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Message-ID: <e1d6913d-bf6f-4403-bf55-6806ed690935@bootlin.com>
Date: Mon, 1 Jul 2024 18:48:35 +0200
From: Richard GENOUD <richard.genoud@...tlin.com>
To: Andrew Davis <afd@...com>, Bjorn Andersson <andersson@...nel.org>,
Mathieu Poirier <mathieu.poirier@...aro.org>
Cc: Philipp Zabel <p.zabel@...gutronix.de>, Suman Anna <s-anna@...com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Udit Kumar <u-kumar1@...com>, Thomas Richard <thomas.richard@...tlin.com>,
Gregory CLEMENT <gregory.clement@...tlin.com>, Hari Nagalla
<hnagalla@...com>, Théo Lebrun <theo.lebrun@...tlin.com>,
linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] remoteproc: k3-r5: support for graceful stop of
remote cores
Le 29/06/2024 à 00:50, Andrew Davis a écrit :
> On 6/21/24 10:00 AM, Richard Genoud wrote:
>> Introduce software IPC handshake between the K3-R5 remote proc driver
>> and the R5 MCU to gracefully stop/reset the remote core.
>>
>> Upon a stop request, K3-R5 remote proc driver sends a RP_MBOX_SHUTDOWN
>> mailbox message to the remote R5 core.
>> The remote core is expected to:
>> - relinquish all the resources acquired through Device Manager (DM)
>> - disable its interrupts
>> - send back a mailbox acknowledgment RP_MBOX_SHUDOWN_ACK
>> - enter WFI state.
>>
>> Meanwhile, the K3-R5 remote proc driver does:
>> - wait for the RP_MBOX_SHUTDOWN_ACK from the remote core
>> - wait for the remote proc to enter WFI state
>> - reset the remote core through device manager
>>
>> Based on work from: Hari Nagalla <hnagalla@...com>
>>
>> Signed-off-by: Richard Genoud <richard.genoud@...tlin.com>
>> ---
>> drivers/remoteproc/omap_remoteproc.h | 9 +++++-
>> drivers/remoteproc/ti_k3_r5_remoteproc.c | 40 ++++++++++++++++++++++++
>> 2 files changed, 48 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/remoteproc/omap_remoteproc.h
>> b/drivers/remoteproc/omap_remoteproc.h
>> index 828e13256c02..c008f11fa2a4 100644
>> --- a/drivers/remoteproc/omap_remoteproc.h
>> +++ b/drivers/remoteproc/omap_remoteproc.h
>> @@ -42,6 +42,11 @@
>> * @RP_MBOX_SUSPEND_CANCEL: a cancel suspend response from a remote
>> processor
>> * on a suspend request
>> *
>> + * @RP_MBOX_SHUTDOWN: shutdown request for the remote processor
>> + *
>> + * @RP_MBOX_SHUTDOWN_ACK: successful response from remote processor
>> for a
>> + * shutdown request. The remote processor should be in WFI state
>> short after.
>> + *
>> * Introduce new message definitions if any here.
>> *
>> * @RP_MBOX_END_MSG: Indicates end of known/defined messages from
>> remote core
>> @@ -59,7 +64,9 @@ enum omap_rp_mbox_messages {
>> RP_MBOX_SUSPEND_SYSTEM = 0xFFFFFF11,
>> RP_MBOX_SUSPEND_ACK = 0xFFFFFF12,
>> RP_MBOX_SUSPEND_CANCEL = 0xFFFFFF13,
>> - RP_MBOX_END_MSG = 0xFFFFFF14,
>> + RP_MBOX_SHUTDOWN = 0xFFFFFF14,
>> + RP_MBOX_SHUTDOWN_ACK = 0xFFFFFF15,
>> + RP_MBOX_END_MSG = 0xFFFFFF16,
>> };
>> #endif /* _OMAP_RPMSG_H */
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index a2ead87952c7..918a15e1dd9a 100644
>> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> @@ -21,6 +21,7 @@
>> #include <linux/pm_runtime.h>
>> #include <linux/remoteproc.h>
>> #include <linux/suspend.h>
>> +#include <linux/iopoll.h>
>> #include <linux/reset.h>
>> #include <linux/slab.h>
>> @@ -172,8 +173,23 @@ struct k3_r5_rproc {
>> struct k3_r5_core *core;
>> struct k3_r5_mem *rmem;
>> int num_rmems;
>> + struct completion shutdown_complete;
>> };
>> +/*
>> + * This will return true if the remote core is in Wait For Interrupt
>> state.
>> + */
>> +static bool k3_r5_is_core_in_wfi(struct k3_r5_core *core)
>> +{
>> + int ret;
>> + u64 boot_vec;
>> + u32 cfg, ctrl, stat;
>> +
>> + ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl,
>> &stat);
>> +
>> + return !ret ? !!(stat & PROC_BOOT_STATUS_FLAG_R5_WFI) : false;
>
> Too fancy for me :) Just return if (ret) right after get_status().
Ok, too much punctuation :)
>
> Looks like this function is called in a polling loop, if
> ti_sci_proc_get_status() fails once, it won't get better,
> no need to keep checking, we should just error out of
> the polling loop.
Ok
Thanks !
>
> Andrew
>
>> +}
>> +
>> /**
>> * k3_r5_rproc_mbox_callback() - inbound mailbox message handler
>> * @client: mailbox client pointer used for requesting the mailbox
>> channel
>> @@ -209,6 +225,10 @@ static void k3_r5_rproc_mbox_callback(struct
>> mbox_client *client, void *data)
>> case RP_MBOX_ECHO_REPLY:
>> dev_info(dev, "received echo reply from %s\n", name);
>> break;
>> + case RP_MBOX_SHUTDOWN_ACK:
>> + dev_dbg(dev, "received shutdown_ack from %s\n", name);
>> + complete(&kproc->shutdown_complete);
>> + break;
>> default:
>> /* silently handle all other valid messages */
>> if (msg >= RP_MBOX_READY && msg < RP_MBOX_END_MSG)
>> @@ -634,6 +654,7 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> struct k3_r5_cluster *cluster = kproc->cluster;
>> struct device *dev = kproc->dev;
>> struct k3_r5_core *core1, *core = kproc->core;
>> + bool wfi;
>> int ret;
>> @@ -650,6 +671,24 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> }
>> }
>> + /* Send SHUTDOWN message to remote proc */
>> + reinit_completion(&kproc->shutdown_complete);
>> + ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_SHUTDOWN);
>> + if (ret < 0) {
>> + dev_err(dev, "Sending SHUTDOWN message failed: %d. Halting
>> core anyway.\n", ret);
>> + } else {
>> + ret = wait_for_completion_timeout(&kproc->shutdown_complete,
>> + msecs_to_jiffies(1000));
>> + if (ret == 0) {
>> + dev_err(dev, "Timeout waiting SHUTDOWN_ACK message.
>> Halting core anyway.\n");
>> + } else {
>> + ret = readx_poll_timeout(k3_r5_is_core_in_wfi, core,
>> + wfi, wfi, 200, 2000);
>> + if (ret)
>> + dev_err(dev, "Timeout waiting for remote proc to be
>> in WFI state. Halting core anyway.\n");
>> + }
>> + }
>> +
>> /* halt all applicable cores */
>> if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
>> list_for_each_entry(core, &cluster->cores, elem) {
>> @@ -1410,6 +1449,7 @@ static int k3_r5_cluster_rproc_init(struct
>> platform_device *pdev)
>> goto err_config;
>> }
>> + init_completion(&kproc->shutdown_complete);
>> init_rmem:
>> k3_r5_adjust_tcm_sizes(kproc);
>>
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