pru: Add initial pru_rpmsg library code for Beaglebone PRU

Add external code for using RPMsg on the Beaglebone PRU. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
2025-07-23 22:54:10 -06:00 · 2017-05-07 21:19:10 -04:00 · 2017-05-07 21:19:10 -04:00 · ccaa25eaa5
commit ccaa25eaa5
parent 969ee4c8f9
20 changed files with 4163 additions and 3 deletions
--- a/lib/pru_rpmsg/pru_virtqueue.c
+++ b/lib/pru_rpmsg/pru_virtqueue.c
@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *	* Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ *
+ *	* 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.
+ *
+ *	* Neither the name of Texas Instruments Incorporated nor the names of
+ *	  its contributors may be used to endorse or promote products derived
+ *	  from this software without specific prior written permission.
+ *
+ * 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.
+ */
+
+/**
+ *  File	:	pru_virtqueue.c
+ *
+ *  Summary	:	A virtual queue implementation to simplify vring usage.
+ *
+ *  Notes	:
+ *  - Implementaion of the interface described in "pru_virtqueue.h"
+ */
+#include <pru_virtqueue.h>
+
+#ifndef __GNUC__
+volatile register uint32_t __R31;
+#else
+#include <pru/io.h>
+#endif
+
+/* bit 5 is the valid strobe to generate system events with __R31 */
+#define INT_ENABLE	(1 << 5)
+
+/* __R31[3:0] can generate 15-0 which maps to system events 31-16 
+ * e.g. to generate PRU-ICSS System Event 17 (pru_mst_intr[1])
+ * __R31 = (INT_ENABLE | (17 - INT_OFFSET));
+ */
+#define INT_OFFSET	16
+
+void pru_virtqueue_init(
+	struct pru_virtqueue 		*vq,
+	struct fw_rsc_vdev_vring 	*vring,
+	uint32_t 			to_arm_event,
+	uint32_t 			from_arm_event
+)
+{
+	vq->id = vring->notifyid;
+	vq->to_arm_event = to_arm_event;
+	vq->from_arm_event = from_arm_event;
+	vq->last_avail_idx = 0;
+
+	vring_init(&vq->vring, vring->num, (void*)vring->da, vring->align);
+}
+
+int16_t pru_virtqueue_get_avail_buf(
+    struct pru_virtqueue	*vq,
+    void			**buf,
+    uint32_t			*len
+)
+{
+	int16_t			head;
+	struct vring_desc	desc;
+	struct vring_avail	*avail;
+
+	avail = vq->vring.avail;
+
+	/* There's nothing available */
+	if (vq->last_avail_idx == avail->idx)
+		return PRU_VIRTQUEUE_NO_BUF_AVAILABLE;
+
+	/*
+	 * Grab the next descriptor number the ARM host is advertising, and
+	 * increment the last available index we've seen.
+	 */
+	head = avail->ring[vq->last_avail_idx++ & (vq->vring.num - 1)];
+
+	desc = vq->vring.desc[head];
+	*buf = (void *)(uint32_t)desc.addr;
+	*len = desc.len;
+
+	return (head);
+}
+
+int16_t pru_virtqueue_add_used_buf(
+    struct pru_virtqueue	*vq,
+    int16_t			head,
+    uint32_t			len
+)
+{
+	struct vring_used_elem	*used_elem;
+	uint32_t		num;
+	struct vring_used	*used;
+
+	num = vq->vring.num;
+	used = vq->vring.used;
+
+	if (head > (int)num)
+		return PRU_VIRTQUEUE_INVALID_HEAD;
+
+	/*
+	 * The virtqueue's vring contains a ring of used buffers.  Get a pointer to
+	 * the next entry in that used ring.
+	 */
+	used_elem = &used->ring[used->idx++ & (num - 1)];
+	used_elem->id = head;
+	used_elem->len = len;
+
+	return PRU_VIRTQUEUE_SUCCESS;
+}
+
+int16_t pru_virtqueue_kick(
+    struct pru_virtqueue	*vq
+)
+{
+	unsigned int r31;
+
+	/* If requested, do not kick the ARM host */
+	if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+		return PRU_VIRTQUEUE_NO_KICK;
+
+	/* Generate a system event to kick the ARM */
+	r31 = (INT_ENABLE | (vq->to_arm_event - INT_OFFSET)); 
+#ifdef __GNUC__
+	write_r31(r31);
+#else
+	__R31 = r31;
+#endif
+
+	return PRU_VIRTQUEUE_SUCCESS;
+}