1 files changed, 430 insertions, 0 deletions

diff --git a/driver/hdm-i2c/hdm_i2c.c b/driver/hdm-i2c/hdm_i2c.c
new file mode 100644
index 0000000..ba0263b
--- /dev/null
+++ b/driver/hdm-i2c/hdm_i2c.c
@@ -0,0 +1,430 @@
+/*
+ * hdm_i2c.c - Hardware Dependent Module for I2C Interface
+ *
+ * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+
+#include <mostcore.h>
+
+enum { CH_RX, CH_TX, NUM_CHANNELS };
+
+#define MAX_BUFFERS_CONTROL 32
+#define MAX_BUF_SIZE_CONTROL 256
+
+/**
+ * list_first_mbo - get the first mbo from a list
+ * @ptr:	the list head to take the mbo from.
+ */
+#define list_first_mbo(ptr) \
+	list_first_entry(ptr, struct mbo, list)
+
+/* IRQ / Polling option */
+static bool polling_req;
+module_param(polling_req, bool, S_IRUGO);
+MODULE_PARM_DESC(polling_req, "Request Polling. Default = 0 (use irq)");
+
+/* Polling Rate */
+static int scan_rate = 100;
+module_param(scan_rate, int, 0644);
+MODULE_PARM_DESC(scan_rate, "Polling rate in times/sec. Default = 100");
+
+struct hdm_i2c {
+	bool is_open[NUM_CHANNELS];
+	bool polling_mode;
+	struct most_interface most_iface;
+	struct most_channel_capability capabilities[NUM_CHANNELS];
+	struct i2c_client *client;
+	struct rx {
+		struct delayed_work dwork;
+		wait_queue_head_t waitq;
+		struct list_head list;
+		struct mutex list_mutex;
+	} rx;
+	char name[64];
+};
+
+#define to_hdm(iface) container_of(iface, struct hdm_i2c, most_iface)
+
+/**
+ * configure_channel - called from MOST core to configure a channel
+ * @iface: interface the channel belongs to
+ * @channel: channel to be configured
+ * @channel_config: structure that holds the configuration information
+ *
+ * Return 0 on success, negative on failure.
+ *
+ * Receives configuration information from MOST core and initialize the
+ * corresponding channel.
+ */
+static int configure_channel(struct most_interface *most_iface,
+			     int ch_idx,
+			     struct most_channel_config *channel_config)
+{
+	struct hdm_i2c *dev = to_hdm(most_iface);
+
+	BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
+	BUG_ON(dev->is_open[ch_idx]);
+
+	if (channel_config->data_type != MOST_CH_CONTROL) {
+		pr_err("bad data type for channel %d\n", ch_idx);
+		return -EPERM;
+	}
+
+	if (channel_config->direction != dev->capabilities[ch_idx].direction) {
+		pr_err("bad direction for channel %d\n", ch_idx);
+		return -EPERM;
+	}
+
+	if ((channel_config->direction == MOST_CH_RX) && (dev->polling_mode)) {
+		schedule_delayed_work(&dev->rx.dwork,
+				      msecs_to_jiffies(MSEC_PER_SEC / 4));
+	}
+	dev->is_open[ch_idx] = true;
+
+	return 0;
+}
+
+/**
+ * enqueue - called from MOST core to enqueue a buffer for data transfer
+ * @iface: intended interface
+ * @channel: ID of the channel the buffer is intended for
+ * @mbo: pointer to the buffer object
+ *
+ * Return 0 on success, negative on failure.
+ *
+ * Transmit the data over I2C if it is a "write" request or push the buffer into
+ * list if it is an "read" request
+ */
+static int enqueue(struct most_interface *most_iface,
+		   int ch_idx, struct mbo *mbo)
+{
+	struct hdm_i2c *dev = to_hdm(most_iface);
+	int ret;
+
+	BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
+	BUG_ON(!dev->is_open[ch_idx]);
+
+	if (ch_idx == CH_RX) {
+		/* RX */
+		mutex_lock(&dev->rx.list_mutex);
+		list_add_tail(&mbo->list, &dev->rx.list);
+		mutex_unlock(&dev->rx.list_mutex);
+		wake_up_interruptible(&dev->rx.waitq);
+	} else {
+		/* TX */
+		ret = i2c_master_send(dev->client, mbo->virt_address,
+				      mbo->buffer_length);
+		if (ret <= 0) {
+			mbo->processed_length = 0;
+			mbo->status = MBO_E_INVAL;
+		} else {
+			mbo->processed_length = mbo->buffer_length;
+			mbo->status = MBO_SUCCESS;
+		}
+		mbo->complete(mbo);
+	}
+
+	return 0;
+}
+
+/**
+ * poison_channel - called from MOST core to poison buffers of a channel
+ * @iface: pointer to the interface the channel to be poisoned belongs to
+ * @channel_id: corresponding channel ID
+ *
+ * Return 0 on success, negative on failure.
+ *
+ * If channel direction is RX, complete the buffers in list with
+ * status MBO_E_CLOSE
+ */
+static int poison_channel(struct most_interface *most_iface,
+			  int ch_idx)
+{
+	struct hdm_i2c *dev = to_hdm(most_iface);
+	struct mbo *mbo;
+
+	BUG_ON(ch_idx < 0 || ch_idx >= NUM_CHANNELS);
+	BUG_ON(!dev->is_open[ch_idx]);
+
+	dev->is_open[ch_idx] = false;
+
+	if (ch_idx == CH_RX) {
+		mutex_lock(&dev->rx.list_mutex);
+		while (!list_empty(&dev->rx.list)) {
+			mbo = list_first_mbo(&dev->rx.list);
+			list_del(&mbo->list);
+			mutex_unlock(&dev->rx.list_mutex);
+
+			mbo->processed_length = 0;
+			mbo->status = MBO_E_CLOSE;
+			mbo->complete(mbo);
+
+			mutex_lock(&dev->rx.list_mutex);
+		}
+		mutex_unlock(&dev->rx.list_mutex);
+		wake_up_interruptible(&dev->rx.waitq);
+	}
+
+	return 0;
+}
+
+static void request_netinfo(struct most_interface *most_iface,
+			    int ch_idx)
+{
+	pr_info("request_netinfo()\n");
+}
+
+static void do_rx_work(struct hdm_i2c *dev)
+{
+	struct mbo *mbo;
+	unsigned char msg[MAX_BUF_SIZE_CONTROL];
+	int ret, ch_idx = CH_RX;
+	u16 pml, data_size;
+
+	/* Read PML (2 bytes) */
+	ret = i2c_master_recv(dev->client, msg, 2);
+	if (ret <= 0) {
+		pr_err("Failed to receive PML\n");
+		return;
+	}
+
+	pml = (msg[0] << 8) | msg[1];
+	if (!pml)
+		return;
+
+	data_size = pml + 2;
+
+	/* Read the whole message, including PML */
+	ret = i2c_master_recv(dev->client, msg, data_size);
+	if (ret <= 0) {
+		pr_err("Failed to receive a Port Message\n");
+		return;
+	}
+
+	for (;;) {
+		/* Conditions to wait for: poisoned channel or free buffer
+		 * available for reading
+		 */
+		if (wait_event_interruptible(dev->rx.waitq,
+					     !dev->is_open[ch_idx] ||
+					     !list_empty(&dev->rx.list))) {
+			pr_err("wait_event_interruptible() failed\n");
+			return;
+		}
+
+		if (!dev->is_open[ch_idx])
+			return;
+
+		mutex_lock(&dev->rx.list_mutex);
+
+		/* list may be empty if poison or remove is called */
+		if (!list_empty(&dev->rx.list))
+			break;
+
+		mutex_unlock(&dev->rx.list_mutex);
+	}
+
+	mbo = list_first_mbo(&dev->rx.list);
+	list_del(&mbo->list);
+	mutex_unlock(&dev->rx.list_mutex);
+
+	mbo->processed_length = min(data_size, mbo->buffer_length);
+	memcpy(mbo->virt_address, msg, mbo->processed_length);
+	mbo->status = MBO_SUCCESS;
+	mbo->complete(mbo);
+}
+
+/**
+ * pending_rx_work - Read pending messages through I2C
+ * @work: definition of this work item
+ *
+ * Invoked by the Interrupt Service Routine, most_irq_handler()
+ */
+static void pending_rx_work(struct work_struct *work)
+{
+	struct hdm_i2c *dev = container_of(work, struct hdm_i2c, rx.dwork.work);
+
+	do_rx_work(dev);
+
+	if (dev->polling_mode) {
+		if (dev->is_open[CH_RX])
+			schedule_delayed_work(&dev->rx.dwork,
+					      msecs_to_jiffies(MSEC_PER_SEC
+							       / scan_rate));
+	} else {
+		enable_irq(dev->client->irq);
+	}
+}
+
+/*
+ * most_irq_handler - Interrupt Service Routine
+ * @irq: irq number
+ * @_dev: private data
+ *
+ * Schedules a delayed work
+ *
+ * By default the interrupt line behavior is Active Low. Once an interrupt is
+ * generated by the device, until driver clears the interrupt (by reading
+ * the PMP message), device keeps the interrupt line in low state. Since i2c
+ * read is done in work queue, the interrupt line must be disabled temporarily
+ * to avoid ISR being called repeatedly. Re-enable the interrupt in workqueue,
+ * after reading the message.
+ *
+ * Note: If we use the interrupt line in Falling edge mode, there is a
+ * possibility to miss interrupts when ISR is getting executed.
+ *
+ */
+static irqreturn_t most_irq_handler(int irq, void *_dev)
+{
+	struct hdm_i2c *dev = _dev;
+
+	disable_irq_nosync(irq);
+
+	schedule_delayed_work(&dev->rx.dwork, 0);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * i2c_probe - i2c probe handler
+ * @client: i2c client device structure
+ * @id: i2c client device id
+ *
+ * Return 0 on success, negative on failure.
+ *
+ * Register the i2c client device as a MOST interface
+ */
+static int i2c_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct hdm_i2c *dev;
+	int ret, i;
+	struct kobject *kobj;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	/* ID format: i2c-<bus>-<address> */
+	snprintf(dev->name, sizeof(dev->name), "i2c-%d-%04x",
+		 client->adapter->nr, client->addr);
+
+	for (i = 0; i < NUM_CHANNELS; i++) {
+		dev->is_open[i] = false;
+		dev->capabilities[i].data_type = MOST_CH_CONTROL;
+		dev->capabilities[i].num_buffers_packet = MAX_BUFFERS_CONTROL;
+		dev->capabilities[i].buffer_size_packet = MAX_BUF_SIZE_CONTROL;
+	}
+	dev->capabilities[CH_RX].direction = MOST_CH_RX;
+	dev->capabilities[CH_RX].name_suffix = "rx";
+	dev->capabilities[CH_TX].direction = MOST_CH_TX;
+	dev->capabilities[CH_TX].name_suffix = "tx";
+
+	dev->most_iface.interface = ITYPE_I2C;
+	dev->most_iface.description = dev->name;
+	dev->most_iface.num_channels = NUM_CHANNELS;
+	dev->most_iface.channel_vector = dev->capabilities;
+	dev->most_iface.configure = configure_channel;
+	dev->most_iface.enqueue = enqueue;
+	dev->most_iface.poison_channel = poison_channel;
+	dev->most_iface.request_netinfo = request_netinfo;
+
+	INIT_LIST_HEAD(&dev->rx.list);
+	mutex_init(&dev->rx.list_mutex);
+	init_waitqueue_head(&dev->rx.waitq);
+
+	INIT_DELAYED_WORK(&dev->rx.dwork, pending_rx_work);
+
+	dev->client = client;
+	i2c_set_clientdata(client, dev);
+
+	kobj = most_register_interface(&dev->most_iface);
+	if (IS_ERR(kobj)) {
+		pr_err("Failed to register i2c as a MOST interface\n");
+		kfree(dev);
+		return PTR_ERR(kobj);
+	}
+
+	dev->polling_mode = polling_req || client->irq <= 0;
+	if (!dev->polling_mode) {
+		pr_info("Requesting IRQ: %d\n", client->irq);
+		ret = request_irq(client->irq, most_irq_handler, 0,
+				  client->name, dev);
+		if (ret) {
+			pr_info("IRQ request failed: %d, falling back to polling\n",
+				ret);
+			dev->polling_mode = true;
+		}
+	}
+
+	if (dev->polling_mode)
+		pr_info("Using polling at rate: %d times/sec\n", scan_rate);
+
+	return 0;
+}
+
+/*
+ * i2c_remove - i2c remove handler
+ * @client: i2c client device structure
+ *
+ * Return 0 on success.
+ *
+ * Unregister the i2c client device as a MOST interface
+ */
+static int i2c_remove(struct i2c_client *client)
+{
+	struct hdm_i2c *dev = i2c_get_clientdata(client);
+	int i;
+
+	if (!dev->polling_mode)
+		free_irq(client->irq, dev);
+
+	most_deregister_interface(&dev->most_iface);
+
+	for (i = 0 ; i < NUM_CHANNELS; i++)
+		if (dev->is_open[i])
+			poison_channel(&dev->most_iface, i);
+	cancel_delayed_work_sync(&dev->rx.dwork);
+	kfree(dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id i2c_id[] = {
+	{ "most_i2c", 0 },
+	{ }, /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(i2c, i2c_id);
+
+static struct i2c_driver i2c_driver = {
+	.driver = {
+		.name = "hdm_i2c",
+	},
+	.probe = i2c_probe,
+	.remove = i2c_remove,
+	.id_table = i2c_id,
+};
+
+module_i2c_driver(i2c_driver);
+
+MODULE_AUTHOR("Jain Roy Ambi <JainRoy.Ambi@microchip.com>");
+MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>");
+MODULE_DESCRIPTION("I2C Hardware Dependent Module");
+MODULE_LICENSE("GPL");