CedarX/Kernel Driver guide

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Driver IOCTL guide

Blob mostly use MMIO Access but CedarX should be gate-on and support PLLs should be confugired before

CORE IOCTL

IOCTL_GET_ENV_INFO = 0x101

copy memory configuration info to userspace struct:

typedef struct ve_info{
  unsigned int reserved;
  int reserved_size;
  unsigned int io_base;
} cedar_env_info_t;


c_info.io_base - constain ioremapped  cedarx hw registers offset. 
Must be used for cedarX hw registers access using mmio
c_info.reserved - constain cedarx reserved memory offset. 
Must be used for hw register access using mmio


c_info.reserved_size - constain cedarx reserved memory size  


Example:

ve_info c_info;
ioctl(cedar, IOCTL_GET_ENV_INFO, (unsigned long)&c_info);


IOCTL_WAIT_VE = 0x102

used for cedar IRQ wait, when some operation ends, for example,
end jpeg decoding process end. don't forget clean IRQ flag after.

IOCTL_RESET_VE = 0x103

do reset cedarx engine

IOCTL_ENABLE_VE = 0x104

start base clocks for cedarx

IOCTL_DISABLE_VE = 0x105

disable base clocks for cedarx

IOCTL_SET_VE_FREQ = 0x106

config cedarx frequency, get in argument freqency in Mhz

for A13 freq are 180 Mhz

Example

ioctl(cedar, IOCTL_SET_VE_FREQ, freq);

AVS2 IOCTL

IOCTL_CONFIG_AVS2 = 0x200

IOCTL_GETVALUE_AVS2 = 0x201

IOCTL_PAUSE_AVS2 = 0x202

IOCTL_START_AVS2 = 0x203

IOCTL_RESET_AVS2 = 0x204

IOCTL_ADJUST_AVS2 = 0x205

ENGINE IOCTL

IOCTL_ENGINE_REQ = 0x206

count references to cedar hardware and more important start some clocks that required for cedar init

IOCTL_ENGINE_REL = 0x207

decrement reference count

IOCTL_ENGINE_CHECK_DELAY = 0x208

IOCTL_GET_IC_VER = 0x209

IOCTL_ADJUST_AVS2_ABS = 0x20a

IOCTL_FLUSH_CACHE = 0x20b do invalidate CPU cache for internal cedar dma

Kernel driver init procedure

This required for make CedarX hardware regs in workable state

   ioctl(cedar, IOCTL_ENABLE_VE,0); /*en*/
   ioctl(cedar, IOCTL_ENGINE_REQ,0);/*eng req*/
   ioctl(cedar, IOCTL_SET_VE_FREQ,180); /*set freq in Mhz*/
   ioctl(cedar, IOCTL_RESET_VE,0); /*ve reset*/

after this step user-space lib must mmap /dev/cedar_dev and get direct access to hardware registers

MMAP procedure

You must request ioremaped cedar base address using IOCTL_GET_ENV_INFO that will fill flowing struct

typedef struct cedarv_env_info{
  unsigned int phymem_start;
  int phymem_total_size;
  unsigned int address_macc;
} cedar_env_info_t;
cedarx_env_info c_info;


ioctl(cedar, IOCTL_GET_ENV_INFO, (unsigned long)&c_info);

Than you must do mmap like that:

io_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, cedar, c_info.address_macc);

Same for reserved memory buffer:

data_base = mmap(NULL, c_info.phymem_total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, c_info.phymem_start);

and after than cedarx version show be checked by reading "VE Revision register" [CEDAR_BASE+0xf2] that constain chip version

0x1623 for a10, 0x1625 for a13
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