drm/komeda: Add event handling for EMPTY/FULL

EMPTY/FULL are HW input/output FIFO condition identifer, which are
useful information for addressing the problem, so expose them.

Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@arm.com>
Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212072737.30116-1-james.qian.wang@arm.com

drm/komeda: Clean warnings: candidate for 'gnu_printf’ format attribute

komeda/komeda_event.c: In function ‘komeda_sprintf’:
komeda/komeda_event.c:31:2: warning: function ‘komeda_sprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
num = vsnprintf(str->str + str->len, free_sz, fmt, args);

v2: Update the comment msg.

Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191114100421.30510-1-james.qian.wang@arm.com

drm/komeda: add rate limiting disable to err_verbosity

It's possible to get multiple events in a single frame/flip, so add an
option to print them all.

Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107114155.54307-6-mihail.atanassov@arm.com

drm/komeda: Add option to print WARN- and INFO-level IRQ events

Extra detail (normally off) almost never hurts.

Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107114155.54307-5-mihail.atanassov@arm.com

drm/komeda: Optionally dump DRM state on interrupts

It's potentially useful information when diagnosing error/warn IRQs, so
dump it to dmesg with a drm_info_printer. Hide this extra debug dumping
behind another komeda_dev->err_verbosity bit.

Note that there's not much sense in dumping it for INFO events,
since the VSYNC event will swamp the log.

Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107114155.54307-4-mihail.atanassov@arm.com

drm/komeda: Add debugfs node to control error verbosity

Named 'err_verbosity', currently with only 1 active bit in that
replicates the existing level - print error events once per flip.

Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107114155.54307-2-mihail.atanassov@arm.com

drm/komeda: Adds error event print functionality

Adds to print the event message when error happens and the same event
will not be printed until next vsync.

Changes since v2:
1. Refine komeda_sprintf();
2. Not using STR_SZ macro for the string size in komeda_print_events().

Changes since v1:
1. Handling the event print by CONFIG_KOMEDA_ERROR_PRINT;
2. Changing the max string size to 256.

Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@arm.com>
Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1564738954-6101-1-git-send-email-lowry.li@arm.com