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This patch adds the support for system suspend/resume to the OMAP remoteproc driver so that the OMAP remoteproc devices can be suspended/resumed during a system suspend/resume. The support is added through the driver PM .suspend/.resume callbacks, and requires appropriate support from the OS running on the remote processors. The IPU & DSP remote processors typically have their own private modules like registers, internal memories, caches etc. The context of these modules need to be saved and restored properly for a suspend/resume to work. These are in general not accessible from the MPU, so the remote processors themselves have to implement the logic for the context save & restore of these modules. The OMAP remoteproc driver initiates a suspend by sending a mailbox message requesting the remote processor to save its context and enter into an idle/standby state. The remote processor should usually stop whatever processing it is doing to switch to a context save mode. The OMAP remoteproc driver detects the completion of the context save by checking the module standby status for the remoteproc device. It also stops any resources used by the remote processors like the timers. The timers need to be running only when the processor is active and executing, and need to be stopped otherwise to allow the timer driver to reach low-power states. The IOMMUs are automatically suspended by the PM core during the late suspend stage, after the remoteproc suspend process is completed by putting the remote processor cores into reset. Thereafter, the Linux kernel can put the domain into further lower power states as possible. The resume sequence undoes the operations performed in the PM suspend callback, by starting the timers and finally releasing the processors from reset. This requires that the remote processor side OS be able to distinguish a power-resume boot from a power-on/cold boot, restore the context of its private modules saved during the suspend phase, and resume executing code from where it was suspended. The IOMMUs would have been resumed by the PM core during early resume, so they are already enabled by the time remoteproc resume callback gets invoked. The remote processors should save their context into System RAM (DDR), as any internal memories are not guaranteed to retain context as it depends on the lowest power domain that the remote processor device is put into. The management of the DDR contents will be managed by the Linux kernel. Signed-off-by: Suman Anna <s-anna@ti.com> [t-kristo@ti.com: converted to use ti-sysc instead of hwmod] Signed-off-by: Tero Kristo <t-kristo@ti.com> Reviewed-by: Andrew F. Davis <afd@ti.com> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200324110035.29907-12-t-kristo@ti.com Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
90 lines
3.5 KiB
C
90 lines
3.5 KiB
C
/*
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* Remote processor messaging
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*
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* Copyright (C) 2011-2020 Texas Instruments, Inc.
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* Copyright (C) 2011 Google, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name Texas Instruments nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _OMAP_RPMSG_H
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#define _OMAP_RPMSG_H
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/*
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* enum - Predefined Mailbox Messages
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*
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* @RP_MBOX_READY: informs the M3's that we're up and running. this is
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* part of the init sequence sent that the M3 expects to see immediately
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* after it is booted.
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*
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* @RP_MBOX_PENDING_MSG: informs the receiver that there is an inbound
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* message waiting in its own receive-side vring. please note that currently
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* this message is optional: alternatively, one can explicitly send the index
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* of the triggered virtqueue itself. the preferred approach will be decided
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* as we progress and experiment with those two different approaches.
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*
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* @RP_MBOX_CRASH: this message is sent if BIOS crashes
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*
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* @RP_MBOX_ECHO_REQUEST: a mailbox-level "ping" message.
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*
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* @RP_MBOX_ECHO_REPLY: a mailbox-level reply to a "ping"
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*
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* @RP_MBOX_ABORT_REQUEST: a "please crash" request, used for testing the
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* recovery mechanism (to some extent).
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*
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* @RP_MBOX_SUSPEND_AUTO: auto suspend request for the remote processor
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*
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* @RP_MBOX_SUSPEND_SYSTEM: system suspend request for the remote processor
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*
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* @RP_MBOX_SUSPEND_ACK: successful response from remote processor for a
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* suspend request
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*
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* @RP_MBOX_SUSPEND_CANCEL: a cancel suspend response from a remote processor
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* on a suspend request
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*
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* Introduce new message definitions if any here.
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*
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* @RP_MBOX_END_MSG: Indicates end of known/defined messages from remote core
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* This should be the last definition.
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*
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*/
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enum omap_rp_mbox_messages {
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RP_MBOX_READY = 0xFFFFFF00,
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RP_MBOX_PENDING_MSG = 0xFFFFFF01,
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RP_MBOX_CRASH = 0xFFFFFF02,
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RP_MBOX_ECHO_REQUEST = 0xFFFFFF03,
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RP_MBOX_ECHO_REPLY = 0xFFFFFF04,
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RP_MBOX_ABORT_REQUEST = 0xFFFFFF05,
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RP_MBOX_SUSPEND_AUTO = 0xFFFFFF10,
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RP_MBOX_SUSPEND_SYSTEM = 0xFFFFFF11,
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RP_MBOX_SUSPEND_ACK = 0xFFFFFF12,
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RP_MBOX_SUSPEND_CANCEL = 0xFFFFFF13,
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RP_MBOX_END_MSG = 0xFFFFFF14,
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};
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#endif /* _OMAP_RPMSG_H */
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