diff options
| -rw-r--r-- | tcl/tools/test_cpu_speed.tcl | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/tcl/tools/test_cpu_speed.tcl b/tcl/tools/test_cpu_speed.tcl new file mode 100644 index 0000000..cef2bbb --- /dev/null +++ b/tcl/tools/test_cpu_speed.tcl @@ -0,0 +1,50 @@ +# SPDX-License-Identifier: GPL-2.0-or-later + +# Description: +# Measure the CPU clock frequency of an ARM Cortex-M based device. +# +# Return: +# The CPU clock frequency in Hz. A negative value indicates that the loop +# counter was saturated. +# +# Note: +# You may need to adapt the number of cycles for your device. +# +add_help_text cortex_m_test_cpu_speed "Measure the CPU clock frequency of an ARM Cortex-M based device" +add_usage_text cortex_m_test_cpu_speed {address [timeout [cycles_per_loop]]} +proc cortex_m_test_cpu_speed { address { timeout 200 } { cycles_per_loop 4 } } { + set loop_counter_start 0xffffffff + + halt + + # Backup registers and memory. + set backup_regs [get_reg -force {pc r0 xPSR}] + set backup_mem [read_memory $address 16 3] + + # We place the following code at the given address to measure the + # CPU clock frequency: + # + # 3801: subs r0, #1 + # d1fd: bne #-2 + # e7fe: b #-4 + write_memory $address 16 {0x3801 0xd1fd 0xe7fe} + + set_reg "pc $address r0 $loop_counter_start" + resume + sleep $timeout + halt + + # Get the loop counter value from register r0. + set loop_counter_end [dict values [get_reg r0]] + set loop_counter_diff [expr {$loop_counter_start - $loop_counter_end}] + + # Restore registers and memory. + set_reg $backup_regs + write_memory $address 16 $backup_mem + + if { [expr {$loop_counter_end == 0}] } { + return -1 + } + + return [expr {double($loop_counter_diff) * $cycles_per_loop / $timeout * 1000}] +} |