tcl: Add default hooks for STM32F3x

Keep clocks running in low power modes. Stop watchdogs from interfering
with the debug session. Set up PLL and increase clock at reset init.

Change-Id: I984d2018f7d47a1042f1e12894563154fa7b566c
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2196
Tested-by: jenkins
Reviewed-by: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

tcl/target/stm32f3x.cfg

@@ -4,6 +4,7 @@
 # stm32 devices support both JTAG and SWD transports.
 #
 source [find target/swj-dp.tcl]
+source [find mem_helper.tcl]
 
 if { [info exists CHIPNAME] } {
    set _CHIPNAME $CHIPNAME
@@ -87,3 +88,33 @@ if {![using_hla]} {
    # perform a soft reset
    cortex_m reset_config sysresetreq
 }
+
+proc stm32f3x_default_reset_start {} {
+	# Reset clock is HSI (8 MHz)
+	adapter_khz 1000
+}
+
+proc stm32f3x_default_examine_end {} {
+	# Enable debug during low power modes (uses more power)
+	mmw 0xe0042004 0x00000007 0 ;# DBGMCU_CR |= DBG_STANDBY | DBG_STOP | DBG_SLEEP
+
+	# Stop watchdog counters during halt
+	mww 0xe0042008 0x00001800 ;# DBGMCU_APB1_FZ = DBG_IWDG_STOP | DBG_WWDG_STOP
+}
+
+proc stm32f3x_default_reset_init {} {
+	# Configure PLL to boost clock to HSI x 8 (64 MHz)
+	mww 0x40021004 0x00380400 ;# RCC_CFGR = PLLMUL[3:1] | PPRE1[2]
+	mwh 0x40021002 0x0100     ;# RCC_CR[31:16] = PLLON
+	mww 0x40022000 0x00000012 ;# FLASH_ACR = PRFTBE | LATENCY[1]
+	sleep 10                  ;# Wait for PLL to lock
+	mww 0x40021004 0x00380402 ;# RCC_CFGR |= SW[1]
+
+	# Boost JTAG frequency
+	adapter_khz 8000
+}
+
+# Default hooks
+$_TARGETNAME configure -event examine-end { stm32f3x_default_examine_end }
+$_TARGETNAME configure -event reset-start { stm32f3x_default_reset_start }
+$_TARGETNAME configure -event reset-init { stm32f3x_default_reset_init }