Hi Mathieu, Sorry for the delay in response here. Somehow all the messages in this thread ended up in spam. Didn't realize there were new msgs until I looked up on lore.
On 17/12/25 03:53, Mathieu Poirier wrote: > Hi Beleswar, > > On Tue, Nov 25, 2025 at 02:07:46PM +0530, Beleswar Padhi wrote: >> From: Richard Genoud <[email protected]> >> >> Introduce software IPC handshake between the host running Linux and the >> remote processors to gracefully stop/reset the remote core. >> >> Upon a stop request, remoteproc driver sends a RP_MBOX_SHUTDOWN mailbox >> message to the remotecore. >> 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 remoteproc driver does: >> - wait for the RP_MBOX_SHUTDOWN_ACK from the remote core >> - wait for the remoteproc to enter WFI state >> - reset the remote core through device manager >> >> Based on work from: Hari Nagalla <[email protected]> >> >> Signed-off-by: Richard Genoud <[email protected]> >> [[email protected]: Extend support to all rprocs] >> Signed-off-by: Beleswar Padhi <[email protected]> >> --- >> v2: Changelog: >> 1. Extend graceful shutdown support for all rprocs (R5, DSP, M4) >> 2. Halt core only if SHUTDOWN_ACK is received from rproc and it has >> entered WFI state. >> 3. Convert return type of is_core_in_wfi() to bool. Works better with >> readx_poll_timeout() condition. >> 4. Cast RP_MBOX_SHUTDOWN to uintptr_t to suppress compiler warnings >> when void* is 64 bit. >> 5. Wrapped Graceful shutdown code in the form of notify_shutdown_rproc >> function. >> 6. Updated commit message to fix minor typos and such. >> >> Link to v1: >> https://lore.kernel.org/all/[email protected]/ >> >> Testing done: >> 1. Tested Boot across all TI K3 EVM/SK boards. >> 2. Tested IPC on all TI K3 J7* EVM/SK boards (& AM62x SK). >> 4. Tested R5 rprocs can now be shutdown and powered back on >> from userspace. >> 3. Tested that each patch in the series generates no new >> warnings/errors. >> >> drivers/remoteproc/omap_remoteproc.h | 9 ++- >> drivers/remoteproc/ti_k3_common.c | 72 +++++++++++++++++++++++ >> drivers/remoteproc/ti_k3_common.h | 4 ++ >> drivers/remoteproc/ti_k3_dsp_remoteproc.c | 2 + >> drivers/remoteproc/ti_k3_m4_remoteproc.c | 2 + >> drivers/remoteproc/ti_k3_r5_remoteproc.c | 5 ++ >> 6 files changed, 93 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/remoteproc/omap_remoteproc.h >> b/drivers/remoteproc/omap_remoteproc.h >> index 828e13256c023..c008f11fa2a43 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_common.c >> b/drivers/remoteproc/ti_k3_common.c >> index 56b71652e449f..5d469f65115c3 100644 >> --- a/drivers/remoteproc/ti_k3_common.c >> +++ b/drivers/remoteproc/ti_k3_common.c >> @@ -18,7 +18,9 @@ >> * Hari Nagalla <[email protected]> >> */ >> >> +#include <linux/delay.h> >> #include <linux/io.h> >> +#include <linux/iopoll.h> >> #include <linux/mailbox_client.h> >> #include <linux/module.h> >> #include <linux/of_address.h> >> @@ -69,6 +71,10 @@ void k3_rproc_mbox_callback(struct mbox_client *client, >> void *data) >> case RP_MBOX_ECHO_REPLY: >> dev_info(dev, "received echo reply from %s\n", rproc->name); >> break; >> + case RP_MBOX_SHUTDOWN_ACK: >> + dev_dbg(dev, "received shutdown_ack from %s\n", rproc->name); >> + complete(&kproc->shutdown_complete); >> + break; >> default: >> /* silently handle all other valid messages */ >> if (msg >= RP_MBOX_READY && msg < RP_MBOX_END_MSG) >> @@ -188,6 +194,67 @@ int k3_rproc_request_mbox(struct rproc *rproc) >> } >> EXPORT_SYMBOL_GPL(k3_rproc_request_mbox); >> >> +/** >> + * is_core_in_wfi - Utility function to check core status >> + * @kproc: remote core pointer used for checking core status >> + * >> + * This utility function is invoked by the shutdown sequence to ensure >> + * the remote core is in wfi, before asserting a reset. >> + */ >> +bool is_core_in_wfi(struct k3_rproc *kproc) >> +{ >> + int ret; >> + u64 boot_vec; >> + u32 cfg, ctrl, stat; >> + >> + ret = ti_sci_proc_get_status(kproc->tsp, &boot_vec, &cfg, &ctrl, &stat); >> + if (ret) >> + return false; >> + >> + return (bool)(stat & PROC_BOOT_STATUS_FLAG_CPU_WFI); >> +} >> +EXPORT_SYMBOL_GPL(is_core_in_wfi); >> + >> +/** >> + * notify_shutdown_rproc - Prepare the remoteproc for a shutdown >> + * @kproc: remote core pointer used for sending mbox msg >> + * >> + * This function sends the shutdown prepare message to remote processor and >> + * waits for an ACK. Further, it checks if the remote processor has entered >> + * into WFI mode. It is invoked in shutdown sequence to ensure the rproc >> + * has relinquished its resources before asserting a reset, so the shutdown >> + * happens cleanly. >> + */ >> +int notify_shutdown_rproc(struct k3_rproc *kproc) >> +{ >> + bool wfi_status = false; >> + int ret; >> + >> + reinit_completion(&kproc->shutdown_complete); >> + >> + ret = mbox_send_message(kproc->mbox, (void >> *)(uintptr_t)RP_MBOX_SHUTDOWN); >> + if (ret < 0) { >> + dev_err(kproc->dev, "PM mbox_send_message failed: %d\n", ret); >> + return ret; >> + } >> + >> + ret = wait_for_completion_timeout(&kproc->shutdown_complete, >> + msecs_to_jiffies(5000)); >> + if (ret == 0) { >> + dev_err(kproc->dev, "%s: timeout waiting for rproc completion >> event\n", >> + __func__); >> + return -EBUSY; >> + } >> + > > Won't that create an issue on systems with an older FW that doesn't send a > RP_MBOX_SHUDOWN_ACK message? Unless I'm missing something, this kind of > feature > needs to be backward compatible. I feel it would be unsafe to just abruptly power off a core without some handshake.. The core could be executing something, there could be pending bus transactions leading to system hangs etc.. We start the IPC mechanism with a handshake, so we should end it with a handshake too.. And for firmwares that don't support this handshake, IMO its better to reject the shutdown request. What do you think? For older TI firmwares also, doing rproc_stop() resulted in those intermittent bugs as mentioned above. So we never really supported the stop() feature until now. Thanks, Beleswar > > Thanks, > Mathieu > >> + ret = readx_poll_timeout(is_core_in_wfi, kproc, wfi_status, wfi_status, >> + 200, 2000); >> + if (ret) >> + return ret; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(notify_shutdown_rproc); >> + >> /* >> * The K3 DSP and M4 cores have a local reset that affects only the CPU, >> and a >> * generic module reset that powers on the device and allows the internal >> @@ -288,6 +355,11 @@ EXPORT_SYMBOL_GPL(k3_rproc_start); >> int k3_rproc_stop(struct rproc *rproc) >> { >> struct k3_rproc *kproc = rproc->priv; >> + int ret; >> + >> + ret = notify_shutdown_rproc(kproc); >> + if (ret) >> + return ret; >> >> return k3_rproc_reset(kproc); >> } >> diff --git a/drivers/remoteproc/ti_k3_common.h >> b/drivers/remoteproc/ti_k3_common.h >> index aee3c28dbe510..2a025f4894b82 100644 >> --- a/drivers/remoteproc/ti_k3_common.h >> +++ b/drivers/remoteproc/ti_k3_common.h >> @@ -22,6 +22,7 @@ >> #define REMOTEPROC_TI_K3_COMMON_H >> >> #define KEYSTONE_RPROC_LOCAL_ADDRESS_MASK (SZ_16M - 1) >> +#define PROC_BOOT_STATUS_FLAG_CPU_WFI 0x00000002 >> >> /** >> * struct k3_rproc_mem - internal memory structure >> @@ -92,6 +93,7 @@ struct k3_rproc { >> u32 ti_sci_id; >> struct mbox_chan *mbox; >> struct mbox_client client; >> + struct completion shutdown_complete; >> void *priv; >> }; >> >> @@ -115,4 +117,6 @@ int k3_rproc_of_get_memories(struct platform_device >> *pdev, >> void k3_mem_release(void *data); >> int k3_reserved_mem_init(struct k3_rproc *kproc); >> void k3_release_tsp(void *data); >> +bool is_core_in_wfi(struct k3_rproc *kproc); >> +int notify_shutdown_rproc(struct k3_rproc *kproc); >> #endif /* REMOTEPROC_TI_K3_COMMON_H */ >> diff --git a/drivers/remoteproc/ti_k3_dsp_remoteproc.c >> b/drivers/remoteproc/ti_k3_dsp_remoteproc.c >> index d6ceea6dc920e..156ae09d8ee25 100644 >> --- a/drivers/remoteproc/ti_k3_dsp_remoteproc.c >> +++ b/drivers/remoteproc/ti_k3_dsp_remoteproc.c >> @@ -133,6 +133,8 @@ static int k3_dsp_rproc_probe(struct platform_device >> *pdev) >> if (ret) >> return ret; >> >> + init_completion(&kproc->shutdown_complete); >> + >> ret = k3_rproc_of_get_memories(pdev, kproc); >> if (ret) >> return ret; >> diff --git a/drivers/remoteproc/ti_k3_m4_remoteproc.c >> b/drivers/remoteproc/ti_k3_m4_remoteproc.c >> index 3a11fd24eb52b..64d99071279b0 100644 >> --- a/drivers/remoteproc/ti_k3_m4_remoteproc.c >> +++ b/drivers/remoteproc/ti_k3_m4_remoteproc.c >> @@ -90,6 +90,8 @@ static int k3_m4_rproc_probe(struct platform_device *pdev) >> if (ret) >> return ret; >> >> + init_completion(&kproc->shutdown_complete); >> + >> ret = k3_rproc_of_get_memories(pdev, kproc); >> if (ret) >> return ret; >> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c >> b/drivers/remoteproc/ti_k3_r5_remoteproc.c >> index 04f23295ffc10..8748dc6089cc2 100644 >> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c >> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c >> @@ -533,6 +533,10 @@ static int k3_r5_rproc_stop(struct rproc *rproc) >> struct k3_r5_cluster *cluster = core->cluster; >> int ret; >> >> + ret = notify_shutdown_rproc(kproc); >> + if (ret) >> + return ret; >> + >> /* halt all applicable cores */ >> if (cluster->mode == CLUSTER_MODE_LOCKSTEP) { >> list_for_each_entry(core, &cluster->cores, elem) { >> @@ -1129,6 +1133,7 @@ static int k3_r5_cluster_rproc_init(struct >> platform_device *pdev) >> goto out; >> } >> >> + init_completion(&kproc->shutdown_complete); >> init_rmem: >> k3_r5_adjust_tcm_sizes(kproc); >> >> -- >> 2.34.1 >>
