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

[Markus Mayer]

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

Signed-off-by: Markus Mayer <mma...@broadcom.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