sx1276_mesh_driver.c

// sx1276_mesh_driver.c: LoRa driver for SX1276 with mesh networking support

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/kthread.h>
#include <linux/delay.h>

#define DEBUG 1

#ifdef DEBUG
#define LOG(fmt, ...) printk(KERN_INFO "sx1276: " fmt, ##__VA_ARGS__)
#else
#define LOG(fmt, ...) 
#endif

// Constants
#define LORA_MAX_PAYLOAD 256
#define HELLO_INTERVAL_DEFAULT 5000  // ms

// LoRa packet structure for mesh networking
struct lora_packet {
    uint8_t src_addr;
    uint8_t dest_addr;
    uint8_t next_hop;
    uint8_t ttl;
    uint8_t payload[LORA_MAX_PAYLOAD];
};

// Routing table entry structure
struct routing_table_entry {
    uint8_t dest_addr;
    uint8_t next_hop;
    uint8_t hops;
};

// Device structure
struct lora_device {
    struct spi_device *spi;
    struct net_device *netdev;
    struct routing_table_entry *routing_table;
    int routing_table_size;
};

// Module parameters
static int hello_interval = HELLO_INTERVAL_DEFAULT;  // Interval for broadcasting hello messages

// Function prototypes
static int lora_open(struct net_device *dev);
static int lora_stop(struct net_device *dev);
static netdev_tx_t lora_start_xmit(struct sk_buff *skb, struct net_device *dev);
static irqreturn_t lora_interrupt(int irq, void *dev_id);

// Dummy SPI functions for now
static int lora_spi_read(uint8_t addr) { return 0; }
static int lora_spi_write(uint8_t addr, uint8_t data) { return 0; }

// Netdevice operations
static const struct net_device_ops lora_netdev_ops = {
    .ndo_open = lora_open,
    .ndo_stop = lora_stop,
    .ndo_start_xmit = lora_start_xmit,
};

// Open the device
static int lora_open(struct net_device *dev) {
    LOG("Opening LoRa device\n");
    netif_start_queue(dev);
    return 0;
}

// Stop the device
static int lora_stop(struct net_device *dev) {
    LOG("Stopping LoRa device\n");
    netif_stop_queue(dev);
    return 0;
}

// Transmit a packet
static netdev_tx_t lora_start_xmit(struct sk_buff *skb, struct net_device *dev) {
    struct lora_packet *pkt;
    LOG("Transmitting packet\n");

    pkt = (struct lora_packet *)skb->data;

    // Add mesh routing logic here
    LOG("Packet from %u to %u via %u\n", pkt->src_addr, pkt->dest_addr, pkt->next_hop);

    // Transmit over SPI (dummy call for now)
    lora_spi_write(0x00, pkt->payload[0]);

    dev_kfree_skb(skb);
    return NETDEV_TX_OK;
}

// Interrupt handler for LoRa events (RX, TX, etc.)
static irqreturn_t lora_interrupt(int irq, void *dev_id) {
    LOG("LoRa interrupt received\n");
    // Handle interrupts (e.g., packet received, etc.)
    return IRQ_HANDLED;
}

// Initialize the LoRa device
static int __init lora_init(void) {
    struct net_device *netdev;
    struct lora_device *lora_dev;

    LOG("Initializing LoRa driver\n");

    // Allocate memory for the net device
    netdev = alloc_netdev(sizeof(struct lora_device), "lora%d", NET_NAME_UNKNOWN, ether_setup);
    if (!netdev) {
        LOG("Failed to allocate net_device\n");
        return -ENOMEM;
    }

    // Set the device operations
    netdev->netdev_ops = &lora_netdev_ops;

    // Allocate memory for the LoRa device structure
    lora_dev = netdev_priv(netdev);
    lora_dev->netdev = netdev;
    lora_dev->routing_table_size = 0;

    // Register the network device
    if (register_netdev(netdev)) {
        LOG("Failed to register net_device\n");
        free_netdev(netdev);
        return -ENODEV;
    }

    LOG("LoRa driver initialized successfully\n");
    return 0;
}

// Exit and cleanup the LoRa device
static void __exit lora_exit(void) {
    LOG("Exiting LoRa driver\n");
    unregister_netdev(lora_dev->netdev);
    free_netdev(lora_dev->netdev);
    LOG("LoRa driver exited\n");
}

module_init(lora_init);
module_exit(lora_exit);

MODULE_LICENSE("MIT");
MODULE_AUTHOR("Mike Wilson - Youroldmangmaing");
MODULE_DESCRIPTION("SX1276 LoRa driver with mesh networking");