Registers

Summary

INTR_STATE

Interrupt State Register

• Offset: 0x0
• Reset default: 0x0
• Reset mask: 0x3

Fields

{"reg": [{"name": "edn_cmd_req_done", "bits": 1, "attr": ["rw1c"], "rotate": -90}, {"name": "edn_fatal_err", "bits": 1, "attr": ["rw1c"], "rotate": -90}, {"bits": 30}], "config": {"lanes": 1, "fontsize": 10, "vspace": 180}}

INTR_ENABLE

Interrupt Enable Register

• Offset: 0x4
• Reset default: 0x0
• Reset mask: 0x3

Fields

{"reg": [{"name": "edn_cmd_req_done", "bits": 1, "attr": ["rw"], "rotate": -90}, {"name": "edn_fatal_err", "bits": 1, "attr": ["rw"], "rotate": -90}, {"bits": 30}], "config": {"lanes": 1, "fontsize": 10, "vspace": 180}}

INTR_TEST

Interrupt Test Register

• Offset: 0x8
• Reset default: 0x0
• Reset mask: 0x3

Fields

{"reg": [{"name": "edn_cmd_req_done", "bits": 1, "attr": ["wo"], "rotate": -90}, {"name": "edn_fatal_err", "bits": 1, "attr": ["wo"], "rotate": -90}, {"bits": 30}], "config": {"lanes": 1, "fontsize": 10, "vspace": 180}}

ALERT_TEST

Alert Test Register

• Offset: 0xc
• Reset default: 0x0
• Reset mask: 0x3

Fields

{"reg": [{"name": "recov_alert", "bits": 1, "attr": ["wo"], "rotate": -90}, {"name": "fatal_alert", "bits": 1, "attr": ["wo"], "rotate": -90}, {"bits": 30}], "config": {"lanes": 1, "fontsize": 10, "vspace": 130}}

REGWEN

Register write enable for all control registers

• Offset: 0x10
• Reset default: 0x1
• Reset mask: 0x1

Fields

{"reg": [{"name": "REGWEN", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"bits": 31}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

CTRL

EDN control register

• Offset: 0x14
• Reset default: 0x9999
• Reset mask: 0xffff
• Register enable: REGWEN

Fields

{"reg": [{"name": "EDN_ENABLE", "bits": 4, "attr": ["rw"], "rotate": -90}, {"name": "BOOT_REQ_MODE", "bits": 4, "attr": ["rw"], "rotate": -90}, {"name": "AUTO_REQ_MODE", "bits": 4, "attr": ["rw"], "rotate": -90}, {"name": "CMD_FIFO_RST", "bits": 4, "attr": ["rw"], "rotate": -90}, {"bits": 16}], "config": {"lanes": 1, "fontsize": 10, "vspace": 150}}

CTRL . CMD_FIFO_RST

Setting this field to kMultiBitBool4True clears the two command FIFOs: the RESEED_CMD FIFO and the GENERATE_CMD FIFO. This field must be set to the reset state by software before any further commands can be issued to these FIFOs.

CTRL . AUTO_REQ_MODE

Setting this field to kMultiBitBool4True enables auto request mode. In this mode, EDN automatically sends generate and reseed command requests to the CSRNG application interface. The purpose of this mode is to continuously deliver entropy to endpoints without firmware intervention.

For this to work, firmware has to 1) configure the GENERATE_CMD, RESEED_CMD, and MAX_NUM_REQS_BETWEEN_RESEEDS registers, and 2) to issue the first instantiate command via the SW_CMD_REQ register. Once this command has been acknowledged by CSRNG, the first generate command is sent out automatically, and a reseed command is sent after every MAX_NUM_REQS_BETWEEN_RESEEDS number of generate commands.

Note that the BOOT_REQ_MODE field takes precedence over this field: If both fields are set, EDN enters boot-time request mode. If none of the fields are set, EDN enters Software Port Mode upon enabling.

CTRL . BOOT_REQ_MODE

Setting this field to kMultiBitBool4True enables the boot-time request mode. In this mode, EDN automatically sends a boot-time request to the CSRNG application interface. The purpose of this mode is to request entropy as fast as possible after reset, and during chip boot time.

Note that this takes precedence over the AUTO_REQ_MODE field: If both fields are set, EDN enters boot-time request mode. If none of the fields are set, EDN enters Software Port Mode upon enabling.

CTRL . EDN_ENABLE

Setting this field to kMultiBitBool4True enables the EDN module. The modules of the entropy complex may only be enabled and disabled in a specific order, see Programmers Guide for details.

BOOT_INS_CMD

EDN boot instantiate command register

• Offset: 0x18
• Reset default: 0x901
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "BOOT_INS_CMD", "bits": 32, "attr": ["rw"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

BOOT_INS_CMD . BOOT_INS_CMD

This field is used as the value for the instantiate command at boot time.

See Command Header for the meaning of the individual bits. Note that the hardware only supports a value of 0 for the clen field. If clen has a different value, EDN will hang. Fixing this requires disabling and restarting both EDN and CSRNG.

BOOT_GEN_CMD

EDN boot generate command register

• Offset: 0x1c
• Reset default: 0xfff003
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "BOOT_GEN_CMD", "bits": 32, "attr": ["rw"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

BOOT_GEN_CMD . BOOT_GEN_CMD

This field is used as the value for the generate command at boot time.

See Command Header for the meaning of the individual bits. Note that the hardware only supports a value of 0 for the clen field. If clen has a different value, EDN will hang. Fixing this requires disabling and restarting both EDN and CSRNG.

SW_CMD_REQ

EDN csrng app command request register

• Offset: 0x20
• Reset default: 0x0
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "SW_CMD_REQ", "bits": 32, "attr": ["wo"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

SW_CMD_REQ . SW_CMD_REQ

Any CSRNG action can be initiated by writing a CSRNG command to this register. Before any write operation to this register, firmware must read SW_CMD_STS to check whether EDN is ready to receive a new command or the next word of a previously started command.

While CTRL.AUTO_REQ_MODE is set, only the first instantiate command has any effect. After that command has been processed, writes to this register will have no effect on operation, until CTRL.AUTO_REQ_MODE is de-asserted and the state machine of EDN enters the SwPortMode state.

Refer to the CSRNG documentation for details on the command format.

SW_CMD_STS

EDN software command status register

• Offset: 0x24
• Reset default: 0x0
• Reset mask: 0x3f

Fields

{"reg": [{"name": "CMD_REG_RDY", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "CMD_RDY", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "CMD_ACK", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "CMD_STS", "bits": 3, "attr": ["ro"], "rotate": -90}, {"bits": 26}], "config": {"lanes": 1, "fontsize": 10, "vspace": 130}}

SW_CMD_STS . CMD_STS

This field represents the status code returned with the CSRNG application command ack. It is updated each time a SW command is acknowledged by CSRNG. To check whether a command was successful, wait for INTR_STATE.EDN_CMD_REQ_DONE or SW_CMD_STS.CMD_ACK to be high and then check the value of this field. A description of the command status types can be found here.

SW_CMD_STS . CMD_ACK

This one bit field indicates when a SW command has been acknowledged by the CSRNG. It is set to low each time a new command is written to SW_CMD_REQ. The field is set to high once a SW command request has been acknowledged by the CSRNG. 0b0: The last SW command has not been acknowledged yet. 0b1: The last SW command has been acknowledged.

SW_CMD_STS . CMD_RDY

This bit indicates when the EDN is ready to accept the next command. Before starting to write a new command to SW_CMD_REQ, this field needs to be polled. 0b0: The EDN is not ready to accept commands or the last command hasn’t been acked yet. 0b1: The EDN is ready to accept the next command.

SW_CMD_STS . CMD_REG_RDY

This bit indicates when SW_CMD_REQ is ready to accept the next word. This bit has to be polled before each word of a command is written to SW_CMD_REQ. 0b0: The EDN is not ready to accept the next word yet. 0b1: The EDN is ready to accept the next word.

HW_CMD_STS

EDN hardware command status register

• Offset: 0x28
• Reset default: 0x0
• Reset mask: 0x3ff

Fields

{"reg": [{"name": "BOOT_MODE", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "AUTO_MODE", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "CMD_TYPE", "bits": 4, "attr": ["ro"], "rotate": -90}, {"name": "CMD_ACK", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "CMD_STS", "bits": 3, "attr": ["ro"], "rotate": -90}, {"bits": 22}], "config": {"lanes": 1, "fontsize": 10, "vspace": 110}}

HW_CMD_STS . CMD_STS

This field represents the status code returned with the CSRNG application command ack. It is updated each time a HW command is acknowledged by CSRNG. A description of the command status types can be found here.

HW_CMD_STS . CMD_ACK

This one bit field indicates when a HW command has been acknowledged by the CSRNG. It is set to low each time a new command is sent to the CSRNG. The field is set to high once a HW command request has been acknowledged by the CSRNG. 0b0: The last HW command has not been acknowledged yet. 0b1: The last HW command has been acknowledged.

HW_CMD_STS . CMD_TYPE

This field contains the application command type of the hardware controlled command issued last. The application command selects one of five operations to perform. A description of the application command types can be found here.

HW_CMD_STS . AUTO_MODE

This one bit field indicates whether the EDN is in the hardware controlled part of auto mode. The instantiate command is issued via SW interface and is thus not part of the hardware controlled part of auto mode. 0b0: The EDN is not in the hardware controlled part of auto mode. 0b1: The EDN is in the hardware controlled part of auto mode.

HW_CMD_STS . BOOT_MODE

This one bit field indicates whether the EDN is in the hardware controlled boot mode. 0b0: The EDN is not in boot mode. 0b1: The EDN is in boot mode.

RESEED_CMD

EDN csrng reseed command register

• Offset: 0x2c
• Reset default: 0x0
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "RESEED_CMD", "bits": 32, "attr": ["wo"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

RESEED_CMD . RESEED_CMD

Writing this register will fill a FIFO with up to 13 command words (32b words). When running in auto request mode, this FIFO is used to automatically send out a reseed command to the CSRNG application interface after every MAX_NUM_REQS_BETWEEN_RESEEDS number of generate commands.

See General Command Format for details about the command format.

Note that the number of additional data words provided must match the value of the clen field of the first word. Otherwise, undefined behavior may result. If more than 13 entries are written to the FIFO, they are ignored and EDN signals an edn_fatal_err interrupt as well as a fatal alert.

GENERATE_CMD

EDN csrng generate command register

• Offset: 0x30
• Reset default: 0x0
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "GENERATE_CMD", "bits": 32, "attr": ["wo"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

GENERATE_CMD . GENERATE_CMD

Writing this register will fill a FIFO with up to 13 command words (32b words). When running auto request mode, this FIFO is used to automatically send out generate commands to the CSRNG application interface.

See General Command Format for details about the command format.

Note that the number of additional data words provided must match the value of the clen field of the first word. Otherwise, undefined behavior may result. If more than 13 entries are written to the FIFO, they are ignored and EDN signals an edn_fatal_err interrupt as well as a fatal alert.

MAX_NUM_REQS_BETWEEN_RESEEDS

EDN maximum number of requests between reseeds register

• Offset: 0x34
• Reset default: 0x0
• Reset mask: 0xffffffff

Fields

{"reg": [{"name": "MAX_NUM_REQS_BETWEEN_RESEEDS", "bits": 32, "attr": ["rw"], "rotate": 0}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}

MAX_NUM_REQS_BETWEEN_RESEEDS . MAX_NUM_REQS_BETWEEN_RESEEDS

Setting this field will set the number of generate command requests that are made to CSRNG before a reseed request is made. This value only has meaning when running in auto request mode. This register supports a maximum of 2^32 generate requests between reseeds. This register will be used by a counter that counts down, triggering an automatic reseed request when it reaches zero.

Note that this value must be chosen smaller than or equal to the value configured in the RESEED_INTERVAL register of CSRNG.

RECOV_ALERT_STS

Recoverable alert status register

• Offset: 0x38
• Reset default: 0x0
• Reset mask: 0x300f

Fields

{"reg": [{"name": "EDN_ENABLE_FIELD_ALERT", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"name": "BOOT_REQ_MODE_FIELD_ALERT", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"name": "AUTO_REQ_MODE_FIELD_ALERT", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"name": "CMD_FIFO_RST_FIELD_ALERT", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"bits": 8}, {"name": "EDN_BUS_CMP_ALERT", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"name": "CSRNG_ACK_ERR", "bits": 1, "attr": ["rw0c"], "rotate": -90}, {"bits": 18}], "config": {"lanes": 1, "fontsize": 10, "vspace": 270}}

ERR_CODE

Hardware detection of fatal error conditions status register

• Offset: 0x3c
• Reset default: 0x0
• Reset mask: 0x70700003

Fields

{"reg": [{"name": "SFIFO_RESCMD_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "SFIFO_GENCMD_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"bits": 18}, {"name": "EDN_ACK_SM_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "EDN_MAIN_SM_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "EDN_CNTR_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"bits": 5}, {"name": "FIFO_WRITE_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "FIFO_READ_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"name": "FIFO_STATE_ERR", "bits": 1, "attr": ["ro"], "rotate": -90}, {"bits": 1}], "config": {"lanes": 1, "fontsize": 10, "vspace": 180}}

ERR_CODE . FIFO_STATE_ERR

This bit will be set to one when any of the source bits (bits 0 through 1 of this register) are asserted as a result of an error pulse generated from any FIFO where both the empty and full status bits are set or in case of error conditions inside the hardened counters. This bit will stay set until the next reset.

ERR_CODE . FIFO_READ_ERR

This bit will be set to one when any of the source bits (bits 0 through 1 of this register) are asserted as a result of an error pulse generated from any empty FIFO that has received a read pulse. This bit will stay set until the next reset.

ERR_CODE . FIFO_WRITE_ERR

This bit will be set to one when any of the source bits (bits 0 through 1 of this register) are asserted as a result of an error pulse generated from any full FIFO that has received a write pulse. This bit will stay set until the next reset.

ERR_CODE . EDN_CNTR_ERR

This bit will be set to one when a hardened counter has detected an error condition. This error will signal a fatal alert. This bit will stay set until the next reset.

ERR_CODE . EDN_MAIN_SM_ERR

This bit will be set to one when an illegal state has been detected for the EDN main stage state machine. This error will signal a fatal alert. This bit will stay set until the next reset.

ERR_CODE . EDN_ACK_SM_ERR

This bit will be set to one when an illegal state has been detected for the EDN ack stage state machine. This error will signal a fatal alert. This bit will stay set until the next reset.

ERR_CODE . SFIFO_GENCMD_ERR

This bit will be set to one when an error has been detected for the generate command FIFO. The type of error is reflected in the type status bits (bits 28 through 30 of this register). When this bit is set, a fatal error condition will result. This bit will stay set until the next reset.

ERR_CODE . SFIFO_RESCMD_ERR

This bit will be set to one when an error has been detected for the reseed command FIFO. The type of error is reflected in the type status bits (bits 28 through 30 of this register). When this bit is set, a fatal error condition will result.

ERR_CODE_TEST

Test error conditions register

• Offset: 0x40
• Reset default: 0x0
• Reset mask: 0x1f

Fields

{"reg": [{"name": "ERR_CODE_TEST", "bits": 5, "attr": ["rw"], "rotate": -90}, {"bits": 27}], "config": {"lanes": 1, "fontsize": 10, "vspace": 150}}

ERR_CODE_TEST . ERR_CODE_TEST

Setting this field will set the bit number for which an error will be forced in the hardware. This bit number is that same one found in the ERR_CODE register. The action of writing this register will force an error pulse. The sole purpose of this register is to test that any error properly propagates to either an interrupt or an alert.

MAIN_SM_STATE

Main state machine state observation register

• Offset: 0x44
• Reset default: 0xc1
• Reset mask: 0x1ff

Fields

{"reg": [{"name": "MAIN_SM_STATE", "bits": 9, "attr": ["ro"], "rotate": 0}, {"bits": 23}], "config": {"lanes": 1, "fontsize": 10, "vspace": 80}}