mailbox/omap: Add ti,mbox-send-noirq quirk to fix AM33xx CPU Idle

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>
ARM: dts: AM33XX: Add ti,mbox-send-noirq to wkup_m3 mailbox

Add ti,mbox-send-noirq to wkup_m3 mailbox so that messages using
wkup_m3 mailbox are sent without triggering any further interrupts.
This is needed to achieve lower power numbers during CPU idle on
AM33xx.

Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
[s-anna@ti.com: revise commit description]
Signed-off-by: Suman Anna <s-anna@ti.com>
ARM: dts: AM4372: Add ti,mbox-send-noirq to wkup_m3 mailbox

Add ti,mbox-send-noirq to wkup_m3 mailbox so that messages using
wkup_m3 mailbox are sent without triggering any further interrupts.
This is required to be able to send multiple messages to the WkupM3
after the mailbox usage logic adjustment in the wkup_m3_ipc driver.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Acked-by: Dave Gerlach <d-gerlach@ti.com>
[s-anna@ti.com: revise commit description]
Signed-off-by: Suman Anna <s-anna@ti.com>
Merge branch 'mailbox-linux-3.14.y' of git://git.ti.com/rpmsg/mailbox into rproc-linux-3.14.y

Pull in the updated mailbox feature branch into the remoteproc
tree, this adds a mailbox quirk to fix AM33xx CPU Idle and the
associated updates for the mailbox communication to work with
the WkupM3 remote processor on AM33xx/AM43xx SoCs.

* 'mailbox-linux-3.14.y' of git://git.ti.com/rpmsg/mailbox:
  ARM: dts: AM4372: Add ti,mbox-send-noirq to wkup_m3 mailbox
  ARM: dts: AM33XX: Add ti,mbox-send-noirq to wkup_m3 mailbox
  mailbox/omap: Add ti,mbox-send-noirq quirk to fix AM33xx CPU Idle

Signed-off-by: Suman Anna <s-anna@ti.com>
Merge branch 'rproc-linux-3.14.y' of git://git.ti.com/rpmsg/remoteproc into rpmsg-ti-linux-3.14.y

Pull in the updated remoteproc feature branch that includes the
updates to the OMAP mailbox driver required for AM33xx/AM43xx
PM fixes.

* 'rproc-linux-3.14.y' of git://git.ti.com/rpmsg/remoteproc:
  ARM: dts: AM4372: Add ti,mbox-send-noirq to wkup_m3 mailbox
  ARM: dts: AM33XX: Add ti,mbox-send-noirq to wkup_m3 mailbox
  mailbox/omap: Add ti,mbox-send-noirq quirk to fix AM33xx CPU Idle

Signed-off-by: Suman Anna <s-anna@ti.com>
Merge branch 'rpmsg-ti-linux-3.14.y' of git://git.ti.com/rpmsg/rpmsg into ti-linux-3.14.y

TI-Feature: rpmsg
TI-Tree: git://git.ti.com/rpmsg/rpmsg.git
TI-Branch: rpmsg-ti-linux-3.14.y

* 'rpmsg-ti-linux-3.14.y' of git://git.ti.com/rpmsg/rpmsg:
  ARM: dts: AM4372: Add ti,mbox-send-noirq to wkup_m3 mailbox
  ARM: dts: AM33XX: Add ti,mbox-send-noirq to wkup_m3 mailbox
  mailbox/omap: Add ti,mbox-send-noirq quirk to fix AM33xx CPU Idle

Signed-off-by: Texas Instruments Auto Merger <lcpd_integration@list.ti.com>