summaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/mscc
diff options
context:
space:
mode:
authorVladimir Oltean <vladimir.oltean@nxp.com>2023-04-15 20:05:47 +0300
committerJakub Kicinski <kuba@kernel.org>2023-04-18 05:01:18 +0300
commit7bf4a5b071e59f48de8d39dfde07a3a65e7f6488 (patch)
treed19c98a3bce97f62bd00bfae5cec30d4dd132d02 /drivers/net/ethernet/mscc
parent3ff468ef987e38740de9ca0a811c55e11bfb2141 (diff)
downloadlinux-7bf4a5b071e59f48de8d39dfde07a3a65e7f6488.tar.xz
net: mscc: ocelot: optimize ocelot_mm_irq()
The MAC Merge IRQ of all ports is shared with the PTP TX timestamp IRQ of all ports, which means that currently, when a PTP TX timestamp is generated, felix_irq_handler() also polls for the MAC Merge layer status of all ports, looking for changes. This makes the kernel do more work, and under certain circumstances may make ptp4l require a tx_timestamp_timeout argument higher than before. Changes to the MAC Merge layer status are only to be expected under certain conditions - its TX direction needs to be enabled - so we can check early if that is the case, and omit register access otherwise. Make ocelot_mm_update_port_status() skip register access if mm->tx_enabled is unset, and also call it once more, outside IRQ context, from ocelot_port_set_mm(), when mm->tx_enabled transitions from true to false, because an IRQ is also expected in that case. Also, a port may have its MAC Merge layer enabled but it may not have generated the interrupt. In that case, there's no point in writing to DEV_MM_STATUS to acknowledge that IRQ. We can reduce the number of register writes per port with MM enabled by keeping an "ack" variable which writes the "write-one-to-clear" bits. Those are 3 in number: PRMPT_ACTIVE_STICKY, UNEXP_RX_PFRM_STICKY and UNEXP_TX_PFRM_STICKY. The other fields in DEV_MM_STATUS are read-only and it doesn't matter what is written to them, so writing zero is just fine. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/ethernet/mscc')
-rw-r--r--drivers/net/ethernet/mscc/ocelot_mm.c30
1 files changed, 28 insertions, 2 deletions
diff --git a/drivers/net/ethernet/mscc/ocelot_mm.c b/drivers/net/ethernet/mscc/ocelot_mm.c
index d2df47e6f8f6..ce6429d46814 100644
--- a/drivers/net/ethernet/mscc/ocelot_mm.c
+++ b/drivers/net/ethernet/mscc/ocelot_mm.c
@@ -54,7 +54,10 @@ static void ocelot_mm_update_port_status(struct ocelot *ocelot, int port)
struct ocelot_port *ocelot_port = ocelot->ports[port];
struct ocelot_mm_state *mm = &ocelot->mm[port];
enum ethtool_mm_verify_status verify_status;
- u32 val;
+ u32 val, ack = 0;
+
+ if (!mm->tx_enabled)
+ return;
val = ocelot_port_readl(ocelot_port, DEV_MM_STATUS);
@@ -71,21 +74,28 @@ static void ocelot_mm_update_port_status(struct ocelot *ocelot, int port)
dev_dbg(ocelot->dev, "Port %d TX preemption %s\n",
port, mm->tx_active ? "active" : "inactive");
+
+ ack |= DEV_MM_STAT_MM_STATUS_PRMPT_ACTIVE_STICKY;
}
if (val & DEV_MM_STAT_MM_STATUS_UNEXP_RX_PFRM_STICKY) {
dev_err(ocelot->dev,
"Unexpected P-frame received on port %d while verification was unsuccessful or not yet verified\n",
port);
+
+ ack |= DEV_MM_STAT_MM_STATUS_UNEXP_RX_PFRM_STICKY;
}
if (val & DEV_MM_STAT_MM_STATUS_UNEXP_TX_PFRM_STICKY) {
dev_err(ocelot->dev,
"Unexpected P-frame requested to be transmitted on port %d while verification was unsuccessful or not yet verified, or MM_TX_ENA=0\n",
port);
+
+ ack |= DEV_MM_STAT_MM_STATUS_UNEXP_TX_PFRM_STICKY;
}
- ocelot_port_writel(ocelot_port, val, DEV_MM_STATUS);
+ if (ack)
+ ocelot_port_writel(ocelot_port, ack, DEV_MM_STATUS);
}
void ocelot_mm_irq(struct ocelot *ocelot)
@@ -107,11 +117,14 @@ int ocelot_port_set_mm(struct ocelot *ocelot, int port,
{
struct ocelot_port *ocelot_port = ocelot->ports[port];
u32 mm_enable = 0, verify_disable = 0, add_frag_size;
+ struct ocelot_mm_state *mm;
int err;
if (!ocelot->mm_supported)
return -EOPNOTSUPP;
+ mm = &ocelot->mm[port];
+
err = ethtool_mm_frag_size_min_to_add(cfg->tx_min_frag_size,
&add_frag_size, extack);
if (err)
@@ -145,6 +158,19 @@ int ocelot_port_set_mm(struct ocelot *ocelot, int port,
QSYS_PREEMPTION_CFG,
port);
+ /* The switch will emit an IRQ when TX is disabled, to notify that it
+ * has become inactive. We optimize ocelot_mm_update_port_status() to
+ * not bother processing MM IRQs at all for ports with TX disabled,
+ * but we need to ACK this IRQ now, while mm->tx_enabled is still set,
+ * otherwise we get an IRQ storm.
+ */
+ if (mm->tx_enabled && !cfg->tx_enabled) {
+ ocelot_mm_update_port_status(ocelot, port);
+ WARN_ON(mm->tx_active);
+ }
+
+ mm->tx_enabled = cfg->tx_enabled;
+
mutex_unlock(&ocelot->fwd_domain_lock);
return 0;