Vhex is a kernel which provide development and retro ingenierie platform for the Casio's OS
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#include <stdint.h>
#include <stddef.h>
#include <sys/types.h>
// Hardware
#include <kernel/hardware/mpu.h>
// Internal helpers
#include <kernel/util/atomic.h>
#include <kernel/util/casio.h>
// Modules
#include <kernel/context.h>
#include <kernel/process.h>
#include <kernel/syscall.h>
#include <kernel/scheduler.h>
#include <kernel/loader.h>
// Devices
#include <kernel/devices/tty.h>
#include <kernel/devices/earlyterm.h>
// File System
#include <kernel/fs/vfs.h>
#include <kernel/fs/stat.h>
#include <kernel/fs/smemfs.h>
#include <kernel/fs/gladfs.h>
// Libs
#include <lib/display.h>
#include <lib/string.h>
// Internal symbols
mpu_t current_mpu = MPU_UNKNOWN;
// Internal hardware context.
fx9860_context_t casio_context;
fx9860_context_t vhex_context;
// Symbols defined by the linker
extern uint32_t bbss;
extern uint32_t sbss;
extern uint32_t bdata_ram;
extern uint32_t bdata_rom;
extern uint32_t sdata;
extern uint32_t bvhex_ram;
extern uint32_t bvhex_rom;
extern uint32_t svhex;
extern uint32_t bubc_ram;
extern uint32_t bubc_rom;
extern uint32_t subc;
extern uint32_t brom;
extern uint32_t srom;
extern uint32_t bctors;
extern uint32_t ectors;
extern uint32_t bdtors;
extern uint32_t edtors;
// Internal functions.
extern void vhex_context_set(void);
extern void kernel_switch(common_context_t *context);
extern mpu_t mpu_get(void);
extern int main(void);
// Internal object
extern struct file_system_type gladfs_filesystem;
extern struct file_system_type smemfs_filesystem;
//
// rom_explore() - explore all add-in ROM part.
// @note:
// For now, we can not use the MMU so we can
// not handle TLB miss. Casio load only the first 4ko
// of the add-in. To avoid TLB miss we explore all
// add-in binary to force Casio to generate all pages
// into the TLB.
//
static void rom_explore(volatile void *rom, int32_t size)
{
uint8_t unused;
(void)unused;
while (size >= 0)
{
unused = *(volatile uint8_t*)rom;
size = size - 1024;
rom = rom + 1024;
}
}
/* section_execute() - Used to execute contructors and destructors */
static void section_execute(void *bsection, void *esection)
{
while (bsection < esection)
{
((void (*)(void))*((void**)bsection))();
bsection = bsection + sizeof(void (*)(void));
}
}
/* start() - Kernel entry point */
__attribute__((section(".pretext")))
int start(void)
{
//--
// Bootstrap part !
//--
// Wipe .bss section and dump .data / Vhex sections
memset(&bbss, 0x00, (size_t)&sbss);
memcpy(&bdata_ram, &bdata_rom, (size_t)&sdata);
// Check MPU hardware.
current_mpu = mpu_get();
if (current_mpu != MPU_SH7305)
return (0);
// Load UBC / VBR space.
memcpy(&bubc_ram, &bubc_rom, (size_t)&subc);
memcpy(&bvhex_ram, &bvhex_rom, (size_t)&svhex);
// Casio do not load all add-in
// page. So we need to "force" update TLB
// before switching the VBR.
rom_explore(&brom, (int32_t)&srom);
// TODO: load driver on-the-fly
extern void screen_driver_load(void);
screen_driver_load();
// Start early terminal device
// This device is used by the kernel to display
// some logs on screen
if (earlyterm_init() != 0)
return (-1);
earlyterm_clear();
earlyterm_write("Kernel initialisation...\n");
// Execute constructor.
section_execute(&bctors, &ectors);
// Save Casio's hardware context and set
// Vhex hardware context.
// @note:
// This operation should be atomic
// because if an interruption or exception
// occur during the hardware context change
// the calculator will crash.
// And this is why between each `atomic_start`
// and `atomic_end()` the code *SHOULD* be
// exception safe.
earlyterm_write("Environment switch...\n");
atomic_start();
fx9860_context_save(&casio_context);
vhex_context_set();
atomic_stop();
//---
// File System part !
//---
// Internal FS init !
earlyterm_write("Initialize File System...\n");
gladfs_initialize();
smemfs_initialize();
// Initilize Virtual File System
earlyterm_write("Init. Virtual File System...\n");
vfs_register_filesystem(&gladfs_filesystem);
vfs_register_filesystem(&smemfs_filesystem);
// Creat initial file tree
earlyterm_write("Create Filesystem Hierarchy...\n");
vfs_mount(NULL, NULL, "gladfs", VFS_MOUNT_ROOT, NULL);
vfs_mkdir("/dev", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
vfs_mkdir("/home", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
vfs_mkdir("/mnt", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
vfs_mkdir("/mnt/casio", S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
vfs_mount(NULL, "/mnt/casio", "smemfs", /*MS_RDONLY*/0, NULL);
// Add devices
earlyterm_write("Add devices...\n");
vfs_mknod("/dev/tty", S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH,
dev_make_major(TTY_DEV_MAJOR));
//---
// Start first process !
//---
// Load programe.
earlyterm_write("Create first process...\n");
struct process *vhex_process = process_create();
if (vhex_process == NULL || loader(vhex_process, "/mnt/casio/VHEX/shell.elf") != 0)
{
// Display message.
earlyterm_clear();
earlyterm_write("Vhex fatal error !\n");
earlyterm_write("Unable to create the first process !\n");
if (vhex_process->context.spc == 0xffffffff)
earlyterm_write("process_create() error\n");
else
earlyterm_write("File \"VHEX/shell.elf\" not found !\n");
earlyterm_write("Press [MENU key]...\n");
// Restore Casio context.
fx9860_context_restore(&casio_context);
atomic_stop();
// Casio VRAM workaround
// @note: GetKey will call Bdisp_PutDD_VRAM(),
// so save the current internal Video RAM data into
// Casio's VRAM.
extern struct earlyterm earlyterm;
memcpy(casio_Bdisp_GetVRAM(), earlyterm.display.vram, 1024);
// Wait MENU key.
unsigned int key;
while (1)
{
casio_GetKey(&key);
}
}
//---
// Initialize sheduler !!
//---
earlyterm_write("Initialize scheduler...\n");
sched_initialize();
sched_add_task(vhex_process);
sched_start();
// normally the kernel SHOULD / CAN not arrive here.
earlyterm_write("Kernel job fini !");
while (1) { __asm__ volatile ("sleep"); }
}