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Message-ID: <ZtsyE2ibvJwuL7oH@p14s> Date: Fri, 6 Sep 2024 10:47:15 -0600 From: Mathieu Poirier <mathieu.poirier@...aro.org> To: Beleswar Padhi <b-padhi@...com> Cc: andersson@...nel.org, afd@...com, hnagalla@...com, s-anna@...com, u-kumar1@...com, linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] remoteproc: k3-r5: Decouple firmware booting from probe routine On Fri, Sep 06, 2024 at 03:10:45PM +0530, Beleswar Padhi wrote: > The current implementation of the waiting mechanism in probe() waits for > the 'released_from_reset' flag to be set which is done in > k3_r5_rproc_prepare() as part of rproc_fw_boot(). This causes unexpected If you are looking at rproc-next, @released_from_reset is set in k3_r5_rproc_start(). Moreover, the waiting mechanic happens in k3_r5_cluster_rproc_init(), which makes reading your changelog highly confusing. > failures in cases where the firmware is unavailable at boot time, > resulting in probe failure and removal of the remoteproc handles in the > sysfs paths. > > To address this, the waiting mechanism is refactored out of the probe > routine into the appropriate k3_r5_rproc_prepare/unprepare() and > k3_r5_rproc_start/stop() functions. This allows the probe routine to > complete without depending on firmware booting, while still maintaining > the required power-synchronization between cores. > > Fixes: 61f6f68447ab ("remoteproc: k3-r5: Wait for core0 power-up before powering up core1") > Signed-off-by: Beleswar Padhi <b-padhi@...com> > --- > Posted this as a Fix as this was breaking usecases where we wanted to load a > firmware by writing to sysfs handles in userspace. > > drivers/remoteproc/ti_k3_r5_remoteproc.c | 170 ++++++++++++++++------- > 1 file changed, 118 insertions(+), 52 deletions(-) > > diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c > index 747ee467da88..df8f124f4248 100644 > --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c > +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c > @@ -131,6 +131,7 @@ struct k3_r5_cluster { > * @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 > + * @unhalted: flag to signal when core is unhalted > */ > struct k3_r5_core { > struct list_head elem; > @@ -148,6 +149,7 @@ struct k3_r5_core { > u32 btcm_enable; > u32 loczrama; > bool released_from_reset; > + bool unhalted; Yet another flag? @released_from_reset is not enough? And why does it need to be "unhalted" rather than something like "running"? I will not move forward with this patch until I get an R-B and a T-B from two other people at TI. The above and the exchange with Jan Kiszka is furthering my belief that this driver is up for a serious refactoring exercise. From hereon I will only consider bug fixes. Thanks, Mathieu > }; > > /** > @@ -448,13 +450,33 @@ static int k3_r5_rproc_prepare(struct rproc *rproc) > { > struct k3_r5_rproc *kproc = rproc->priv; > struct k3_r5_cluster *cluster = kproc->cluster; > - struct k3_r5_core *core = kproc->core; > + struct k3_r5_core *core0, *core1, *core = kproc->core; > struct device *dev = kproc->dev; > u32 ctrl = 0, cfg = 0, stat = 0; > u64 boot_vec = 0; > bool mem_init_dis; > int ret; > > + /* > + * R5 cores require to be powered on sequentially, core0 should be in > + * higher power state than core1 in a cluster. So, wait for core0 to > + * power up before proceeding to core1 and put timeout of 2sec. This > + * waiting mechanism is necessary because rproc_auto_boot_callback() for > + * core1 can be called before core0 due to thread execution order. > + */ > + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem); > + core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem); > + if (cluster->mode == CLUSTER_MODE_SPLIT && core == core1 && > + core0->released_from_reset == false) { > + ret = wait_event_interruptible_timeout(cluster->core_transition, > + core0->released_from_reset, > + msecs_to_jiffies(2000)); > + if (ret <= 0) { > + dev_err(dev, "can not power up core1 before core0"); > + return -EPERM; > + } > + } > + > ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl, &stat); > if (ret < 0) > return ret; > @@ -470,6 +492,12 @@ static int k3_r5_rproc_prepare(struct rproc *rproc) > return ret; > } > > + /* Notify all threads in the wait queue when core state has changed so > + * that threads waiting for this condition can be executed. > + */ > + core->released_from_reset = true; > + wake_up_interruptible(&cluster->core_transition); > + > /* > * Newer IP revisions like on J7200 SoCs support h/w auto-initialization > * of TCMs, so there is no need to perform the s/w memzero. This bit is > @@ -515,14 +543,46 @@ static int k3_r5_rproc_unprepare(struct rproc *rproc) > { > struct k3_r5_rproc *kproc = rproc->priv; > struct k3_r5_cluster *cluster = kproc->cluster; > - struct k3_r5_core *core = kproc->core; > + struct k3_r5_core *core0, *core1, *core = kproc->core; > struct device *dev = kproc->dev; > int ret; > > /* Re-use LockStep-mode reset logic for Single-CPU mode */ > - ret = (cluster->mode == CLUSTER_MODE_LOCKSTEP || > - cluster->mode == CLUSTER_MODE_SINGLECPU) ? > - k3_r5_lockstep_reset(cluster) : k3_r5_split_reset(core); > + if (cluster->mode == CLUSTER_MODE_LOCKSTEP || > + cluster->mode == CLUSTER_MODE_SINGLECPU) > + ret = k3_r5_lockstep_reset(cluster); > + else { > + /* > + * R5 cores require to be powered off sequentially, core0 should > + * be in higher power state than core1 in a cluster. So, wait > + * for core1 to powered off before proceeding to core0 and put > + * timeout of 2sec. This waiting mechanism is necessary to > + * prevent stopping core0 before core1 from sysfs. > + */ > + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem); > + core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem); > + > + if (core == core0 && core1->released_from_reset == true) { > + ret = wait_event_interruptible_timeout(cluster->core_transition, > + !core1->released_from_reset, > + msecs_to_jiffies(2000)); > + > + if (ret <= 0) { > + dev_err(dev, "can not power off core0 before core1"); > + return -EPERM; > + } > + } > + > + ret = k3_r5_split_reset(core); > + > + /* Notify all threads in the wait queue when core state has > + * changed so that threads waiting for this condition can be > + * executed. > + */ > + core->released_from_reset = false; > + wake_up_interruptible(&cluster->core_transition); > + } > + > if (ret) > dev_err(dev, "unable to disable cores, ret = %d\n", ret); > > @@ -551,16 +611,34 @@ static int k3_r5_rproc_start(struct rproc *rproc) > struct k3_r5_rproc *kproc = rproc->priv; > struct k3_r5_cluster *cluster = kproc->cluster; > struct device *dev = kproc->dev; > - struct k3_r5_core *core0, *core; > + struct k3_r5_core *core0, *core1, *core = kproc->core; > u32 boot_addr; > int ret; > > + /* > + * R5 cores require to be powered on sequentially, core0 should be in > + * higher power state than core1 in a cluster. So, wait for core0 to > + * power up before proceeding to core1 and put timeout of 2sec. This > + * waiting mechanism is necessary because rproc_auto_boot_callback() for > + * core1 can be called before core0 due to thread execution order. > + */ > + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem); > + core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem); > + if (cluster->mode == CLUSTER_MODE_SPLIT && core == core1 && core0->unhalted == false) { > + ret = wait_event_interruptible_timeout(cluster->core_transition, > + core0->unhalted, > + msecs_to_jiffies(2000)); > + if (ret <= 0) { > + dev_err(dev, "can not power up core1 before core0"); > + return -EPERM; > + } > + } > + > boot_addr = rproc->bootaddr; > /* TODO: add boot_addr sanity checking */ > dev_dbg(dev, "booting R5F core using boot addr = 0x%x\n", boot_addr); > > /* boot vector need not be programmed for Core1 in LockStep mode */ > - core = kproc->core; > ret = ti_sci_proc_set_config(core->tsp, boot_addr, 0, 0); > if (ret) > return ret; > @@ -573,20 +651,15 @@ static int k3_r5_rproc_start(struct rproc *rproc) > goto unroll_core_run; > } > } else { > - /* 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) { > - dev_err(dev, "%s: can not start core 1 before core 0\n", > - __func__); > - return -EPERM; > - } > - > ret = k3_r5_core_run(core); > if (ret) > return ret; > > - core->released_from_reset = true; > + /* Notify all threads in the wait queue when core state has > + * changed so that threads waiting for this condition can be > + * executed. > + */ > + core->unhalted = true; > wake_up_interruptible(&cluster->core_transition); > } > > @@ -629,7 +702,7 @@ static int k3_r5_rproc_stop(struct rproc *rproc) > struct k3_r5_rproc *kproc = rproc->priv; > struct k3_r5_cluster *cluster = kproc->cluster; > struct device *dev = kproc->dev; > - struct k3_r5_core *core1, *core = kproc->core; > + struct k3_r5_core *core0, *core1, *core = kproc->core; > int ret; > > /* halt all applicable cores */ > @@ -642,19 +715,38 @@ static int k3_r5_rproc_stop(struct rproc *rproc) > } > } > } else { > - /* 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) { > - dev_err(dev, "%s: can not stop core 0 before core 1\n", > - __func__); > - ret = -EPERM; > - goto out; > + /* > + * R5 cores require to be powered off sequentially, core0 should > + * be in higher power state than core1 in a cluster. So, wait > + * for core1 to powered off before proceeding to core0 and put > + * timeout of 2sec. This waiting mechanism is necessary to > + * prevent stopping core0 before core1 from sysfs. > + */ > + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem); > + core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem); > + > + if (core == core0 && core1->unhalted == true) { > + ret = wait_event_interruptible_timeout(cluster->core_transition, > + !core1->unhalted, > + msecs_to_jiffies(2000)); > + > + if (ret <= 0) { > + dev_err(dev, "can not power off core0 before core1"); > + ret = -EPERM; > + goto out; > + } > } > > ret = k3_r5_core_halt(core); > if (ret) > goto out; > + > + /* Notify all threads in the wait queue when core state has > + * changed so that threads waiting for this condition can be > + * executed. > + */ > + core->unhalted = false; > + wake_up_interruptible(&cluster->core_transition); > } > > return 0; > @@ -1145,12 +1237,6 @@ static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc) > return reset_ctrl_status; > } > > - /* > - * Skip the waiting mechanism for sequential power-on of cores if the > - * core has already been booted by another entity. > - */ > - core->released_from_reset = c_state; > - > ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl, > &stat); > if (ret < 0) { > @@ -1296,25 +1382,6 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev) > 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. > - * > - * This waiting mechanism is necessary because > - * rproc_auto_boot_callback() for core1 can be called before > - * core0 due to thread execution order. > - */ > - 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); > - goto err_powerup; > - } > } > > return 0; > @@ -1329,7 +1396,6 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev) > } > } > > -err_powerup: > rproc_del(rproc); > err_add: > k3_r5_reserved_mem_exit(kproc); > -- > 2.34.1 >
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