SOC architecture with secure, selective peripheral enabling/disabling
A SOC includes a core, peripherals, and a bus for interconnecting the core and peripherals. Some peripherals can be selectively enabled or disabled on-demand. The SoC further includes peripheral enabling/disabling electronics and peripheral enabling/disabling circuitry coupled to the peripherals. The peripheral enabling/disabling electronics are directly connected to the peripheral enabling/disabling circuitry and are configured to store information items related to an enabled/disabled peripheral configuration, indicate the peripherals that are enabled and the peripherals that are disabled according to the enabled/disabled peripheral configuration, and provide the peripheral enabling/disabling circuitry with signals based on the stored information items. The peripheral enabling/disabling circuitry allows operation of the enabled peripherals and prevents operation of the disabled peripherals based on the signals received from the peripheral enabling/disabling electronics. The peripheral enabling/disabling electronics implement a secure mechanism allowing access to the peripheral enabling/disabling electronics and modification of the stored information items if security criteria are met.
1 . A system-on-chip device, comprising:
at least one core;
a plurality of peripherals;
at least one bus for interconnecting the at least one core and the plurality of peripherals, wherein the plurality of peripherals comprise a set of peripherals that can be selectively enabled or disabled on demand; and
peripheral enabling/disabling electronics and peripheral enabling/disabling circuitry coupled to the plurality of peripherals, wherein the peripheral enabling/disabling electronics are directly connected to the peripheral enabling/disabling circuitry and are configured to:
store information items related to an enabled/disabled peripheral configuration and indicating the peripherals of the plurality of peripherals that are enabled and the peripherals of the plurality of peripherals that are disabled according to said enabled/disabled peripheral configuration; and
provide the peripheral enabling/disabling circuitry with first signals based on the stored information items;
wherein the peripheral enabling/disabling circuitry is configured to allow operation of the peripherals of the set of peripherals that are enabled and prevent operation of the peripherals of the plurality of peripherals that are disabled based on the first signals received from the peripheral enabling/disabling electronics; and
wherein the peripheral enabling/disabling electronics includes a One Time Programmable memory coupled to a security stub, wherein the One Time Programmable memory stores the information items and the security stub allows modification of the stored information items in the One Time Programmable memory if security criteria are met.
2 . The system-on-chip device of claim 1 , wherein the peripheral enabling/disabling electronics include the One Time Programmable memory and a plurality of registers that are configured to:
be written/loaded with enabling/disabling data based on the stored information items; and
provide the peripheral enabling/disabling circuitry with the first signals based the written/loaded enabling/disabling data and with a second signal indicating whether the first signals are valid or not;
wherein the peripheral enabling/disabling circuitry is configured to allow operation of the peripherals of the set of peripherals that are enabled and prevent operation of the peripherals of the plurality of peripherals that are disabled based on the first signals received from the plurality of registers if the second signal received from the plurality of registers indicates that the first signals are valid.
3 . The system-on-chip device of claim 2 , wherein the security stub is provided between the at least one bus or an interconnect of the system-on-chip device and the One Time Programmable memory, and is configured to:
receive a secure signal indicating whether access to said One Time Programmable memory and the modification of the stored information items is allowed or not; and
allow or block, based on the received secure signal, the access to the One Time Programmable memory and the modification of the stored information items via the at least one bus or the interconnect.
4 . The system-on-chip device of claim 3 , wherein the at least one core is configured to implement a secure firmware module configured to:
provide the security stub with the secure signal;
access the One Time Programmable memory via the at least one bus or the interconnect;
carry out a modification of the stored information items; and
manage the secure signal so that the security stub allows the access to the One Time Programmable memory and the modification of the stored information items.
5 . The system-on-chip device according to claim 3 , further comprising a user interface;
wherein the at least one core is configured to implement a peripheral enabling/disabling firmware module that is:
operable to access the One Time Programmable memory via the at least one bus or the interconnect and to modify the stored information items; and
configured to provide the security stub with the secure signal;
wherein the user interface is configured to:
allow a user to request a modification of the enabled/disabled peripheral configuration; and
upon user request, provide the peripheral enabling/disabling firmware module with a corresponding command to modify the information items stored on the One Time Programmable memory; and
wherein the peripheral enabling/disabling firmware module is further configured to, upon receipt of the command from the user interface, access the One Time Programmable memory and modify the stored information items by managing the secure signal so that the security stub allows said access and said modification.
6 . The system-on-chip device of claim 5 , wherein the peripheral enabling/disabling firmware module and the user interface are configured to implement a cryptography technique in sending the command from said user interface to said peripheral enabling/disabling firmware module.
7 . The system-on-chip device according to claim 2 , wherein the plurality of registers are persistent registers configured to be rewritten/reloaded with the enabling/disabling data after each power-up of the system-on-chip device.
8 . The system-on-chip device according to claim 2 , wherein the plurality of registers are non-persistent registers configured to be rewritten/reloaded with the enabling/disabling data after each power-up and each standby of the system-on-chip device.
9 . The system-on-chip device according to claim 2 , wherein the plurality of registers are directly connected to the One Time Programmable memory.
10 . The system-on-chip device according to claim 2 , wherein the plurality of registers are connected to the One Time Programmable memory via an interconnect of the system-on-chip device, and wherein a master unit is provided in said system-on-chip device, the master unit being configured to manage reading of the information items from the One Time Programmable memory and writing/loading of the corresponding enabling/disabling data in/on the plurality of registers via the interconnect.
11 . A method for selectively enabling/disabling operation of peripherals of a system-on-chip device that comprises a core, peripherals that can be selectively enabled or disabled on demand, at least one bus for interconnecting the core and the peripherals, peripheral enabling/disabling circuitry coupled to the peripherals, and peripheral enabling/disabling electronics directly connected to the peripheral enabling/disabling circuitry, the method comprising:
storing, on the peripheral enabling/disabling electronics, information items that are related to an enabled/disabled peripheral configuration and that indicate enabled and disabled peripherals according to said enabled/disabled peripheral configuration;
operating the peripheral enabling/disabling electronics to provide the peripheral enabling/disabling circuitry with first signals based on the stored information items; and
operating the peripheral enabling/disabling circuitry to allow operation of the enabled peripherals and to prevent operation of the disabled peripherals based on the first signals received by the peripheral enabling/disabling circuitry from the peripheral enabling/disabling electronics
providing the peripheral enabling/disabling electronics with a One Time Programmable (OTP) memory coupled to a security stub, wherein the OTP memory stores the information items and the security stub allows modification of the stored information items in the OTP memory if security criteria are met.
12 . The method of claim 11 , further comprising:
storing enabling/disabling data in registers;
providing the peripheral enabling/disabling circuitry with the first signals based the stored enabling/disabling data and with a second signal indicating whether the first signals are valid;
allowing operation of the peripherals of the system-on-chip device that are enabled and preventing operation of the peripherals of the system-on-chip device that are disabled based on the first signals received from the registers if the second signal received from the registers indicates that the first signals are valid.
13 . The method of claim 12 , further comprising, at the security stub:
receiving a secure signal indicating whether access to said OTP memory and the modification of the stored information items is allowed or not; and
allow or block, based on the received secure signal, the access to the OTP memory and the modification of the stored information items via the at least one bus.
14 . The method of claim 13 , further comprising, at the core, implementing a secure firmware module configured to:
provide the security stub with the secure signal;
access the OTP memory via the at least one bus or the interconnect;
carry out a modification of the stored information items; and
manage the secure signal so that the security stub allows the access to the OTP memory and the modification of the stored information items.