linux/include/soc/mscc
Vladimir Oltean 7bf4a5b071 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>
2023-04-17 19:01:18 -07:00
..
ocelot_ana.h net: dsa: felix: support psfp filter on vsc9959 2021-11-18 12:07:24 +00:00
ocelot_dev.h net: mscc: ocelot: add MAC Merge layer support for VSC9959 2023-01-23 12:44:18 +00:00
ocelot_hsio.h
ocelot_ptp.h net: mscc: ocelot: avoid overflowing the PTP timestamp FIFO 2021-10-12 17:35:17 -07:00
ocelot_qsys.h net: mscc: ocelot: add ops for decoding watermark threshold and occupancy 2021-01-15 20:02:34 -08:00
ocelot_sys.h net: mscc: ocelot: convert SYS_PAUSE_CFG register access to regfield 2020-07-13 17:40:02 -07:00
ocelot_vcap.h net: dsa: felix: tag_8021q preparation for multiple CPU ports 2022-05-23 10:39:55 +01:00
ocelot.h net: mscc: ocelot: optimize ocelot_mm_irq() 2023-04-17 19:01:18 -07:00
vsc7514_regs.h net: mscc: ocelot: un-export unused regmap symbols 2023-02-06 22:33:15 -08:00