Re: [PATCH 4/4] remoteproc: k3-r5: support for graceful stop of remote cores

Richard GENOUD
2024-07-01T16:38:41Z

[adding Vibhore in Cc]

Le 28/06/2024 à 23:20, Mathieu Poirier a écrit :
> On Fri, Jun 21, 2024 at 05:00:58PM +0200, 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@ti.com>
>>
>
> Why is this needed now and what happens to system with a new kernel driver and
> an older K3R5 firmware?

Without this patch, the IPC firwmares from recent TI PDK prevent the
suspend:
platform 5d00000.r5f: ti-sci processor set_control failed: -19
remoteproc remoteproc1: can't stop rproc: -19
platform 5c00000.r5f: Failed to shutdown rproc (-19)
platform 5c00000.r5f: k3_r5_rproc_suspend failed (-19)

With a new kernel driver and an old firmware, this will add a timeout
before stopping it, and the message:

platform 5c00000.r5f: Timeout waiting SHUTDOWN_ACK message. Halting core
anyway.

(tested on old FW 09.00.00.01 and new FW 09.02.01.18, on J7200)

Regards,
Richard

>
> Thanks,
> Mathieu
>
>> Signed-off-by: Richard Genoud <richard.genoud@bootlin.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;
>> +}
>> +
>> /**
>> * 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);
>>