Secure vs Non-secure addresses

• Certain devices are reachable at different addresses depending on whether the access is ���secure��� or ���non-secure���
  • Need to express multiple addresses in Device Tree and System Device Tree for each device node
  • Introducing ���secure-reg��� vs.��extending ���reg���
  • Impact on ���simple-bus��� and its ranges property
  • Impact on the CPU clusters��� ���address-map���

    #address-cells = <0x1>;
    #size-cells = <0x1>;

    cpus-cluster@0 {
        compatible = "cpus,cluster";
        #address-cells = <0x1>;
        #size-cells = <0x1>;

        address-map = <0xff110000 &amba 0xff110000 0x1000>;
    };

    amba {
        compatible = "simple-bus";
        #address-cells = <0x1>;
        #size-cells = <0x1>;
        ranges = <0xff110000 0xff110000 0x1000;

        timer0: timer@ff110000 {
            compatible = "cdns,ttc";
            status = "okay";

            reg = <0xff110000 0x1000>;
        };
    };

Introducing ���secure-bus��� and extending ���regs���

• Introducing a new type of bus: ���secure-bus���
  • first cell in ���regs��� specifies the execution mode
    • #address-cells = <0x2>
    • 0x0: non-secure
    • 0x1: secure

    amba {
        compatible = "secure-bus";
        #address-cells = <0x2>;
        #size-cells = <0x1>;

        timer0: timer@ff110000 {
            compatible = "cdns,ttc";
            status = "okay";

                   /* non-secure addresses */
            reg = <0x0 0xff110000 0x1000
                   /* secure addresses */
                   0x1 0xc0110000 0x1000>;
        };

Introducing ���secure-bus��� and extending ���regs���

• Introducing a new type of bus: ���secure-bus���
  • first cell in ���regs��� specifies the execution mode
  • secure-bus ranges property maps both secure and non-secure addresses
    • #address-cells = <0x2>
    • first cell in ���ranges��� specifies the execution mode
    • 0x0: non-secure
    • 0x1: secure
  • how to distinguish between #address-cells = <0x2> to specify 64-bit addresses vs first cells to specify secure/non-secure?

    #address-cells = <0x1>;
    #size-cells = <0x1>;

    amba {
        compatible = "secure-bus";
        #address-cells = <0x2>;
        #size-cells = <0x1>;

                  /* non-secure mapping */
        ranges = <0x0 0xff110000 0xff110000 0x1000
                  /* secure mapping */
                  0x1 0xc0110000 0xc0110000 0x1000>;

        timer0: timer@ff110000 {
            compatible = "cdns,ttc";
            status = "okay";

                   /* non-secure addresses */
            reg = <0x0 0xff110000 0x1000
                   /* secure addresses */
                   0x1 0xc0110000 0x1000>
        };

���secure-address-map��� or extending ���address-map���

• Introducing ���secure-address-map��� to express CPU clusters mappings of secure addresses
• Alternatively, the first cell of ���address-map��� could be used to express the execution mode

    #address-cells = <0x1>;
    #size-cells = <0x1>;

    cpus-cluster@0 {
        compatible = "cpus,cluster";
        #address-cells = <0x2>;
        #size-cells = <0x1>;

        /* traditional address-map property here as a reference */
        address-map = <0xff110000 &amba 0xff110000 0x1000>;

        /* secure-address-map specifies the CPU cluster's mapping of secure addresses */
        secure-address-map = <0xc0110000 &amba 0xc0110000 0x1000>;

        /* extending address-map with a secure/non-secure execution mode cell */
        address-map = <0x0 0xff110000 &amba 0xff110000 0x1000
                       0x1 0xc0110000 &amba 0xc0110000 0x1000>;
    };

    amba {
        compatible = "secure-bus";
        #address-cells = <0x2>;
        #size-cells = <0x1>;
                  /* non-secure mapping */
        ranges = <0x0 0xff110000 0xff110000 0x1000
                  /* secure mapping */
                  0x1 0xc0110000 0xc0110000 0x1000>;

        timer0: timer@ff110000 {
            compatible = "cdns,ttc";
            status = "okay";

                   /* non-secure addresses */
            reg = <0x0 0xff110000 0x1000
                   /* secure addresses */
                   0x1 0xc0110000 0x1000>
        };

Execution Domains

• Execution domains are unaffected as they already had a property to specify the execution mode
  • 3rd cell of the ���cpus��� property

domains {

    domains {
        zephyr@0 {
            compatible = "openamp,domain-v1";

            /* execution mode: secure */
            cpus = <&cpus_r5 0x2 0x80000000>;

            #access-flags-cells = <1>;
            /* timer0 resolves to address 0xc0110000 */
            access = <&timer0 0x0>;
        };

        linux@1 {
            compatible = "openamp,domain-v1";

            /* execution mode: non-secure EL1 */
            cpus = <&cpus_a72 0x2 0x00000001>;

            #access-flags-cells = <1>;
            /* timer0 resolves to address 0xff110000 */
            access = <&timer0 0x0>;
        };
    };  

};

Full Example

    #address-cells = <0x1>;
    #size-cells = <0x1>;

    cpus-cluster@0 {
        compatible = "cpus,cluster";
        #address-cells = <0x2>;
        #size-cells = <0x1>;

        /* extending address-map with a secure/non-secure execution mode cell */
        address-map = <0x0 0xff110000 &amba 0xff110000 0x1000
                       0x1 0xc0110000 &amba 0xc0110000 0x1000>;
    };

    amba {
        compatible = "secure-bus";
        #address-cells = <0x2>;
        #size-cells = <0x1>;
                  /* non-secure mapping */
        ranges = <0x0 0xff110000 0xff110000 0x1000
                  /* secure mapping */
                  0x1 0xc0110000 0xc0110000 0x1000>;

        timer0: timer@ff110000 {
            compatible = "cdns,ttc";
            status = "okay";

                   /* non-secure addresses */
            reg = <0x0 0xff110000 0x1000
                   /* secure addresses */
                   0x1 0xc0110000 0x1000>
        };
    };

    domains {
        zephyr@0 {
            compatible = "openamp,domain-v1";

            /* execution mode: secure */
            cpus = <&cpus_r5 0x2 0x80000000>;

            #access-flags-cells = <1>;
            /* timer0 resolves to address 0xc0110000 */
            access = <&timer0 0x0>;
        };

        linux@1 {
            compatible = "openamp,domain-v1";

            /* execution mode: non-secure EL1 */
            cpus = <&cpus_a72 0x2 0x00000001>;

            #access-flags-cells = <1>;
            /* timer0 resolves to address 0xff110000 */
            access = <&timer0 0x0>;
        };
    };