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# ====================================================================
#
# counters.cdl
#
# configuration data related to the kernel counters and clocks
#
# ====================================================================
#####ECOSGPLCOPYRIGHTBEGIN####
## -------------------------------------------
## This file is part of eCos, the Embedded Configurable Operating System.
## Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
##
## eCos is free software; you can redistribute it and/or modify it under
## the terms of the GNU General Public License as published by the Free
## Software Foundation; either version 2 or (at your option) any later version.
##
## eCos is distributed in the hope that it will be useful, but WITHOUT ANY
## WARRANTY; without even the implied warranty of MERCHANTABILITY or
## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
## for more details.
##
## You should have received a copy of the GNU General Public License along
## with eCos; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
##
## As a special exception, if other files instantiate templates or use macros
## or inline functions from this file, or you compile this file and link it
## with other works to produce a work based on this file, this file does not
## by itself cause the resulting work to be covered by the GNU General Public
## License. However the source code for this file must still be made available
## in accordance with section (3) of the GNU General Public License.
##
## This exception does not invalidate any other reasons why a work based on
## this file might be covered by the GNU General Public License.
##
## Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
## at http://sources.redhat.com/ecos/ecos-license/
## -------------------------------------------
#####ECOSGPLCOPYRIGHTEND####
# ====================================================================
######DESCRIPTIONBEGIN####
#
# Author(s): jskov
# Original data: nickg
# Contributors:
# Date: 1999-07-05
#
#####DESCRIPTIONEND####
#
# ====================================================================
cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK {
display "Provide real-time clock"
requires CYGIMP_KERNEL_INTERRUPTS_DSRS
default_value 1
description "
On all current target systems the kernel can provide a
real-time clock. This clock serves two purposes. First it is
necessary to support clock and alarm related functions.
Second it is needed to implement timeslicing in some of the
schedulers including the mlqueue scheduler. If the
application does not require any of these facilities then it
is possible to disable the real time clock support
completely."
}
cdl_component CYGPKG_KERNEL_COUNTERS_CLOCK_OVERRIDE {
display "Override default clock settings"
requires CYGVAR_KERNEL_COUNTERS_CLOCK
default_value 0
description "
The kernel has default settings for the clock interrupt
frequency. These settings will vary from platform to
platform, but typically there will be a 100 clock interrupts
every second. It is possible to change this frequency, but
it requires some knowledge of the target hardware."
cdl_option CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_PERIOD {
display "Clock hardware initialization value"
flavor data
legal_values 1 to 0x7fffffff
default_value 9999
description "
During system initialization this value is used to initialize
the clock hardware. The exact meaning of the value and the
range of legal values therefore depends on the target hardware,
and the hardware documentation should be consulted for further
details. In addition the clock resolution numerator and
denominator values should be updated. Typical values for
this option would be 150000 on the MN10300 stdeval1 board,
15625 on the tx39 jmr3904 board, and 20833 on the powerpc
cogent board."
}
cdl_option CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_NUMERATOR {
display "Clock resolution numerator"
flavor data
legal_values 1 to 0x7fffffff
default_value 1000000000
description "
If a non-default clock interrupt frequency is used then it
is necessary to specify the clock resolution explicitly.
This resolution involves two separate values, the numerator
and the denominator. The result of dividing the numerator by
the denominator should correspond to the number of
nanoseconds between clock interrupts. For example a
numerator of 1000000000 and a denominator of 100 means that
there are 10000000 nanoseconds (or 10 milliseconds) between
clock interrupts. Expressing the resolution as a fraction
should minimize clock drift even for frequencies that cannot
be expressed as a simple integer. For example a frequency of
60Hz corresponds to a clock resolution of 16666666.66...
nanoseconds. This can be expressed accurately as 1000000000
over 60."
}
cdl_option CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_DENOMINATOR {
display "Clock resolution denominator"
flavor data
legal_values 1 to 0x7fffffff
default_value 100
description "
If a non-default clock interrupt frequency is used then it
is necessary to specify the clock resolution explicitly.
This resolution involves two separate values, the numerator
and the denominator. The result of dividing the numerator by
the denominator should correspond to the number of
nanoseconds between clock interrupts. For example a
numerator of 1000000000 and a denominator of 100 means that
there are 10000000 nanoseconds (or 10 milliseconds) between
clock interrupts. Expressing the resolution as a fraction
should minimize clock drift even for frequencies that cannot
be expressed as a simple integer. For example a frequency of
60Hz corresponds to a clock resolution of 16666666.66...
nanoseconds. This can be expressed accurately as 1000000000
over 60."
}
}
cdl_interface CYGINT_KERNEL_COUNTERS {
requires 1 == CYGINT_KERNEL_COUNTERS
no_define
}
# NOTE: these option should really be a single enum.
cdl_option CYGIMP_KERNEL_COUNTERS_SINGLE_LIST {
display "Implement counters using a single list"
default_value 1
implements CYGINT_KERNEL_COUNTERS
description "
There are two different implementations of the counter
objects. The first implementation stores all alarms in a
single linked list. The alternative implementation uses a
table of linked lists. A single list is more efficient in
terms of memory usage and is generally adequate when the
application only makes use of a small number of alarms."
}
cdl_component CYGIMP_KERNEL_COUNTERS_MULTI_LIST {
display "Implement counters using a table of lists"
default_value 0
implements CYGINT_KERNEL_COUNTERS
description "
There are two different implementations of the counter
objects. The first implementation stores all alarms in a
single linked list. The alternative implementation uses a
table of linked lists, with the size of the table being a
separate configurable option. For more complicated
operations it is better to have a table of lists since this
reduces the amount of computation whenever the timer goes
off. Assuming a table size of 8 (the default value) on
average the timer code will only need to check 1/8 of the
pending alarms instead of all of them."
cdl_option CYGNUM_KERNEL_COUNTERS_MULTI_LIST_SIZE {
display "Size of counter list table"
flavor data
legal_values 1 to 1024
default_value 8
description "
If counters are implemented using an array of linked lists
then this option controls the size of the array. A larger
size reduces the amount of computation that needs to take
place whenever the timer goes off, but requires extra
memory."
}
}
cdl_option CYGIMP_KERNEL_COUNTERS_SORT_LIST {
display "Sort the counter list"
default_value 0
description "
Sorting the counter lists reduces the amount of work that
has to be done when a counter tick is processed, since the
next alarm to expire is always at the front of the list.
However, it makes adding an alarm to the list more expensive
since a search must be done for the correct place to put it.
Many alarms are used to implement timeouts, which seldom trigger,
so it is worthwhile optimizing this case. For this reason
sorted list are disabled by default."
}
cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY {
display "Measure real-time \[clock\] interrupt latency"
requires CYGVAR_KERNEL_COUNTERS_CLOCK
default_value 0
description "
Measure the interrupt latency as seen by the real-time clock
timer interrupt. This requires hardware support, defined by
the HAL_CLOCK_LATENCY() macro."
}
cdl_option CYGVAR_KERNEL_COUNTERS_CLOCK_DSR_LATENCY {
display "Measure real-time \[clock\] DSR latency"
requires CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY
default_value CYGVAR_KERNEL_COUNTERS_CLOCK_LATENCY
description "
Measure the DSR latency as seen by the real-time clock
timer interrupt. This requires hardware support, defined by
the HAL_CLOCK_LATENCY() macro."
}
cdl_option CYGNUM_KERNEL_COUNTERS_RTC_RESOLUTION {
display "RTC resolution"
flavor data
calculated { CYGPKG_KERNEL_COUNTERS_CLOCK_OVERRIDE ? \
"{CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_NUMERATOR, \
CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_DENOMINATOR}" \
: "{CYGNUM_HAL_RTC_NUMERATOR, CYGNUM_HAL_RTC_DENOMINATOR}"}
description "
This option automatically defines the tuple which is used to
initialize the RTC resolution, consisting of a numerator and
denominator. For more information, see the option to
override default clock settings
(CYGPKG_KERNEL_COUNTERS_CLOCK_OVERRIDE) and associated options."
}
cdl_option CYGNUM_KERNEL_COUNTERS_RTC_PERIOD {
display "RTC period"
flavor data
calculated { CYGPKG_KERNEL_COUNTERS_CLOCK_OVERRIDE ? \
"CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_PERIOD" \
: "CYGNUM_HAL_RTC_PERIOD"}
description "
This option automatically defines the RTC period to be used in
setting the system clock hardware. For more information, see the
option to override default clock settings
(CYGPKG_KERNEL_COUNTERS_CLOCK_OVERRIDE) and associated options."
}
# EOF counters.cdl
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