One of the issues w/ the /dev/ion interface is that we have to
provide the complexity of a heap query interface and we end up
multiplexing all the heap access through that one interface via
a bit mask (which currently limits the heaps to 32).

There has been a long running todo to provide per-heap devices
which would make the heap discovery/query interface "ls", and
would allow for different heaps to have different permisisons
and sepolicy rules.

TODOs:
* Android doesn't use udev so "ion_heaps/%s" names don't
  automatically create a /dev/ subdir. I need to rework
  from miscdev to creating a proper device class and add
  a "subsystem" entry for the DeviceHandler to match with

* Each CMA region is exposed via a separate heap, not sure
  if this is desired or not, and we may need to improve the
  naming.

Cc: Laura Abbott <labb...@redhat.com>
Cc: Sumit Semwal <sumit.sem...@linaro.org>
Cc: Liam Mark <lm...@codeaurora.org>
Cc: Brian Starkey <brian.star...@arm.com>
Cc: Andrew F. Davis <a...@ti.com>
Cc: Alistair Strachan <astrac...@google.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stu...@linaro.org>
---
 drivers/staging/android/ion/ion-ioctl.c | 62 +++++++++++++++++++++++++++++++++
 drivers/staging/android/ion/ion.c       | 18 ++++++++++
 drivers/staging/android/ion/ion.h       |  2 ++
 drivers/staging/android/uapi/ion.h      | 28 +++++++++++++++
 4 files changed, 110 insertions(+)

diff --git a/drivers/staging/android/ion/ion-ioctl.c 
b/drivers/staging/android/ion/ion-ioctl.c
index 458a9f2..ea8d263 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_heap_allocation_data heap_allocation;
        struct ion_heap_query query;
        u32 version;
 };
@@ -100,3 +101,64 @@ long ion_ioctl(struct file *filp, unsigned int cmd, 
unsigned long arg)
        }
        return ret;
 }
+
+long ion_heap_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+       int ret = 0;
+       unsigned int dir;
+       union ion_ioctl_arg data;
+
+       dir = ion_ioctl_dir(cmd);
+
+       if (_IOC_SIZE(cmd) > sizeof(data))
+               return -EINVAL;
+
+       /*
+        * The copy_from_user is unconditional here for both read and write
+        * to do the validate. If there is no write for the ioctl, the
+        * buffer is cleared
+        */
+       if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
+               return -EFAULT;
+
+       ret = validate_ioctl_arg(cmd, &data);
+       if (ret) {
+               pr_warn_once("%s: ioctl validate failed\n", __func__);
+               return ret;
+       }
+
+       if (!(dir & _IOC_WRITE))
+               memset(&data, 0, sizeof(data));
+
+       switch (cmd) {
+       case ION_IOC_HEAP_ALLOC:
+       {
+               struct miscdevice *miscdev = filp->private_data;
+               struct ion_heap *heap;
+               int fd;
+
+               heap = container_of(miscdev, struct ion_heap, heap_dev);
+
+               fd = ion_alloc(data.heap_allocation.len,
+                              (1 << heap->id),
+                              data.heap_allocation.flags);
+               if (fd < 0)
+                       return fd;
+
+               data.heap_allocation.fd = fd;
+
+               break;
+       }
+       case ION_IOC_VERSION:
+               data.version = ION_VERSION;
+               break;
+       default:
+               return -ENOTTY;
+       }
+
+       if (dir & _IOC_READ) {
+               if (copy_to_user((void __user *)arg, &data, _IOC_SIZE(cmd)))
+                       return -EFAULT;
+       }
+       return ret;
+}
diff --git a/drivers/staging/android/ion/ion.c 
b/drivers/staging/android/ion/ion.c
index 6f5afab..1f7c893 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -492,6 +492,14 @@ int ion_query_heaps(struct ion_heap_query *query)
        return ret;
 }
 
+static const struct file_operations ion_heap_fops = {
+       .owner          = THIS_MODULE,
+       .unlocked_ioctl = ion_heap_ioctl,
+#ifdef CONFIG_COMPAT
+       .compat_ioctl   = ion_heap_ioctl,
+#endif
+};
+
 static const struct file_operations ion_fops = {
        .owner          = THIS_MODULE,
        .unlocked_ioctl = ion_ioctl,
@@ -540,12 +548,22 @@ void ion_device_add_heap(struct ion_heap *heap)
        struct ion_device *dev = internal_dev;
        int ret;
        struct dentry *heap_root;
+       char *heap_name;
        char debug_name[64];
 
        if (!heap->ops->allocate || !heap->ops->free)
                pr_err("%s: can not add heap with invalid ops struct.\n",
                       __func__);
 
+       heap_name = kasprintf(GFP_KERNEL, "ion_heaps/%s", heap->name);
+       heap->heap_dev.name = heap_name;
+       heap->heap_dev.minor = MISC_DYNAMIC_MINOR;
+       heap->heap_dev.fops = &ion_heap_fops;
+       heap->heap_dev.parent = NULL;
+       ret = misc_register(&heap->heap_dev);
+       if (ret)
+               pr_err("ion: failed to register misc device.\n");
+
        spin_lock_init(&heap->free_lock);
        spin_lock_init(&heap->stat_lock);
        heap->free_list_size = 0;
diff --git a/drivers/staging/android/ion/ion.h 
b/drivers/staging/android/ion/ion.h
index 439e682..7ed4a6a 100644
--- a/drivers/staging/android/ion/ion.h
+++ b/drivers/staging/android/ion/ion.h
@@ -170,6 +170,7 @@ struct ion_heap_ops {
  */
 struct ion_heap {
        struct plist_node node;
+       struct miscdevice heap_dev;
        struct ion_device *dev;
        enum ion_heap_type type;
        struct ion_heap_ops *ops;
@@ -333,6 +334,7 @@ int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t 
gfp_mask,
                         int nr_to_scan);
 
 long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
+long ion_heap_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
 
 int ion_query_heaps(struct ion_heap_query *query);
 
diff --git a/drivers/staging/android/uapi/ion.h 
b/drivers/staging/android/uapi/ion.h
index c480448..20db09f 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -57,6 +57,25 @@ enum ion_heap_type {
  */
 
 /**
+ * struct ion_heap_allocation_data - metadata passed from userspace for
+ *                                   allocations
+ * @len:               size of the allocation
+ * @heap_id_mask:      mask of heap ids to allocate from
+ * @flags:             flags passed to heap
+ * @handle:            pointer that will be populated with a cookie to use to
+ *                     refer to this allocation
+ *
+ * Provided by userspace as an argument to the ioctl
+ */
+struct ion_heap_allocation_data {
+       __u64 len;
+       __u32 flags;
+       __u32 fd;
+       __u32 reserved0;
+       __u32 reserved1;
+};
+
+/**
  * struct ion_allocation_data - metadata passed from userspace for allocations
  * @len:               size of the allocation
  * @heap_id_mask:      mask of heap ids to allocate from
@@ -131,4 +150,13 @@ struct ion_heap_query {
  */
 #define ION_IOC_VERSION                _IOR(ION_IOC_MAGIC, 9, u32)
 
+/**
+ * DOC: ION_IOC_HEAP_ALLOC - allocate memory from heap
+ *
+ * Takes an ion_heap_allocation_data struct and returns it with the handle 
field
+ * populated with the opaque handle for the allocation.
+ */
+#define ION_IOC_HEAP_ALLOC     _IOWR(ION_IOC_MAGIC, 10, \
+                                     struct ion_heap_allocation_data)
+
 #endif /* _UAPI_LINUX_ION_H */
-- 
2.7.4

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