linux-kernel - [PATCH] can: m_can: m_can_platform: Fix iomap_read_fifo() and iomap_write

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Message-ID: <20210920123344.2320-1-a-govindraju@ti.com>
Date:   Mon, 20 Sep 2021 18:03:43 +0530
From:   Aswath Govindraju <a-govindraju@...com>
To:     unlisted-recipients:; (no To-header on input)
CC:     Lokesh Vutla <lokeshvutla@...com>,
        Aswath Govindraju <a-govindraju@...com>,
        Chandrasekar Ramakrishnan <rcsekar@...sung.com>,
        Wolfgang Grandegger <wg@...ndegger.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Matt Kline <matt@...bashing.io>, <linux-can@...r.kernel.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] can: m_can: m_can_platform: Fix iomap_read_fifo() and iomap_write_fifo()

The read and writes from the fifo are from a buffer, with various fields
and data at predefined offsets. So, they should not be done to the same
address(or port) in case of val_count greater than 1. Therefore, fix this
by using iowrite32/ioread32 instead of ioread32_rep/iowrite32_rep.

Also, the write into fifo must be performed with an offset from the message
ram base address. Therefore, fix the base address to mram_base.

Fixes: e39381770ec9 ("can: m_can: Disable IRQs on FIFO bus errors")
Signed-off-by: Aswath Govindraju <a-govindraju@...com>
---
 drivers/net/can/m_can/m_can_platform.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c
index 308d4f2fff00..eee47bad0592 100644
--- a/drivers/net/can/m_can/m_can_platform.c
+++ b/drivers/net/can/m_can/m_can_platform.c
@@ -32,8 +32,13 @@ static u32 iomap_read_reg(struct m_can_classdev *cdev, int reg)
 static int iomap_read_fifo(struct m_can_classdev *cdev, int offset, void *val, size_t val_count)
 {
 	struct m_can_plat_priv *priv = cdev_to_priv(cdev);
+	void __iomem *src = priv->mram_base + offset;
 
-	ioread32_rep(priv->mram_base + offset, val, val_count);
+	while (val_count--) {
+		*(unsigned int *)val = ioread32(src);
+		val += 4;
+		src += 4;
+	}
 
 	return 0;
 }
@@ -51,8 +56,13 @@ static int iomap_write_fifo(struct m_can_classdev *cdev, int offset,
 			    const void *val, size_t val_count)
 {
 	struct m_can_plat_priv *priv = cdev_to_priv(cdev);
+	void __iomem *dst = priv->mram_base + offset;
 
-	iowrite32_rep(priv->base + offset, val, val_count);
+	while (val_count--) {
+		iowrite32(*(unsigned int *)val, dst);
+		val += 4;
+		dst += 4;
+	}
 
 	return 0;
 }
-- 
2.17.1