[PATCH V4 2/2] firmware: ti_sci: Add comment explaining the is_secure code

[Dhruva Gole]

Add a comment to explain the code under is_secure condition of
ti_sci_do_xfer. This will help avoid confusion amongst people who may in
future touch upon this code.

Signed-off-by: Dhruva Gole <d-gole at ti.com>
---
 drivers/firmware/ti_sci.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 49d2696a6d09..d969470b5221 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -239,6 +239,12 @@ static int ti_sci_do_xfer(struct ti_sci_info *info,
 	struct ti_sci_secure_msg_hdr *secure_hdr = (struct ti_sci_secure_msg_hdr *)secure_buf;
 	int ret;
 
+	/*
+	 * The reason why we need the is_secure code is because of boot R5.
+	 * boot R5 starts off in "secure mode" when it hands off from Boot
+	 * ROM over to the Secondary bootloader. The initial set of calls
+	 * we have to make need to be on a secure pipe.
+	 */
 	if (info->is_secure) {
 		/* ToDo: get checksum of the entire message */
 		secure_hdr->checksum = 0;
-- 
2.34.1