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From: Wesley Cheng <quic_wcheng@quicinc.com>
To: <srinivas.kandagatla@linaro.org>, <mathias.nyman@intel.com>,
        <perex@perex.cz>, <conor+dt@kernel.org>, <corbet@lwn.net>,
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CC: <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-sound@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <alsa-devel@alsa-project.org>,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Wesley Cheng <quic_wcheng@quicinc.com>
Subject: [PATCH v13 05/53] xhci: make isoc_bei_interval variable interrupter specific.
Date: Fri, 2 Feb 2024 18:35:57 -0800
Message-ID: <20240203023645.31105-6-quic_wcheng@quicinc.com>
In-Reply-To: <20240203023645.31105-1-quic_wcheng@quicinc.com>
References: <20240203023645.31105-1-quic_wcheng@quicinc.com>
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From: Mathias Nyman <mathias.nyman@linux.intel.com>

isoc_bei_interval is used to balance how often completed isochronous
events cause interrupts. If interval is too large then the event ring
may fill up before the completed isoc TRBs are handled.

isoc_bei_interval is tuned based on how full the event ring is.

isoc_bei_interval variable needs to be per interrupter as
with several interrupters each one has its own event ring.

move isoc_bei_interval variable to the interrupter structure.

if a secondary interrupter does not care about this feature then
keep isoc_bei_interval 0.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
 drivers/usb/host/xhci-mem.c  |  2 +-
 drivers/usb/host/xhci-ring.c | 15 +++++++++------
 drivers/usb/host/xhci.h      |  2 +-
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index a7716202a8dd..450adaca68ee 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2533,7 +2533,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	if (xhci_add_interrupter(xhci, ir, 0))
 		goto fail;
 
-	xhci->isoc_bei_interval = AVOID_BEI_INTERVAL_MAX;
+	ir->isoc_bei_interval = AVOID_BEI_INTERVAL_MAX;
 
 	/*
 	 * XXX: Might need to set the Interrupter Moderation Register to
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f8e78068c36f..1b619a290446 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3103,8 +3103,8 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
 		event_ring_deq = ir->event_ring->dequeue;
 
 		/* ring is half-full, force isoc trbs to interrupt more often */
-		if (xhci->isoc_bei_interval > AVOID_BEI_INTERVAL_MIN)
-			xhci->isoc_bei_interval = xhci->isoc_bei_interval / 2;
+		if (ir->isoc_bei_interval > AVOID_BEI_INTERVAL_MIN)
+			ir->isoc_bei_interval = ir->isoc_bei_interval / 2;
 
 		event_loop = 0;
 	}
@@ -3972,7 +3972,8 @@ static int xhci_get_isoc_frame_id(struct xhci_hcd *xhci,
 }
 
 /* Check if we should generate event interrupt for a TD in an isoc URB */
-static bool trb_block_event_intr(struct xhci_hcd *xhci, int num_tds, int i)
+static bool trb_block_event_intr(struct xhci_hcd *xhci, int num_tds, int i,
+				 struct xhci_interrupter *ir)
 {
 	if (xhci->hci_version < 0x100)
 		return false;
@@ -3983,8 +3984,8 @@ static bool trb_block_event_intr(struct xhci_hcd *xhci, int num_tds, int i)
 	 * If AVOID_BEI is set the host handles full event rings poorly,
 	 * generate an event at least every 8th TD to clear the event ring
 	 */
-	if (i && xhci->quirks & XHCI_AVOID_BEI)
-		return !!(i % xhci->isoc_bei_interval);
+	if (i && ir->isoc_bei_interval && xhci->quirks & XHCI_AVOID_BEI)
+		return !!(i % ir->isoc_bei_interval);
 
 	return true;
 }
@@ -3993,6 +3994,7 @@ static bool trb_block_event_intr(struct xhci_hcd *xhci, int num_tds, int i)
 static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		struct urb *urb, int slot_id, unsigned int ep_index)
 {
+	struct xhci_interrupter *ir;
 	struct xhci_ring *ep_ring;
 	struct urb_priv *urb_priv;
 	struct xhci_td *td;
@@ -4010,6 +4012,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
 	xep = &xhci->devs[slot_id]->eps[ep_index];
 	ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
+	ir = xhci->interrupters[0];
 
 	num_tds = urb->number_of_packets;
 	if (num_tds < 1) {
@@ -4097,7 +4100,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 				td->last_trb = ep_ring->enqueue;
 				td->last_trb_seg = ep_ring->enq_seg;
 				field |= TRB_IOC;
-				if (trb_block_event_intr(xhci, num_tds, i))
+				if (trb_block_event_intr(xhci, num_tds, i, ir))
 					field |= TRB_BEI;
 			}
 			/* Calculate TRB length */
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index daee202cd369..44e447fdad62 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1432,6 +1432,7 @@ struct xhci_interrupter {
 	struct xhci_intr_reg __iomem *ir_set;
 	unsigned int		intr_num;
 	bool			ip_autoclear;
+	u32			isoc_bei_interval;
 	/* For interrupter registers save and restore over suspend/resume */
 	u32	s3_irq_pending;
 	u32	s3_irq_control;
@@ -1504,7 +1505,6 @@ struct xhci_hcd {
 	u8		isoc_threshold;
 	/* imod_interval in ns (I * 250ns) */
 	u32		imod_interval;
-	u32		isoc_bei_interval;
 	int		event_ring_max;
 	/* 4KB min, 128MB max */
 	int		page_size;