leon,can: introduce common CAN baud-rate calculation function

Reimplemented the baud-rate algorithm from scratch to cope with
GRCAN, GRCANFD and OC_CAN devices.

Update #4306.

1 files changed, 94 insertions, 0 deletions

diff --git a/bsps/include/grlib/canbtrs.h b/bsps/include/grlib/canbtrs.h
new file mode 100644
index 0000000000..7369136931
--- /dev/null
+++ b/bsps/include/grlib/canbtrs.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ * @ingroup can
+ * @brief Common CAN baud-rate routines for OCCAN/GRCAN/GRCANFD controllers
+ */
+
+/*
+ * Copyright (C) 2019, 2020 Cobham Gaisler AB
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __GRLIB_CANBTRS_H__
+#define __GRLIB_CANBTRS_H__
+
+/**
+ * @defgroup can CAN
+ *
+ * @ingroup RTEMSBSPsSharedGRLIB
+ *
+ * @brief CAN routines shared between OCCAN, GRCAN and GRCANFD controllers
+ *
+ * @{
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* CAN Baud-rate parameters, range of valid parameter values */
+struct grlib_canbtrs_ranges {
+	unsigned int max_scaler;
+	char has_bpr;
+	unsigned char divfactor;
+	unsigned char min_tseg1;
+	unsigned char max_tseg1;
+	unsigned char min_tseg2;
+	unsigned char max_tseg2;
+};
+
+struct grlib_canbtrs_timing {
+	unsigned char scaler;
+	unsigned char ps1;
+	unsigned char ps2;
+	unsigned char rsj;
+	unsigned char bpr;
+};
+
+/* @brief Calculate CAN baud-rate generation parameters from requested baud-rate
+ *
+ * @param baud            The CAN baud rate requested
+ * @param core_hz         Input clock [Hz] to CAN core
+ * @param sampl_pt        CAN sample point in %, 80 means 80%
+ * @param br              CAN Baud-rate parameters limitations
+ * @param[out] timing     result is placed here
+ *
+ * @retval 0 Baud-rate parameters sucessfully calculated
+ * @retval negative Failure to generate parameters with less than 5% error
+ *   margin from requested baud-rate
+ */
+int grlib_canbtrs_calc_timing(
+	unsigned int baud,
+	unsigned int core_hz,
+	unsigned int sampl_pt,
+	struct grlib_canbtrs_ranges *br,
+	struct grlib_canbtrs_timing *timing
+	);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif