firmware: ti_sci: fix the secure_hdr in do_xfer

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)")
Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>

diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
index 6e9f93e9a302279290e63b15729af413c3c66be0..b77ac36af284940e4302931c0fa6a60fa302c6ef 100644 (file)
--- 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(*secure_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(*secure_hdr);
 
                if (xfer->rx_len)
-                       xfer->rx_len += sizeof(secure_hdr);
+                       xfer->rx_len += sizeof(*secure_hdr);
        }
 
        /* Send the message */