[PATCH] staging: android: ion: add buffer flag update ioctl

[Zeng Tao]

In some usecases, the buffer cached attribute is not determined at
allocation time, it's determined just before the real cpu mapping.
And from the memory view of point, a buffer should not have the cached
attribute util is really mapped by the cpu. So in this patch, we
introduced the new ioctl command to target the requirement.

Signed-off-by: Zeng Tao <prime.zeng@xxxxxxxxxxxxx>
---
 drivers/staging/android/ion/ion-ioctl.c |  4 ++++
 drivers/staging/android/ion/ion.c       | 17 +++++++++++++++++
 drivers/staging/android/ion/ion.h       |  1 +
 drivers/staging/android/uapi/ion.h      | 22 ++++++++++++++++++++++
 4 files changed, 44 insertions(+)

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index a8d3cc4..60bb702 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -12,6 +12,7 @@
 
 union ion_ioctl_arg {
 	struct ion_allocation_data allocation;
+	struct ion_buffer_flag_data update;
 	struct ion_heap_query query;
 };
 
@@ -83,6 +84,9 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 		break;
 	}
+	case ION_IOC_BUFFER_UPDATE:
+		ret = ion_buffer_update(data.update.fd, data.update.flags);
+		break;
 	case ION_IOC_HEAP_QUERY:
 		ret = ion_query_heaps(&data.query);
 		break;
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 9907332..f1404dc 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -436,6 +436,23 @@ int ion_alloc(size_t len, unsigned int heap_id_mask, unsigned int flags)
 	return fd;
 }
 
+int ion_buffer_update(unsigned int fd, unsigned int flags)
+{
+	struct dma_buf *dmabuf;
+	struct ion_buffer *buffer;
+
+	dmabuf = dma_buf_get(fd);
+
+	if (!dmabuf)
+		return -EINVAL;
+
+	buffer = dmabuf->priv;
+	buffer->flags = flags;
+	dma_buf_put(dmabuf);
+
+	return 0;
+}
+
 int ion_query_heaps(struct ion_heap_query *query)
 {
 	struct ion_device *dev = internal_dev;
diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
index c006fc1..99bf9ab 100644
--- a/drivers/staging/android/ion/ion.h
+++ b/drivers/staging/android/ion/ion.h
@@ -199,6 +199,7 @@ int ion_heap_pages_zero(struct page *page, size_t size, pgprot_t pgprot);
 int ion_alloc(size_t len,
 	      unsigned int heap_id_mask,
 	      unsigned int flags);
+int ion_buffer_update(unsigned int fd, unsigned int flags);
 
 /**
  * ion_heap_init_shrinker
diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
index 5d70098..99753fc 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -74,6 +74,20 @@ struct ion_allocation_data {
 	__u32 unused;
 };
 
+/**
+ * struct ion_buffer_flag_data - metadata passed from userspace for update
+ * buffer flags
+ * @fd:			file descriptor of the buffer
+ * @flags:		flags passed to the buffer
+ *
+ * Provided by userspace as an argument to the ioctl
+ */
+
+struct ion_buffer_flag_data {
+	__u32 fd;
+	__u32 flags;
+}
+
 #define MAX_HEAP_NAME			32
 
 /**
@@ -116,6 +130,14 @@ struct ion_heap_query {
 				      struct ion_allocation_data)
 
 /**
+ * DOC: ION_IOC_BUFFER_UPDATE - update the specified ion buffer flags
+ *
+ * Takes an ion_buffer_flag_data structure and returns the result of the
+ * buffer flag update operation.
+ */
+#define ION_IOC_BUFFER_UPDATE	_IOWR(ION_IOC_MAGIC, 1, \
+				      struct ion_buffer_flag_data)
+/**
  * DOC: ION_IOC_HEAP_QUERY - information about available heaps
  *
  * Takes an ion_heap_query structure and populates information about
-- 
2.7.4