usb: dwc3: remove num_event_buffers

We never, ever route any of the other event buffers
so we might as well drop support for them.

Until someone has a real, proper benefit for
multiple event buffers, we will rely on a single
one. This also helps reduce memory footprint of
dwc3.ko which won't allocate memory for the extra
event buffers.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/core.c

@@ -203,13 +203,10 @@ static struct dwc3_event_buffer *dwc3_alloc_one_event_buffer(struct dwc3 *dwc,
 static void dwc3_free_event_buffers(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
-	int i;
 
-	for (i = 0; i < dwc->num_event_buffers; i++) {
-		evt = dwc->ev_buffs[i];
-		if (evt)
-			dwc3_free_one_event_buffer(dwc, evt);
-	}
+	evt = dwc->ev_buffs[0];
+	if (evt)
+		dwc3_free_one_event_buffer(dwc, evt);
 }
 
 /**
@@ -222,27 +219,19 @@ static void dwc3_free_event_buffers(struct dwc3 *dwc)
  */
 static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length)
 {
-	int			num;
-	int			i;
-
-	num = DWC3_NUM_INT(dwc->hwparams.hwparams1);
-	dwc->num_event_buffers = num;
+	struct dwc3_event_buffer *evt;
 
-	dwc->ev_buffs = devm_kzalloc(dwc->dev, sizeof(*dwc->ev_buffs) * num,
+	dwc->ev_buffs = devm_kzalloc(dwc->dev, sizeof(*dwc->ev_buffs),
 			GFP_KERNEL);
 	if (!dwc->ev_buffs)
 		return -ENOMEM;
 
-	for (i = 0; i < num; i++) {
-		struct dwc3_event_buffer	*evt;
-
-		evt = dwc3_alloc_one_event_buffer(dwc, length);
-		if (IS_ERR(evt)) {
-			dev_err(dwc->dev, "can't allocate event buffer\n");
-			return PTR_ERR(evt);
-		}
-		dwc->ev_buffs[i] = evt;
+	evt = dwc3_alloc_one_event_buffer(dwc, length);
+	if (IS_ERR(evt)) {
+		dev_err(dwc->dev, "can't allocate event buffer\n");
+		return PTR_ERR(evt);
 	}
+	dwc->ev_buffs[0] = evt;
 
 	return 0;
 }
@@ -256,25 +245,22 @@ static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length)
 static int dwc3_event_buffers_setup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
-	int				n;
 
-	for (n = 0; n < dwc->num_event_buffers; n++) {
-		evt = dwc->ev_buffs[n];
-		dwc3_trace(trace_dwc3_core,
-				"Event buf %p dma %08llx length %d\n",
-				evt->buf, (unsigned long long) evt->dma,
-				evt->length);
-
-		evt->lpos = 0;
-
-		dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(n),
-				lower_32_bits(evt->dma));
-		dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(n),
-				upper_32_bits(evt->dma));
-		dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(n),
-				DWC3_GEVNTSIZ_SIZE(evt->length));
-		dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(n), 0);
-	}
+	evt = dwc->ev_buffs[0];
+	dwc3_trace(trace_dwc3_core,
+			"Event buf %p dma %08llx length %d\n",
+			evt->buf, (unsigned long long) evt->dma,
+			evt->length);
+
+	evt->lpos = 0;
+
+	dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(0),
+			lower_32_bits(evt->dma));
+	dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(0),
+			upper_32_bits(evt->dma));
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0),
+			DWC3_GEVNTSIZ_SIZE(evt->length));
+	dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), 0);
 
 	return 0;
 }
@@ -282,19 +268,16 @@ static int dwc3_event_buffers_setup(struct dwc3 *dwc)
 static void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
-	int				n;
 
-	for (n = 0; n < dwc->num_event_buffers; n++) {
-		evt = dwc->ev_buffs[n];
+	evt = dwc->ev_buffs[0];
 
-		evt->lpos = 0;
+	evt->lpos = 0;
 
-		dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(n), 0);
-		dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(n), 0);
-		dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(n), DWC3_GEVNTSIZ_INTMASK
-				| DWC3_GEVNTSIZ_SIZE(0));
-		dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(n), 0);
-	}
+	dwc3_writel(dwc->regs, DWC3_GEVNTADRLO(0), 0);
+	dwc3_writel(dwc->regs, DWC3_GEVNTADRHI(0), 0);
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), DWC3_GEVNTSIZ_INTMASK
+			| DWC3_GEVNTSIZ_SIZE(0));
+	dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), 0);
 }
 
 static int dwc3_alloc_scratch_buffers(struct dwc3 *dwc)

drivers/usb/dwc3/core.h

@@ -667,7 +667,6 @@ struct dwc3_scratchpad_array {
  * @regs: base address for our registers
  * @regs_size: address space size
  * @nr_scratch: number of scratch buffers
- * @num_event_buffers: calculated number of event buffers
  * @u1u2: only used on revisions <1.83a for workaround
  * @maximum_speed: maximum speed requested (mainly for testing purposes)
  * @revision: revision register contents
@@ -778,7 +777,6 @@ struct dwc3 {
 	u32			gctl;
 
 	u32			nr_scratch;
-	u32			num_event_buffers;
 	u32			u1u2;
 	u32			maximum_speed;
 

drivers/usb/dwc3/gadget.c

@@ -2602,14 +2602,14 @@ static void dwc3_process_event_entry(struct dwc3 *dwc,
 	}
 }
 
-static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
+static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer *evt;
 	irqreturn_t ret = IRQ_NONE;
 	int left;
 	u32 reg;
 
-	evt = dwc->ev_buffs[buf];
+	evt = dwc->ev_buffs[0];
 	left = evt->count;
 
 	if (!(evt->flags & DWC3_EVENT_PENDING))
@@ -2634,7 +2634,7 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
 		evt->lpos = (evt->lpos + 4) % DWC3_EVENT_BUFFERS_SIZE;
 		left -= 4;
 
-		dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(buf), 4);
+		dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), 4);
 	}
 
 	evt->count = 0;
@@ -2642,9 +2642,9 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
 	ret = IRQ_HANDLED;
 
 	/* Unmask interrupt */
-	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(buf));
+	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
 	reg &= ~DWC3_GEVNTSIZ_INTMASK;
-	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(buf), reg);
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
 
 	return ret;
 }
@@ -2654,27 +2654,23 @@ static irqreturn_t dwc3_thread_interrupt(int irq, void *_dwc)
 	struct dwc3 *dwc = _dwc;
 	unsigned long flags;
 	irqreturn_t ret = IRQ_NONE;
-	int i;
 
 	spin_lock_irqsave(&dwc->lock, flags);
-
-	for (i = 0; i < dwc->num_event_buffers; i++)
-		ret |= dwc3_process_event_buf(dwc, i);
-
+	ret = dwc3_process_event_buf(dwc);
 	spin_unlock_irqrestore(&dwc->lock, flags);
 
 	return ret;
 }
 
-static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc, u32 buf)
+static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer *evt;
 	u32 count;
 	u32 reg;
 
-	evt = dwc->ev_buffs[buf];
+	evt = dwc->ev_buffs[0];
 
-	count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(buf));
+	count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
 	count &= DWC3_GEVNTCOUNT_MASK;
 	if (!count)
 		return IRQ_NONE;
@@ -2683,9 +2679,9 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc, u32 buf)
 	evt->flags |= DWC3_EVENT_PENDING;
 
 	/* Mask interrupt */
-	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(buf));
+	reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0));
 	reg |= DWC3_GEVNTSIZ_INTMASK;
-	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(buf), reg);
+	dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), reg);
 
 	return IRQ_WAKE_THREAD;
 }
@@ -2693,18 +2689,8 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3 *dwc, u32 buf)
 static irqreturn_t dwc3_interrupt(int irq, void *_dwc)
 {
 	struct dwc3			*dwc = _dwc;
-	int				i;
-	irqreturn_t			ret = IRQ_NONE;
-
-	for (i = 0; i < dwc->num_event_buffers; i++) {
-		irqreturn_t status;
 
-		status = dwc3_check_event_buf(dwc, i);
-		if (status == IRQ_WAKE_THREAD)
-			ret = status;
-	}
-
-	return ret;
+	return dwc3_check_event_buf(dwc);
 }
 
 /**