support: add loader script for 64k sram/256k flash

Preparation for 32F01CDiscovery board bringup

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
Signed-off-by: Perry Hung <perry@leaflabs.com>
Add STM32F2 I2C support.

Untested, but fixes the build and at least provides the correct
register map and base pointers.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
Rename various "stm32f2" directories "stm32f2-f4".

Preparatory patch for adding STM32F4 support.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
stm32f2-f4: refactor <series/stm32.h>

Prep work for adding F4 support.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
libmaple/stm32.h: add a FIXME for USART config

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
systick.h: add systick_attach_callback() prototype

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
nvic.h: silence some GCC inline warnings

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
HardwareSPI.cpp: allow for missing SPI peripherals

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
HardwareTimer.cpp: use STM32_TIMER_MASK

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
wirish: allow boards to override more init() subroutines

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
wirish: allow boards to override PLL input clock

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
Wire: release the bus on error
stm32f1: gpio.h: silence yet more __always_inline warnings

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>