dts - linux,usable-memory

[Laurentiu-Cristian Duca]

On 8/2/23, Samuel Holland <samuel.holland at sifive.com> wrote:
> Hi Laurentiu,
>
> On 2023-08-02 9:37 AM, Laurentiu-Cristian Duca wrote:
>> On 8/2/23, Laurentiu-Cristian Duca <laurentiu.duca at gmail.com> wrote:
>>> On 8/2/23, Conor Dooley <conor at kernel.org> wrote:
>>>> Hey,
>>>>
>>>> On Wed, Aug 02, 2023 at 04:51:47PM +0300, Laurentiu-Cristian Duca
>>>> wrote:
>>>>>   my name is laurentiu-cristian duca and i am an open-source
>>>>> enthusiast.
>>>>> lately i have tried to use the linux,usable-memory in the dts memory
>>>>> node
>>>>> and linux freezes.
>>>>>   if i use only reg, linux boots fine.
>>>>>   does anybody used linux,usable-memory and can you show a working
>>>>> example.
>>>>>
>>>>>   here is what i tried
>>>>>         memory at 80000000 {
>>>>>                 device_type = "memory";
>>>>>                 reg = <0x0 0x80000000 0x0 0x700000>;
>>>>>                 //linux,usable-memory = <0x80000000 0x700000>;
>>>>>         };
>>>>
>>>> What are you actually doing when you freeze? A normal boot? Kexec?
>>>> What hardware is this?
>>>> Are you using OpenSBI, and if so what version?
>>>> What version of the kernel is this?
>>>
>>>   linux5.13.19 with busybox minimal rootfs, bbl (berkeley boot loader),
>>> hardware fpga board with only uart and memory 8MB
>>> i simulate in verilator the verilog sources and i have success if the
>>> dts has reg.
>>>  when it freezes, i can not see any message in simulation
>> [    0.000000] Linux version 5.13.19 (laur at laurPC-100)
>> (riscv32-linux-gcc.br_real (Buildroot 2021.08) 11.1.0, GNU ld (GNU
>> Binutils) 2.37) #402 SMP Wed Aug 2 15:27:14 EEST 2023
>> [    0.000000] OF: fdt: memory scan node memory at 80000000, reg size 8,
>> [    0.000000] Machine model: kise-lab,simrv
>> [    0.000000] earlycon: sbi0 at I/O port 0x0 (options '')
>> [    0.000000] printk: bootconsole [sbi0] enabled
>> [    0.000000] printk: debug: ignoring loglevel setting.
>> from here i can not see anything
>>
>>
>>> if you want to, i can send you the sources
>>>
>>>   please tell me if the dts memory property is written correctly for
>>> linux,usable-memory
>
> It is not. The number of cells you need is given by the #address-cells and
> #size-cells properties of the root node (see early_init_dt_scan_memory()).
> You
> didn't include that part of the DTS in your example, but I am guessing the
> "reg"
> property is correct, and it has two cells each. linux,usable-memory should
> look
> the same. So the correct format would be:
>
>         linux,usable-memory = <0x0 0x80000000 0x0 0x700000>;
>

  I tried this also without success. The same error.
here is my devicetree.dts:

/dts-v1/;

/ {
        #address-cells = <0x2>;
        #size-cells = <0x2>;
        model = "kise-lab,simrv";
        compatible = "kise_lab,simrv";

        cpus {
                #address-cells = <0x1>;
                #size-cells = <0x0>;
                // 104 * 10^6 = 0x632ea00
                timebase-frequency = <0x632ea00>;

                cpu at 0 {
                        device_type = "cpu";
                        reg = <0x0>;
                        status = "okay";
                        compatible = "riscv";
                        riscv,isa = "rv32acim";
                        mmu-type = "riscv,sv32";
                        // 104 * 10^6 = 0x632ea00
                        clock-frequency = <0x632ea00>;

                        interrupt-controller {
                                #interrupt-cells = <0x1>;
                                interrupt-controller;
                                compatible = "riscv,cpu-intc";
                                phandle = <0x1>;
                                linux,phandle = <0x01>;
                        };
                };

                cpu at 1 {
                        device_type = "cpu";
                        reg = <0x1>;
                        status = "okay";
                        compatible = "riscv";
                        riscv,isa = "rv32acim";
                        mmu-type = "riscv,sv32";
                        clock-frequency = <0x632ea00>;

                        interrupt-controller {
                                #interrupt-cells = <0x01>;
                                interrupt-controller;
                                compatible = "riscv,cpu-intc";
                                phandle = <0x02>;
                                linux,phandle = <0x02>;
                        };
                };
        };

        memory at 80000000 {
                device_type = "memory";
                //reg = <0x0 0x80000000 0x0 0x4000000>;
                // tangnano
                reg = <0x0 0x80000000 0x0 0x700000>;
                linux,usable-memory = <0x0 0x80000000 0x0 0x700000>;
        };

       soc {
                #address-cells = <0x2>;
                #size-cells = <0x2>;
                compatible = "simple-bus";
                ranges;

                clint at 60000000 {
                        compatible = "riscv,clint0";
                        reg = <0x0 0x60000000 0x0 0x8000000>;
                        //interrupts-extended = <0x01 0x03 0x01 0x07
0x02 0x03 0x02 0x07>; // m priv level
                        interrupts-extended = <0x01 0x01 0x01 0x05
0x02 0x01 0x02 0x05>; // s priv level
                };

                plic at 50000000 {
                        #interrupt-cells = <0x1>;
                        interrupt-controller;
                        compatible = "riscv,plic0";
                        riscv,ndev = <0x1f>;
                        reg = <0x0 0x50000000 0x0 0x8000000>;
                        interrupts-extended = <0x01 0x09 0x01 0x0b
0x02 0x09 0x02 0x0b>;
                        phandle = <0x3>;
                };
        };

        chosen {
                //bootargs = "console=hvc0 earlycon=sbi root=/dev/vda
rw initcall_debug=1 ignore_loglevel=1";
                bootargs = "console=hvc0 earlycon=sbi root=/dev/vda rw
ignore_loglevel=1";
                //bootargs = "console=hvc0 earlycon=sbi root=/dev/vda
rw ignore_loglevel=1 memmap=3800K at 80002000,4000K at 80400000";
                //bootargs = "console=hvc0 earlycon=sbi root=/dev/vda rw";
        };
};


thank you,
laurentiu


> Regards,
> Samuel
>
>