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From:   Chengfeng Ye <dg573847474@gmail.com>
To:     andi.shyti@kernel.org, rjui@broadcom.com, sbranden@broadcom.com,
        wsa@kernel.org
Cc:     bcm-kernel-feedback-list@broadcom.com, linux-i2c@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Chengfeng Ye <dg573847474@gmail.com>
Subject: [PATCH RESEND] i2c: bcm-iproc: Fix bcm_iproc_i2c_isr deadlock issue
Date:   Thu,  6 Jul 2023 21:14:14 +0000
Message-Id: <20230706211414.10660-1-dg573847474@gmail.com>
Precedence: bulk

iproc_i2c_rd_reg and iproc_i2c_wr_reg are called from both
interrupt context (e.g. bcm_iproc_i2c_isr) and process context
(e.g. bcm_iproc_i2c_suspend). Therefore, interrupts should be
disabled to avoid potential deadlock. To prevent this scenario,
use spin_lock_irqsave.

Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
---
 drivers/i2c/busses/i2c-bcm-iproc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
index 85d8a6b04885..d02245e4db8c 100644
--- a/drivers/i2c/busses/i2c-bcm-iproc.c
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -233,13 +233,14 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
 				   u32 offset)
 {
 	u32 val;
+	unsigned long flags;
 
 	if (iproc_i2c->idm_base) {
-		spin_lock(&iproc_i2c->idm_lock);
+		spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
 		writel(iproc_i2c->ape_addr_mask,
 		       iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
 		val = readl(iproc_i2c->base + offset);
-		spin_unlock(&iproc_i2c->idm_lock);
+		spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
 	} else {
 		val = readl(iproc_i2c->base + offset);
 	}
@@ -250,12 +251,13 @@ static inline u32 iproc_i2c_rd_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
 static inline void iproc_i2c_wr_reg(struct bcm_iproc_i2c_dev *iproc_i2c,
 				    u32 offset, u32 val)
 {
+	unsigned long flags;
 	if (iproc_i2c->idm_base) {
-		spin_lock(&iproc_i2c->idm_lock);
+		spin_lock_irqsave(&iproc_i2c->idm_lock, flags);
 		writel(iproc_i2c->ape_addr_mask,
 		       iproc_i2c->idm_base + IDM_CTRL_DIRECT_OFFSET);
 		writel(val, iproc_i2c->base + offset);
-		spin_unlock(&iproc_i2c->idm_lock);
+		spin_unlock_irqrestore(&iproc_i2c->idm_lock, flags);
 	} else {
 		writel(val, iproc_i2c->base + offset);
 	}
-- 
2.17.1