greybus: ap message loop added.

drivers/staging/greybus/Makefile

-greybus-y := core.o gbuf.o debugfs.o i2c-gb.o gpio-gb.o sdio-gb.o uart-gb.o
+greybus-y :=	core.o		\
+		gbuf.o		\
+		debugfs.o	\
+		ap.o		\
+		i2c-gb.o	\
+		gpio-gb.o	\
+		sdio-gb.o	\
+		uart-gb.o
 
 obj-m += greybus.o
 obj-m += es1-ap-usb.o

drivers/staging/greybus/ap.c

+/*
+ * Greybus "AP" message loop handling
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/kthread.h>
+#include <linux/device.h>
+#include "greybus.h"
+
+struct ap_msg {
+	u8 *data;
+	int size;
+	struct list_head list;
+};
+
+static LIST_HEAD(ap_msg_list);
+static spinlock_t ap_msg_list_lock;
+static struct task_struct *ap_thread;
+static wait_queue_head_t ap_wait;
+
+static struct ap_msg *get_ap_msg(void)
+{
+	struct ap_msg *ap_msg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ap_msg_list_lock, flags);
+
+	ap_msg = list_first_entry_or_null(&ap_msg_list, struct ap_msg, list);
+	if (ap_msg != NULL)
+		list_del(&ap_msg->list);
+	spin_unlock_irqrestore(&ap_msg_list_lock, flags);
+
+	return ap_msg;
+}
+
+static int ap_process_loop(void *data)
+{
+	struct ap_msg *ap_msg;
+
+	while (!kthread_should_stop()) {
+		wait_event_interruptible(ap_wait, kthread_should_stop());
+
+		if (kthread_should_stop())
+			break;
+
+		/* Get some data off of the ap list and process it */
+		ap_msg = get_ap_msg();
+		if (!ap_msg)
+			continue;
+
+		// FIXME - process the message
+
+		/* clean the message up */
+		kfree(ap_msg->data);
+		kfree(ap_msg);
+	}
+	return 0;
+}
+
+int gb_new_ap_msg(u8 *data, int size)
+{
+	struct ap_msg *ap_msg;
+	unsigned long flags;
+
+	/*
+	 * Totally naive copy the message into a new structure that we slowly
+	 * create and add it to the list.  Let's get this working, the odds of
+	 * this being any "slow path" for AP messages is really low at this
+	 * point in time, but you never know, so this comment is here to point
+	 * out that maybe we should use a slab allocator, or even just not copy
+	 * the data, but use it directly and force the urbs to be "new" each
+	 * time.
+	 */
+
+	/* Note - this can, and will, be called in interrupt context. */
+	ap_msg = kmalloc(sizeof(*ap_msg), GFP_ATOMIC);
+	if (!ap_msg)
+		return -ENOMEM;
+	ap_msg->data = kmalloc(size, GFP_ATOMIC);
+	if (!ap_msg->data) {
+		kfree(ap_msg);
+		return -ENOMEM;
+	}
+	memcpy(ap_msg->data, data, size);
+	ap_msg->size = size;
+
+	spin_lock_irqsave(&ap_msg_list_lock, flags);
+	list_add(&ap_msg->list, &ap_msg_list);
+	spin_unlock_irqrestore(&ap_msg_list_lock, flags);
+
+	/* kick our thread to handle the message */
+	wake_up_interruptible(&ap_wait);
+
+	return 0;
+}
+
+int gb_thread_init(void)
+{
+	init_waitqueue_head(&ap_wait);
+	spin_lock_init(&ap_msg_list_lock);
+
+	ap_thread = kthread_run(ap_process_loop, NULL, "greybus_ap");
+	if (IS_ERR(ap_thread))
+		return PTR_ERR(ap_thread);
+
+	return 0;
+}
+
+void gb_thread_destroy(void)
+{
+	kthread_stop(ap_thread);
+}
+
+

drivers/staging/greybus/core.c

@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/device.h>
 
 #include "greybus.h"
@@ -199,7 +200,7 @@ static int __init gb_init(void)
 {
 	int retval;
 
-	retval = greybus_debugfs_init();
+	retval = gb_debugfs_init();
 	if (retval)
 		return retval;
 
@@ -207,6 +208,10 @@ static int __init gb_init(void)
 	if (retval)
 		goto error_bus;
 
+	retval = gb_thread_init();
+	if (retval)
+		goto error_thread;
+
 	// FIXME - more gb core init goes here
 
 	retval = gb_tty_init();
@@ -216,10 +221,13 @@ static int __init gb_init(void)
 	return 0;
 
 error_tty:
+	gb_thread_destroy();
+
+error_thread:
 	bus_unregister(&greybus_bus_type);
 
 error_bus:
-	greybus_debugfs_cleanup();
+	gb_debugfs_cleanup();
 
 	return retval;
 }
@@ -228,7 +236,7 @@ static void __exit gb_exit(void)
 {
 	gb_tty_exit();
 	bus_unregister(&greybus_bus_type);
-	greybus_debugfs_cleanup();
+	gb_debugfs_cleanup();
 }
 
 module_init(gb_init);

drivers/staging/greybus/debugfs.c

@@ -19,7 +19,7 @@
 
 static struct dentry *gb_debug_root;
 
-int greybus_debugfs_init(void)
+int gb_debugfs_init(void)
 {
 	gb_debug_root = debugfs_create_dir("greybus", NULL);
 	if (!gb_debug_root)
@@ -28,7 +28,7 @@ int greybus_debugfs_init(void)
 	return 0;
 }
 
-void greybus_debugfs_cleanup(void)
+void gb_debugfs_cleanup(void)
 {
 	debugfs_remove_recursive(gb_debug_root);
 }

drivers/staging/greybus/es1-ap-usb.c

@@ -10,7 +10,7 @@
 #include <linux/slab.h>
 #include <linux/errno.h>
 #include <linux/usb.h>
-
+#include "greybus.h"
 
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x0000, 0x0000) },		// FIXME
@@ -34,6 +34,68 @@ struct es1_ap_dev {
  */
 static struct es1_ap_dev *es1_ap_dev;
 
+static void ap_in_callback(struct urb *urb)
+{
+	struct device *dev = &urb->dev->dev;
+	int status = urb->status;
+	int retval;
+
+	switch (status) {
+	case 0:
+		break;
+	case -EOVERFLOW:
+		dev_err(dev, "%s: overflow actual length is %d\n",
+			__func__, urb->actual_length);
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+	case -EILSEQ:
+		/* device is gone, stop sending */
+		return;
+	default:
+		dev_err(dev, "%s: unknown status %d\n", __func__, status);
+		goto exit;
+	}
+
+	/* We have a message, create a new message structure, add it to the
+	 * list, and wake up our thread that will process the messages.
+	 */
+	gb_new_ap_msg(urb->transfer_buffer, urb->actual_length);
+
+exit:
+	/* resubmit the urb to get more messages */
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(dev, "Can not submit urb for AP data: %d\n", retval);
+}
+
+static void ap_out_callback(struct urb *urb)
+{
+	struct device *dev = &urb->dev->dev;
+	int status = urb->status;
+
+	switch (status) {
+	case 0:
+		break;
+	case -EOVERFLOW:
+		dev_err(dev, "%s: overflow actual length is %d\n",
+			__func__, urb->actual_length);
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+	case -EILSEQ:
+		/* device is gone, stop sending */
+		return;
+	default:
+		dev_err(dev, "%s: unknown status %d\n", __func__, status);
+		goto exit;
+	}
+
+	// FIXME - queue up next AP message to send???
+exit:
+	return;
+}
+
 
 static int ap_probe(struct usb_interface *interface,
 		    const struct usb_device_id *id)

drivers/staging/greybus/greybus.h

@@ -176,8 +176,16 @@ void greybus_deregister(struct greybus_driver *driver);
 
 int greybus_disabled(void);
 
-int greybus_debugfs_init(void);
-void greybus_debugfs_cleanup(void);
+
+/* Internal functions to gb module, move to internal .h file eventually. */
+
+int gb_new_ap_msg(u8 *data, int length);
+int gb_thread_init(void);
+void gb_thread_destroy(void);
+int gb_debugfs_init(void);
+void gb_debugfs_cleanup(void);
+
+
 
 #endif /* __KERNEL__ */
 #endif /* __LINUX_GREYBUS_H */