k3_udma_glue_enable_rx/tx_chn returns error code on failure.
Bail out on error while enabling TX/RX channel.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 7c440899c93c..340f25bf33b1 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
 static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 {
 	struct am65_cpsw_host *host_p = am65_common_get_host(common);
-	int port_idx, i, ret;
+	int port_idx, i, ret, tx;
 	struct sk_buff *skb;
 	u32 val, port_mask;
 
@@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 		}
 		kmemleak_not_leak(skb);
 	}
-	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
 
-	for (i = 0; i < common->tx_ch_num; i++) {
-		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
-		if (ret)
-			return ret;
-		napi_enable(&common->tx_chns[i].napi_tx);
+	ret = k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
+	if (ret) {
+		dev_err(common->dev, "couldn't enable rx chn: %d\n", ret);
+		return ret;
+	}
+
+	for (tx = 0; tx < common->tx_ch_num; tx++) {
+		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[tx].tx_chn);
+		if (ret) {
+			dev_err(common->dev, "couldn't enable tx chn %d: %d\n",
+				tx, ret);
+			tx--;
+			goto fail_tx;
+		}
+		napi_enable(&common->tx_chns[tx].napi_tx);
 	}
 
 	napi_enable(&common->napi_rx);
@@ -470,6 +479,16 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
 
 	dev_dbg(common->dev, "cpsw_nuss started\n");
 	return 0;
+
+fail_tx:
+	while (tx >= 0) {
+		napi_disable(&common->tx_chns[tx].napi_tx);
+		k3_udma_glue_disable_tx_chn(common->tx_chns[tx].tx_chn);
+		tx--;
+	}
+
+	k3_udma_glue_disable_rx_chn(common->rx_chns.rx_chn);
+	return ret;
 }
 
 static void am65_cpsw_nuss_tx_cleanup(void *data, dma_addr_t desc_dma);
-- 
2.34.1

On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
> Bail out on error while enabling TX/RX channel.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 7c440899c93c..340f25bf33b1 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
>  static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>  {
>  	struct am65_cpsw_host *host_p = am65_common_get_host(common);
> -	int port_idx, i, ret;
> +	int port_idx, i, ret, tx;
>  	struct sk_buff *skb;
>  	u32 val, port_mask;
>  
> @@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>  		}
>  		kmemleak_not_leak(skb);
>  	}
> -	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
>  
> -	for (i = 0; i < common->tx_ch_num; i++) {
> -		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
> -		if (ret)
> -			return ret;

Can you comment on the kmemleak_not_leak(skb) call above, and its
relationship to the pre-existing error handling path in am65_cpsw_nuss_common_open()?
I see that the dev_kfree_skb_any() call is being made from am65_cpsw_nuss_rx_cleanup(),
which is only called from am65_cpsw_nuss_common_stop().

So if there are errors during am65_cpsw_nuss_common_open() and
descriptors have already been added to the RX DMA channel, they will not
be removed either from hardware or from software. How does that work?

On 14/11/2023 14:07, Vladimir Oltean wrote:
> On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
>> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
>> Bail out on error while enabling TX/RX channel.
>>
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> ---
>>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 33 +++++++++++++++++++-----
>>  1 file changed, 26 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> index 7c440899c93c..340f25bf33b1 100644
>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>> @@ -372,7 +372,7 @@ static void am65_cpsw_init_port_emac_ale(struct am65_cpsw_port *port);
>>  static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>>  {
>>  	struct am65_cpsw_host *host_p = am65_common_get_host(common);
>> -	int port_idx, i, ret;
>> +	int port_idx, i, ret, tx;
>>  	struct sk_buff *skb;
>>  	u32 val, port_mask;
>>  
>> @@ -453,13 +453,22 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common)
>>  		}
>>  		kmemleak_not_leak(skb);
>>  	}
>> -	k3_udma_glue_enable_rx_chn(common->rx_chns.rx_chn);
>>  
>> -	for (i = 0; i < common->tx_ch_num; i++) {
>> -		ret = k3_udma_glue_enable_tx_chn(common->tx_chns[i].tx_chn);
>> -		if (ret)
>> -			return ret;
> 
> Can you comment on the kmemleak_not_leak(skb) call above, and its
> relationship to the pre-existing error handling path in am65_cpsw_nuss_common_open()?

I am not aware why it was added. It sure looks odd and I'll get rid of it
and add the necessary error handling.

> I see that the dev_kfree_skb_any() call is being made from am65_cpsw_nuss_rx_cleanup(),
> which is only called from am65_cpsw_nuss_common_stop().
> 
> So if there are errors during am65_cpsw_nuss_common_open() and
> descriptors have already been added to the RX DMA channel, they will not
> be removed either from hardware or from software. How does that work?

I believe this is a gap and I will address it in the next revision. Thanks!

-- 
cheers,
-roger

On Mon, Nov 13, 2023 at 01:07:08PM +0200, Roger Quadros wrote:
> k3_udma_glue_enable_rx/tx_chn returns error code on failure.
> Bail out on error while enabling TX/RX channel.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew