net: dsa: microchip: ptp: add support for perout programmable pins

There are two programmable pins available for Trigger output unit to
generate periodic pulses. This patch add verify_pin for the available 2
pins and configure it with respect to GPIO index for the TOU unit.

Tested using testptp
./testptp -i 0 -L 0,2
./testptp -i 0 -d /dev/ptp0 -p 1000000000
./testptp -i 1 -L 1,2
./testptp -i 1 -d /dev/ptp0 -p 100000000

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: add periodic output signal

LAN937x and KSZ PTP supported switches has Three Trigger output unit.
This TOU can used to generate the periodic signal for PTP. TOU has the
cycle width register of 32 bit in size and period width register of 24
bit, each value is of 8ns so the pulse width can be maximum 125ms.

Tested using ./testptp -d /dev/ptp0 -p 1000000000 -w 100000000 for
generating the 10ms pulse width

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: add packet transmission timestamping

This patch adds the routines for transmission of ptp packets. When the
ptp pdelay_req packet to be transmitted, it uses the deferred xmit
worker to schedule the packets.
During irq_setup, interrupt for Sync, Pdelay_req and Pdelay_rsp are
enabled. So interrupt is triggered for all three packets. But for
p2p1step, we require only time stamp of Pdelay_req packet. Hence to
avoid posting of the completion from ISR routine for Sync and
Pdelay_resp packets, ts_en flag is introduced. This controls which
packets need to processed for timestamp.
After the packet is transmitted, ISR is triggered. The time at which
packet transmitted is recorded to separate register.
This value is reconstructed to absolute time and posted to the user
application through socket error queue.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: add packet reception timestamping

Rx Timestamping is done through 4 additional bytes in tail tag.
Whenever the ptp packet is received, the 4 byte hardware time stamped
value is added before 1 byte tail tag. Also, bit 7 in tail tag indicates
it as PTP frame. This 4 byte value is extracted from the tail tag and
reconstructed to absolute time and assigned to skb hwtstamp.
If the packet received in PDelay_Resp, then partial ingress timestamp
is subtracted from the correction field. Since user space tools expects
to be done in hardware.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: enable interrupt for timestamping

PTP Interrupt mask and status register differ from the global and port
interrupt mechanism by two methods. One is that for global/port
interrupt enabling we have to clear the bit but for ptp interrupt we
have to set the bit. And other is bit12:0 is reserved in ptp interrupt
registers. This forced to not use the generic implementation of
global/port interrupt method routine. This patch implement the ptp
interrupt mechanism to read the timestamp register for sync, pdelay_req
and pdelay_resp.

Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: manipulating absolute time using ptp hw clock

This patch is used for reconstructing the absolute time from the 32bit
hardware time stamping value. The do_aux ioctl is used for reading the
ptp hardware clock and store it to global variable.
The timestamped value in tail tag during rx and register during tx are
32 bit value (2 bit seconds and 30 bit nanoseconds). The time taken to
read entire ptp clock will be time consuming. In order to speed up, the
software clock is maintained. This clock time will be added to 32 bit
timestamp to get the absolute time stamp.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: Initial hardware time stamping support

This patch adds the routine for get_ts_info, hwstamp_get, set. This enables
the PTP support towards userspace applications such as linuxptp.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: microchip: ptp: add the posix clock support

This patch implement routines (adjfine, adjtime, gettime and settime)
for manipulating the chip's PTP clock. It registers the ptp caps
to posix clock register.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com> # mostly api
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>