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