Fixing a possible case for race condition where an up mbox
interrupt over writes the down mbox message.
Although mbox_wait_for_zero() makes sure no up/down message
is pending before raising an up mbox interrupt. But there is a
small window were a VF may send a down mbox request to PF after
mbox_wait_for_zero() and before PF attempts to send a up
message to same VF. In such scenario interrupt register which has
down message bit set will get overwritten by up message bit.
As a solution, read interrupt register and OR the status with
required up/down bit before writing to the interrupt register.
Fixes: fa4ee2d43188 ("common/cnxk: sync between mbox up and down messages")
Signed-off-by: Harman Kalra <hka...@marvell.com>
---
drivers/common/cnxk/roc_mbox.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/common/cnxk/roc_mbox.c b/drivers/common/cnxk/roc_mbox.c
index c91fa63e83..7b734fcd24 100644
--- a/drivers/common/cnxk/roc_mbox.c
+++ b/drivers/common/cnxk/roc_mbox.c
@@ -209,10 +209,9 @@ static void
mbox_msg_send_data(struct mbox *mbox, int devid, uint8_t data)
{
struct mbox_dev *mdev = &mbox->dev[devid];
- struct mbox_hdr *tx_hdr =
- (struct mbox_hdr *)((uintptr_t)mdev->mbase + mbox->tx_start);
- struct mbox_hdr *rx_hdr =
- (struct mbox_hdr *)((uintptr_t)mdev->mbase + mbox->rx_start);
+ struct mbox_hdr *tx_hdr = (struct mbox_hdr *)((uintptr_t)mdev->mbase +
mbox->tx_start);
+ struct mbox_hdr *rx_hdr = (struct mbox_hdr *)((uintptr_t)mdev->mbase +
mbox->rx_start);
+ uint64_t intr_val;
/* Reset header for next messages */
tx_hdr->msg_size = mdev->msg_size;
@@ -229,11 +228,16 @@ mbox_msg_send_data(struct mbox *mbox, int devid, uint8_t
data)
/* Sync mbox data into memory */
plt_wmb();
+ /* Check for any pending interrupt */
+ intr_val = plt_read64(
+ (volatile void *)(mbox->reg_base + (mbox->trigger | (devid <<
mbox->tr_shift))));
+
+ intr_val |= (uint64_t)data;
/* The interrupt should be fired after num_msgs is written
* to the shared memory
*/
- plt_write64(data, (volatile void *)(mbox->reg_base +
- (mbox->trigger | (devid << mbox->tr_shift))));
+ plt_write64(intr_val, (volatile void *)(mbox->reg_base +
+ (mbox->trigger | (devid <<
mbox->tr_shift))));
}
/**
--
2.18.0
