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Message-ID: <CANLsYky9Mz7FeJjU-jo9q2QrkPFnHR+_8a97iT+SGizR_-Z+rg@mail.gmail.com>
Date: Wed, 4 Oct 2023 11:30:38 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Apurva Nandan <a-nandan@...com>
Cc: Nishanth Menon <nm@...com>, Bjorn Andersson <andersson@...nel.org>,
Suman Anna <s-anna@...com>, linux-remoteproc@...r.kernel.org,
linux-kernel@...r.kernel.org, Devarsh Thakkar <devarsht@...com>,
Hari Nagalla <hnagalla@...com>, Udit Kumar <u-kumar1@...com>
Subject: Re: [PATCH] remoteproc: k3-r5: Wait for core0 power-up before
powering up core1
On Wed, 4 Oct 2023 at 07:51, Apurva Nandan <a-nandan@...com> wrote:
>
> Hi Mathieu,
>
> On 11/09/23 22:15, Mathieu Poirier wrote:
> > Hi Apurva,
> >
> > On Wed, Sep 06, 2023 at 06:17:56PM +0530, Apurva Nandan wrote:
> >> PSC controller has a limitation that it can only power-up the second core
> >> when the first core is in ON state. Power-state for core0 should be equal
> >> to or higher than core1, else the kernel is seen hanging during rproc
> >> loading.
> >>
> >> Make the powering up of cores sequential, by waiting for the current core
> >> to power-up before proceeding to the next core, with a timeout of 2sec.
> >> Add a wait queue event in k3_r5_cluster_rproc_init call, that will wait
> >> for the current core to be released from reset before proceeding with the
> >> next core.
> >>
> >> Fixes: 6dedbd1d5443 ("remoteproc: k3-r5: Add a remoteproc driver for R5F subsystem")
> >>
> >> Signed-off-by: Apurva Nandan <a-nandan@...com>
> >> ---
> >>
> >> kpv report: https://gist.githubusercontent.com/apurvanandan1997/feb3b304121c265b7827be43752b7ae8/raw
> >>
> >> drivers/remoteproc/ti_k3_r5_remoteproc.c | 23 +++++++++++++++++++++++
> >> 1 file changed, 23 insertions(+)
> >>
> >> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> >> index ad3415a3851b..ba5e503f7c9c 100644
> >> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> >> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> >> @@ -103,12 +103,14 @@ struct k3_r5_soc_data {
> >> * @dev: cached device pointer
> >> * @mode: Mode to configure the Cluster - Split or LockStep
> >> * @cores: list of R5 cores within the cluster
> >> + * @core_transition: wait queue to sync core state changes
> >> * @soc_data: SoC-specific feature data for a R5FSS
> >> */
> >> struct k3_r5_cluster {
> >> struct device *dev;
> >> enum cluster_mode mode;
> >> struct list_head cores;
> >> + wait_queue_head_t core_transition;
> >> const struct k3_r5_soc_data *soc_data;
> >> };
> >>
> >> @@ -128,6 +130,7 @@ struct k3_r5_cluster {
> >> * @atcm_enable: flag to control ATCM enablement
> >> * @btcm_enable: flag to control BTCM enablement
> >> * @loczrama: flag to dictate which TCM is at device address 0x0
> >> + * @released_from_reset: flag to signal when core is out of reset
> >> */
> >> struct k3_r5_core {
> >> struct list_head elem;
> >> @@ -144,6 +147,7 @@ struct k3_r5_core {
> >> u32 atcm_enable;
> >> u32 btcm_enable;
> >> u32 loczrama;
> >> + bool released_from_reset;
> >> };
> >>
> >> /**
> >> @@ -460,6 +464,8 @@ static int k3_r5_rproc_prepare(struct rproc *rproc)
> >> ret);
> >> return ret;
> >> }
> >> + core->released_from_reset = true;
> >> + wake_up_interruptible(&cluster->core_transition);
> >>
> >> /*
> >> * Newer IP revisions like on J7200 SoCs support h/w auto-initialization
> >> @@ -1140,6 +1146,7 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> >> return ret;
> >> }
> >>
> >> + core->released_from_reset = c_state;
> >> ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl,
> >> &stat);
> >> if (ret < 0) {
> >> @@ -1280,6 +1287,21 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> >> cluster->mode == CLUSTER_MODE_SINGLECPU ||
> >> cluster->mode == CLUSTER_MODE_SINGLECORE)
> >> break;
> >> +
> >> + /* R5 cores require to be powered on sequentially, core0
> >> + * should be in higher power state than core1 in a cluster
> >> + * So, wait for current core to power up before proceeding
> >> + * to next core and put timeout of 2sec for each core.
> >> + */
> > Wrong multi-line comment format.
> Okay will fix this.
> >> + ret = wait_event_interruptible_timeout(cluster->core_transition,
> >> + core->released_from_reset,
> >> + msecs_to_jiffies(2000));
> >> + if (ret <= 0) {
> >> + dev_err(dev,
> >> + "Timed out waiting for %s core to power up!\n",
> >> + rproc->name);
> >> + return ret;
> >> + }
> > From my perspective, this is needed because rproc_auto_boot_callback() for core1
> > can be called before core0 due to thread execution order. Am I correct?
> Yes
> > If so please add this explanation to the comment you have above. Also, let's
> > say a user decides to switch both cores off after reboot. At that time, what
> > prevents a user from switching on core1 before core0 via sysfs?
> Okay, will add the explanation.
> Currently, adding support for graceful shutdown is in progress. As of
> now in order
> to stop/start core or change firmware, we recommend users to restart the
> OS.
You will need to address access via debugfs and sysfs if you want this
patch to move forward.
> > Thanks,
> > Mathieu
> >
> >> }
> >>
> >> return 0;
> >> @@ -1709,6 +1731,7 @@ static int k3_r5_probe(struct platform_device *pdev)
> >> cluster->dev = dev;
> >> cluster->soc_data = data;
> >> INIT_LIST_HEAD(&cluster->cores);
> >> + init_waitqueue_head(&cluster->core_transition);
> >>
> >> ret = of_property_read_u32(np, "ti,cluster-mode", &cluster->mode);
> >> if (ret < 0 && ret != -EINVAL) {
> >> --
> >> 2.34.1
> >>
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