linux-kernel - [PATCH 3/8] memory: brcmstb: dpfe: add locking around DCPU enable/disable

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Message-Id: <20191015224513.16969-4-mmayer@broadcom.com>
Date:   Tue, 15 Oct 2019 15:45:08 -0700
From:   Markus Mayer <mmayer@...adcom.com>
To:     Brian Norris <computersforpeace@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>
Cc:     Markus Mayer <mmayer@...adcom.com>,
        Broadcom Kernel List <bcm-kernel-feedback-list@...adcom.com>,
        ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/8] memory: brcmstb: dpfe: add locking around DCPU enable/disable

To ensure consistency, we add locking primitives inside the DCPU enable
and disable routines.

Signed-off-by: Markus Mayer <mmayer@...adcom.com>
---
 drivers/memory/brcmstb_dpfe.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/memory/brcmstb_dpfe.c b/drivers/memory/brcmstb_dpfe.c
index 2ef3e365c1b5..c10c24a76729 100644
--- a/drivers/memory/brcmstb_dpfe.c
+++ b/drivers/memory/brcmstb_dpfe.c
@@ -290,32 +290,41 @@ static const struct dpfe_api dpfe_api_v3 = {
 	},
 };
 
-static bool is_dcpu_enabled(void __iomem *regs)
+static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv)
 {
 	u32 val;
 
-	val = readl_relaxed(regs + REG_DCPU_RESET);
+	mutex_lock(&priv->lock);
+	val = readl_relaxed(priv->regs + REG_DCPU_RESET);
+	mutex_unlock(&priv->lock);
 
 	return !(val & DCPU_RESET_MASK);
 }
 
-static void __disable_dcpu(void __iomem *regs)
+static void __disable_dcpu(struct brcmstb_dpfe_priv *priv)
 {
 	u32 val;
 
-	if (!is_dcpu_enabled(regs))
+	if (!is_dcpu_enabled(priv))
 		return;
 
+	mutex_lock(&priv->lock);
+
 	/* Put DCPU in reset if it's running. */
-	val = readl_relaxed(regs + REG_DCPU_RESET);
+	val = readl_relaxed(priv->regs + REG_DCPU_RESET);
 	val |= (1 << DCPU_RESET_SHIFT);
-	writel_relaxed(val, regs + REG_DCPU_RESET);
+	writel_relaxed(val, priv->regs + REG_DCPU_RESET);
+
+	mutex_unlock(&priv->lock);
 }
 
-static void __enable_dcpu(void __iomem *regs)
+static void __enable_dcpu(struct brcmstb_dpfe_priv *priv)
 {
+	void __iomem *regs = priv->regs;
 	u32 val;
 
+	mutex_lock(&priv->lock);
+
 	/* Clear mailbox registers. */
 	writel_relaxed(0, regs + REG_TO_DCPU_MBOX);
 	writel_relaxed(0, regs + REG_TO_HOST_MBOX);
@@ -329,6 +338,8 @@ static void __enable_dcpu(void __iomem *regs)
 	val = readl_relaxed(regs + REG_DCPU_RESET);
 	val &= ~(1 << DCPU_RESET_SHIFT);
 	writel_relaxed(val, regs + REG_DCPU_RESET);
+
+	mutex_unlock(&priv->lock);
 }
 
 static unsigned int get_msg_chksum(const u32 msg[], unsigned int max)
@@ -590,7 +601,7 @@ static int brcmstb_dpfe_download_firmware(struct platform_device *pdev,
 	 * Skip downloading the firmware if the DCPU is already running and
 	 * responding to commands.
 	 */
-	if (is_dcpu_enabled(priv->regs)) {
+	if (is_dcpu_enabled(priv)) {
 		u32 response[MSG_FIELD_MAX];
 
 		ret = __send_command(priv, DPFE_CMD_GET_INFO, response);
@@ -615,7 +626,7 @@ static int brcmstb_dpfe_download_firmware(struct platform_device *pdev,
 	if (ret)
 		return -EFAULT;
 
-	__disable_dcpu(priv->regs);
+	__disable_dcpu(priv);
 
 	is_big_endian = init->is_big_endian;
 	dmem_size = init->dmem_len;
@@ -641,7 +652,7 @@ static int brcmstb_dpfe_download_firmware(struct platform_device *pdev,
 	if (ret)
 		return ret;
 
-	__enable_dcpu(priv->regs);
+	__enable_dcpu(priv);
 
 	return 0;
 }
-- 
2.17.1