On 11 October 2016 at 08:10, Horng-Shyang Liao [off-list ref] wrote:

On Thu, 2016-10-06 at 18:40 +0530, Jassi Brar wrote:

quoted

On 6 October 2016 at 18:31, Horng-Shyang Liao [off-list ref] wrote:

quoted

Back to our original statement, we need to flush all tasks to queue
in GCE HW; i.e. we need to use mbox_client_txdone after
mbox_send_message, or send tx_done once mailbox controller receive
message (task). However, we still need a way to notice done tasks to
clients. Currently, we don't have a good way to call callback in mailbox
framework. Therefore, CMDQ driver has its owner callback functions.

mbox_client_txdone() is called by the client driver when only it knows
the messages has been transmitted (i.e your submitted tasks are done).
Obviously the client driver should do any callbacks to its users
upstream.

Hi Jassi,

In current CMDQ driver, mbox_client_txdone() is called to prevent the
blocking of chan->active_req. It is not the real point of CMDQ task
done, so the client driver cannot do any callbacks to its user upstream.

(1) If we don't use mbox_client_txdone(), could you tell us an
    alternative way to prevent the blocking of chan->active_req?
    And then we can use tx_done when CMDQ task is relly done.

mbox_client_txdone() should be used only when the mailbox controller
driver can't figure when the TX is done. Client driver (by like some
reply packet) realises the TX is done (for the reply to have arrived).

 If your hardware does flag/irq when tx is done, you should prefer
that over mbox_client_txdone().

(2) If we use mbox_client_txdone() to prevent the blocking of
    chan->active_req, could CMDQ driver just uses self-defined callback
    function to notice client driver CMDQ task done?

Anything above the mailbox api, is none of its business. Your platform
specific 'server' driver can implement its own callbacks to notify its
users.