Slightly improve and generify the USB infrastructure.

The good news is that <libmaple/usb.h> and <libmaple/usb_cdcacm.h> did
turn out generic enough in what they specify to go on unchanged.

However, we can't just go on assuming that there's USB just because
we're on an F1. Now that there's value line in the tree, we need to be
more careful (value line F1s don't have USB peripherals). To that end,
make all the F1 board-includes/*.mk files specify what line their MCU
is with an MCU_F1_LINE variable. Use that to hack
libmaple/usb/rules.mk so we only try to build the USB module under
appropriate circumstances.

While we're at it, add a vector_symbols.inc for value line MCUs under
support/ld/. We need this to get the target-config.mk modifications
implied by the addition of MCU_F1_LINE. We'll fix up some other
performance-line-isms under libmaple/stm32f1 in a separate commit.

Also in libmaple/usb/:

- Move everything into a new stm32f1 directory. Due to aforementioned
  rules.mk hacks, there is no immediate need for an stm32f2
  directory (USB support doesn't exist there).

- Update the README for style and content.

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

7 files changed, 9 insertions, 3 deletions

diff --git a/support/make/board-includes/VLDiscovery.mk b/support/make/board-includes/VLDiscovery.mk
index 82d1b23..441f078 100644
--- a/support/make/board-includes/VLDiscovery.mk
+++ b/support/make/board-includes/VLDiscovery.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOC
 ERROR_LED_PIN  := 9
 MCU_SERIES := stm32f1
+MCU_F1_LINE := value
diff --git a/support/make/board-includes/maple.mk b/support/make/board-includes/maple.mk
index d31ad83..4de4bab 100644
--- a/support/make/board-includes/maple.mk
+++ b/support/make/board-includes/maple.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOA
 ERROR_LED_PIN  := 5
 MCU_SERIES := stm32f1
+MCU_F1_LINE := performance
diff --git a/support/make/board-includes/maple_RET6.mk b/support/make/board-includes/maple_RET6.mk
index d06f068..104ae08 100644
--- a/support/make/board-includes/maple_RET6.mk
+++ b/support/make/board-includes/maple_RET6.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOA
 ERROR_LED_PIN := 5
 MCU_SERIES := stm32f1
+MCU_F1_LINE := performance
diff --git a/support/make/board-includes/maple_mini.mk b/support/make/board-includes/maple_mini.mk
index 835adc3..70ef506 100644
--- a/support/make/board-includes/maple_mini.mk
+++ b/support/make/board-includes/maple_mini.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOB
 ERROR_LED_PIN  := 1
 MCU_SERIES := stm32f1
+MCU_F1_LINE := performance
diff --git a/support/make/board-includes/maple_native.mk b/support/make/board-includes/maple_native.mk
index 3e88e7b..86746a6 100644
--- a/support/make/board-includes/maple_native.mk
+++ b/support/make/board-includes/maple_native.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOC
 ERROR_LED_PIN  := 15
 MCU_SERIES := stm32f1
+MCU_F1_LINE := performance
diff --git a/support/make/board-includes/olimex_stm32_h103.mk b/support/make/board-includes/olimex_stm32_h103.mk
index 96d6976..31f2c04 100644
--- a/support/make/board-includes/olimex_stm32_h103.mk
+++ b/support/make/board-includes/olimex_stm32_h103.mk
@@ -3,3 +3,4 @@ PRODUCT_ID := 0003
 ERROR_LED_PORT := GPIOC
 ERROR_LED_PIN := 12
 MCU_SERIES := stm32f1
+MCU_F1_LINE := performance
diff --git a/support/make/target-config.mk b/support/make/target-config.mk
index 48a33de..e13504d 100644
--- a/support/make/target-config.mk
+++ b/support/make/target-config.mk
@@ -15,9 +15,9 @@ TARGET_FLAGS += -DBOARD_$(BOARD) -DMCU_$(MCU) \
 
 LD_SERIES_PATH := $(LDDIR)/stm32/series/$(MCU_SERIES)
 ifeq ($(MCU_SERIES), stm32f1)
-   # Hack: force F1 to performance line; this will need to change if
-   # you add connectivity etc. line support.
-   LD_SERIES_PATH := $(LD_SERIES_PATH)/performance
+# Due to the Balkanization on F1, we need to specify the line when
+# making linker decisions.
+LD_SERIES_PATH := $(LD_SERIES_PATH)/$(MCU_F1_LINE)
 endif
 LIBMAPLE_MODULE_SERIES := $(LIBMAPLE_PATH)/$(MCU_SERIES)