linux-kernel - [PATCH 4.8 15/92] pinctrl: cherryview: Serialize register access in suspend/resume

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Message-Id: <20161117103224.834064630@linuxfoundation.org>
Date:   Thu, 17 Nov 2016 11:31:48 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH 4.8 15/92] pinctrl: cherryview: Serialize register access in suspend/resume

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mika Westerberg <mika.westerberg@...ux.intel.com>

commit 56211121c0825cd188caad05574fdc518d5cac6f upstream.

If async suspend is enabled, the driver may access registers concurrently
with another instance which may fail because of the bug in Cherryview GPIO
hardware. Prevent this by taking the shared lock while accessing the
hardware in suspend and resume hooks.

Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/pinctrl/intel/pinctrl-cherryview.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -1638,8 +1638,11 @@ static int chv_pinctrl_suspend(struct de
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
+	unsigned long flags;
 	int i;
 
+	raw_spin_lock_irqsave(&chv_lock, flags);
+
 	pctrl->saved_intmask = readl(pctrl->regs + CHV_INTMASK);
 
 	for (i = 0; i < pctrl->community->npins; i++) {
@@ -1660,6 +1663,8 @@ static int chv_pinctrl_suspend(struct de
 		ctx->padctrl1 = readl(reg);
 	}
 
+	raw_spin_unlock_irqrestore(&chv_lock, flags);
+
 	return 0;
 }
 
@@ -1667,8 +1672,11 @@ static int chv_pinctrl_resume(struct dev
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
+	unsigned long flags;
 	int i;
 
+	raw_spin_lock_irqsave(&chv_lock, flags);
+
 	/*
 	 * Mask all interrupts before restoring per-pin configuration
 	 * registers because we don't know in which state BIOS left them
@@ -1713,6 +1721,8 @@ static int chv_pinctrl_resume(struct dev
 	chv_writel(0xffff, pctrl->regs + CHV_INTSTAT);
 	chv_writel(pctrl->saved_intmask, pctrl->regs + CHV_INTMASK);
 
+	raw_spin_unlock_irqrestore(&chv_lock, flags);
+
 	return 0;
 }
 #endif