diff mbox series

[net-next,v2,4/5] net: ravb: Do not apply RX checksum settings to hardware if the interface is down

Message ID 20240209170459.4143861-5-claudiu.beznea.uj@bp.renesas.com
State New
Headers
Series net: ravb: Add runtime PM support (part 2) |

Commit Message

claudiu beznea Feb. 9, 2024, 5:04 p.m. UTC 
  From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

Do not apply the RX checksum settings to hardware if the interface is down.
In case runtime PM is enabled, and while the interface is down, the IP will
be in reset mode (as for some platforms disabling the clocks will switch
the IP to reset mode, which will lead to losing register contents) and
applying settings in reset mode is not an option. Instead, cache the RX
checksum settings and apply them in ravb_open() through ravb_emac_init().
This has been solved by introducing pm_runtime_active() check. The device
runtime PM usage counter has been incremented to avoid disabling the device
clocks while the check is in progress (if any).

Commit prepares for the addition of runtime PM.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---

Changes in v2:
- fixed typo in patch description
- adjusted ravb_set_features_gbeth(); didn't collect the Sergey's Rb
  tag due to this 

Changes since [2]:
- use pm_runtime_get_noresume() and pm_runtime_active() and updated the
  commit message to describe that
- fixed typos
- s/CSUM/checksum in patch title and description

Changes in v3 of [2]:
- this was patch 20/21 in v2
- fixed typos in patch description
- removed code from ravb_open()
- use ndev->flags & IFF_UP checks instead of netif_running()

Changes in v2 of [2]:
- none; this patch is new

[2] https://lore.kernel.org/all/20240105082339.1468817-1-claudiu.beznea.uj@bp.renesas.com/

 drivers/net/ethernet/renesas/ravb_main.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

Comments

Sergey Shtylyov Feb. 10, 2024, 8:37 p.m. UTC | #1 
On 2/9/24 11:41 PM, Biju Das wrote:
[...]

>>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>>
>>> Do not apply the RX checksum settings to hardware if the interface is
>>> down.
>>> In case runtime PM is enabled, and while the interface is down, the IP
>>> will be in reset mode (as for some platforms disabling the clocks will
>>> switch the IP to reset mode, which will lead to losing register
>>> contents) and applying settings in reset mode is not an option.
>>> Instead, cache the RX checksum settings and apply them in ravb_open()
>>> through ravb_emac_init().
>>> This has been solved by introducing pm_runtime_active() check. The
>>> device runtime PM usage counter has been incremented to avoid
>>> disabling the device clocks while the check is in progress (if any).
>>>
>>> Commit prepares for the addition of runtime PM.
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
> 
> This will do the same job, without code duplication right?
> 
> static int ravb_set_features(struct net_device *ndev,
> 			     netdev_features_t features)
> {
> 	struct ravb_private *priv = netdev_priv(ndev);
> 	struct device *dev = &priv->pdev->dev;
> 	const struct ravb_hw_info *info = priv->info;
> 
> 	pm_runtime_get_noresume(dev);
> 	if (!pm_runtime_active(dev)) {
> 		pm_runtime_put_noidle(dev);
> 		ndev->features = features;
> 		return 0;
> 	}
> 		
> 	return info->set_feature(ndev, features);

   We now leak the device reference by not calling pm_runtime_put_noidle()
after this statement...
   The approach seems sane though -- Claudiu, please consider following it.

[...]

> Cheers,
> Biju

MBR, Sergey
diff mbox series

Patch

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 7a7f743a1fef..f4be08f0198d 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2478,8 +2478,14 @@  static int ravb_change_mtu(struct net_device *ndev, int new_mtu)
 static void ravb_set_rx_csum(struct net_device *ndev, bool enable)
 {
 	struct ravb_private *priv = netdev_priv(ndev);
+	struct device *dev = &priv->pdev->dev;
 	unsigned long flags;
 
+	pm_runtime_get_noresume(dev);
+
+	if (!pm_runtime_active(dev))
+		goto out_rpm_put;
+
 	spin_lock_irqsave(&priv->lock, flags);
 
 	/* Disable TX and RX */
@@ -2492,6 +2498,9 @@  static void ravb_set_rx_csum(struct net_device *ndev, bool enable)
 	ravb_rcv_snd_enable(ndev);
 
 	spin_unlock_irqrestore(&priv->lock, flags);
+
+out_rpm_put:
+	pm_runtime_put_noidle(dev);
 }
 
 static int ravb_endisable_csum_gbeth(struct net_device *ndev, enum ravb_reg reg,
@@ -2515,10 +2524,16 @@  static int ravb_set_features_gbeth(struct net_device *ndev,
 {
 	netdev_features_t changed = ndev->features ^ features;
 	struct ravb_private *priv = netdev_priv(ndev);
+	struct device *dev = &priv->pdev->dev;
 	unsigned long flags;
 	int ret = 0;
 	u32 val;
 
+	pm_runtime_get_noresume(dev);
+
+	if (!pm_runtime_active(dev))
+		goto out_rpm_put;
+
 	spin_lock_irqsave(&priv->lock, flags);
 	if (changed & NETIF_F_RXCSUM) {
 		if (features & NETIF_F_RXCSUM)
@@ -2542,9 +2557,12 @@  static int ravb_set_features_gbeth(struct net_device *ndev,
 			goto done;
 	}
 
-	ndev->features = features;
 done:
 	spin_unlock_irqrestore(&priv->lock, flags);
+out_rpm_put:
+	pm_runtime_put_noidle(dev);
+	if (!ret)
+		ndev->features = features;
 
 	return ret;
 }