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> --- drivers/mailbox/mailbox-mpfs.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) 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); } } -- 2.36.1
