[PATCH v2 0/3] Fix sleeping function called from invalid context

[PATCH v2 0/3] Fix sleeping function called from invalid context

[Jason-JH Lin]

We found that there is a spin_lock_irqsave protection in msg_submit()
of mailbox.c and it is in the atomic context.
So when the mailbox controller driver calls pm_runtime_get_sync() in
mbox_chan_ops->send_data(), it will get this BUG report.
"BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1164"

Additionally, pm_runtime_put_autosuspend() should be invoked from the
GCE IRQ handler to ensure the hardware has actually completed its work.

To resolve these issues, remove the pm_runtime calls from
cmdq_mbox_send_data() and delegate power management responsibilities
to the client driver.
---
Changes in v2:
- Move pm_runtmie APIs from cmdq driver to client drivers.
- Move pm_runtime_put_autosuspend to GCE irq callback function.
- Link to v1: https://lore.kernel.org/r/20240614040133.24967-1-jason-jh.lin@mediatek.com
---
Jason-JH Lin (3):
  mailbox: mtk-cmdq: Remove pm_runtime APIs from cmdq_mbox_send_data()
  drm/mediatek: Add pm_runtime support for GCE power control
  media: platform: mtk-mdp3: Add pm_runtime support for GCE power
    control

 drivers/gpu/drm/mediatek/mtk_crtc.c                  |  7 +++++++
 drivers/mailbox/mtk-cmdq-mailbox.c                   | 12 +-----------
 drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c | 11 +++++++++++
 3 files changed, 19 insertions(+), 11 deletions(-)

-- 
2.43.0

[PATCH v2 1/3] mailbox: mtk-cmdq: Remove pm_runtime APIs from cmdq_mbox_send_data()

[Jason-JH Lin]

pm_runtime_get_sync() and pm_runtime_put_autosuspend() were previously
called in cmdq_mbox_send_data(), which is under a spinlock in msg_submit()
(mailbox.c). This caused lockdep warnings such as "sleeping function
called from invalid context" when running with lockdebug enabled.

The BUG report:
  BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1164
  in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 3616, name: kworker/u17:3
    preempt_count: 1, expected: 0
    RCU nest depth: 0, expected: 0
    INFO: lockdep is turned off.
    irq event stamp: 0
    CPU: 1 PID: 3616 Comm: kworker/u17:3 Not tainted 6.1.87-lockdep-14133-g26e933aca785 #1
    Hardware name: Google Ciri sku0/unprovisioned board (DT)
    Workqueue: imgsys_runner imgsys_runner_func
    Call trace:
     dump_backtrace+0x100/0x120
     show_stack+0x20/0x2c
     dump_stack_lvl+0x84/0xb4
     dump_stack+0x18/0x48
     __might_resched+0x354/0x4c0
     __might_sleep+0x98/0xe4
     __pm_runtime_resume+0x70/0x124
     cmdq_mbox_send_data+0xe4/0xb1c
     msg_submit+0x194/0x2dc
     mbox_send_message+0x190/0x330
     imgsys_cmdq_sendtask+0x1618/0x2224
     imgsys_runner_func+0xac/0x11c
     process_one_work+0x638/0xf84
     worker_thread+0x808/0xcd0
     kthread+0x24c/0x324
     ret_from_fork+0x10/0x20

Additionally, pm_runtime_put_autosuspend() should be invoked from the
GCE IRQ handler to ensure the hardware has actually completed its work.

To resolve these issues, remove the pm_runtime calls from
cmdq_mbox_send_data() and delegate power management responsibilities
to the client driver.

Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
---
 drivers/mailbox/mtk-cmdq-mailbox.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index 532929916e99..654a60f63756 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c
@@ -379,20 +379,13 @@ static int cmdq_mbox_send_data(struct mbox_chan *chan, void *data)
 	struct cmdq *cmdq = dev_get_drvdata(chan->mbox->dev);
 	struct cmdq_task *task;
 	unsigned long curr_pa, end_pa;
-	int ret;
 
 	/* Client should not flush new tasks if suspended. */
 	WARN_ON(cmdq->suspended);
 
-	ret = pm_runtime_get_sync(cmdq->mbox.dev);
-	if (ret < 0)
-		return ret;
-
 	task = kzalloc(sizeof(*task), GFP_ATOMIC);
-	if (!task) {
-		pm_runtime_put_autosuspend(cmdq->mbox.dev);
+	if (!task)
 		return -ENOMEM;
-	}
 
 	task->cmdq = cmdq;
 	INIT_LIST_HEAD(&task->list_entry);
@@ -439,9 +432,6 @@ static int cmdq_mbox_send_data(struct mbox_chan *chan, void *data)
 	}
 	list_move_tail(&task->list_entry, &thread->task_busy_list);
 
-	pm_runtime_mark_last_busy(cmdq->mbox.dev);
-	pm_runtime_put_autosuspend(cmdq->mbox.dev);
-
 	return 0;
 }
 
-- 
2.43.0

[PATCH v2 2/3] drm/mediatek: Add pm_runtime support for GCE power control

[Jason-JH Lin]

Call pm_runtime_resume_and_get() before accessing GCE hardware in
mbox_send_message(), and invoke pm_runtime_put_autosuspend() in the
cmdq callback to release the PM reference and start autosuspend for
GCE. This ensures correct power management for the GCE device.

Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_crtc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c
index bc7527542fdc..c4c6d0249df5 100644
--- a/drivers/gpu/drm/mediatek/mtk_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_crtc.c
@@ -283,6 +283,10 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
 	unsigned int i;
 	unsigned long flags;
 
+	/* release GCE HW usage and start autosuspend */
+	pm_runtime_mark_last_busy(cmdq_cl->chan->mbox->dev);
+	pm_runtime_put_autosuspend(cmdq_cl->chan->mbox->dev);
+
 	if (data->sta < 0)
 		return;
 
@@ -618,6 +622,9 @@ static void mtk_crtc_update_config(struct mtk_crtc *mtk_crtc, bool needs_vblank)
 		mtk_crtc->config_updating = false;
 		spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
 
+		if (pm_runtime_resume_and_get(mtk_crtc->cmdq_client.chan->mbox->dev) < 0)
+			goto update_config_out;
+
 		mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
 		mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
 		goto update_config_out;
-- 
2.43.0

[PATCH v2 3/3] media: platform: mtk-mdp3: Add pm_runtime support for GCE power control

[Jason-JH Lin]

Call pm_runtime_resume_and_get() before accessing GCE hardware in
mbox_send_message(), and invoke pm_runtime_put_autosuspend() in the
cmdq callback to release the PM reference and start autosuspend for
GCE. This ensures correct power management for the GCE device.

Fixes: 8afe816b0c99 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH Lin <jason-jh.lin@mediatek.com>
---
 drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
index e5ccf673e152..bb7a895318af 100644
--- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
+++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
@@ -6,6 +6,7 @@
 
 #include <linux/mailbox_controller.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include "mtk-mdp3-cfg.h"
 #include "mtk-mdp3-cmdq.h"
 #include "mtk-mdp3-comp.h"
@@ -521,6 +522,9 @@ static void mdp_handle_cmdq_callback(struct mbox_client *cl, void *mssg)
 	mdp = cmd->mdp;
 	dev = &mdp->pdev->dev;
 
+	pm_runtime_mark_last_busy(mdp->cmdq_clt[cmd->pp_idx]->chan->mbox->dev);
+	pm_runtime_put_autosuspend(mdp->cmdq_clt[cmd->pp_idx]->chan->mbox->dev);
+
 	INIT_WORK(&cmd->auto_release_work, mdp_auto_release_work);
 	if (!queue_work(mdp->clock_wq, &cmd->auto_release_work)) {
 		struct mtk_mutex *mutex;
@@ -702,6 +706,13 @@ int mdp_cmdq_send(struct mdp_dev *mdp, struct mdp_cmdq_param *param)
 					   cmd[i]->pkt.pa_base, cmd[i]->pkt.cmd_buf_size,
 					   DMA_TO_DEVICE);
 
+		ret = pm_runtime_resume_and_get(mdp->cmdq_clt[i]->chan->mbox->dev);
+		if (ret < 0) {
+			dev_err(dev, "pm_runtime_resume_and_get fail: %d!\n", ret);
+			i = pp_used;
+			goto err_clock_off;
+		}
+
 		ret = mbox_send_message(mdp->cmdq_clt[i]->chan, &cmd[i]->pkt);
 		if (ret < 0) {
 			dev_err(dev, "mbox send message fail %d!\n", ret);
-- 
2.43.0