path: root/drivers/mailbox/mailbox-test.c
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authorDave Gerlach <d-gerlach@ti.com>2015-09-22 19:14:52 -0500
committerJassi Brar <jaswinder.singh@linaro.org>2015-10-23 11:19:27 +0530
commit8e3c5952144f045a0c81bf674d3f5e1d9aafceb7 (patch)
tree56542626b3ca34a7087eeccfb7d83f7734e67ee3 /drivers/mailbox/mailbox-test.c
parenta133f8b65d591101e48336050ceb7e2f51026502 (diff)
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> Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
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