msm: smem: add smem_get_free_space()
The smem_get_free_space() API is a private helper function to optimize the
SMD client's table scanning usecase.
Change-Id: I00b12bf3b667001f973fd5126278536b47e052f4
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
diff --git a/arch/arm/mach-msm/smem_private.h b/arch/arm/mach-msm/smem_private.h
index ceb8028..3fa842f 100644
--- a/arch/arm/mach-msm/smem_private.h
+++ b/arch/arm/mach-msm/smem_private.h
@@ -76,4 +76,21 @@
* @nb: Notifier block to be unregistered
*/
int smem_module_init_notifier_unregister(struct notifier_block *nb);
+
+/**
+ * smem_get_free_space() - Get the available allocation free space for a
+ * partition
+ *
+ * @to_proc: remote SMEM host. Determines the applicable partition
+ * @returns: size in bytes available to allocate
+ *
+ * Helper function for SMD so that SMD only scans the channel allocation
+ * table for a partition when it is reasonably certain that a channel has
+ * actually been created, because scanning can be expensive. Creating a channel
+ * will consume some of the free space in a partition, so SMD can compare the
+ * last free space size against the current free space size to determine if
+ * a channel may have been created. SMD can't do this directly, because the
+ * necessary partition internals are restricted to just SMEM.
+ */
+unsigned smem_get_free_space(unsigned to_proc);
#endif /* _ARCH_ARM_MACH_MSM_SMEM_PRIVATE_H_ */