RE: [PATCH v2 2/2] dpaa_eth: add ethtool coalesce control

[Madalin-cristian Bucur]

> -Original Message-
> From: David Miller 
> Sent: Saturday, November 17, 2018 5:42 AM
> To: Madalin-cristian Bucur 
> Subject: Re: [PATCH v2 2/2] dpaa_eth: add ethtool coalesce control
> 
> From: Madalin Bucur 
> Date: Tue, 13 Nov 2018 18:29:51 +0200
> 
> > +   for_each_cpu(cpu, cpus) {
> > +   portal = qman_get_affine_portal(cpu);
> > +   res = qman_portal_set_iperiod(portal, period);
> > +   if (res)
> > +   return res;
> > +   res = qman_dqrr_set_ithresh(portal, thresh);
> > +   if (res)
> > +   return res;
> 
> Nope, you can't do it like this.
> 
> If any intermediate change fails, you have to unwind all of the
> changes made up until that point.
> 
> Which means you'll have to store the previous setting somewhere
> and reinstall those saved values in the error path.

Thank you, I'll come back with a v3.

Madalin

Re: [PATCH v2 2/2] dpaa_eth: add ethtool coalesce control

[David Miller]

From: Madalin Bucur 
Date: Tue, 13 Nov 2018 18:29:51 +0200

> + for_each_cpu(cpu, cpus) {
> + portal = qman_get_affine_portal(cpu);
> + res = qman_portal_set_iperiod(portal, period);
> + if (res)
> + return res;
> + res = qman_dqrr_set_ithresh(portal, thresh);
> + if (res)
> + return res;

Nope, you can't do it like this.

If any intermediate change fails, you have to unwind all of the
changes made up until that point.

Which means you'll have to store the previous setting somewhere
and reinstall those saved values in the error path.

[PATCH v2 2/2] dpaa_eth: add ethtool coalesce control

[Madalin Bucur]

Allow ethtool control of the DPAA QMan portal interrupt coalescing
settings.

Signed-off-by: Madalin Bucur 
---
 drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c | 49 ++
 1 file changed, 49 insertions(+)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c 
b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c
index 13d6e2272ece..4df366b05976 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c
@@ -529,6 +529,53 @@ static int dpaa_get_ts_info(struct net_device *net_dev,
return 0;
 }
 
+static int dpaa_get_coalesce(struct net_device *dev,
+struct ethtool_coalesce *c)
+{
+   struct qman_portal *portal;
+   u32 period;
+   u8 thresh;
+
+   portal = qman_get_affine_portal(smp_processor_id());
+   qman_portal_get_iperiod(portal, );
+   qman_dqrr_get_ithresh(portal, );
+
+   c->rx_coalesce_usecs = period;
+   c->rx_max_coalesced_frames = thresh;
+   c->use_adaptive_rx_coalesce = false;
+
+   return 0;
+}
+
+static int dpaa_set_coalesce(struct net_device *dev,
+struct ethtool_coalesce *c)
+{
+   const cpumask_t *cpus = qman_affine_cpus();
+   struct qman_portal *portal;
+   u32 period;
+   u8 thresh;
+   int cpu;
+   int res;
+
+   if (c->use_adaptive_rx_coalesce)
+   return -EINVAL;
+
+   period = c->rx_coalesce_usecs;
+   thresh = c->rx_max_coalesced_frames;
+
+   for_each_cpu(cpu, cpus) {
+   portal = qman_get_affine_portal(cpu);
+   res = qman_portal_set_iperiod(portal, period);
+   if (res)
+   return res;
+   res = qman_dqrr_set_ithresh(portal, thresh);
+   if (res)
+   return res;
+   }
+
+   return 0;
+}
+
 const struct ethtool_ops dpaa_ethtool_ops = {
.get_drvinfo = dpaa_get_drvinfo,
.get_msglevel = dpaa_get_msglevel,
@@ -545,4 +592,6 @@ const struct ethtool_ops dpaa_ethtool_ops = {
.get_rxnfc = dpaa_get_rxnfc,
.set_rxnfc = dpaa_set_rxnfc,
.get_ts_info = dpaa_get_ts_info,
+   .get_coalesce = dpaa_get_coalesce,
+   .set_coalesce = dpaa_set_coalesce,
 };
-- 
2.1.0