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From 8b6aa431b277cc3c49c0c8be2b49b395d29325cf Mon Sep 17 00:00:00 2001
From: John Cox <jc@kynesim.co.uk>
Date: Thu, 11 Mar 2021 18:43:15 +0000
Subject: [PATCH] media: rpivid: Add an enable count to irq claim Qs
Add an enable count to the irq Q structures to allow the irq logic to
block further callbacks if resources associated with the irq are not
yet available.
Signed-off-by: John Cox <jc@kynesim.co.uk>
---
drivers/staging/media/rpivid/rpivid.h | 2 +
drivers/staging/media/rpivid/rpivid_hw.c | 118 +++++++++++++++--------
drivers/staging/media/rpivid/rpivid_hw.h | 3 +
3 files changed, 85 insertions(+), 38 deletions(-)
--- a/drivers/staging/media/rpivid/rpivid.h
+++ b/drivers/staging/media/rpivid/rpivid.h
@@ -151,6 +151,8 @@ struct rpivid_hw_irq_ctrl {
struct rpivid_hw_irq_ent *irq;
/* Non-zero => do not start a new job - outer layer sched pending */
int no_sched;
+ /* Enable count. -1 always OK, 0 do not sched, +ve shed & count down */
+ int enable;
/* Thread CB requested */
bool thread_reqed;
};
--- a/drivers/staging/media/rpivid/rpivid_hw.c
+++ b/drivers/staging/media/rpivid/rpivid_hw.c
@@ -42,35 +42,62 @@ static void pre_irq(struct rpivid_dev *d
ient->cb = cb;
ient->v = v;
- // Not sure this lock is actually required
spin_lock_irqsave(&ictl->lock, flags);
ictl->irq = ient;
+ ictl->no_sched++;
spin_unlock_irqrestore(&ictl->lock, flags);
}
-static void sched_claim(struct rpivid_dev * const dev,
- struct rpivid_hw_irq_ctrl * const ictl)
+/* Should be called from inside ictl->lock */
+static inline bool sched_enabled(const struct rpivid_hw_irq_ctrl * const ictl)
{
- for (;;) {
- struct rpivid_hw_irq_ent *ient = NULL;
- unsigned long flags;
+ return ictl->no_sched <= 0 && ictl->enable;
+}
- spin_lock_irqsave(&ictl->lock, flags);
+/* Should be called from inside ictl->lock & after checking sched_enabled() */
+static inline void set_claimed(struct rpivid_hw_irq_ctrl * const ictl)
+{
+ if (ictl->enable > 0)
+ --ictl->enable;
+ ictl->no_sched = 1;
+}
- if (--ictl->no_sched <= 0) {
- ient = ictl->claim;
- if (!ictl->irq && ient) {
- ictl->claim = ient->next;
- ictl->no_sched = 1;
- }
- }
+/* Should be called from inside ictl->lock */
+static struct rpivid_hw_irq_ent *get_sched(struct rpivid_hw_irq_ctrl * const ictl)
+{
+ struct rpivid_hw_irq_ent *ient;
- spin_unlock_irqrestore(&ictl->lock, flags);
+ if (!sched_enabled(ictl))
+ return NULL;
+
+ ient = ictl->claim;
+ if (!ient)
+ return NULL;
+ ictl->claim = ient->next;
+
+ set_claimed(ictl);
+ return ient;
+}
- if (!ient)
- break;
+/* Run a callback & check to see if there is anything else to run */
+static void sched_cb(struct rpivid_dev * const dev,
+ struct rpivid_hw_irq_ctrl * const ictl,
+ struct rpivid_hw_irq_ent *ient)
+{
+ while (ient) {
+ unsigned long flags;
ient->cb(dev, ient->v);
+
+ spin_lock_irqsave(&ictl->lock, flags);
+
+ /* Always dec no_sched after cb exec - must have been set
+ * on entry to cb
+ */
+ --ictl->no_sched;
+ ient = get_sched(ictl);
+
+ spin_unlock_irqrestore(&ictl->lock, flags);
}
}
@@ -84,7 +111,7 @@ static void pre_thread(struct rpivid_dev
ient->v = v;
ictl->irq = ient;
ictl->thread_reqed = true;
- ictl->no_sched++;
+ ictl->no_sched++; /* This is unwound in do_thread */
}
// Called in irq context
@@ -96,17 +123,10 @@ static void do_irq(struct rpivid_dev * c
spin_lock_irqsave(&ictl->lock, flags);
ient = ictl->irq;
- if (ient) {
- ictl->no_sched++;
- ictl->irq = NULL;
- }
+ ictl->irq = NULL;
spin_unlock_irqrestore(&ictl->lock, flags);
- if (ient) {
- ient->cb(dev, ient->v);
-
- sched_claim(dev, ictl);
- }
+ sched_cb(dev, ictl, ient);
}
static void do_claim(struct rpivid_dev * const dev,
@@ -127,7 +147,7 @@ static void do_claim(struct rpivid_dev *
ictl->tail->next = ient;
ictl->tail = ient;
ient = NULL;
- } else if (ictl->no_sched || ictl->irq) {
+ } else if (!sched_enabled(ictl)) {
// Empty Q but other activity in progress so Q
ictl->claim = ient;
ictl->tail = ient;
@@ -135,16 +155,34 @@ static void do_claim(struct rpivid_dev *
} else {
// Nothing else going on - schedule immediately and
// prevent anything else scheduling claims
- ictl->no_sched = 1;
+ set_claimed(ictl);
}
spin_unlock_irqrestore(&ictl->lock, flags);
- if (ient) {
- ient->cb(dev, ient->v);
+ sched_cb(dev, ictl, ient);
+}
- sched_claim(dev, ictl);
- }
+/* Enable n claims.
+ * n < 0 set to unlimited (default on init)
+ * n = 0 if previously unlimited then disable otherwise nop
+ * n > 0 if previously unlimited then set to n enables
+ * otherwise add n enables
+ * The enable count is automatically decremented every time a claim is run
+ */
+static void do_enable_claim(struct rpivid_dev * const dev,
+ int n,
+ struct rpivid_hw_irq_ctrl * const ictl)
+{
+ unsigned long flags;
+ struct rpivid_hw_irq_ent *ient;
+
+ spin_lock_irqsave(&ictl->lock, flags);
+ ictl->enable = n < 0 ? -1 : ictl->enable <= 0 ? n : ictl->enable + n;
+ ient = get_sched(ictl);
+ spin_unlock_irqrestore(&ictl->lock, flags);
+
+ sched_cb(dev, ictl, ient);
}
static void ictl_init(struct rpivid_hw_irq_ctrl * const ictl)
@@ -154,6 +192,8 @@ static void ictl_init(struct rpivid_hw_i
ictl->tail = NULL;
ictl->irq = NULL;
ictl->no_sched = 0;
+ ictl->enable = -1;
+ ictl->thread_reqed = false;
}
static void ictl_uninit(struct rpivid_hw_irq_ctrl * const ictl)
@@ -203,11 +243,7 @@ static void do_thread(struct rpivid_dev
spin_unlock_irqrestore(&ictl->lock, flags);
- if (ient) {
- ient->cb(dev, ient->v);
-
- sched_claim(dev, ictl);
- }
+ sched_cb(dev, ictl, ient);
}
static irqreturn_t rpivid_irq_thread(int irq, void *data)
@@ -231,6 +267,12 @@ void rpivid_hw_irq_active1_thread(struct
pre_thread(dev, ient, thread_cb, ctx, &dev->ic_active1);
}
+void rpivid_hw_irq_active1_enable_claim(struct rpivid_dev *dev,
+ int n)
+{
+ do_enable_claim(dev, n, &dev->ic_active1);
+}
+
void rpivid_hw_irq_active1_claim(struct rpivid_dev *dev,
struct rpivid_hw_irq_ent *ient,
rpivid_irq_callback ready_cb, void *ctx)
--- a/drivers/staging/media/rpivid/rpivid_hw.h
+++ b/drivers/staging/media/rpivid/rpivid_hw.h
@@ -272,6 +272,9 @@ static inline void apb_write_vc_len(cons
ARG_IC_ICTRL_ACTIVE1_INT_SET |\
ARG_IC_ICTRL_ACTIVE2_INT_SET)
+/* Regulate claim Q */
+void rpivid_hw_irq_active1_enable_claim(struct rpivid_dev *dev,
+ int n);
/* Auto release once all CBs called */
void rpivid_hw_irq_active1_claim(struct rpivid_dev *dev,
struct rpivid_hw_irq_ent *ient,
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