[v8,0/2] clocksource: davinci-timer: new driver

Message

Bartosz Golaszewski June 24, 2019, 9:50 a.m. UTC

From: Bartosz Golaszewski <[e-mail]>

Now that we have an agreement on the driver and only minor issues are left
to fix, I'm dropping the RFC tag and continuing the numbering from before
RFCs.

This is the davinci clocksource driver but it with a sparse warning fixed
and with a small tweak to kzalloc() call.

RFC history:

v1 -> v2:
- changed the format of the copyright notice
- removed all mentiones of the periodic timer setting
- added caching of the TCR register value so that its updating doesn't
  require a read
- split the timer configuration for clock events into the
  set_state_oneshot() and set_state_shutdown() callbacks

v2 -> v3:
- tim34, if used, should run in periodic mode for clocksource, now fixed
- dropped all the configuration variables from struct davinci_clockevent
  as clockevent always uses tim12
- dropped caching of the TCR register with the following reasoning: on
  systems using tim34 for clocksource, the TCR register is only touched
  by the clock driver and we know that we need to keep tim34 in periodic
  mode; on da830 the RTOS running on the DSP may modify the TCR register
  but we on the other hand never change its settings when only using tim12
- subsequently the whole routine for TCR updating was dropped
- dropped the shift variable from most places
- added separate routines for initializing clocksource for da830 and all
  other systems
- sprinkled a bunch of comments all over the driver to explain things
  that caused confusion before

Changes since last RFC:

- fixed the following sparse warning:

>> drivers/clocksource/timer-davinci.c:198:14: sparse: sparse: incorrect type in assignment (different address spaces) @@    expected void [noderef] <asn:2> *base @@    got oderef] <asn:2> *base @@
>> drivers/clocksource/timer-davinci.c:198:14: sparse:    expected void [noderef] <asn:2> *base
>> drivers/clocksource/timer-davinci.c:198:14: sparse:    got struct resource *

- added the __GFP_NOFAIL flag to kzalloc() call so that we don't get warnings
  about not freeing the memory later

Bartosz Golaszewski (2):
  clocksource: davinci-timer: add support for clockevents
  clocksource: timer-davinci: add support for clocksource

 drivers/clocksource/Kconfig         |   5 +
 drivers/clocksource/Makefile        |   1 +
 drivers/clocksource/timer-davinci.c | 369 ++++++++++++++++++++++++++++
 include/clocksource/timer-davinci.h |  44 ++++
 4 files changed, 419 insertions(+)
 create mode 100644 drivers/clocksource/timer-davinci.c
 create mode 100644 include/clocksource/timer-davinci.h