = copy_from_user(buf, user_ptr, chunk_size);
+		if (rv)
+			dev_err(inst->dev, "copy_*_user() failed!: %d", rv);
+		user_ptr += chunk_size;
+		count_left -= chunk_size;
+		chunk_no++;
+	}
+	return count;
+}
+
+static ssize_t
+bcm2835_read_file(struct file *f, char __user *user_ptr,
+		  size_t count, loff_t *offs)
+{
+	int odd_bytes;
+
+	dev_dbg(inst->dev, "User reading %zu bytes from SMI.", count);
+	/* We don't want to DMA a number of bytes % 4 != 0 (32 bit FIFO) */
+	if (count > DMA_THRESHOLD_BYTES)
+		odd_bytes = count & 0x3;
+	else
+		odd_bytes = count;
+	count -= odd_bytes;
+	if (count) {
+		struct bcm2835_smi_bounce_info *bounce;
+
+		count = bcm2835_smi_user_dma(smi_inst,
+			DMA_DEV_TO_MEM, user_ptr, count,
+			&bounce);
+		if (count)
+			count = dma_bounce_user(DMA_DEV_TO_MEM, user_ptr,
+				count, bounce);
+	}
+	if (odd_bytes) {
+		/* Read from FIFO directly if not using DMA */
+		uint8_t buf[DMA_THRESHOLD_BYTES];
+
+		bcm2835_smi_read_buf(smi_inst, buf, odd_bytes);
+		if (copy_to_user(user_ptr, buf, odd_bytes))
+			dev_err(inst->dev, "copy_to_user() failed.");
+		count += odd_bytes;
+
+	}
+	return count;
+}
+
+static ssize_t
+bcm2835_write_file(struct file *f, const char __user *user_ptr,
+		   size_t count, loff_t *offs)
+{
+	int odd_bytes;
+
+	dev_dbg(inst->dev, "User writing %zu bytes to SMI.", count);
+	if (count > DMA_THRESHOLD_BYTES)
+		odd_bytes = count & 0x3;
+	else
+		odd_bytes = count;
+	count -= odd_bytes;
+	if (count) {
+		struct bcm2835_smi_bounce_info *bounce;
+
+		count = bcm2835_smi_user_dma(smi_inst,
+			DMA_MEM_TO_DEV, (char __user *)user_ptr, count,
+			&bounce);
+		if (count)
+			count = dma_bounce_user(DMA_MEM_TO_DEV,
+				(char __user *)user_ptr,
+				count, bounce);
+	}
+	if (odd_bytes) {
+		uint8_t buf[DMA_THRESHOLD_BYTES];
+
+		if (copy_from_user(buf, user_ptr, odd_bytes))
+			dev_err(inst->dev, "copy_from_user() failed.");
+		else
+			bcm2835_smi_write_buf(smi_inst, buf, odd_bytes);
+		count += odd_bytes;
+	}
+	return count;
+}
+
+static const struct file_operations
+bcm2835_smi_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = bcm2835_smi_ioctl,
+	.open = bcm2835_smi_open,
+	.release = bcm2835_smi_release,
+	.read = bcm2835_read_file,
+	.write = bcm2835_write_file,
+};
+
+
+/****************************************************************************
+*
+*   bcm2835_smi_probe - called when the driver is loaded.
+*
+***************************************************************************/
+
+static int bcm2835_smi_dev_probe(struct platform_device *pdev)
+{
+	int err;
+	void *ptr_err;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node, *smi_node;
+
+	if (!node) {
+		dev_err(dev, "No device tree node supplied!");
+		return -EINVAL;
+	}
+
+	smi_node = of_parse_phandle(node, "smi_handle", 0);
+
+	if (!smi_node) {
+		dev_err(dev, "No such property: smi_handle");
+		return -ENXIO;
+	}
+
+	smi_inst = bcm2835_smi_get(smi_node);
+
+	if (!smi_inst)
+		return -EPROBE_DEFER;
+
+	/* Allocate buffers and instance data */
+
+	inst = devm_kzalloc(dev, sizeof(*inst), GFP_KERNEL);
+
+	if (!inst)
+		return -ENOMEM;
+
+	inst->dev = dev;
+
+	/* Create character device entries */
+
+	err = alloc_chrdev_region(&bcm2835_smi_devid,
+				  DEVICE_MINOR, 1, DEVICE_NAME);
+	if (err != 0) {
+		dev_err(inst->dev, "unable to allocate device number");
+		return -ENOMEM;
+	}
+	cdev_init(&bcm2835_smi_cdev, &bcm2835_smi_fops);
+	bcm2835_smi_cdev.owner = THIS_MODULE;
+	err = cdev_add(&bcm2835_smi_cdev, bcm2835_smi_devid, 1);
+	if (err != 0) {
+		dev_err(inst->dev, "unable to register device");
+		err = -ENOMEM;
+		goto failed_cdev_add;
+	}
+
+	/* Create sysfs entries */
+
+	bcm2835_smi_class = class_create(THIS_MODULE, DEVICE_NAME);
+	ptr_err = bcm2835_smi_class;
+	if (IS_ERR(ptr_err))
+		goto failed_class_create;
+
+	bcm2835_smi_dev = device_create(bcm2835_smi_class, NULL,
+					bcm2835_smi_devid, NULL,
+					"smi");
+	ptr_err = bcm2835_smi_dev;
+	if (IS_ERR(ptr_err))
+		goto failed_device_create;
+
+	dev_info(inst->dev, "initialised");
+
+	return 0;
+
+failed_device_create:
+	class_destroy(bcm2835_smi_class);
+failed_class_create:
+	cdev_del(&bcm2835_smi_cdev);
+	err = PTR_ERR(ptr_err);
+failed_cdev_add:
+	unregister_chrdev_region(bcm2835_smi_devid, 1);
+	dev_err(dev, "could not load bcm2835_smi_dev");
+	return err;
+}
+
+/****************************************************************************
+*
+*   bcm2835_smi_remove - called when the driver is unloaded.
+*
+***************************************************************************/
+
+static int bcm2835_smi_dev_remove(struct platform_device *pdev)
+{
+	device_destroy(bcm2835_smi_class, bcm2835_smi_devid);
+	class_destroy(bcm2835_smi_class);
+	cdev_del(&bcm2835_smi_cdev);
+	unregister_chrdev_region(bcm2835_smi_devid, 1);
+
+	dev_info(inst->dev, "SMI character dev removed - OK");
+	return 0;
+}
+
+/****************************************************************************
+*
+*   Register the driver with device tree
+*
+***************************************************************************/
+
+static const struct of_device_id bcm2835_smi_dev_of_match[] = {
+	{.compatible = "brcm,bcm2835-smi-dev",},
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, bcm2835_smi_dev_of_match);
+
+static struct platform_driver bcm2835_smi_dev_driver = {
+	.probe = bcm2835_smi_dev_probe,
+	.remove = bcm2835_smi_dev_remove,
+	.driver = {
+		   .name = DRIVER_NAME,
+		   .owner = THIS_MODULE,
+		   .of_match_table = bcm2835_smi_dev_of_match,
+		   },
+};
+
+module_platform_driver(bcm2835_smi_dev_driver);
+
+MODULE_ALIAS("platform:smi-dev-bcm2835");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(
+	"Character device driver for BCM2835's secondary memory interface");
+MODULE_AUTHOR("Luke Wren <luke@raspberrypi.org>");