The mailbox framework controls the transmission queue and requires
either its controller implementations or clients to run the state
machine for the Tx queue. The OMAP mailbox controller uses a Tx-ready
interrupt as the equivalent of a Tx-done interrupt to run this Tx
queue state-machine.
The WkupM3 processor on AM33xx and AM43xx SoCs is used to offload
certain PM tasks, like doing the necessary operations for Device
PM suspend/resume or for entering lower c-states during cpuidle.
The CPUIdle on AM33xx requires the messages to be sent without
having to trigger the Tx-ready interrupts, as the interrupt
would immediately terminate the CPUIdle operation. Support for
this has been added by introducing a DT quirk, "ti,mbox-send-noirq"
and using it to modify the normal OMAP mailbox controller behavior
on the sub-mailboxes used to communicate with the WkupM3 remote
processor. This also requires the wkup_m3_ipc driver to adjust
its mailbox usage logic to run the Tx state machine.
NOTE:
- AM43xx does not communicate with WkupM3 for CPU Idle, so is
not affected by this behavior. But, it uses the same IPC driver
for PM suspend/resume functionality, so requires the quirk as
well, because of changes to the common wkup_m3_ipc driver.
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
[s-anna@ti.com: revise logic and update comments/patch description]
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
The OMAP mailbox driver and its existing clients (remoteproc
for OMAP4+) are adapted to use the generic mailbox framework.
The main changes for the adaptation are:
- The tasklet used for Tx is replaced with the state machine from
the generic mailbox framework. The workqueue used for processing
the received messages stays intact for minimizing the effects on
the OMAP mailbox clients.
- The existing exported client API, omap_mbox_get, omap_mbox_put and
omap_mbox_send_msg are deleted, as the framework provides equivalent
functionality. A OMAP-specific omap_mbox_request_channel is added
though to support non-DT way of requesting mailboxes.
- The OMAP mailbox driver is integrated with the mailbox framework
through the proper implementations of mbox_chan_ops, except for
.last_tx_done and .peek_data. The OMAP mailbox driver does not need
these ops, as it is completely interrupt driven.
- The OMAP mailbox driver uses a custom of_xlate controller ops that
allows phandles for the pargs specifier instead of indexing to avoid
any channel registration order dependencies.
- The new framework does not support multiple clients operating on a
single channel, so the reference counting logic is simplified.
- The remoteproc driver (current client) is adapted to use the new API.
The notifier callbacks used within this client is replaced with the
regular callbacks from the newer framework.
- The exported OMAP mailbox API are limited to omap_mbox_save_ctx,
omap_mbox_restore_ctx, omap_mbox_enable_irq & omap_mbox_disable_irq,
with the signature modified to take in the new mbox_chan handle instead
of the OMAP specific omap_mbox handle. The first 2 will be removed when
the OMAP mailbox driver is adapted to runtime_pm. The other exported
API omap_mbox_request_channel will be removed once existing legacy
users are converted to DT.
Signed-off-by: Suman Anna <s-anna@ti.com>
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Add the device tree bindings document for OMAP2+ mailbox.
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Dave Gerlach