cedar_ve driver not able to allocate memory

[cooler]

I've managed to install the driver.
But there are several things to consider and I'm not sure that resolved them correctly.

First, the shared memory pool required by the driver cedar_ve.ko is hardcoded to 80 Megabytes. We cannot spend so much RAM because there is about 128 onboard. So I've decreased hardcoded value to 16M and rebuilt the driver.

Code:

#if !defined(USE_ION)
    cedar_devp->ve_size = 16 * SZ_1M;  // was 80

I've also updated the device tree that way:

Code:

        reserved-memory {
                #address-cells = <1>;
                #size-cells = <1>;
                ranges;

                /* Address must be kept in the lower 256 MiBs of DRAM for VE. */
            cma_pool: linux,cma {
                compatible = "shared-dma-pool";
                size = <0x2000000>;
                alignment = <0x2000>;
                /*alloc-ranges = <0x4a000000 0x6000000>;*/
                reusable;
                linux,cma-default;
            };

        };

...

Code:

syscon: system-control@1c00000 {
            compatible = "allwinner,sun8i-v3s-system-control","allwinner,sun8i-h3-system-control","syscon";
            reg = <0x01c00000 0x1000>;
            #address-cells = <1>;
            #size-cells = <1>;
            ranges;

            sram_c: sram@1d00000 {
                compatible = "mmio-sram";
                reg = <0x01d00000 0x80000>;
                #address-cells = <1>;
                #size-cells = <1>;
                ranges = <0 0x01d00000 0x80000>;

                ve_sram: sram-section@0 {
                    compatible = "allwinner,sun8i-h3-sram-c1",
                     "allwinner,sun4i-a10-sram-c1";
                    reg = <0x000000 0x80000>;
                };
            };
        };

        ve: video-engine@01c0e000 {
            compatible = "allwinner,sunxi-cedar-ve";
            reg = <0x01c0e000 0x1000>,
                      <0x01c00000 0x10>,
                      <0x01c20000 0x800>;
                        memory-region = <&cma_pool>;
            syscon = <&syscon>;
            clocks = <&ccu CLK_BUS_VE>, <&ccu CLK_VE>,
                     <&ccu CLK_DRAM_VE>;
            clock-names = "ahb", "mod", "ram";
            resets = <&ccu RST_BUS_VE>;
            interrupts = <GIC_SPI 58 IRQ_TYPE_LEVEL_HIGH>;
            allwinner,sram = <&ve_sram 1>;
        };

Don't even ask about why I've done it that way, I know literally nothing about that device trees, I've just compiled several examples from Orange PI giving a heuristics about how little RAM we have 


dmesg output:

Code:

[    0.000000] Memory policy: Data cache writealloc
[    0.000000] Reserved memory: created CMA memory pool at 0x45c00000, size 32 MiB
[    0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool

....

Code:

[    8.063755] sunxi cedar version 0.1
[    8.063952] [cedar]: install start!!!
[    8.064021] cedar_ve: cedar-ve the get irq is 30
[    8.064046] sunxi-cedar 1c0e000.video-engine: assigned reserved memory node linux,cma
[    8.064345] [cedar]: Success claim SRAM
[    8.070282] systemd[1]: Finished Load Kernel Module configfs.
[    8.085820] [cedar]: memory allocated at address PA: 45D00000, VA: C5D00000
[    8.085835] [cedar]: install end!!!

and now I have

Code:

root@pinecube:/dev# ls -l
total 0
crw-r--r-- 1 root root     10, 235 Dec 14 08:13 autofs
drwxr-xr-x 2 root root         380 Dec 14 08:13 block
crw-rw---- 1 root disk     10, 234 Dec 14 08:13 btrfs-control
drwxr-xr-x 3 root root          60 Jan  1  1970 bus
crw-rw---- 1 root video   150,   0 Dec 14 08:13 cedar_dev         <----------
drwxr-xr-x 2 root root        2660 Dec 14 08:13 char
crw------- 1 root root      5,   1 Dec 14 08:14 console
crw------- 1 root root     10,  61 Dec 14 08:13 cpu_dma_latency

But... so what, how do we utilize this module to encode camera stream to video files then?