drm/msm/dpu: allow just single IRQ callback

DPU interrupts code allows multiple callbacks per interrut. In reality
none of the interrupts is shared between blocks (and will probably never
be). Drop support for registering multiple callbacks per interrupt to
simplify interrupt handling code.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/474701/
Link: https://lore.kernel.org/r/20220217043148.480898-4-dmitry.baryshkov@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_core_irq.h

@@ -44,10 +44,8 @@ u32 dpu_core_irq_read(
  *                             interrupt
  * @dpu_kms:		DPU handle
  * @irq_idx:		irq index
- * @irq_cb:		IRQ callback structure, containing callback function
- *			and argument. Passing NULL for irq_cb will unregister
- *			the callback for the given irq_idx
- *			This must exist until un-registration.
+ * @irq_cb:		IRQ callback funcion.
+ * @irq_arg:		IRQ callback argument.
  * @return:		0 for success registering callback, otherwise failure
  *
  * This function supports registration of multiple callbacks for each interrupt.
@@ -55,25 +53,21 @@ u32 dpu_core_irq_read(
 int dpu_core_irq_register_callback(
 		struct dpu_kms *dpu_kms,
 		int irq_idx,
-		struct dpu_irq_callback *irq_cb);
+		void (*irq_cb)(void *arg, int irq_idx),
+		void *irq_arg);
 
 /**
  * dpu_core_irq_unregister_callback - For unregistering callback function on IRQ
  *                             interrupt
  * @dpu_kms:		DPU handle
  * @irq_idx:		irq index
- * @irq_cb:		IRQ callback structure, containing callback function
- *			and argument. Passing NULL for irq_cb will unregister
- *			the callback for the given irq_idx
- *			This must match with registration.
  * @return:		0 for success registering callback, otherwise failure
  *
  * This function supports registration of multiple callbacks for each interrupt.
  */
 int dpu_core_irq_unregister_callback(
 		struct dpu_kms *dpu_kms,
-		int irq_idx,
-		struct dpu_irq_callback *irq_cb);
+		int irq_idx);
 
 /**
  * dpu_debugfs_core_irq_init - register core irq debugfs

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -328,7 +328,7 @@ int dpu_encoder_helper_wait_for_irq(struct dpu_encoder_phys *phys_enc,
 				      phys_enc->hw_pp->idx - PINGPONG_0,
 				      atomic_read(wait_info->atomic_cnt));
 			local_irq_save(flags);
-			irq->cb.func(phys_enc, irq->irq_idx);
+			irq->func(phys_enc, irq->irq_idx);
 			local_irq_restore(flags);
 			ret = 0;
 		} else {
@@ -369,7 +369,7 @@ int dpu_encoder_helper_register_irq(struct dpu_encoder_phys *phys_enc,
 	}
 
 	ret = dpu_core_irq_register_callback(phys_enc->dpu_kms, irq->irq_idx,
-			&irq->cb);
+			irq->func, phys_enc);
 	if (ret) {
 		DPU_ERROR_PHYS(phys_enc,
 			"failed to register IRQ callback for %s\n",
@@ -400,8 +400,7 @@ int dpu_encoder_helper_unregister_irq(struct dpu_encoder_phys *phys_enc,
 		return 0;
 	}
 
-	ret = dpu_core_irq_unregister_callback(phys_enc->dpu_kms, irq->irq_idx,
-			&irq->cb);
+	ret = dpu_core_irq_unregister_callback(phys_enc->dpu_kms, irq->irq_idx);
 	if (ret) {
 		DRM_ERROR("unreg cb fail id=%u, intr=%d, irq=%d ret=%d",
 			  DRMID(phys_enc->parent), intr_idx,

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h

@@ -165,7 +165,7 @@ struct dpu_encoder_irq {
 	const char *name;
 	enum dpu_intr_idx intr_idx;
 	int irq_idx;
-	struct dpu_irq_callback cb;
+	void (*func)(void *arg, int irq_idx);
 };
 
 /**

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c

@@ -757,30 +757,28 @@ struct dpu_encoder_phys *dpu_encoder_phys_cmd_init(
 	phys_enc->enable_state = DPU_ENC_DISABLED;
 	for (i = 0; i < INTR_IDX_MAX; i++) {
 		irq = &phys_enc->irq[i];
-		INIT_LIST_HEAD(&irq->cb.list);
 		irq->irq_idx = -EINVAL;
-		irq->cb.arg = phys_enc;
 	}
 
 	irq = &phys_enc->irq[INTR_IDX_CTL_START];
 	irq->name = "ctl_start";
 	irq->intr_idx = INTR_IDX_CTL_START;
-	irq->cb.func = dpu_encoder_phys_cmd_ctl_start_irq;
+	irq->func = dpu_encoder_phys_cmd_ctl_start_irq;
 
 	irq = &phys_enc->irq[INTR_IDX_PINGPONG];
 	irq->name = "pp_done";
 	irq->intr_idx = INTR_IDX_PINGPONG;
-	irq->cb.func = dpu_encoder_phys_cmd_pp_tx_done_irq;
+	irq->func = dpu_encoder_phys_cmd_pp_tx_done_irq;
 
 	irq = &phys_enc->irq[INTR_IDX_RDPTR];
 	irq->name = "pp_rd_ptr";
 	irq->intr_idx = INTR_IDX_RDPTR;
-	irq->cb.func = dpu_encoder_phys_cmd_pp_rd_ptr_irq;
+	irq->func = dpu_encoder_phys_cmd_pp_rd_ptr_irq;
 
 	irq = &phys_enc->irq[INTR_IDX_UNDERRUN];
 	irq->name = "underrun";
 	irq->intr_idx = INTR_IDX_UNDERRUN;
-	irq->cb.func = dpu_encoder_phys_cmd_underrun_irq;
+	irq->func = dpu_encoder_phys_cmd_underrun_irq;
 
 	atomic_set(&phys_enc->vblank_refcount, 0);
 	atomic_set(&phys_enc->pending_kickoff_cnt, 0);

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c

@@ -711,20 +711,18 @@ struct dpu_encoder_phys *dpu_encoder_phys_vid_init(
 	phys_enc->enc_spinlock = p->enc_spinlock;
 	for (i = 0; i < INTR_IDX_MAX; i++) {
 		irq = &phys_enc->irq[i];
-		INIT_LIST_HEAD(&irq->cb.list);
 		irq->irq_idx = -EINVAL;
-		irq->cb.arg = phys_enc;
 	}
 
 	irq = &phys_enc->irq[INTR_IDX_VSYNC];
 	irq->name = "vsync_irq";
 	irq->intr_idx = INTR_IDX_VSYNC;
-	irq->cb.func = dpu_encoder_phys_vid_vblank_irq;
+	irq->func = dpu_encoder_phys_vid_vblank_irq;
 
 	irq = &phys_enc->irq[INTR_IDX_UNDERRUN];
 	irq->name = "underrun";
 	irq->intr_idx = INTR_IDX_UNDERRUN;
-	irq->cb.func = dpu_encoder_phys_vid_underrun_irq;
+	irq->func = dpu_encoder_phys_vid_underrun_irq;
 
 	atomic_set(&phys_enc->vblank_refcount, 0);
 	atomic_set(&phys_enc->pending_kickoff_cnt, 0);

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c

@@ -151,21 +151,17 @@ static const struct dpu_intr_reg dpu_intr_set[] = {
  */
 static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, int irq_idx)
 {
-	struct dpu_irq_callback *cb;
-
 	VERB("irq_idx=%d\n", irq_idx);
 
-	if (list_empty(&dpu_kms->hw_intr->irq_cb_tbl[irq_idx]))
+	if (!dpu_kms->hw_intr->irq_tbl[irq_idx].cb)
 		DRM_ERROR("no registered cb, idx:%d\n", irq_idx);
 
-	atomic_inc(&dpu_kms->hw_intr->irq_counts[irq_idx]);
+	atomic_inc(&dpu_kms->hw_intr->irq_tbl[irq_idx].count);
 
 	/*
 	 * Perform registered function callback
 	 */
-	list_for_each_entry(cb, &dpu_kms->hw_intr->irq_cb_tbl[irq_idx], list)
-		if (cb->func)
-			cb->func(cb->arg, irq_idx);
+	dpu_kms->hw_intr->irq_tbl[irq_idx].cb(dpu_kms->hw_intr->irq_tbl[irq_idx].arg, irq_idx);
 }
 
 irqreturn_t dpu_core_irq(struct msm_kms *kms)
@@ -414,24 +410,18 @@ struct dpu_hw_intr *dpu_hw_intr_init(void __iomem *addr,
 		struct dpu_mdss_cfg *m)
 {
 	struct dpu_hw_intr *intr;
+	int nirq = MDP_INTR_MAX * 32;
 
 	if (!addr || !m)
 		return ERR_PTR(-EINVAL);
 
-	intr = kzalloc(sizeof(*intr), GFP_KERNEL);
+	intr = kzalloc(struct_size(intr, irq_tbl, nirq), GFP_KERNEL);
 	if (!intr)
 		return ERR_PTR(-ENOMEM);
 
 	__intr_offset(m, addr, &intr->hw);
 
-	intr->total_irqs = ARRAY_SIZE(dpu_intr_set) * 32;
-
-	intr->cache_irq_mask = kcalloc(ARRAY_SIZE(dpu_intr_set), sizeof(u32),
-			GFP_KERNEL);
-	if (intr->cache_irq_mask == NULL) {
-		kfree(intr);
-		return ERR_PTR(-ENOMEM);
-	}
+	intr->total_irqs = nirq;
 
 	intr->irq_mask = m->mdss_irqs;
 
@@ -442,31 +432,19 @@ struct dpu_hw_intr *dpu_hw_intr_init(void __iomem *addr,
 
 void dpu_hw_intr_destroy(struct dpu_hw_intr *intr)
 {
-	if (intr) {
-		kfree(intr->cache_irq_mask);
-
-		kfree(intr->irq_cb_tbl);
-		kfree(intr->irq_counts);
-
+	if (intr)
 		kfree(intr);
-	}
 }
 
 int dpu_core_irq_register_callback(struct dpu_kms *dpu_kms, int irq_idx,
-		struct dpu_irq_callback *register_irq_cb)
+		void (*irq_cb)(void *arg, int irq_idx),
+		void *irq_arg)
 {
 	unsigned long irq_flags;
+	int ret;
 
-	if (!dpu_kms->hw_intr->irq_cb_tbl) {
-		DPU_ERROR("invalid params\n");
-		return -EINVAL;
-	}
-
-	if (!register_irq_cb || !register_irq_cb->func) {
-		DPU_ERROR("invalid irq_cb:%d func:%d\n",
-				register_irq_cb != NULL,
-				register_irq_cb ?
-					register_irq_cb->func != NULL : -1);
+	if (!irq_cb) {
+		DPU_ERROR("invalid ird_idx:%d irq_cb:%ps\n", irq_idx, irq_cb);
 		return -EINVAL;
 	}
 
@@ -478,41 +456,32 @@ int dpu_core_irq_register_callback(struct dpu_kms *dpu_kms, int irq_idx,
 	VERB("[%pS] irq_idx=%d\n", __builtin_return_address(0), irq_idx);
 
 	spin_lock_irqsave(&dpu_kms->hw_intr->irq_lock, irq_flags);
-	trace_dpu_core_irq_register_callback(irq_idx, register_irq_cb);
-	list_del_init(&register_irq_cb->list);
-	list_add_tail(&register_irq_cb->list,
-			&dpu_kms->hw_intr->irq_cb_tbl[irq_idx]);
-	if (list_is_first(&register_irq_cb->list,
-			&dpu_kms->hw_intr->irq_cb_tbl[irq_idx])) {
-		int ret = dpu_hw_intr_enable_irq_locked(
+
+	if (unlikely(WARN_ON(dpu_kms->hw_intr->irq_tbl[irq_idx].cb))) {
+		spin_unlock_irqrestore(&dpu_kms->hw_intr->irq_lock, irq_flags);
+
+		return -EBUSY;
+	}
+
+	trace_dpu_core_irq_register_callback(irq_idx, irq_cb);
+	dpu_kms->hw_intr->irq_tbl[irq_idx].arg = irq_arg;
+	dpu_kms->hw_intr->irq_tbl[irq_idx].cb = irq_cb;
+
+	ret = dpu_hw_intr_enable_irq_locked(
 				dpu_kms->hw_intr,
 				irq_idx);
 	if (ret)
 		DPU_ERROR("Fail to enable IRQ for irq_idx:%d\n",
 					irq_idx);
-	}
 	spin_unlock_irqrestore(&dpu_kms->hw_intr->irq_lock, irq_flags);
 
 	return 0;
 }
 
-int dpu_core_irq_unregister_callback(struct dpu_kms *dpu_kms, int irq_idx,
-		struct dpu_irq_callback *register_irq_cb)
+int dpu_core_irq_unregister_callback(struct dpu_kms *dpu_kms, int irq_idx)
 {
 	unsigned long irq_flags;
-
-	if (!dpu_kms->hw_intr->irq_cb_tbl) {
-		DPU_ERROR("invalid params\n");
-		return -EINVAL;
-	}
-
-	if (!register_irq_cb || !register_irq_cb->func) {
-		DPU_ERROR("invalid irq_cb:%d func:%d\n",
-				register_irq_cb != NULL,
-				register_irq_cb ?
-					register_irq_cb->func != NULL : -1);
-		return -EINVAL;
-	}
+	int ret;
 
 	if (irq_idx < 0 || irq_idx >= dpu_kms->hw_intr->total_irqs) {
 		DPU_ERROR("invalid IRQ index: [%d]\n", irq_idx);
@@ -522,18 +491,16 @@ int dpu_core_irq_unregister_callback(struct dpu_kms *dpu_kms, int irq_idx,
 	VERB("[%pS] irq_idx=%d\n", __builtin_return_address(0), irq_idx);
 
 	spin_lock_irqsave(&dpu_kms->hw_intr->irq_lock, irq_flags);
-	trace_dpu_core_irq_unregister_callback(irq_idx, register_irq_cb);
-	list_del_init(&register_irq_cb->list);
-	/* empty callback list but interrupt is still enabled */
-	if (list_empty(&dpu_kms->hw_intr->irq_cb_tbl[irq_idx])) {
-		int ret = dpu_hw_intr_disable_irq_locked(
-				dpu_kms->hw_intr,
-				irq_idx);
+	trace_dpu_core_irq_unregister_callback(irq_idx);
+
+	ret = dpu_hw_intr_disable_irq_locked(dpu_kms->hw_intr, irq_idx);
 	if (ret)
-			DPU_ERROR("Fail to disable IRQ for irq_idx:%d\n",
-					irq_idx);
-		VERB("irq_idx=%d ret=%d\n", irq_idx, ret);
-	}
+		DPU_ERROR("Fail to disable IRQ for irq_idx:%d: %d\n",
+					irq_idx, ret);
+
+	dpu_kms->hw_intr->irq_tbl[irq_idx].cb = NULL;
+	dpu_kms->hw_intr->irq_tbl[irq_idx].arg = NULL;
+
 	spin_unlock_irqrestore(&dpu_kms->hw_intr->irq_lock, irq_flags);
 
 	return 0;
@@ -543,24 +510,18 @@ int dpu_core_irq_unregister_callback(struct dpu_kms *dpu_kms, int irq_idx,
 static int dpu_debugfs_core_irq_show(struct seq_file *s, void *v)
 {
 	struct dpu_kms *dpu_kms = s->private;
-	struct dpu_irq_callback *cb;
 	unsigned long irq_flags;
-	int i, irq_count, cb_count;
-
-	if (WARN_ON(!dpu_kms->hw_intr->irq_cb_tbl))
-		return 0;
+	int i, irq_count;
+	void *cb;
 
 	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++) {
 		spin_lock_irqsave(&dpu_kms->hw_intr->irq_lock, irq_flags);
-		cb_count = 0;
-		irq_count = atomic_read(&dpu_kms->hw_intr->irq_counts[i]);
-		list_for_each_entry(cb, &dpu_kms->hw_intr->irq_cb_tbl[i], list)
-			cb_count++;
+		irq_count = atomic_read(&dpu_kms->hw_intr->irq_tbl[i].count);
+		cb = dpu_kms->hw_intr->irq_tbl[i].cb;
 		spin_unlock_irqrestore(&dpu_kms->hw_intr->irq_lock, irq_flags);
 
-		if (irq_count || cb_count)
-			seq_printf(s, "idx:%d irq:%d cb:%d\n",
-					i, irq_count, cb_count);
+		if (irq_count || cb)
+			seq_printf(s, "idx:%d irq:%d cb:%ps\n", i, irq_count, cb);
 	}
 
 	return 0;
@@ -586,15 +547,8 @@ void dpu_core_irq_preinstall(struct msm_kms *kms)
 	dpu_disable_all_irqs(dpu_kms);
 	pm_runtime_put_sync(&dpu_kms->pdev->dev);
 
-	/* Create irq callbacks for all possible irq_idx */
-	dpu_kms->hw_intr->irq_cb_tbl = kcalloc(dpu_kms->hw_intr->total_irqs,
-			sizeof(struct list_head), GFP_KERNEL);
-	dpu_kms->hw_intr->irq_counts = kcalloc(dpu_kms->hw_intr->total_irqs,
-			sizeof(atomic_t), GFP_KERNEL);
-	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++) {
-		INIT_LIST_HEAD(&dpu_kms->hw_intr->irq_cb_tbl[i]);
-		atomic_set(&dpu_kms->hw_intr->irq_counts[i], 0);
-	}
+	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++)
+		atomic_set(&dpu_kms->hw_intr->irq_tbl[i].count, 0);
 }
 
 void dpu_core_irq_uninstall(struct msm_kms *kms)
@@ -604,7 +558,7 @@ void dpu_core_irq_uninstall(struct msm_kms *kms)
 
 	pm_runtime_get_sync(&dpu_kms->pdev->dev);
 	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++)
-		if (!list_empty(&dpu_kms->hw_intr->irq_cb_tbl[i]))
+		if (dpu_kms->hw_intr->irq_tbl[i].cb)
 			DPU_ERROR("irq_idx=%d still enabled/registered\n", i);
 
 	dpu_clear_irqs(dpu_kms);

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.h

@@ -44,19 +44,21 @@ enum dpu_hw_intr_reg {
  * @save_irq_status:  array of IRQ status reg storage created during init
  * @total_irqs: total number of irq_idx mapped in the hw_interrupts
  * @irq_lock:         spinlock for accessing IRQ resources
- * @irq_cb_tbl:       array of IRQ callbacks lists
- * @irq_counts:       array of IRQ counts
+ * @irq_cb_tbl:       array of IRQ callbacks
  */
 struct dpu_hw_intr {
 	struct dpu_hw_blk_reg_map hw;
-	u32 *cache_irq_mask;
+	u32 cache_irq_mask[MDP_INTR_MAX];
 	u32 *save_irq_status;
 	u32 total_irqs;
 	spinlock_t irq_lock;
 	unsigned long irq_mask;
 
-	struct list_head *irq_cb_tbl;
-	atomic_t *irq_counts;
+	struct {
+		void (*cb)(void *arg, int irq_idx);
+		void *arg;
+		atomic_t count;
+	} irq_tbl[];
 };
 
 /**

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h

@@ -65,18 +65,6 @@
 
 #define DPU_NAME_SIZE  12
 
-/*
- * struct dpu_irq_callback - IRQ callback handlers
- * @list: list to callback
- * @func: intr handler
- * @arg: argument for the handler
- */
-struct dpu_irq_callback {
-	struct list_head list;
-	void (*func)(void *arg, int irq_idx);
-	void *arg;
-};
-
 struct dpu_kms {
 	struct msm_kms base;
 	struct drm_device *dev;

drivers/gpu/drm/msm/disp/dpu1/dpu_trace.h

@@ -871,27 +871,31 @@ TRACE_EVENT(dpu_pp_connect_ext_te,
 	TP_printk("pp:%d cfg:%u", __entry->pp, __entry->cfg)
 );
 
-DECLARE_EVENT_CLASS(dpu_core_irq_callback_template,
-	TP_PROTO(int irq_idx, struct dpu_irq_callback *callback),
+TRACE_EVENT(dpu_core_irq_register_callback,
+	TP_PROTO(int irq_idx, void *callback),
 	TP_ARGS(irq_idx, callback),
 	TP_STRUCT__entry(
 		__field(	int,				irq_idx	)
-		__field(	struct dpu_irq_callback *,	callback)
+		__field(	void *,				callback)
 	),
 	TP_fast_assign(
 		__entry->irq_idx = irq_idx;
 		__entry->callback = callback;
 	),
-	TP_printk("irq_idx:%d callback:%pK", __entry->irq_idx,
+	TP_printk("irq_idx:%d callback:%ps", __entry->irq_idx,
 		  __entry->callback)
 );
-DEFINE_EVENT(dpu_core_irq_callback_template, dpu_core_irq_register_callback,
-	TP_PROTO(int irq_idx, struct dpu_irq_callback *callback),
-	TP_ARGS(irq_idx, callback)
-);
-DEFINE_EVENT(dpu_core_irq_callback_template, dpu_core_irq_unregister_callback,
-	TP_PROTO(int irq_idx, struct dpu_irq_callback *callback),
-	TP_ARGS(irq_idx, callback)
+
+TRACE_EVENT(dpu_core_irq_unregister_callback,
+	TP_PROTO(int irq_idx),
+	TP_ARGS(irq_idx),
+	TP_STRUCT__entry(
+		__field(	int,				irq_idx	)
+	),
+	TP_fast_assign(
+		__entry->irq_idx = irq_idx;
+	),
+	TP_printk("irq_idx:%d", __entry->irq_idx)
 );
 
 TRACE_EVENT(dpu_core_perf_update_clk,