Re: [PATCH 2/4] remoteproc: k3-r5: Introduce PM suspend/resume handlers

Richard GENOUD
2024-07-01T07:30:22Z

Le 28/06/2024 à 22:48, Mathieu Poirier a écrit :
> On Fri, Jun 21, 2024 at 05:00:56PM +0200, Richard Genoud wrote:
>> This patch adds the support for system suspend/resume to the ti_k3_R5
>> remoteproc driver.
>>
>> In order to save maximum power, the approach here is to shutdown
>> completely the cores that were started by the kernel (i.e. those in
>> RUNNING state).
>> Those which were started before the kernel (in attached mode) will be
>> detached.
>>
>> The pm_notifier mechanism is used here because the remote procs firmwares
>> have to be reloaded at resume, and thus the driver must have access to
>> the file system were the firmware is stored.
>>
>> On suspend, the running remote procs are stopped, the attached remote
>> procs are detached and processor control released.
>>
>> On resume, the reverse operation is done.
>>
>> Based on work from: Hari Nagalla <hnagalla@ti.com>
>>
>> Signed-off-by: Richard Genoud <richard.genoud@bootlin.com>
>> ---
>> drivers/remoteproc/ti_k3_r5_remoteproc.c | 123 ++++++++++++++++++++++-
>> 1 file changed, 121 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> index 39a47540c590..1f18b08618c8 100644
>> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
>> @@ -20,6 +20,7 @@
>> #include <linux/platform_device.h>
>> #include <linux/pm_runtime.h>
>> #include <linux/remoteproc.h>
>> +#include <linux/suspend.h>
>> #include <linux/reset.h>
>> #include <linux/slab.h>
>>
>> @@ -112,6 +113,7 @@ struct k3_r5_cluster {
>> struct list_head cores;
>> wait_queue_head_t core_transition;
>> const struct k3_r5_soc_data *soc_data;
>> + struct notifier_block pm_notifier;
>> };
>>
>> /**
>> @@ -577,7 +579,8 @@ static int k3_r5_rproc_start(struct rproc *rproc)
>> /* do not allow core 1 to start before core 0 */
>> core0 = list_first_entry(&cluster->cores, struct k3_r5_core,
>> elem);
>> - if (core != core0 && core0->rproc->state == RPROC_OFFLINE) {
>> + if (core != core0 && (core0->rproc->state == RPROC_OFFLINE ||
>> + core0->rproc->state == RPROC_SUSPENDED)) {
>
> If I understand correctly, this is to address a possible race condition between
> user space wanting to start core1 via sysfs while the system is being suspended.
> Is this correct? If so, please add a comment to explain what is going on.
> Otherwise a comment is obviously needed.
Yes, you're right, I'll add a comment on the race condition at suspend.

>
>> dev_err(dev, "%s: can not start core 1 before core 0\n",
>> __func__);
>> ret = -EPERM;
>> @@ -646,7 +649,8 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
>> /* do not allow core 0 to stop before core 1 */
>> core1 = list_last_entry(&cluster->cores, struct k3_r5_core,
>> elem);
>> - if (core != core1 && core1->rproc->state != RPROC_OFFLINE) {
>> + if (core != core1 && core1->rproc->state != RPROC_OFFLINE &&
>> + core1->rproc->state != RPROC_SUSPENDED) {
>> dev_err(dev, "%s: can not stop core 0 before core 1\n",
>> __func__);
>> ret = -EPERM;
>> @@ -1238,6 +1242,117 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
>> return ret;
>> }
>>
>> +static int k3_r5_rproc_suspend(struct k3_r5_rproc *kproc)
>> +{
>> + unsigned int rproc_state = kproc->rproc->state;
>> + int ret;
>> +
>> + if (rproc_state != RPROC_RUNNING && rproc_state != RPROC_ATTACHED)
>> + return 0;
>> +
>> + if (rproc_state == RPROC_RUNNING)
>> + ret = rproc_shutdown(kproc->rproc);
>> + else
>> + ret = rproc_detach(kproc->rproc);
>> +
>> + if (ret) {
>> + dev_err(kproc->dev, "Failed to %s rproc (%d)\n",
>> + (rproc_state == RPROC_RUNNING) ? "shutdown" : "detach",
>> + ret);
>> + return ret;
>> + }
>> +
>> + kproc->rproc->state = RPROC_SUSPENDED;
>> +
>> + return ret;
>> +}
>> +
>> +static int k3_r5_rproc_resume(struct k3_r5_rproc *kproc)
>> +{
>> + int ret;
>> +
>> + if (kproc->rproc->state != RPROC_SUSPENDED)
>> + return 0;
>> +
>> + ret = k3_r5_rproc_configure_mode(kproc);
>> + if (ret < 0)
>> + return -EBUSY;
>> +
>> + /*
>> + * ret > 0 for IPC-only mode
>> + * ret == 0 for remote proc mode
>> + */
>> + if (ret == 0) {
>> + /*
>> + * remote proc looses its configuration when powered off.
>> + * So, we have to configure it again on resume.
>> + */
>> + ret = k3_r5_rproc_configure(kproc);
>> + if (ret < 0) {
>> + dev_err(kproc->dev, "k3_r5_rproc_configure failed (%d)\n", ret);
>> + return -EBUSY;
>> + }
>> + }
>> +
>> + return rproc_boot(kproc->rproc);
>> +}
>> +
>> +static int k3_r5_cluster_pm_notifier_call(struct notifier_block *bl,
>> + unsigned long state, void *unused)
>> +{
>> + struct k3_r5_cluster *cluster = container_of(bl, struct k3_r5_cluster,
>> + pm_notifier);
>> + struct k3_r5_core *core;
>> + int ret;
>> +
>> + switch (state) {
>> + case PM_HIBERNATION_PREPARE:
>> + case PM_RESTORE_PREPARE:
>> + case PM_SUSPEND_PREPARE:
>> + /* core1 should be suspended before core0 */
>> + list_for_each_entry_reverse(core, &cluster->cores, elem) {
>> + /*
>> + * In LOCKSTEP mode, rproc is allocated only for
>> + * core0
>> + */
>> + if (core->rproc) {
>> + ret = k3_r5_rproc_suspend(core->rproc->priv);
>> + if (ret)
>> + dev_warn(core->dev,
>> + "k3_r5_rproc_suspend failed (%d)\n", ret);
>> + }
>> +
>> + ret = ti_sci_proc_release(core->tsp);
>> + if (ret)
>> + dev_warn(core->dev, "ti_sci_proc_release failed (%d)\n", ret);
>> + }
>> + break;
>> + case PM_POST_HIBERNATION:
>> + case PM_POST_RESTORE:
>> + case PM_POST_SUSPEND:
>> + /* core0 should be started before core1 */
>> + list_for_each_entry(core, &cluster->cores, elem) {
>> + ret = ti_sci_proc_request(core->tsp);
>> + if (ret)
>> + dev_warn(core->dev, "ti_sci_proc_request failed (%d)\n", ret);
>> +
>> + /*
>> + * In LOCKSTEP mode, rproc is allocated only for
>> + * core0
>> + */
>> + if (core->rproc) {
>> + ret = k3_r5_rproc_resume(core->rproc->priv);
>> + if (ret)
>> + dev_warn(core->dev,
>> + "k3_r5_rproc_resume failed (%d)\n", ret);
>> + }
>> + }
>> + break;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
>> {
>> struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
>> @@ -1336,6 +1451,9 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
>> }
>> }
>>
>> + cluster->pm_notifier.notifier_call = k3_r5_cluster_pm_notifier_call;
>> + register_pm_notifier(&cluster->pm_notifier);
>> +
>> return 0;
>>
>> err_split:
>> @@ -1402,6 +1520,7 @@ static void k3_r5_cluster_rproc_exit(void *data)
>> rproc_free(rproc);
>> core->rproc = NULL;
>> }
>> + unregister_pm_notifier(&cluster->pm_notifier);
>> }
>>
>> static int k3_r5_core_of_get_internal_memories(struct platform_device *pdev,

Thanks !