TCPMv2: Separate DPM and DP from PE

Create separate modules representing DisplayPort (which decides whether
and how we can set up the DP alt mode) and the Device Policy Manager
(which decides whether we should). The end goal is to have essentially
all code with DP-specific decisions or information in the DP module and
all code with DPM-specific decisions or information in the DPM module.
This will allow the PE to map as directly as practical to its behaviors
defined in the PD spec.

Essentially detach PE_DO_PORT_DISCOVERY from the rest of the PE state
machine in preparation for deleting it.

This change paves the way for
1) Allowing the AP to drive mode entry and
2) Allowing new alt modes to be supported via largely self-contained
   modules.

BUG=b:155890173
TEST=Attach DP dongle; observe discovery and DP setup via Twinkie
BRANCH=none

Change-Id: Ie63a2e62d1ac6178722477dc53244898a04ef92f
Signed-off-by: Abe Levkoy <alevkoy@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2203842
Reviewed-by: Diana Z <dzigterman@chromium.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/usb_pd_dpm.h b/include/usb_pd_dpm.h
new file mode 100644
index 0000000000..22fb2d71bd
--- /dev/null
+++ b/include/usb_pd_dpm.h
@@ -0,0 +1,62 @@
+/* Copyright 2020 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.
+ */
+
+/*
+ * Device Policy Manager implementation
+ * Refer to USB PD 3.0 spec, version 2.0, sections 8.2 and 8.3
+ */
+
+#ifndef __CROS_EC_USB_DPM_H
+#define __CROS_EC_USB_DPM_H
+
+/*
+ * Initializes DPM state for a port.
+ *
+ * @param port USB-C port number
+ */
+void dpm_init(int port);
+
+/*
+ * Informs the DPM that the mode entry sequence (including appropriate
+ * configuration) is done for a port.
+ *
+ * @param port USB-C port number
+ */
+void dpm_set_mode_entry_done(int port);
+
+/*
+ * Informs the DPM that a VDM ACK was received.
+ *
+ * @param port      USB-C port number
+ * @param type      Transmit type (SOP, SOP') for received ACK
+ * @param vdo_count The number of VDOs in vdm; must be at least 1
+ * @param vdm       The VDM payload of the ACK
+ */
+void dpm_vdm_acked(int port, enum tcpm_transmit_type type, int vdo_count,
+		uint32_t *vdm);
+
+/*
+ * Informs the DPM that a VDM NAK was received. Also applies when a VDM request
+ * received a Not Supported response or timed out waiting for a response.
+ *
+ * @param port    USB-C port number
+ * @param type    Transmit type (SOP, SOP') for request
+ * @param svid    The SVID of the request
+ * @param vdm_cmd The VDM command of the request
+ */
+void dpm_vdm_naked(int port, enum tcpm_transmit_type type, uint16_t svid,
+		uint8_t vdm_cmd);
+
+/*
+ * Drives the Policy Engine through the mode entry/configuration process. Each
+ * call to this function requests that the PE send one VDM, whichever is next in
+ * the mode entry sequence. This only happens if preconditions for mode entry
+ * are met.
+ *
+ * @param port USB-C port number
+ */
+void dpm_attempt_mode_entry(int port);
+
+#endif  /* __CROS_EC_USB_DPM_H */