linux-kernel - [PATCH v13 03/53] xhci: Add interrupt pending autoclear flag to each interrupter

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Date: Fri, 2 Feb 2024 18:35:55 -0800
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
        <perex@...ex.cz>, <conor+dt@...nel.org>, <corbet@....net>,
        <lgirdwood@...il.com>, <andersson@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <gregkh@...uxfoundation.org>,
        <Thinh.Nguyen@...opsys.com>, <broonie@...nel.org>,
        <bgoswami@...cinc.com>, <tiwai@...e.com>, <robh+dt@...nel.org>,
        <konrad.dybcio@...aro.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-sound@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <alsa-devel@...a-project.org>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH v13 03/53] xhci: Add interrupt pending autoclear flag to each interrupter

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

Each interrupter has an interrupt pending (IP) bit that should be cleared
in the interrupt handler. This is done automatically for systems using
MSI/MSI-X interrupts.

Secondary interrupters used by audio offload may not actually trigger
MSI/MSI-X messages, so driver may need to clear the IP bit manually for
these, even if the primary interrupter IP is cleared automatically.

Add an ip_autoclear flag to each interrupter that driver can configure
when requesting an interrupt for that xHC interrupter, and move
the interrupt pending clearing code to its own helper function.
Use this ip_autoclear flag instead of the current hcd->msi_enabled
to check if IP flag is cleared by software.

[Moved ip_autoclear into xhci and set based on msi_enabled -wcheng]

Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
 drivers/usb/host/xhci-ring.c | 21 +++++++++++++++------
 drivers/usb/host/xhci.c      |  3 +++
 drivers/usb/host/xhci.h      |  1 +
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 33806ae966f9..f8e78068c36f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3013,6 +3013,19 @@ static void xhci_update_erst_dequeue(struct xhci_hcd *xhci,
 	xhci_write_64(xhci, temp_64, &ir->ir_set->erst_dequeue);
 }
 
+/* Clear the interrupt pending bit for a specific interrupter. */
+static void xhci_clear_interrupt_pending(struct xhci_hcd *xhci,
+					 struct xhci_interrupter *ir)
+{
+	if (!ir->ip_autoclear) {
+		u32 irq_pending;
+
+		irq_pending = readl(&ir->ir_set->irq_pending);
+		irq_pending |= IMAN_IP;
+		writel(irq_pending, &ir->ir_set->irq_pending);
+	}
+}
+
 /*
  * xHCI spec says we can get an interrupt, and if the HC has an error condition,
  * we might get bad data out of the event ring.  Section 4.10.2.7 has a list of
@@ -3062,12 +3075,8 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
 
 	/* This is the handler of the primary interrupter */
 	ir = xhci->interrupters[0];
-	if (!hcd->msi_enabled) {
-		u32 irq_pending;
-		irq_pending = readl(&ir->ir_set->irq_pending);
-		irq_pending |= IMAN_IP;
-		writel(irq_pending, &ir->ir_set->irq_pending);
-	}
+
+	xhci_clear_interrupt_pending(xhci, ir);
 
 	if (xhci->xhc_state & XHCI_STATE_DYING ||
 	    xhci->xhc_state & XHCI_STATE_HALTED) {
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index c057c42c36f4..0886829d53e5 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -538,6 +538,9 @@ int xhci_run(struct usb_hcd *hcd)
 	 */
 
 	hcd->uses_new_polling = 1;
+	if (hcd->msi_enabled)
+		ir->ip_autoclear = true;
+
 	if (!usb_hcd_is_primary_hcd(hcd))
 		return xhci_run_finished(xhci);
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index c6349e7e1e95..daee202cd369 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1431,6 +1431,7 @@ struct xhci_interrupter {
 	struct xhci_erst	erst;
 	struct xhci_intr_reg __iomem *ir_set;
 	unsigned int		intr_num;
+	bool			ip_autoclear;
 	/* For interrupter registers save and restore over suspend/resume */
 	u32	s3_irq_pending;
 	u32	s3_irq_control;