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@xxxxxx>
> ---
>
> 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.
> + 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?
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?
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
>
