From 35eb2302caf8eb74e7ad2e80b1509525286e2fc6 Mon Sep 17 00:00:00 2001
From: jpeg729 <jpeg729@gmail.com>
Date: Tue, 11 Jun 2013 18:37:05 +0200
Subject: UMS: f_mass_storage: Added cdrom option to UMS-lun-devices

This patch allows programs to change the cdrom option at runtime
through sysfs.

Indentation corrected.

Change-Id: I4beab26133e3ac325ecbded1414d4e6215e377e8
---
 drivers/usb/gadget/f_mass_storage.c |  6 ++++++
 drivers/usb/gadget/storage_common.c | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

(limited to 'drivers/usb')

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index ec1d520..884caa8 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -3145,6 +3145,7 @@ static int fsg_main_thread(void *common_)
 static DEVICE_ATTR(ro, 0644, fsg_show_ro, fsg_store_ro);
 static DEVICE_ATTR(nofua, 0644, fsg_show_nofua, fsg_store_nofua);
 static DEVICE_ATTR(file, 0644, fsg_show_file, fsg_store_file);
+static DEVICE_ATTR(cdrom, 0644, fsg_show_cdrom, fsg_store_cdrom);
 
 
 /****************************** FSG COMMON ******************************/
@@ -3260,6 +3261,10 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
 		rc = device_create_file(&curlun->dev, &dev_attr_nofua);
 		if (rc)
 			goto error_luns;
+		rc = device_create_file(&curlun->dev, &dev_attr_cdrom);
+		if (rc)
+			goto error_luns;
+
 
 		if (lcfg->filename) {
 			rc = fsg_lun_open(curlun, lcfg->filename);
@@ -3401,6 +3406,7 @@ static void fsg_common_release(struct kref *ref)
 			device_remove_file(&lun->dev, &dev_attr_nofua);
 			device_remove_file(&lun->dev, &dev_attr_ro);
 			device_remove_file(&lun->dev, &dev_attr_file);
+			device_remove_file(&lun->dev, &dev_attr_cdrom);
 			fsg_lun_close(lun);
 			device_unregister(&lun->dev);
 		}
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 70a474c..0c7f16b 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -913,3 +913,40 @@ static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
 	up_write(filesem);
 	return (rc < 0 ? rc : count);
 }
+
+static ssize_t fsg_show_cdrom (struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
+
+	return sprintf(buf, "%d\n", curlun->cdrom);
+}
+
+static ssize_t fsg_store_cdrom(struct device *dev, struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	ssize_t    rc;
+	struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
+	struct rw_semaphore  *filesem = dev_get_drvdata(dev);
+	unsigned  cdrom;
+
+	rc = kstrtouint(buf, 2, &cdrom);
+	if (rc)
+		return rc;
+
+	/*
+	 * Allow the cdrom status to change only while the
+	 * backing file is closed.
+	 */
+	down_read(filesem);
+	if (fsg_lun_is_open(curlun)) {
+		LDBG(curlun, "cdrom status change prevented\n");
+		rc = -EBUSY;
+	} else {
+		curlun->cdrom = cdrom;
+		LDBG(curlun, "cdrom status set to %d\n", curlun->cdrom);
+		rc = count;
+	}
+	up_read(filesem);
+	return rc;
+}
-- 
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