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remoteproc: k3-m4: support for graceful shutdown of remote cores

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Upon a stop request, K3-M4 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-M4 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

Signed-off-by: Hari Nagalla <hnagalla@ti.com>
This commit is contained in:
Hari Nagalla
2024-07-02 21:14:52 -05:00
committed by Heinrich Toews
parent 8811cb9cf5
commit 0436682951
1 changed files with 54 additions and 0 deletions
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drivers/remoteproc/ti_k3_m4_remoteproc.c
+54
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@@ -6,7 +6,9 @@
* Hari Nagalla <hnagalla@ti.com>
*/
#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>
@@ -20,6 +22,9 @@
#include "remoteproc_internal.h"
#include "ti_sci_proc.h"
/* M4 TI-SCI Processor Status Flags */
#define PROC_BOOT_STATUS_FLAG_M4_WFI 0x00000002
/**
* struct k3_m4_rproc_mem - internal memory structure
* @cpu_addr: MPU virtual address of the memory region
@@ -86,8 +91,31 @@ struct k3_m4_rproc {
u32 ti_sci_id;
struct mbox_chan *mbox;
struct mbox_client client;
struct completion shut_comp;
};
/**
* is_core_in_wfi - local 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.
*/
static int is_core_in_wfi(struct k3_m4_rproc *core)
{
int ret;
u64 boot_vec;
u32 cfg, ctrl, stat;
ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl, &stat);
if (ret < 0)
return 0;
return (stat & PROC_BOOT_STATUS_FLAG_M4_WFI);
}
/**
* k3_m4_rproc_mbox_callback() - inbound mailbox message handler
* @client: mailbox client pointer used for requesting the mailbox channel
@@ -123,6 +151,10 @@ static void k3_m4_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->shut_comp);
break;
default:
/* silently handle all other valid messages */
if (msg >= RP_MBOX_READY && msg < RP_MBOX_END_MSG)
@@ -583,10 +615,31 @@ put_mbox:
*/
static int k3_m4_rproc_stop(struct rproc *rproc)
{
unsigned long to = msecs_to_jiffies(3000);
struct k3_m4_rproc *kproc = rproc->priv;
u32 msg = (u32)(uintptr_t) RP_MBOX_SHUTDOWN;
struct device *dev = kproc->dev;
int ret;
u32 stat = 0;
reinit_completion(&kproc->shut_comp);
ret = mbox_send_message(kproc->mbox, (void *) (uintptr_t)msg);
if (ret < 0) {
dev_err(dev, "PM mbox_send_message failed: %d\n", ret);
return ret;
}
ret = wait_for_completion_timeout(&kproc->shut_comp, to);
if (ret == 0) {
dev_err(dev, "%s: timedout waiting for rproc completion event\n", __func__);
};
mbox_free_channel(kproc->mbox);
ret = readx_poll_timeout(is_core_in_wfi, kproc, stat, stat, 200, 2000);
if (ret)
return ret;
k3_m4_rproc_reset(kproc);
return 0;
@@ -694,6 +747,7 @@ static int k3_m4_rproc_probe(struct platform_device *pdev)
if (IS_ERR(kproc->tsp))
return dev_err_probe(dev, PTR_ERR(kproc->tsp),
"failed to construct ti-sci proc control\n");
init_completion(&kproc->shut_comp);
ret = ti_sci_proc_request(kproc->tsp);
if (ret < 0)