Merge branch 'net-ethernet-ti-cpts-add-irq-and-HW_TS_PUSH-events'

Merge branch 'net-ethernet-ti-cpts-add-irq-and-HW_TS_PUSH-events'

Grygorii Strashko says:

====================
net: ethernet: ti: cpts: add irq and HW_TS_PUSH events

This is re-spin of patches to add CPSW IRQ and HW_TS_PUSH events support I've
sent long time ago [1]. In this series, I've tried to restructure and split changes,
and also add few additional optimizations comparing to initial RFC submission [1].

The HW_TS_PUSH events intended to serve for different timesync purposes on of
which is to add PPS generation function, which can be implemented as below:

                     +-----------------+
                     | Control         |
                     | application     |
            +------->+                 +----------+
            |        |                 |          |
            |        |                 |          |
            |        +-----------------+          |
            |                                     |
            |                                     |
            | PTP_EXTTS_REQUEST                   |
            |                                     |
            |                                     |
 +----------------------------------------------------------------+
            |                                     |    Kernel
    +-------+----------+                  +-------v--------+
    |  \dev\ptpX       |                  | /sys/class/pwm/|
    |                  |                  |                |
    +-------^----------+                  +-------+--------+
            |                                     |
            |                                     |
            |                             +-------v-------------------+
    +-------+----------+                  |                           |
    | CPTS driver      |                  |pwm/pwm-omap-dmtimer.c     |
    |                  |                  +---------------------------+
    +-------^----------+                  |clocksource/timer_ti_dm.c  |
            |                             +-------+-------------------+
            |HWx_TS_PUSH evt                      |
 +----------------------------------------------------------------+
            |                                     |         HW
    +-------+----------+                  +-------v--------+
    | CPTS             |                  | DMTimer        |
    |                  |                  |                |
    |      HWx_TS_PUSH X<-----------------+                |
    |                  +                  |                |
    +------------------+                  +-------+--------+
                                                  |
                                                  X timer4

As per my knowledge there is at least one public implemented above PPS generation
schema from Tusori Tibor [2] based on initial HW_TS_PUSH enable submission[1].
And now there is work done by Lokesh Vutla <lokeshvutla@ti.com> published to
enable PWM enable/improve PWM adjustment from user space [3][4][5].

Main changes comparing to initial submission:
- TX timestamp processing deferred to ptp worker only
- both CPTS IRQ and polling events processing supported to make it work for
  Keystone 2 also
- switch to use new .gettimex64() interface
- no DT updates as number of HWx_TS_PUSH inputs is static per HW

Testing on am571x-idk/omap2plus_defconfig/+CONFIG_PREEMPT=y:
1) testing HW_TS_PUSH
 - enable pwm in DT
	pwm16: dmtimer-pwm {
		compatible = "ti,omap-dmtimer-pwm";
		ti,timers = <&timer16>;
		#pwm-cells = <3>;
	};
 - configure and start pwm
  echo 0 > /sys/class/pwm/pwmchip0/export
  echo 1000000000 > /sys/class/pwm/pwmchip0/pwm0/period
  echo 500000000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
  echo 1 > /sys/class/pwm/pwmchip0/pwm0/enable
 - test HWx_TS_PUSH using Kernel selftest testptp application
  ./tools/testing/selftests/ptp/testptp -d /dev/ptp0 -e 1000 -i 3

2) testing phc2sys
phc2sys[1616.791]: eth0 rms 408190379792180864 max 1580914543017209856 freq +864 +/- 4635 delay 645 +/- 29
phc2sys[1646.795]: eth0 rms 41 max 108 freq +0 +/- 36 delay 656 +/- 29
phc2sys[1676.800]: eth0 rms 43 max 83 freq +2 +/- 38 delay 650 +/- 0
phc2sys[1706.804]: eth0 rms 39 max 87 freq +4 +/- 34 delay 672 +/- 55
phc2sys[1736.808]: eth0 rms 35 max 66 freq +1 +/- 30 delay 667 +/- 49
phc2sys[1766.813]: eth0 rms 38 max 79 freq +2 +/- 33 delay 656 +/- 29
phc2sys[1796.817]: eth0 rms 45 max 98 freq +1 +/- 39 delay 656 +/- 29
phc2sys[1826.821]: eth0 rms 40 max 87 freq +5 +/- 35 delay 650 +/- 0
phc2sys[1856.826]: eth0 rms 29 max 76 freq -0 +/- 25 delay 656 +/- 29
phc2sys[1886.830]: eth0 rms 40 max 97 freq +4 +/- 35 delay 667 +/- 49
phc2sys[1916.834]: eth0 rms 42 max 94 freq +2 +/- 36 delay 661 +/- 41
phc2sys[1946.839]: eth0 rms 40 max 91 freq +2 +/- 35 delay 661 +/- 41
phc2sys[1976.843]: eth0 rms 46 max 88 freq -0 +/- 40 delay 667 +/- 49
phc2sys[2006.847]: eth0 rms 49 max 97 freq +2 +/- 43 delay 650 +/- 0

3) testing ptp4l
- 1G connection
ptp4l[862.891]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED
ptp4l[923.894]: rms 1019697354682 max 5768279314068 freq +26053 +/- 72 delay 488 +/- 1
ptp4l[987.896]: rms 13 max 26 freq +26005 +/- 29 delay 488 +/- 1
ptp4l[1051.899]: rms 14 max 50 freq +25895 +/- 21 delay 488 +/- 1
ptp4l[1115.901]: rms 11 max 27 freq +25878 +/- 17 delay 488 +/- 1
ptp4l[1179.904]: rms 10 max 27 freq +25857 +/- 12 delay 488 +/- 1
ptp4l[1243.906]: rms 14 max 37 freq +25851 +/- 15 delay 488 +/- 1
ptp4l[1307.909]: rms 12 max 33 freq +25835 +/- 15 delay 488 +/- 1
ptp4l[1371.911]: rms 11 max 27 freq +25832 +/- 14 delay 488 +/- 1
ptp4l[1435.914]: rms 11 max 26 freq +25823 +/- 11 delay 488 +/- 1
ptp4l[1499.916]: rms 10 max 29 freq +25829 +/- 11 delay 489 +/- 1
ptp4l[1563.919]: rms 11 max 27 freq +25827 +/- 12 delay 488 +/- 1

- 10M connection
ptp4l[51.955]: port 1: UNCALIBRATED to SLAVE on MASTER_CLOCK_SELECTED
ptp4l[112.957]: rms 279468848453933920 max 1580914542977391360 freq +25390 +/- 3207 delay 8222 +/- 36
ptp4l[176.960]: rms 254 max 522 freq +25809 +/- 219 delay 8271 +/- 30
ptp4l[240.962]: rms 271 max 684 freq +25868 +/- 234 delay 8249 +/- 22
ptp4l[304.965]: rms 263 max 556 freq +25894 +/- 227 delay 8225 +/- 47
ptp4l[368.967]: rms 238 max 648 freq +25908 +/- 204 delay 8234 +/- 40
ptp4l[432.970]: rms 274 max 658 freq +25932 +/- 237 delay 8241 +/- 22
ptp4l[496.972]: rms 247 max 557 freq +25943 +/- 213 delay 8223 +/- 26
ptp4l[560.974]: rms 291 max 756 freq +25968 +/- 251 delay 8244 +/- 41
ptp4l[624.977]: rms 249 max 697 freq +25975 +/- 216 delay 8258 +/- 22

Changes in v5:
 - fixed build issue

Changes in v4:
 - fixed comments from Richard Cochran
 - dropped patch "net: ethernet: ti: cpts: move rx timestamp processing to ptp
   worker only"
 - added "Acked-by" from Richard Cochran <richardcochran@gmail.com>
 - dependencies resolved, patch merged

Changes in v3:
 - fixed rebase mess
 - fixed build issues

Changes in v2 (broken):
 - fixed (formatting) comments from David Miller <davem@davemloft.net>

v4: https://patchwork.ozlabs.org/project/netdev/cover/20200422201254.15232-1-grygorii.strashko@ti.com/
v3: https://patchwork.ozlabs.org/project/netdev/cover/20200320194244.4703-1-grygorii.strashko@ti.com/
v2: https://patchwork.ozlabs.org/cover/1258339/
v1: https://patchwork.ozlabs.org/cover/1254708/

[1] https://lore.kernel.org/patchwork/cover/799251/
[2] https://usermanual.wiki/Document/SetupGuide.632280828.pdf
    https://github.com/t-tibor/msc_thesis
[3] https://patchwork.kernel.org/cover/11421329/
[4] https://patchwork.kernel.org/cover/11433197/
[5] https://sourceforge.net/p/linuxptp/mailman/message/36943248/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>