USB: Fix issue with USB RAM sizes

Previously the USB RAM size was off by a factor of two
for chips that required 32-bit alignment of accesses,
even though the underlying memory was 16-bits in size.
This change adds an additional configuration for the
access size (it still assumes that the underlying memory
is 16-bits in size) and uses that to adjust the USB_RAM
memory section in the linker scripts.

This change also removes the default values for the USB
RAM from stm32/config_chip.h because they mask issues
when new chips are added.  It is better for a new chip
to fail to compile until these values are provided.

Finally, this change introduces a common USB API header
so that common code doesn't need to include the STM32
specific header.

Signed-off-by: Anton Staaf <robotboy@chromium.org>

BRANCH=None
BUG=None
TEST=make buildall -j
     Enable console on ryu_p2 and discovery-stm32f072 board
     Verify that it works on both

Change-Id: Id118627f53e9e8ff1bd09fb51f1f9634ff495d19
Reviewed-on: https://chromium-review.googlesource.com/228833
Tested-by: Anton Staaf <robotboy@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Commit-Queue: Anton Staaf <robotboy@chromium.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/include/usb_api.h b/include/usb_api.h
new file mode 100644
index 0000000000..feeb6abb27
--- /dev/null
+++ b/include/usb_api.h
@@ -0,0 +1,41 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * USB API definitions.
+ *
+ * This file includes definitions needed by common code that wants to control
+ * the state of the USB peripheral, but doesn't need to know about the specific
+ * implementation.
+ */
+
+#ifndef USB_API_H
+#define USB_API_H
+
+/*
+ * Initialize the USB peripheral, enabling its clock and configuring the DP/DN
+ * GPIOs correctly.  This function is called via an init hook, but may need to
+ * be called again if usb_release is called.  This function will call
+ * usb_connect by default unless CONFIG_USB_INHIBIT is defined.
+ */
+void usb_init(void);
+
+/*
+ * Enable the pullup on the DP line to signal that this device exists to the
+ * host and to start the enumeration process.
+ */
+void usb_connect(void);
+
+/*
+ * Disable the pullup on the DP line.  This causes the device to be disconnected
+ * from the host.
+ */
+void usb_disconnect(void);
+
+/*
+ * Disconnect from the host by calling usb_disconnect and then turn off the USB
+ * peripheral, releasing its GPIOs and disabling its clock.
+ */
+void usb_release(void);
+
+#endif /* USB_API_H */