Some sensors connected to Unisoc mailbox will send data very frequently.
This makes channel 0 very busy and the messages from other remote cores
not able to be handled as soon as possible.
It's a trick (un-documented) from Unisoc ASIC designers to resolve this
special requirement that an inbox assigned to one of the remote cores
before was modified to be exposed to host cpu core.
Then from host side, a supplementary inbox is added for transferring mass
but not emergency messages from the remote cores, such as step counting
sensor, with an independent FIFO and interrupt which is as same as channel
0. Meanwihle, inbox part of this channel is still kept for original remote
core to use.
Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Unisoc mailbox has no way to be enabled/disabled for any single channel.
They can only be set to startup or shutdown as a whole device at same time.
Add a variable to count references to avoid mailbox FIFO being reset
unexpectedly when clients are requesting or freeing channels.
Also add a lock to dismiss possible conflicts from register r/w in
different startup or shutdown threads. And fix the crash problem when early
interrupts come from channel which has not been requested by client yet.
Fixes: ca27fc26cd ("mailbox: sprd: Add Spreadtrum mailbox driver")
Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
According to the specification, bit[2] represents SPRD_OUTBOX_FIFO_FULL,
not bit[0], so correct it.
Fixes: ca27fc26cd ("mailbox: sprd: Add Spreadtrum mailbox driver")
Signed-off-by: Magnum Shan <magnum.shan@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
The Spreadtrum mailbox controller supports 8 channels to communicate
with MCUs, and it contains 2 different parts: inbox and outbox, which
are used to send and receive messages by IRQ mode.
Signed-off-by: Baolin Wang <baolin.wang@unisoc.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
