pru: Move communication code to second PRU
Perform input and output in the second PRU so that more space is available in the primary PRU. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
229
src/pru/pru0.c
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229
src/pru/pru0.c
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// Code to handle IO on PRU0 and pass the messages to PRU1
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//
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// Copyright (C) 2017 Kevin O'Connor <kevin@koconnor.net>
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//
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// This file may be distributed under the terms of the GNU GPLv3 license.
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#include <stdint.h> // uint32_t
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#include <string.h> // memset
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#include <pru/io.h> // write_r31
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#include <pru_cfg.h> // CT_CFG
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#include <pru_intc.h> // CT_INTC
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#include <pru_rpmsg.h> // pru_rpmsg_send
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#include <pru_virtio_ids.h> // VIRTIO_ID_RPMSG
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#include <rsc_types.h> // resource_table
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#include "board/io.h" // readl
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#include "compiler.h" // __section
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#include "internal.h" // SHARED_MEM
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/****************************************************************
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* IO
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****************************************************************/
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#define CHAN_NAME "rpmsg-pru"
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#define CHAN_DESC "Channel 30"
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#define CHAN_PORT 30
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static uint16_t transport_dst;
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static void
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check_can_send(struct pru_rpmsg_transport *transport)
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{
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for (;;) {
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uint32_t send_pop_pos = SHARED_MEM->send_pop_pos;
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uint32_t count = readl(&SHARED_MEM->send_data[send_pop_pos].count);
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if (!count)
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// Queue empty
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break;
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pru_rpmsg_send(
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transport, CHAN_PORT, transport_dst
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, &SHARED_MEM->send_data[send_pop_pos].data, count);
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barrier();
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writel(&SHARED_MEM->send_data[send_pop_pos].count, 0);
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SHARED_MEM->send_pop_pos = (
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(send_pop_pos + 1) % ARRAY_SIZE(SHARED_MEM->send_data));
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}
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}
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static void
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check_can_read(struct pru_rpmsg_transport *transport)
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{
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if (readl(&SHARED_MEM->read_count))
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// main processing pru is busy
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return;
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uint16_t dst, len;
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int16_t ret = pru_rpmsg_receive(
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transport, &transport_dst, &dst, SHARED_MEM->read_data, &len);
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if (ret || !len)
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return;
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SHARED_MEM->read_pos = 0;
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barrier();
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writel(&SHARED_MEM->read_count, len);
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write_r31(R31_WRITE_IRQ_SELECT | (KICK_PRU1_EVENT - R31_WRITE_IRQ_OFFSET));
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}
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static void
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process_io(struct pru_rpmsg_transport *transport)
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{
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for (;;) {
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if (!(read_r31() & (1 << (WAKE_PRU0_IRQ + R31_IRQ_OFFSET))))
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continue;
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CT_INTC.SECR0 = (1 << KICK_PRU0_FROM_ARM_EVENT) | (1 << KICK_PRU0_EVENT);
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check_can_send(transport);
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check_can_read(transport);
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}
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}
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/****************************************************************
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* Resource table
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****************************************************************/
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/*
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* Sizes of the virtqueues (expressed in number of buffers supported,
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* and must be power of 2)
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*/
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#define PRU_RPMSG_VQ0_SIZE 16
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#define PRU_RPMSG_VQ1_SIZE 16
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/*
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* The feature bitmap for virtio rpmsg
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*/
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#define VIRTIO_RPMSG_F_NS 0 //name service notifications
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/* This firmware supports name service notifications as one of its features */
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#define RPMSG_PRU_C0_FEATURES (1 << VIRTIO_RPMSG_F_NS)
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/* Definition for unused interrupts */
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#define HOST_UNUSED 255
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/* Mapping sysevts to a channel. Each pair contains a sysevt, channel. */
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static struct ch_map pru_intc_map[] = {
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{IEP_EVENT, WAKE_PRU1_IRQ},
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{KICK_ARM_EVENT, WAKE_ARM_IRQ},
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{KICK_PRU0_FROM_ARM_EVENT, WAKE_PRU0_IRQ},
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{KICK_PRU0_EVENT, WAKE_PRU0_IRQ},
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{KICK_PRU1_EVENT, WAKE_PRU1_IRQ},
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};
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struct my_resource_table {
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struct resource_table base;
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uint32_t offset[2]; /* Should match 'num' in actual definition */
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/* rpmsg vdev entry */
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struct fw_rsc_vdev rpmsg_vdev;
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struct fw_rsc_vdev_vring rpmsg_vring0;
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struct fw_rsc_vdev_vring rpmsg_vring1;
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/* intc definition */
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struct fw_rsc_custom pru_ints;
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} resourceTable __section(".resource_table") = {
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{
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1, /* Resource table version: only version 1 is
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* supported by the current driver */
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2, /* number of entries in the table */
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{ 0, 0 }, /* reserved, must be zero */
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},
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/* offsets to entries */
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{
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offsetof(struct my_resource_table, rpmsg_vdev),
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offsetof(struct my_resource_table, pru_ints),
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},
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/* rpmsg vdev entry */
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{
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(uint32_t)TYPE_VDEV, //type
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(uint32_t)VIRTIO_ID_RPMSG, //id
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(uint32_t)0, //notifyid
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(uint32_t)RPMSG_PRU_C0_FEATURES, //dfeatures
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(uint32_t)0, //gfeatures
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(uint32_t)0, //config_len
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(uint8_t)0, //status
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(uint8_t)2, //num_of_vrings, only two is supported
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{(uint8_t)0, (uint8_t)0 }, //reserved
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/* no config data */
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},
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/* the two vrings */
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{
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0, //da, will be populated by host, can't pass it in
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16, //align (bytes),
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PRU_RPMSG_VQ0_SIZE, //num of descriptors
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0, //notifyid, will be populated, can't pass right now
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0 //reserved
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},
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{
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0, //da, will be populated by host, can't pass it in
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16, //align (bytes),
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PRU_RPMSG_VQ1_SIZE, //num of descriptors
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0, //notifyid, will be populated, can't pass right now
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0 //reserved
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},
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{
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TYPE_CUSTOM, TYPE_PRU_INTS,
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sizeof(struct fw_rsc_custom_ints),
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{ /* PRU_INTS version */
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{
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0x0000,
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/* Channel-to-host mapping, 255 for unused */
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{
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WAKE_PRU0_IRQ, WAKE_PRU1_IRQ, WAKE_ARM_IRQ,
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HOST_UNUSED, HOST_UNUSED, HOST_UNUSED,
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HOST_UNUSED, HOST_UNUSED, HOST_UNUSED, HOST_UNUSED
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},
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/* Number of evts being mapped to channels */
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(sizeof(pru_intc_map) / sizeof(struct ch_map)),
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/* Pointer to the structure containing mapped events */
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pru_intc_map,
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},
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},
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},
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};
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/****************************************************************
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* Startup
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****************************************************************/
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#define VIRTIO_CONFIG_S_DRIVER_OK 4
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int
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main(void)
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{
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// allow access to external memory
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CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
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// clear all irqs
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CT_INTC.SECR0 = 0xffffffff;
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CT_INTC.SECR1 = 0xffffffff;
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/* Make sure the Linux drivers are ready for RPMsg communication */
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volatile uint8_t *status = &resourceTable.rpmsg_vdev.status;
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while (!(*status & VIRTIO_CONFIG_S_DRIVER_OK))
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;
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/* Initialize the RPMsg transport structure */
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struct pru_rpmsg_transport transport;
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pru_rpmsg_init(&transport,
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&resourceTable.rpmsg_vring0,
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&resourceTable.rpmsg_vring1,
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KICK_ARM_EVENT,
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KICK_PRU0_FROM_ARM_EVENT);
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/* Create the RPMsg channel between the PRU and ARM user space
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* using the transport structure. */
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while (pru_rpmsg_channel(RPMSG_NS_CREATE, &transport, CHAN_NAME
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, CHAN_DESC, CHAN_PORT) != PRU_RPMSG_SUCCESS)
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;
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// Wait for PRU1 to be ready
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memset(SHARED_MEM, 0, sizeof(*SHARED_MEM));
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writel(&SHARED_MEM->signal, SIGNAL_PRU0_WAITING);
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while (readl(&SHARED_MEM->signal) != SIGNAL_PRU1_READY)
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;
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writel(&SHARED_MEM->signal, 0);
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process_io(&transport);
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}
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