From: Conor Dooley conor.dooley@microchip.com
[ Upstream commit ab47d0bfdf88faac0eb02749e5bfaa306e004300 ]
Some services explicitly return an error code in their response, but others rely on the system controller to set a status in its status register. The meaning of the bits varies based on what service is requested, so pass it back up to the driver that requested the service in the first place. The field in the message struct already existed, but was unused until now.
If the system controller is busy, in which case we should never actually be in the interrupt handler, or if the service fails the mailbox itself should not be read. Callers should check the status before operating on the response.
There's an existing, but unused, #define for the mailbox mask - but it was incorrect. It was doing a GENMASK_ULL(32, 16) which should've just been a GENMASK(31, 16), so fix that up and start using it.
Fixes: 83d7b1560810 ("mbox: add polarfire soc system controller mailbox") Signed-off-by: Conor Dooley conor.dooley@microchip.com Reviewed-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Jassi Brar jaswinder.singh@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mailbox/mailbox-mpfs.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c index cfacb3f320a6..853901acaeec 100644 --- a/drivers/mailbox/mailbox-mpfs.c +++ b/drivers/mailbox/mailbox-mpfs.c @@ -2,7 +2,7 @@ /* * Microchip PolarFire SoC (MPFS) system controller/mailbox controller driver * - * Copyright (c) 2020 Microchip Corporation. All rights reserved. + * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved. * * Author: Conor Dooley conor.dooley@microchip.com * @@ -56,7 +56,7 @@ #define SCB_STATUS_NOTIFY_MASK BIT(SCB_STATUS_NOTIFY)
#define SCB_STATUS_POS (16) -#define SCB_STATUS_MASK GENMASK_ULL(SCB_STATUS_POS + SCB_MASK_WIDTH, SCB_STATUS_POS) +#define SCB_STATUS_MASK GENMASK(SCB_STATUS_POS + SCB_MASK_WIDTH - 1, SCB_STATUS_POS)
struct mpfs_mbox { struct mbox_controller controller; @@ -130,13 +130,38 @@ static void mpfs_mbox_rx_data(struct mbox_chan *chan) struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv; struct mpfs_mss_response *response = mbox->response; u16 num_words = ALIGN((response->resp_size), (4)) / 4U; - u32 i; + u32 i, status;
if (!response->resp_msg) { dev_err(mbox->dev, "failed to assign memory for response %d\n", -ENOMEM); return; }
+ /* + * The status is stored in bits 31:16 of the SERVICES_SR register. + * It is only valid when BUSY == 0. + * We should *never* get an interrupt while the controller is + * still in the busy state. If we do, something has gone badly + * wrong & the content of the mailbox would not be valid. + */ + if (mpfs_mbox_busy(mbox)) { + dev_err(mbox->dev, "got an interrupt but system controller is busy\n"); + response->resp_status = 0xDEAD; + return; + } + + status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET); + + /* + * If the status of the individual servers is non-zero, the service has + * failed. The contents of the mailbox at this point are not be valid, + * so don't bother reading them. Set the status so that the driver + * implementing the service can handle the result. + */ + response->resp_status = (status & SCB_STATUS_MASK) >> SCB_STATUS_POS; + if (response->resp_status) + return; + if (!mpfs_mbox_busy(mbox)) { for (i = 0; i < num_words; i++) { response->resp_msg[i] =