net: ethernet: ti: cpdma: correct error handling for chan create

It's not correct to return NULL when that is actually an error and
function returns errors in any other wrong case. In the same time,
the cpsw driver and davinci emac doesn't check error case while
creating channel and it can miss actual error. Also remove WARNs
replacing them on dev_err msgs.
Signed-off-by: NIvan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Reviewed-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -3065,10 +3065,16 @@ static int cpsw_probe(struct platform_device *pdev)
 	}
 
 	cpsw->txv[0].ch = cpdma_chan_create(cpsw->dma, 0, cpsw_tx_handler, 0);
+	if (IS_ERR(cpsw->txv[0].ch)) {
+		dev_err(priv->dev, "error initializing tx dma channel\n");
+		ret = PTR_ERR(cpsw->txv[0].ch);
+		goto clean_dma_ret;
+	}
+
 	cpsw->rxv[0].ch = cpdma_chan_create(cpsw->dma, 0, cpsw_rx_handler, 1);
-	if (WARN_ON(!cpsw->rxv[0].ch || !cpsw->txv[0].ch)) {
-		dev_err(priv->dev, "error initializing dma channels\n");
-		ret = -ENOMEM;
+	if (IS_ERR(cpsw->rxv[0].ch)) {
+		dev_err(priv->dev, "error initializing rx dma channel\n");
+		ret = PTR_ERR(cpsw->rxv[0].ch);
 		goto clean_dma_ret;
 	}
 

drivers/net/ethernet/ti/davinci_cpdma.c

@@ -893,7 +893,7 @@ struct cpdma_chan *cpdma_chan_create(struct cpdma_ctlr *ctlr, int chan_num,
 	chan_num = rx_type ? rx_chan_num(chan_num) : tx_chan_num(chan_num);
 
 	if (__chan_linear(chan_num) >= ctlr->num_chan)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	chan = devm_kzalloc(ctlr->dev, sizeof(*chan), GFP_KERNEL);
 	if (!chan)

drivers/net/ethernet/ti/davinci_emac.c

@@ -1870,10 +1870,17 @@ static int davinci_emac_probe(struct platform_device *pdev)
 
 	priv->txchan = cpdma_chan_create(priv->dma, EMAC_DEF_TX_CH,
 					 emac_tx_handler, 0);
+	if (IS_ERR(priv->txchan)) {
+		dev_err(&pdev->dev, "error initializing tx dma channel\n");
+		rc = PTR_ERR(priv->txchan);
+		goto no_cpdma_chan;
+	}
+
 	priv->rxchan = cpdma_chan_create(priv->dma, EMAC_DEF_RX_CH,
 					 emac_rx_handler, 1);
-	if (WARN_ON(!priv->txchan || !priv->rxchan)) {
-		rc = -ENOMEM;
+	if (IS_ERR(priv->rxchan)) {
+		dev_err(&pdev->dev, "error initializing rx dma channel\n");
+		rc = PTR_ERR(priv->rxchan);
 		goto no_cpdma_chan;
 	}