Samsung Android Modem Device Driver -mss Ver.3- Access

// samsung_mss_v3_diag.c
// Mock interface for MSS v3 modem diagnostics (Linux TTY/IPC)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#define MSS_DEVICE "/dev/mss_v3_modem"
#define MSS_IOCTL_GET_VERSION  _IOR('M', 1, int)
#define MSS_IOCTL_SEND_URC     _IOW('M', 2, char*)
#define MSS_IOCTL_RESET        _IO('M', 3)
int mss_fd = -1;
int mss_open()  O_NOCTTY);
if (mss_fd < 0) 
perror("Failed to open MSS v3 modem device");
return -1;
return 0;

void mss_get_version() 
int version;
if (ioctl(mss_fd, MSS_IOCTL_GET_VERSION, &version) == 0) 
printf("MSS version 3.x — sub-version: %d\n", version);
 else 
perror("Version query failed");
 samsung android modem device driver -mss ver.3-
void mss_send_command(const char *cmd) 
if (write(mss_fd, cmd, strlen(cmd)) != (ssize_t)strlen(cmd)) 
perror("Write to modem failed");

void mss_read_response(char *buf, size_t len) 
ssize_t n = read(mss_fd, buf, len - 1);
if (n > 0) 
buf[n] = '\0';
printf("Modem MSS v3 reply: %s\n", buf);

int main() {
if (mss_open() < 0) return 1;
mss_get_version();
mss_send_command("AT+CRESET\r\n");
mss_read_response((char[128]){}, 128);
close(mss_fd);
return 0;

}

struct mss_v3_device 
    struct device *dev;
    void __iomem *sram_base;
    void __iomem *reg_base;
    struct mss_ipc_endpoint *ep[ MSS_V3_MAX_CHANNELS ];
    struct mss_power_ctrl pwr;
    struct mss_fw_info fw;
    struct clk_bulk_data *clks;
    int num_clks;
;
struct mss_v3_ring 
u32 head;   // volatile, updated by AP
u32 tail;   // volatile, updated by CP
u8 *buffer;
size_t size;
spinlock_t lock;
;

E IPC_RTR : mss_ver3_recv_data: invalid header
E MSS_V3  : tx timeout on channel 7

Analysis: Use samsung-ipc-log from LineageOS’s tools: // samsung_mss_v3_diag

adb shell "echo 0xFFFF > /sys/kernel/debug/sipc5/debug_mask"
adb shell cat /sys/kernel/debug/sipc5/stats

/* Pseudocode */
ret = request_firmware(&fw, "mss_fw.bin", dev);
if (ret) return ret;
if (!verify_signature(fw->data, fw->size)) 
  release_firmware(fw);
  return -EACCES;
copy_to_modem_bar(fw->data, fw->size);
release_firmware(fw);

struct net_device *ndev = alloc_netdev(...);
register_netdev(ndev);
setup_rmnet(ndev);

Samsung USB Composite Device Driver (MSS Ver.3) is a component of the Samsung Android USB Driver

package. It facilitates communication between a Windows PC and Samsung mobile devices for tasks like tethering, firmware flashing via Odin, and Android debugging. Microsoft Learn Technical Components and Architecture The "MSS Ver.3" designation typically refers to the Modem Sub-System version 3 contained within the ssudbus.sys driver file. Microsoft Learn

While MSS Ver.3 is mature, you can optimize its behavior: