linux-kernel - [PATCH v2] usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses

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Date:   Wed, 21 Jul 2021 16:29:05 +0300
From:   Claudiu Beznea <claudiu.beznea@...rochip.com>
To:     <stern@...land.harvard.edu>, <gregkh@...uxfoundation.org>,
        <nicolas.ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
        <ludovic.desroches@...rochip.com>
CC:     <linux-usb@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>
Subject: [PATCH v2] usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses

On SAMA7G5 suspending ports will cut the access to OHCI registers and
any subsequent access to them will lead to CPU being blocked trying to
access that memory. Same thing happens on resume: if OHCI memory is
accessed before resuming ports the CPU will block on that access. The
OCHI memory is accessed on suspend/resume though
ohci_suspend()/ohci_resume().

Acked-by: Alan Stern <stern@...land.harvard.edu>
Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
---

Changes in v2:
- rebase on top of v5.14-rc2
- collected tag

 drivers/usb/host/ohci-at91.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index 9bbd7ddd0003..a24aea3d2759 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -611,8 +611,6 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
 	if (ohci_at91->wakeup)
 		enable_irq_wake(hcd->irq);
 
-	ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
-
 	ret = ohci_suspend(hcd, ohci_at91->wakeup);
 	if (ret) {
 		if (ohci_at91->wakeup)
@@ -632,7 +630,10 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
 		/* flush the writes */
 		(void) ohci_readl (ohci, &ohci->regs->control);
 		msleep(1);
+		ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
 		at91_stop_clock(ohci_at91);
+	} else {
+		ohci_at91_port_suspend(ohci_at91->sfr_regmap, 1);
 	}
 
 	return ret;
@@ -644,6 +645,8 @@ ohci_hcd_at91_drv_resume(struct device *dev)
 	struct usb_hcd	*hcd = dev_get_drvdata(dev);
 	struct ohci_at91_priv *ohci_at91 = hcd_to_ohci_at91_priv(hcd);
 
+	ohci_at91_port_suspend(ohci_at91->sfr_regmap, 0);
+
 	if (ohci_at91->wakeup)
 		disable_irq_wake(hcd->irq);
 	else
@@ -651,8 +654,6 @@ ohci_hcd_at91_drv_resume(struct device *dev)
 
 	ohci_resume(hcd, false);
 
-	ohci_at91_port_suspend(ohci_at91->sfr_regmap, 0);
-
 	return 0;
 }
 
-- 
2.25.1