TCPM: Add OCP module

Currently, the overcurrent protection is tracked in the PPC code.
However, as different chips are able to report overcurrent move this
code into a generic module.

Logic for not sourcing Vbus or Vconn on latched ports moves into
the TC layer, and an overridable board overcurrent function is provided
for boards which have no special actions to take.

BRANCH=None
BUG=b:171501161
TEST=make -j buildall; TCPMv2 tested with following drawcia patch

Signed-off-by: Diana Z <dzigterman@chromium.org>
Change-Id: I75919e345a5b0bce4a0b67432a13515e7716cf6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2532676
Reviewed-by: Keith Short <keithshort@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

1 files changed, 131 insertions, 0 deletions

diff --git a/common/usbc_ocp.c b/common/usbc_ocp.c
new file mode 100644
index 0000000000..e20cf9f1f8
--- /dev/null
+++ b/common/usbc_ocp.c
@@ -0,0 +1,131 @@
+/* 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.
+ */
+
+/* USB-C Overcurrent Protection Common Code */
+
+#include "atomic.h"
+#include "common.h"
+#include "console.h"
+#include "hooks.h"
+#include "timer.h"
+#include "usb_pd.h"
+#include "usbc_ocp.h"
+#include "util.h"
+
+#ifndef TEST_BUILD
+#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
+#define CPRINTS(format, args...) cprints(CC_USBPD, format, ## args)
+#else
+#define CPRINTF(args...)
+#define CPRINTS(args...)
+#endif
+
+/*
+ * Number of times a port may overcurrent before we latch off the port until a
+ * physical disconnect is detected.
+ */
+#define OCP_CNT_THRESH 3
+
+/*
+ * Number of seconds until a latched-off port is re-enabled for sourcing after
+ * detecting a physical disconnect.
+ */
+#define OCP_COOLDOWN_DELAY_US (2 * SECOND)
+
+/*
+ * A per-port table that indicates how many VBUS overcurrent events have
+ * occurred.  This table is cleared after detecting a physical disconnect of the
+ * sink.
+ */
+static uint8_t oc_event_cnt_tbl[CONFIG_USB_PD_PORT_MAX_COUNT];
+
+/* A flag for ports with sink device connected. */
+static uint32_t snk_connected_ports;
+
+static void clear_oc_tbl(void)
+{
+	int port;
+
+	for (port = 0; port < board_get_usb_pd_port_count(); port++)
+		/*
+		 * Only clear the table if the port partner is no longer
+		 * attached after debouncing.
+		 */
+		if ((!(BIT(port) & snk_connected_ports)) &&
+		    oc_event_cnt_tbl[port]) {
+			oc_event_cnt_tbl[port] = 0;
+			CPRINTS("C%d: OC events cleared", port);
+		}
+}
+DECLARE_DEFERRED(clear_oc_tbl);
+
+int usbc_ocp_add_event(int port)
+{
+	if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
+		CPRINTS("%s(%d) Invalid port!", __func__, port);
+		return EC_ERROR_INVAL;
+	}
+
+	oc_event_cnt_tbl[port]++;
+
+	/* The port overcurrented, so don't clear it's OC events. */
+	atomic_clear_bits(&snk_connected_ports, 1 << port);
+
+	if (oc_event_cnt_tbl[port] >= OCP_CNT_THRESH)
+		CPRINTS("C%d: OC event limit reached! "
+			   "Source path disabled until physical disconnect.",
+			   port);
+	return EC_SUCCESS;
+}
+
+
+int usbc_ocp_clear_event_counter(int port)
+{
+	if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
+		CPRINTS("%s(%d) Invalid port!", __func__, port);
+		return EC_ERROR_INVAL;
+	}
+
+	/*
+	 * If we are clearing our event table in quick succession, we may be in
+	 * an overcurrent loop where we are also detecting a disconnect on the
+	 * CC pins.  Therefore, let's not clear it just yet and the let the
+	 * limit be reached.  This way, we won't send the hard reset and
+	 * actually detect the physical disconnect.
+	 */
+	if (oc_event_cnt_tbl[port]) {
+		hook_call_deferred(&clear_oc_tbl_data,
+				   OCP_COOLDOWN_DELAY_US);
+	}
+	return EC_SUCCESS;
+}
+
+int usbc_ocp_is_port_latched_off(int port)
+{
+	if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
+		CPRINTS("%s(%d) Invalid port!", __func__, port);
+		return 0;
+	}
+
+	return oc_event_cnt_tbl[port] >= OCP_CNT_THRESH;
+}
+
+void usbc_ocp_snk_is_connected(int port, bool connected)
+{
+	if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
+		CPRINTS("%s(%d) Invalid port!", __func__, port);
+		return;
+	}
+
+	if (connected)
+		atomic_or(&snk_connected_ports, 1 << port);
+	else
+		atomic_clear_bits(&snk_connected_ports, 1 << port);
+}
+
+__overridable void board_overcurrent_event(int port, int is_overcurrented)
+{
+	/* Do nothing by default.  Boards with overcurrent GPIOs may override */
+}