The Switch makes use of a customized NVIDIA driver.
nvdrv:a
Main NVIDIA driver service.
Open
| Word | Value | 
| 0 | 0x00100004 | 
| 1 | 0x00000008 | 
| 2-4 | Type 5 descriptor: Device path | 
| 0-1 | "SFCI" | 
| 2-3 | Cmd id (0) | 
Ioctl
| Word | Value | 
| 0 | 0x11100004 | 
| 1 | 0x00000C0B | 
| ? | Type 0x21 descriptor: Input buffer | 
| ? | Type 0x22 descriptor: Output buffer | 
| 0-1 | "SFCI" | 
| 2-3 | Cmd id (1) | 
| 4 | Device fd | 
| 5 | Ioctl Cmd | 
Close
| Word | Value | 
| 0 | 0x00000004 | 
| 1 | 0x00000009 | 
| 0-1 | "SFCI" | 
| 2-3 | Cmd id (2) | 
| 4 | Device fd | 
Initialize
| Word | Value | 
| 0 | 0x00000004 | 
| 1 | 0x80000009 | 
| ? | Handle descriptor: Current process | 
| ? | Handle descriptor: Shared memory mirror | 
| 0-1 | "SFCI" | 
| 2-3 | Cmd id (3) | 
| 4 | Shared memory size | 
Webkit applet creates the shared memory with perm = 0 and size 0x300000.
Ioctls
The ioctl number is generated with the following primitive (see Linux kernel):
#define _IOC(inout, group, num, len) \
   (inout | ((len & IOCPARM_MASK) << 16) | ((group) << 8) | (num))
The following table contains known ioctls.
/dev/nvhost-ctrl
| Value | Direction | Size | Description | Notes | 
| 0xC0080014 | Inout | 8 | NVHOST_IOCTL_CTRL_SYNCPT_READ |  | 
| 0x40040015 | In | 4 | NVHOST_IOCTL_CTRL_SYNCPT_INCR |  | 
| 0xC00C0016 | Inout | 12 | NVHOST_IOCTL_CTRL_SYNCPT_WAIT |  | 
| 0x40080017 | In | 8 | NVHOST_IOCTL_CTRL_MODULE_MUTEX |  | 
| 0xC0180018 | Inout | 24 | NVHOST32_IOCTL_CTRL_MODULE_REGRDWR |  | 
| 0xC0100019 | Inout | 16 | NVHOST_IOCTL_CTRL_SYNCPT_WAITEX |  | 
| 0xC008001A | Inout | 8 | NVHOST_IOCTL_CTRL_SYNCPT_READ_MAX |  | 
| 0xC004001C | Inout | 4 |  |  | 
| 0xC010001D | Inout | 16 |  | NvRmSyncWaitEvent (wait on event?) | 
| 0xC010001E | Inout | 16 |  | NvRmSyncWaitEvent (wait on event?) | 
| 0xC004001F | Inout | 4 |  | NvRmSyncWaitEvent (signal event?) | 
| 0xC0040020 | Inout | 4 |  | NvRmSyncWaitEvent (signal event?) | 
| 0x40080021 | In | 8 | cancel_wait_event | Cancels all events | 
/dev/nvmap
| Value | Direction | Size | Description | Notes | 
| 0xC0080101 | Inout | 8 | NVMAP_IOC_CREATE |  | 
| 0x00000102 | - | 0 | NVMAP_IOC_CLAIM | Returns NotSupported | 
| 0xC0080103 | Inout | 8 | NVMAP_IOC_FROM_ID |  | 
| 0xC0200104 | Inout | 32 | NVMAP_IOC_ALLOC |  | 
| 0xC0180105 | Inout | 24 | NVMAP_IOC_FREE |  | 
| 0xC0280106 | Inout | 40 | NVMAP_IOC_MMAP | Returns NotSupported | 
| 0xC0280107 | Inout | 40 | NVMAP_IOC_WRITE | Returns NotSupported | 
| 0xC0280108 | Inout | 40 | NVMAP_IOC_READ | Returns NotSupported | 
| 0xC00C0109 | Inout | 12 | NVMAP_IOC_PARAM |  | 
| 0xC010010A | Inout | 16 | NVMAP_IOC_PIN_MULT | Returns NotSupported | 
| 0xC010010B | Inout | 16 | NVMAP_IOC_UNPIN_MULT | Returns NotSupported | 
| 0xC008010C | Inout | 8 | NVMAP_IOC_CACHE | Returns NotSupported | 
| 0xC004010D | Inout | 4 | Returns NotSupported | 
| 0xC008010E | Inout | 8 | NVMAP_IOC_GET_ID |  | 
| 0xC004010F | Inout | 4 | Returns NotSupported | 
| 0x40040110 | In | 4 | Returns NotSupported | 
| 0x00000111 | - | 0 | Returns NotSupported | 
Channels
Channels are a concept for  NVIDIA hardware blocks that share a common interface.
| Path | Name | 
| /dev/nvhost-tsec |  | 
| /dev/nvhost-gpu |  | 
| /dev/nvhost-vic |  | 
| /dev/nvhost-nvdec |  | 
| /dev/nvhost-nvjpg |  | 
Channel Ioctls
| Value | Size | Description | Notes | 
| 0xC0??0001 | Variable | NVHOST_IOCTL_CHANNEL_SUBMIT |  | 
| 0xC0080002 | 8 | NVHOST_IOCTL_CHANNEL_GET_SYNCPOINT |  | 
| 0xC0080003 | 8 | NVHOST_IOCTL_CHANNEL_GET_WAITBASE |  | 
| 0xC0080004 | 8 | NVHOST_IOCTL_CHANNEL_SET_TIMEOUT_EX |  | 
| 0x40040007 | 4 |  |  | 
| 0xC0??0009 | Variable | NVHOST_IOCTL_CHANNEL_MAP_BUFFER |  | 
| 0xC0??000A | Variable | NVHOST_IOCTL_CHANNEL_UNMAP_BUFFER |  | 
| 0x00000013 | 0 |  |  | 
| 0x40044801 | 4 | NVGPU_IOCTL_CHANNEL_SET_NVMAP_FD |  | 
| 0x40044803 | 4 | NVGPU_IOCTL_CHANNEL_SET_PRIORITY |  | 
| 0x40084805 | 8 | NVGPU_IOCTL_CHANNEL_ALLOC_GPFIFO |  | 
| 0xC0044807 | 4 | NVGPU_IOCTL_CHANNEL_CYCLE_STATS |  | 
| 0xC0184808 | 24 | NVGPU_IOCTL_CHANNEL_SUBMIT_GPFIFO |  | 
| 0xC0104809 | 16 | NVGPU_IOCTL_CHANNEL_ALLOC_OBJ_CTX |  | 
| 0x4008480A | 8 | NVGPU_IOCTL_CHANNEL_FREE_OBJ_CTX |  | 
| 0xC010480B | 16 | NVGPU_IOCTL_CHANNEL_ZCULL_BIND |  | 
| 0xC018480C | 24 | NVGPU_IOCTL_CHANNEL_SET_ERROR_NOTIFIER |  | 
| 0x4004480D | 4 | NVGPU_IOCTL_CHANNEL_OPEN |  | 
| 0x0000480E | 0 | NVGPU_IOCTL_CHANNEL_ENABLE |  | 
| 0x0000480F | 0 | NVGPU_IOCTL_CHANNEL_DISABLE |  | 
| 0x00004810 | 0 | NVGPU_IOCTL_CHANNEL_PREEMPT |  | 
| 0x00004811 | 0 | NVGPU_IOCTL_CHANNEL_FORCE_RESET |  | 
| 0x40084812 | 8 | NVGPU_IOCTL_CHANNEL_EVENTS_CTRL |  | 
| 0xC0104813 | 16 | NVGPU_IOCTL_CHANNEL_CYCLE_STATS_SNAPSHOT |  | 
| 0x80804816 | 128 |  | 
| 0xC0104817 | 16 |  |  | 
| 0x40204818 | 32 | NVGPU_IOCTL_CHANNEL_ALLOC_GPFIFO_EX |  | 
| 0xC0484819 | 72 |  | 
| 0xC020481A | 32 | NVGPU_IOCTL_CHANNEL_ALLOC_GPFIFO_EX2 |  | 
| 0x40084714 | 8 | set_user_address | Group ID is 'H' for Horizon | 
| 0x80084715 | 8 | get_user_address | Group ID is 'H' for Horizon | 
Remaining Ioctls
| Device | Value | Description | Notes | 
| /dev/nvhost-as-gpu | 0x40044101 | NVGPU_AS_IOCTL_BIND_CHANNEL |  | 
| /dev/nvhost-as-gpu | 0xC0184102 | NVGPU_AS_IOCTL_ALLOC_SPACE |  | 
| /dev/nvhost-as-gpu | 0xC0104103 | NVGPU_AS_IOCTL_FREE_SPACE |  | 
| /dev/nvhost-as-gpu | 0xC0184104 | NVGPU_AS_IOCTL_MAP_BUFFER |  | 
| /dev/nvhost-as-gpu | 0xC0084105 | NVGPU_AS_IOCTL_UNMAP_BUFFER |  | 
| /dev/nvhost-as-gpu | 0xC0284106 | NVGPU_AS_IOCTL_MAP_BUFFER_EX |  | 
| /dev/nvhost-as-gpu | 0x40104107 | init_as_gpu | Initializes the as-gpu node | 
| /dev/nvhost-as-gpu | 0xC0404108 | NVGPU_AS_IOCTL_GET_VA_REGIONS? |  | 
| /dev/nvhost-as-gpu | 0x40284109 | init_as_gpu_ex | Initializes the as-gpu node (with more params) | 
| /dev/nvhost-as-gpu | 0xC0144114 |  |  | 
| /dev/nvhost-dbg-gpu | 0x40084401 | NVGPU_DBG_GPU_IOCTL_BIND_CHANNEL |  | 
| /dev/nvhost-dbg-gpu | 0xC0??4402 | NVGPU_DBG_GPU_IOCTL_REG_OPS | ?? == size is unknown | 
| /dev/nvhost-dbg-gpu | 0x40084403 | NVGPU_DBG_GPU_IOCTL_EVENTS_CTRL |  | 
| /dev/nvhost-dbg-gpu | 0x40044404 | NVGPU_DBG_GPU_IOCTL_POWERGATE |  | 
| /dev/nvhost-dbg-gpu | 0x40044405 | NVGPU_DBG_GPU_IOCTL_SMPC_CTXSW_MODE |  | 
| /dev/nvhost-dbg-gpu | 0xC0184407 | NVGPU_DBG_GPU_IOCTL_PERFBUF_MAP |  | 
| /dev/nvhost-dbg-gpu | 0x40084408 | NVGPU_DBG_GPU_IOCTL_PERFBUF_UNMAP |  | 
| /dev/nvhost-dbg-gpu | 0x40084409 | NVGPU_DBG_GPU_IOCTL_PC_SAMPLING |  | 
| /dev/nvhost-ctrl-gpu | 0x80044701 | NVGPU_GPU_IOCTL_ZCULL_GET_CTX_SIZE |  | 
| /dev/nvhost-ctrl-gpu | 0x80284702 | NVGPU_GPU_IOCTL_ZCULL_GET_INFO |  | 
| /dev/nvhost-ctrl-gpu | 0x402C4703 | NVGPU_GPU_IOCTL_ZBC_SET_TABLE |  | 
| /dev/nvhost-ctrl-gpu | 0xC0344704 | NVGPU_GPU_IOCTL_ZBC_QUERY_TABLE |  | 
| /dev/nvhost-ctrl-gpu | 0xC0B04705 | NVGPU_GPU_IOCTL_GET_CHARACTERISTICS |  | 
| /dev/nvhost-ctrl-gpu | 0xC0184706 | NVGPU_GPU_IOCTL_GET_TPC_MASKS |  | 
| /dev/nvhost-ctrl-gpu | 0x40084707 | NVGPU_GPU_IOCTL_OPEN_CHANNEL |  | 
| /dev/nvhost-ctrl-gpu | 0x4008470E |  |  | 
| /dev/nvhost-ctrl-gpu | 0x4010470F |  |  | 
| /dev/nvhost-ctrl-gpu | 0xC0084710 |  |  | 
| /dev/nvhost-ctrl-gpu | 0x80084711 |  |  | 
| /dev/nvhost-ctrl-gpu | 0x80084712 |  |  | 
| /dev/nvhost-ctrl-gpu | 0xC0044713 |  |  | 
| /dev/nvhost-ctrl-gpu | 0x80084714 |  |  | 
| /dev/nvhost-ctrl-gpu | 0x80044715 |  |  | 
| /dev/nvhost-ctrl-gpu | 0x8018471A |  |  | 
| /dev/nvhost-ctrl-gpu | 0xC008471B |  |  | 
| /dev/nvhost-ctrl-gpu | 0xC010471C |  |  | 
nvmemp
NVIDIA memory profiler (this service is not available on retail units).
mm:u
NVIDIA multimedia (NvMM) platform service.
| Cmd | Name | 
| 0 | ? | 
| 1 | ? | 
| 2 | ? | 
| 3 | ? | 
| 4 | module_init_clk | 
| 5 | module_deinit_clk | 
| 6 | module_set_clk_rate | 
| 7 | module_get_clk_rate | 
Errors
Most nvidia driver commands return an error code apart from the normal return code.
| Cmd | Name | 
| 0 | Success | 
| 1 | NotImplemented | 
| 2 | NotSupported | 
| 3 | NotInitialized | 
| 4 | BadParameter | 
| 5 | Timeout | 
| 6 | InsufficientMemory | 
| 7 | ReadOnlyAttribute | 
| 8 | InvalidState | 
| 9 | InvalidAddress | 
| 0xA | InvalidSize | 
| 0xB | BadValue | 
| 0xD | AlreadyAllocated | 
| 0xE | Busy | 
| 0xF | ResourceError | 
| 0x10 | CountMismatch | 
| 0x1000 | Shared memory too small |