Patch "mailbox: mpfs: account for mbox offsets while sending" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    mailbox: mpfs: account for mbox offsets while sending

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mailbox-mpfs-account-for-mbox-offsets-while-sending.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit de58616df806bf710e5d7454e0d55d77d51be957
Author: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
Date:   Wed Aug 24 08:08:12 2022 +0100

    mailbox: mpfs: account for mbox offsets while sending
    
    [ Upstream commit 0d1aadfe10ba17ebdeb96abb9638eb0f623f9b55 ]
    
    The mailbox offset is not only used for receiving messages, but it is
    also used by messages sent to the system controller by Linux that have a
    payload, such as the "digital signature service". It is also overloaded
    by certain other services (reprogramming of the FPGA fabric, see Link:)
    to have a meaning other than the offset the system controller should
    read from.
    When the driver was written, no such services of the latter type were
    in use & those of the former used an offset of zero so this has gone
    un-noticed.
    
    Link: https://www.microsemi.com/document-portal/doc_download/1245815-polarfire-fpga-and-polarfire-soc-fpga-system-services-user-guide # Section 5.2
    Fixes: 83d7b1560810 ("mbox: add polarfire soc system controller mailbox")
    Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
    Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c
index e432a8f0d148..cfacb3f320a6 100644
--- a/drivers/mailbox/mailbox-mpfs.c
+++ b/drivers/mailbox/mailbox-mpfs.c
@@ -100,21 +100,20 @@ static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
 
 		for (index = 0; index < (msg->cmd_data_size / 4); index++)
 			writel_relaxed(word_buf[index],
-				       mbox->mbox_base + index * 0x4);
+				       mbox->mbox_base + msg->mbox_offset + index * 0x4);
 		if (extra_bits) {
 			u8 i;
 			u8 byte_off = ALIGN_DOWN(msg->cmd_data_size, 4);
 			u8 *byte_buf = msg->cmd_data + byte_off;
 
-			val = readl_relaxed(mbox->mbox_base + index * 0x4);
+			val = readl_relaxed(mbox->mbox_base + msg->mbox_offset + index * 0x4);
 
 			for (i = 0u; i < extra_bits; i++) {
 				val &= ~(0xffu << (i * 8u));
 				val |= (byte_buf[i] << (i * 8u));
 			}
 
-			writel_relaxed(val,
-				       mbox->mbox_base + index * 0x4);
+			writel_relaxed(val, mbox->mbox_base + msg->mbox_offset + index * 0x4);
 		}
 	}