[PATCH V4 1/2] firmware: ti_sci: fix the secure_hdr in do_xfer

[Dhruva Gole]

The ti_sci driver in U-Boot has support for secure_msg as part of it's
do_xfer function. This let's U-boot send secure messages during boot up.

The protocol to send such secure messages is described as part of the
struct ti_sci_secure_msg_hdr. As part of this, there are 2 fields for
checksum and reserved that occupy the first 4 bytes of any secure
message. This is called as the secure_hdr.

As of now, the secure_hdr needs to be 0 init-ed before sending secure
messages. However the existing code was never putting the zero-inited vars
into the secure_buf, leading to possibility of the first 4 bytes of
secure_buf being possibly garbage.

Fix this by initialising the secure_hdr itself to the secure_buf
location, thus when we make secure_hdr members 0, it automatically ensures
the first 4 bytes of secure_buf are 0.

Fixes: 32cd25128bd849 ("firmware: Add basic support for TI System Control Interface (TI SCI)")
Cc: Nishanth Menon <nm at ti.com>
Cc: Andrew Davis <afd at ti.com>
Cc: Manorit Chawdhry <m-chawdhry at ti.com>
Signed-off-by: Dhruva Gole <d-gole at ti.com>
---
 drivers/firmware/ti_sci.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 6e9f93e9a302..49d2696a6d09 100644
--- a/drivers/firmware/ti_sci.c
+++ b/drivers/firmware/ti_sci.c
@@ -236,21 +236,21 @@ static int ti_sci_do_xfer(struct ti_sci_info *info,
 {
 	struct k3_sec_proxy_msg *msg = &xfer->tx_message;
 	u8 secure_buf[info->desc->max_msg_size];
-	struct ti_sci_secure_msg_hdr secure_hdr;
+	struct ti_sci_secure_msg_hdr *secure_hdr = (struct ti_sci_secure_msg_hdr *)secure_buf;
 	int ret;
 
 	if (info->is_secure) {
 		/* ToDo: get checksum of the entire message */
-		secure_hdr.checksum = 0;
-		secure_hdr.reserved = 0;
-		memcpy(&secure_buf[sizeof(secure_hdr)], xfer->tx_message.buf,
+		secure_hdr->checksum = 0;
+		secure_hdr->reserved = 0;
+		memcpy(&secure_buf[sizeof(struct ti_sci_secure_msg_hdr)], xfer->tx_message.buf,
 		       xfer->tx_message.len);
 
 		xfer->tx_message.buf = (u32 *)secure_buf;
-		xfer->tx_message.len += sizeof(secure_hdr);
+		xfer->tx_message.len += sizeof(struct ti_sci_secure_msg_hdr);
 
 		if (xfer->rx_len)
-			xfer->rx_len += sizeof(secure_hdr);
+			xfer->rx_len += sizeof(struct ti_sci_secure_msg_hdr);
 	}
 
 	/* Send the message */
-- 
2.34.1