[PATCH v1 06/14] tee: optee: add page list manipulation functions

[Volodymyr Babchuk]

From: Volodymyr Babchuk <vlad.babchuk at gmail.com>

These functions will be used to pass information about shared
buffers to OP-TEE.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk at gmail.com>
---
 drivers/tee/optee/call.c          | 48 +++++++++++++++++++++++++++++++++++++++
 drivers/tee/optee/optee_private.h |  4 ++++
 2 files changed, 52 insertions(+)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index f7b7b40..f8e044d 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -11,6 +11,7 @@
  * GNU General Public License for more details.
  *
  */
+#include <asm/pgtable.h>
 #include <linux/arm-smccc.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -442,3 +443,50 @@ void optee_disable_shm_cache(struct optee *optee)
 	}
 	optee_cq_wait_final(&optee->call_queue, &w);
 }
+
+/**
+ * optee_fill_pages_list() - write list of user pages to given shared
+ * buffer.
+ *
+ * @dst: page-aligned buffer where list of pages will be stored
+ * @pages: array of pages that represents shared buffer
+ * @num_pages: number of entries in @pages
+ *
+ * @dst should be big enough to hold list of user page addresses and
+ *	links to the next pages of buffer
+ */
+void optee_fill_pages_list(u64 *dst, struct page **pages, size_t num_pages)
+{
+	size_t i;
+
+	/* TODO: add support for RichOS page sizes that != 4096 */
+	BUILD_BUG_ON(PAGE_SIZE != OPTEE_MSG_NONCONTIG_PAGE_SIZE);
+	for (i = 0; i < num_pages; i++, dst++) {
+		/* Check if we are going to roll over the page boundary */
+		if (IS_ALIGNED((uintptr_t)(dst + 1),
+			       OPTEE_MSG_NONCONTIG_PAGE_SIZE)) {
+			*dst = virt_to_phys(dst + 1);
+			dst++;
+		}
+		*dst = page_to_phys(pages[i]);
+	}
+}
+
+static size_t get_pages_array_size(size_t num_entries)
+{
+	/* Number of user pages + number of pages to hold list of user pages */
+	return sizeof(u64) *
+		(num_entries + (sizeof(u64) * num_entries) /
+		 OPTEE_MSG_NONCONTIG_PAGE_SIZE);
+}
+
+u64 *optee_allocate_pages_array(size_t num_entries)
+{
+	return alloc_pages_exact(get_pages_array_size(num_entries), GFP_KERNEL);
+}
+
+void optee_free_pages_array(void *array, size_t num_entries)
+{
+	free_pages_exact(array, get_pages_array_size(num_entries));
+}
+
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index c374cd5..caa3c04 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -165,6 +165,10 @@ int optee_from_msg_param(struct tee_param *params, size_t num_params,
 int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params,
 		       const struct tee_param *params);
 
+u64 *optee_allocate_pages_array(size_t num_entries);
+void optee_free_pages_array(void *array, size_t num_entries);
+void optee_fill_pages_list(u64 *dst, struct page **pages, size_t num_pages);
+
 /*
  * Small helpers
  */
-- 
2.7.4