tcl/interface: universal config for all Raspberry Pi models

[openocd.git] / tcl / interface / raspberrypi-native.cfg

diff --git a/tcl/interface/raspberrypi-native.cfg b/tcl/interface/raspberrypi-native.cfg
index 02a35635006063561ead1f12dd9d944c07d530a3..95426c226318407e9381723998ff282bf92118b0 100644 (file)
--- a/tcl/interface/raspberrypi-native.cfg
+++ b/tcl/interface/raspberrypi-native.cfg
@@ -1,44 +1,71 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-#
-# Config for using Raspberry Pi's expansion header
-#
-# This is best used with a fast enough buffer but also
-# is suitable for direct connection if the target voltage
-# matches RPi's 3.3V and the cable is short enough.
-#
-# Do not forget the GND connection, pin 6 of the expansion header.
-#
+# Config for Raspberry Pi used as a bitbang adapter.
+# https://www.raspberrypi.com/documentation/computers/raspberry-pi.html
+
+# Supports all models with 40-pin or 26-pin GPIO connector up to Raspberry Pi 4 B
+# also supports Raspberry Pi Zero, Zero W and Zero 2 W.
+
+# Adapter speed calibration is computed from cpufreq/scaling_max_freq.
+# Adjusts automatically if CPU is overclocked.
 
 adapter driver bcm2835gpio
 
-bcm2835gpio peripheral_base 0x20000000
+proc read_file { name } {
+       if {[catch {open $name r} fd]} {
+               return ""
+       }
+       set result [read $fd]
+       close $fd
+       return $result
+}
 
-# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
-# These depend on system clock, calibrated for stock 700MHz
-# bcm2835gpio speed SPEED_COEFF SPEED_OFFSET
-bcm2835gpio speed_coeffs 113714 28
+proc measure_clock {} {
+       set result [exec vcgencmd measure_clock arm]
+       set clock_hz [lindex [split $result "="] 1]
+       expr { $clock_hz / 1000 }
+}
+
+proc get_max_cpu_clock { default } {
+       set clock [read_file /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq]
+       if { $clock > 100000 } {
+               return $clock
+       }
 
-# Each of the JTAG lines need a gpio number set: tck tms tdi tdo
-# Header pin numbers: 23 22 19 21
-adapter gpio tck -chip 0 11
-adapter gpio tms -chip 0 25
-adapter gpio tdi -chip 0 10
-adapter gpio tdo -chip 0 9
+       # cpufreq not available. As the last resort try Broadcom's proprietary utility
+       if {![catch measure_clock clock] && $clock > 100000} {
+               return $clock
+       }
 
-# Each of the SWD lines need a gpio number set: swclk swdio
-# Header pin numbers: 23 22
-adapter gpio swclk -chip 0 11
-adapter gpio swdio -chip 0 25
+       echo "WARNING: Host CPU clock unknown."
+       echo "WARNING: Using the highest possible value $default kHz as a safe default."
+       echo "WARNING: Expect JTAG/SWD clock significantly slower than requested."
 
-# If you define trst or srst, use appropriate reset_config
-# Header pin numbers: TRST - 26, SRST - 18
+       return $default
+}
 
-# adapter gpio trst -chip 0 7
-# reset_config trst_only
+set compat [read_file /proc/device-tree/compatible]
+set clocks_per_timing_loop 4
 
-# adapter gpio srst -chip 0 24
-# reset_config srst_only srst_push_pull
+if {[string match *bcm2711* $compat]} {
+       set speed_offset 52
+} elseif {[string match *bcm2837* $compat] || [string match *bcm2710* $compat]} {
+       set speed_offset 34
+} elseif {[string match *bcm2836* $compat] || [string match *bcm2709* $compat]} {
+       set speed_offset 36
+} elseif {[string match *bcm2835* $compat] || [string match *bcm2708* $compat]} {
+       set clocks_per_timing_loop 6
+       set speed_offset 32
+} else {
+       set speed_offset 32
+       echo "WARNING: Unknown type of the host SoC. Expect JTAG/SWD clock slower than requested."
+}
+
+set clock [get_max_cpu_clock 2000000]
+set speed_coeff [expr { $clock / $clocks_per_timing_loop }]
+
+# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
+# The coefficients depend on system clock and CPU frequency scaling.
+bcm2835gpio speed_coeffs $speed_coeff $speed_offset
 
-# or if you have both connected,
-# reset_config trst_and_srst srst_push_pull
+source raspberrypi-gpio-connector.cfg