Revert "soc: qcom: smp2p: Prevent suspend for threaded irq"

This reverts commit 9dcdb6f.

The IRQ subsystem already blocks suspend on waiting for IRQ threads to
finish running (in dpm_noirq_begin()). This PM wakeup does nothing but add
latency to the IRQ handler for non-RT kernels, and it isn't RT-friendly
either:
[   42.466403] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:974
[   42.466407] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/3
[   42.466408] Preemption disabled at:
[   42.466421] [<00000000100c9f7d>] secondary_start_kernel+0xa8/0x130
[   42.466427] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G S      W       4.14.212-rt102-Sultan #1
[   42.466429] Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Coral (DT)
[   42.466432] Call trace:
[   42.466436]  dump_backtrace+0x0/0x1ac
[   42.466439]  show_stack+0x14/0x1c
[   42.466444]  dump_stack+0x84/0xac
[   42.466448]  ___might_sleep+0x140/0x150
[   42.466452]  rt_spin_lock+0x3c/0x50
[   42.466458]  __pm_stay_awake+0x20/0x50
[   42.466462]  qcom_smp2p_isr+0x10/0x1c
[   42.466467]  __handle_irq_event_percpu+0x60/0xd4
[   42.466469]  handle_irq_event_percpu+0x58/0xb0
[   42.466471]  handle_irq_event+0x68/0xe0
[   42.466474]  handle_fasteoi_irq+0x140/0x1fc
[   42.466476]  generic_handle_irq+0x18/0x2c
[   42.466478]  __handle_domain_irq+0xf8/0xfc
[   42.466481]  gic_handle_irq+0xc8/0x164
[   42.466483]  el1_irq+0xb0/0x130
[   42.466487]  finish_task_switch+0xcc/0x1e4
[   42.466491]  __schedule+0x3f0/0x4e0
[   42.466493]  schedule_idle+0x28/0x44
[   42.466497]  do_idle+0x78/0x230
[   42.466500]  cpu_startup_entry+0x20/0x28
[   42.466502]  secondary_start_kernel+0x124/0x130

Remove it since it's useless.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Zlatan Radovanovic <zlatan.radovanovic@fet.ba>

drivers/soc/qcom/smp2p.c

@@ -18,7 +18,6 @@
 #include <linux/soc/qcom/smem.h>
 #include <linux/soc/qcom/smem_state.h>
 #include <linux/spinlock.h>
-#include <linux/pm_wakeup.h>
 
 #include <linux/ipc_logging.h>
 
@@ -153,7 +152,6 @@ struct qcom_smp2p {
 	struct regmap *ipc_regmap;
 	int ipc_offset;
 	int ipc_bit;
-	struct wakeup_source *ws;
 
 	struct mbox_client mbox_client;
 	struct mbox_chan *mbox_chan;
@@ -297,14 +295,6 @@ static void qcom_smp2p_notify_in(struct qcom_smp2p *smp2p)
 	}
 }
 
-static irqreturn_t qcom_smp2p_isr(int irq, void *data)
-{
-	struct qcom_smp2p *smp2p = data;
-
-	__pm_stay_awake(smp2p->ws);
-	return IRQ_WAKE_THREAD;
-}
-
 /**
  * qcom_smp2p_intr() - interrupt handler for incoming notifications
  * @irq:	unused
@@ -329,7 +319,7 @@ static irqreturn_t qcom_smp2p_intr(int irq, void *data)
 		if (IS_ERR(in)) {
 			dev_err(smp2p->dev,
 				"Unable to acquire remote smp2p item\n");
-			goto out;
+			return IRQ_HANDLED;
 		}
 
 		smp2p->in = in;
@@ -348,8 +338,6 @@ static irqreturn_t qcom_smp2p_intr(int irq, void *data)
 			qcom_smp2p_do_ssr_ack(smp2p);
 	}
 
-out:
-	__pm_relax(smp2p->ws);
 	return IRQ_HANDLED;
 }
 
@@ -676,7 +664,7 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
 	qcom_smp2p_kick(smp2p);
 
 	ret = devm_request_threaded_irq(&pdev->dev, smp2p->irq,
-					qcom_smp2p_isr, qcom_smp2p_intr,
+					NULL, qcom_smp2p_intr,
 					IRQF_ONESHOT,
 					"smp2p", (void *)smp2p);
 	if (ret) {
@@ -814,8 +802,6 @@ static int qcom_smp2p_freeze(struct device *dev)
 	/* make null to point it to valid smem item during first interrupt */
 	smp2p->in = NULL;
 	smp2p->valid_entries = 0;
-	/* remove wakeup source */
-	wakeup_source_unregister(smp2p->ws);
 	return 0;
 }