Re: [PATCH] net: axi_emac: Fix timeout test

[Michal Simek]

On 8/6/25 13:10, Andrew Goodbody wrote:

The timeout test in axi_dma_init is not correct due to the
post-decrement used on the timeout variable which will mean timeout is
not 0 if the timeout occurs. Make the timeout variable an int instead of
a u32 and then test for timeout being -1.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodb...@linaro.org>
---
  drivers/net/xilinx_axi_emac.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/xilinx_axi_emac.c b/drivers/net/xilinx_axi_emac.c
index c8038ddef1b..c46678c1f3b 100644
--- a/drivers/net/xilinx_axi_emac.c
+++ b/drivers/net/xilinx_axi_emac.c
@@ -558,7 +558,7 @@ static int axiemac_write_hwaddr(struct udevice *dev)
  /* Reset DMA engine */
  static void axi_dma_init(struct axidma_priv *priv)
  {
-       u32 timeout = 500;
+       int timeout = 500;

/* Reset the engine so the hardware starts from a known state */

        writel(XAXIDMA_CR_RESET_MASK, &priv->dmatx->control);
@@ -574,7 +574,7 @@ static void axi_dma_init(struct axidma_priv *priv)
                        break;
                }
        }
-       if (!timeout)
+       if (timeout == -1)
                printf("%s: Timeout\n", __func__);
  }

---
base-commit: 007610da2cca405ea7739fc120d90085be4b6ac2
change-id: 20250806-net_xilinx_axi-9ca9a791d611

Best regards,

What about to do it like this?
diff --git a/drivers/net/xilinx_axi_emac.c b/drivers/net/xilinx_axi_emac.c
index c8038ddef1b8..22e119370c84 100644
--- a/drivers/net/xilinx_axi_emac.c
+++ b/drivers/net/xilinx_axi_emac.c
@@ -558,7 +558,7 @@ static int axiemac_write_hwaddr(struct udevice *dev)
 /* Reset DMA engine */
 static void axi_dma_init(struct axidma_priv *priv)
 {
-       u32 timeout = 500;
+       int timeout = 500;

        /* Reset the engine so the hardware starts from a known state */
        writel(XAXIDMA_CR_RESET_MASK, &priv->dmatx->control);
@@ -571,11 +571,11 @@ static void axi_dma_init(struct axidma_priv *priv)
                if (!((readl(&priv->dmatx->control) |
                                readl(&priv->dmarx->control))
                                                & XAXIDMA_CR_RESET_MASK)) {
-                       break;
+                       return;
                }
        }
-       if (!timeout)
-               printf("%s: Timeout\n", __func__);
+
+       printf("%s: Timeout\n", __func__);
 }

 static int axiemac_start(struct udevice *dev)

M