net: ethernet: ti: davinci_cpdma: allow desc split while down

That's possible to set ring params while interfaces are down. When
interface gets up it uses number of descs to fill rx queue and on
later on changes to create rx pools. Usually, this resplit can happen
after phy is up, but it can be needed before this, so allow it to
happen while setting number of rx descs, when interfaces are down.
Also, if no dependency on intf state, move it to cpdma layer, where
it should be.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw_ethtool.c

@@ -650,7 +650,7 @@ int cpsw_set_ringparam(struct net_device *ndev,
 {
 	struct cpsw_priv *priv = netdev_priv(ndev);
 	struct cpsw_common *cpsw = priv->cpsw;
-	int ret;
+	int descs_num, ret;
 
 	/* ignore ering->tx_pending - only rx_pending adjustment is supported */
 
@@ -659,20 +659,25 @@ int cpsw_set_ringparam(struct net_device *ndev,
 	    ering->rx_pending > (cpsw->descs_pool_size - CPSW_MAX_QUEUES))
 		return -EINVAL;
 
-	if (ering->rx_pending == cpdma_get_num_rx_descs(cpsw->dma))
+	descs_num = cpdma_get_num_rx_descs(cpsw->dma);
+	if (ering->rx_pending == descs_num)
 		return 0;
 
 	cpsw_suspend_data_pass(ndev);
 
-	cpdma_set_num_rx_descs(cpsw->dma, ering->rx_pending);
+	ret = cpdma_set_num_rx_descs(cpsw->dma, ering->rx_pending);
+	if (ret) {
+		if (cpsw_resume_data_pass(ndev))
+			goto err;
 
-	if (cpsw->usage_count)
-		cpdma_chan_split_pool(cpsw->dma);
+		return ret;
+	}
 
 	ret = cpsw_resume_data_pass(ndev);
 	if (!ret)
 		return 0;
-
+err:
+	cpdma_set_num_rx_descs(cpsw->dma, descs_num);
 	dev_err(cpsw->dev, "cannot set ring params, closing device\n");
 	dev_close(ndev);
 	return ret;

drivers/net/ethernet/ti/davinci_cpdma.c

@@ -1423,8 +1423,23 @@ int cpdma_get_num_tx_descs(struct cpdma_ctlr *ctlr)
 	return ctlr->num_tx_desc;
 }
 
-void cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc)
+int cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc)
 {
+	unsigned long flags;
+	int temp, ret;
+
+	spin_lock_irqsave(&ctlr->lock, flags);
+
+	temp = ctlr->num_rx_desc;
 	ctlr->num_rx_desc = num_rx_desc;
 	ctlr->num_tx_desc = ctlr->pool->num_desc - ctlr->num_rx_desc;
+	ret = cpdma_chan_split_pool(ctlr);
+	if (ret) {
+		ctlr->num_rx_desc = temp;
+		ctlr->num_tx_desc = ctlr->pool->num_desc - ctlr->num_rx_desc;
+	}
+
+	spin_unlock_irqrestore(&ctlr->lock, flags);
+
+	return ret;
 }

drivers/net/ethernet/ti/davinci_cpdma.h

@@ -116,8 +116,7 @@ enum cpdma_control {
 int cpdma_control_get(struct cpdma_ctlr *ctlr, int control);
 int cpdma_control_set(struct cpdma_ctlr *ctlr, int control, int value);
 int cpdma_get_num_rx_descs(struct cpdma_ctlr *ctlr);
-void cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc);
+int cpdma_set_num_rx_descs(struct cpdma_ctlr *ctlr, int num_rx_desc);
 int cpdma_get_num_tx_descs(struct cpdma_ctlr *ctlr);
-int cpdma_chan_split_pool(struct cpdma_ctlr *ctlr);
 
 #endif