diff options
Diffstat (limited to 'lib/pru_rpmsg/pru_virtqueue.c')
| -rw-r--r-- | lib/pru_rpmsg/pru_virtqueue.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/lib/pru_rpmsg/pru_virtqueue.c b/lib/pru_rpmsg/pru_virtqueue.c new file mode 100644 index 00000000..5b14c6e4 --- /dev/null +++ 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; +} |