linux-kernel - [PATCH AUTOSEL 6.3 08/24] xhci: Avoid PCI MSI/MSIX interrupt reinitialization at resume

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Date:   Sat,  6 May 2023 20:30:04 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Josue David Hernandez Gutierrez 
        <josue.d.hernandez.gutierrez@...el.com>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Sasha Levin <sashal@...nel.org>, mathias.nyman@...el.com,
        linux-usb@...r.kernel.org
Subject: [PATCH AUTOSEL 6.3 08/24] xhci: Avoid PCI MSI/MSIX interrupt reinitialization at resume

From: Josue David Hernandez Gutierrez <josue.d.hernandez.gutierrez@...el.com>

[ Upstream commit 944e7deb4238d10cd16905474574236ac8a8e847 ]

xhci MSI setup is currently done at the same time as xHC host is started
in xhci_run(). This couples the generic xhci code with PCI, and will
reconfigure MSI/MSIX interrupts every time xHC is started.

Decouple MSI/MSIX configuration from generic xhci code by moving MSI/MSIX
part to a PCI specific xhci_pci_run() function overriding xhci_run().

This allows us to remove unnecessay MSI/MSIX reconfiguration done every
time PCI xhci resumes from suspend. i.e. remove the xhci_cleanup_msix()
call from xhci_resume() and the xhci_try_enale_msi() call in xhci_run()
called a bit later by xhci_resume()

[minor changes and commit message rewrite -Mathias]

Signed-off-by: Josue David Hernandez Gutierrez <josue.d.hernandez.gutierrez@...el.com>
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Link: https://lore.kernel.org/r/20230317154715.535523-10-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/usb/host/xhci-pci.c | 15 +++++++++++++++
 drivers/usb/host/xhci.c     |  8 ++------
 drivers/usb/host/xhci.h     |  1 +
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 6db07ca419c31..8060782a2367d 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -78,14 +78,29 @@ static const char hcd_name[] = "xhci_hcd";
 static struct hc_driver __read_mostly xhci_pci_hc_driver;
 
 static int xhci_pci_setup(struct usb_hcd *hcd);
+static int xhci_pci_run(struct usb_hcd *hcd);
 static int xhci_pci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev,
 				      struct usb_tt *tt, gfp_t mem_flags);
 
 static const struct xhci_driver_overrides xhci_pci_overrides __initconst = {
 	.reset = xhci_pci_setup,
+	.start = xhci_pci_run,
 	.update_hub_device = xhci_pci_update_hub_device,
 };
 
+static int xhci_pci_run(struct usb_hcd *hcd)
+{
+	int ret;
+
+	if (usb_hcd_is_primary_hcd(hcd)) {
+		ret = xhci_try_enable_msi(hcd);
+		if (ret)
+			return ret;
+	}
+
+	return xhci_run(hcd);
+}
+
 /* called after powerup, by probe or system-pm "wakeup" */
 static int xhci_pci_reinit(struct xhci_hcd *xhci, struct pci_dev *pdev)
 {
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6307bae9cddff..f498df6b02c80 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -436,7 +436,7 @@ static void __maybe_unused xhci_msix_sync_irqs(struct xhci_hcd *xhci)
 	}
 }
 
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
+int xhci_try_enable_msi(struct usb_hcd *hcd)
 {
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 	struct pci_dev  *pdev;
@@ -490,6 +490,7 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
 	hcd->irq = pdev->irq;
 	return 0;
 }
+EXPORT_SYMBOL_GPL(xhci_try_enable_msi);
 
 #else
 
@@ -705,10 +706,6 @@ int xhci_run(struct usb_hcd *hcd)
 
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "xhci_run");
 
-	ret = xhci_try_enable_msi(hcd);
-	if (ret)
-		return ret;
-
 	temp_64 = xhci_read_64(xhci, &ir->ir_set->erst_dequeue);
 	temp_64 &= ~ERST_PTR_MASK;
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
@@ -1250,7 +1247,6 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		spin_unlock_irq(&xhci->lock);
 		if (retval)
 			return retval;
-		xhci_cleanup_msix(xhci);
 
 		xhci_dbg(xhci, "// Disabling event ring interrupts\n");
 		temp = readl(&xhci->op_regs->status);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 786002bb35db0..26fccc8d90556 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2143,6 +2143,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated);
 
 irqreturn_t xhci_irq(struct usb_hcd *hcd);
 irqreturn_t xhci_msi_irq(int irq, void *hcd);
+int xhci_try_enable_msi(struct usb_hcd *hcd);
 int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev);
 int xhci_alloc_tt_info(struct xhci_hcd *xhci,
 		struct xhci_virt_device *virt_dev,
-- 
2.39.2