Testplan

Testpoints

Stage V1 Testpoints

smoke

Test: aon_timer_smoke

Smoke test initializes and starts AON Timer according to the programmers guide.

Stimulus:

  • Register writes to Watchdog/Wakeup COUNT, CTRL and THOLD registers

Checks:

  • If we are changing WDOG_BARK_THOLD to be lower than the current WDOG_COUNT watchdog timer should raise the interrupt wdog_timer_bark.
  • If we are changing WDOG_BITE_THOLD to be lower than the current WDOG_COUNT watchdog timer should trigger a reset request.
  • If we are changing WKUP_THOLD to be lower than the current WKUP_COUNT wakeup timer should raise the interrupt wkup_timer_expired.

csr_hw_reset

Test: aon_timer_csr_hw_reset

Verify the reset values as indicated in the RAL specification.

  • Write all CSRs with a random value.
  • Apply reset to the DUT as well as the RAL model.
  • Read each CSR and compare it against the reset value. it is mandatory to replicate this test for each reset that affects all or a subset of the CSRs.
  • It is mandatory to run this test for all available interfaces the CSRs are accessible from.
  • Shuffle the list of CSRs first to remove the effect of ordering.

csr_rw

Test: aon_timer_csr_rw

Verify accessibility of CSRs as indicated in the RAL specification.

  • Loop through each CSR to write it with a random value.
  • Read the CSR back and check for correctness while adhering to its access policies.
  • It is mandatory to run this test for all available interfaces the CSRs are accessible from.
  • Shuffle the list of CSRs first to remove the effect of ordering.

csr_bit_bash

Test: aon_timer_csr_bit_bash

Verify no aliasing within individual bits of a CSR.

  • Walk a 1 through each CSR by flipping 1 bit at a time.
  • Read the CSR back and check for correctness while adhering to its access policies.
  • This verify that writing a specific bit within the CSR did not affect any of the other bits.
  • It is mandatory to run this test for all available interfaces the CSRs are accessible from.
  • Shuffle the list of CSRs first to remove the effect of ordering.

csr_aliasing

Test: aon_timer_csr_aliasing

Verify no aliasing within the CSR address space.

  • Loop through each CSR to write it with a random value
  • Shuffle and read ALL CSRs back.
  • All CSRs except for the one that was written in this iteration should read back the previous value.
  • The CSR that was written in this iteration is checked for correctness while adhering to its access policies.
  • It is mandatory to run this test for all available interfaces the CSRs are accessible from.
  • Shuffle the list of CSRs first to remove the effect of ordering.

csr_mem_rw_with_rand_reset

Test: aon_timer_csr_mem_rw_with_rand_reset

Verify random reset during CSR/memory access.

  • Run csr_rw sequence to randomly access CSRs
  • If memory exists, run mem_partial_access in parallel with csr_rw
  • Randomly issue reset and then use hw_reset sequence to check all CSRs are reset to default value
  • It is mandatory to run this test for all available interfaces the CSRs are accessible from.

regwen_csr_and_corresponding_lockable_csr

Tests:

  • aon_timer_csr_rw
  • aon_timer_csr_aliasing

Verify regwen CSR and its corresponding lockable CSRs.

  • Randomly access all CSRs
  • Test when regwen CSR is set, its corresponding lockable CSRs become read-only registers

Note:

  • If regwen CSR is HW read-only, this feature can be fully tested by common CSR tests - csr_rw and csr_aliasing.
  • If regwen CSR is HW updated, a separate test should be created to test it.

This is only applicable if the block contains regwen and locakable CSRs.

mem_walk

Test: aon_timer_mem_walk

Verify accessibility of all memories in the design.

  • Run the standard UVM mem walk sequence on all memories in the RAL model.
  • It is mandatory to run this test from all available interfaces the memories are accessible from.

mem_partial_access

Test: aon_timer_mem_partial_access

Verify partial-accessibility of all memories in the design.

  • Do partial reads and writes into the memories and verify the outcome for correctness.
  • Also test outstanding access on memories

Stage V2 Testpoints

prescaler

Test: aon_timer_prescaler

Switch prescaler value at random times without locking configuration registers of watchdog timer.

Stimulus:

  • Register writes to WKUP_CTRL while running.

Checks:

  • WKUP_COUNT should reflect expected -and changed- passing of real time regardless of its changing prescaler value.

jump

Test: aon_timer_jump

Change threshold values and prescaler value on random times without locking configuration registers of watchdog timer.

Stimulus:

  • Register writes to WDOG_BARK_THOLD, WDOG_BITE_THOLD, WKUP_THOLD, WKUP_CTRL

Checks:

  • If we are changing WDOG_BARK_THOLD to be lower than the current WDOG_COUNT watchdog timer should raise the interrupt wdog_timer_bark.
  • If we are changing WDOG_BITE_THOLD to be lower than the current WDOG_COUNT watchdog timer should trigger a reset request.
  • If we are changing WKUP_THOLD to be lower than the current WKUP_COUNT wakeup timer should raise the interrupt wkup_timer_expired.
  • WKUP_COUNT should reflect expected passing of real time regardless of prescaler value.

stress_all

Test: aon_timer_stress_all

This runs random sequences in succession.

Randomly chooses from the following sequences:

  • aon_timer_intr_test
  • aon_timer_jump
  • aon_timer_prescaler
  • aon_timer_smoke

alert_test

Test: aon_timer_alert_test

Verify common alert_test CSR that allows SW to mock-inject alert requests.

  • Enable a random set of alert requests by writing random value to alert_test CSR.
  • Check each alert_tx.alert_p pin to verify that only the requested alerts are triggered.
  • During alert_handshakes, write alert_test CSR again to verify that: If alert_test writes to current ongoing alert handshake, the alert_test request will be ignored. If alert_test writes to current idle alert handshake, a new alert_handshake should be triggered.
  • Wait for the alert handshakes to finish and verify alert_tx.alert_p pins all sets back to 0.
  • Repeat the above steps a bunch of times.

intr_test

Test: aon_timer_intr_test

Verify common intr_test CSRs that allows SW to mock-inject interrupts.

  • Enable a random set of interrupts by writing random value(s) to intr_enable CSR(s).
  • Randomly “turn on” interrupts by writing random value(s) to intr_test CSR(s).
  • Read all intr_state CSR(s) back to verify that it reflects the same value as what was written to the corresponding intr_test CSR.
  • Check the cfg.intr_vif pins to verify that only the interrupts that were enabled and turned on are set.
  • Clear a random set of interrupts by writing a randomly value to intr_state CSR(s).
  • Repeat the above steps a bunch of times.

tl_d_oob_addr_access

Test: aon_timer_tl_errors

Access out of bounds address and verify correctness of response / behavior

tl_d_illegal_access

Test: aon_timer_tl_errors

Drive unsupported requests via TL interface and verify correctness of response / behavior. Below error cases are tested bases on the TLUL spec

  • TL-UL protocol error cases
    • invalid opcode
    • some mask bits not set when opcode is PutFullData
    • mask does not match the transfer size, e.g. a_address = 0x00, a_size = 0, a_mask = 'b0010
    • mask and address misaligned, e.g. a_address = 0x01, a_mask = 'b0001
    • address and size aren’t aligned, e.g. a_address = 0x01, a_size != 0
    • size is greater than 2
  • OpenTitan defined error cases
    • access unmapped address, expect d_error = 1
    • write a CSR with unaligned address, e.g. a_address[1:0] != 0
    • write a CSR less than its width, e.g. when CSR is 2 bytes wide, only write 1 byte
    • write a memory with a_mask != '1 when it doesn’t support partial accesses
    • read a WO (write-only) memory
    • write a RO (read-only) memory
    • write with instr_type = True

tl_d_outstanding_access

Tests:

  • aon_timer_csr_hw_reset
  • aon_timer_csr_rw
  • aon_timer_csr_aliasing
  • aon_timer_same_csr_outstanding

Drive back-to-back requests without waiting for response to ensure there is one transaction outstanding within the TL device. Also, verify one outstanding when back- to-back accesses are made to the same address.

tl_d_partial_access

Tests:

  • aon_timer_csr_hw_reset
  • aon_timer_csr_rw
  • aon_timer_csr_aliasing
  • aon_timer_same_csr_outstanding

Access CSR with one or more bytes of data. For read, expect to return all word value of the CSR. For write, enabling bytes should cover all CSR valid fields.

Stage V2S Testpoints

tl_intg_err

Tests:

  • aon_timer_tl_intg_err
  • aon_timer_sec_cm

Verify that the data integrity check violation generates an alert.

  • Randomly inject errors on the control, data, or the ECC bits during CSR accesses. Verify that triggers the correct fatal alert.
  • Inject a fault at the onehot check in u_reg.u_prim_reg_we_check and verify the corresponding fatal alert occurs

sec_cm_bus_integrity

Test: aon_timer_tl_intg_err

Verify the countermeasure(s) BUS.INTEGRITY.

Stage V3 Testpoints

max_threshold

Test: aon_timer_smoke_max_thold

Run the basic smoke sequence, but constrained to set max thresholds. This helps close coverage.

min_threshold

Test: aon_timer_smoke_min_thold

Run the basic smoke sequence, but constrained to set min thresholds. This helps close coverage.

wkup_count_hi_cdc

Test: aon_timer_wkup_count_cdc_hi

Run aon_timer_wkup_count_cdc_hi_vseq which maximises the chances to hit conditional and branch coverage in wkup_count_hi_cdc (prim_reg_cdc and prim_reg_cdc_arb).

custom_intr

Test: aon_timer_custom_intr

Run aon_timer_custom_intr_vseq, which drives random wdog/wkup control enables as well as intr_test writes in order to help close intr_test_cg covergroup.

alternating_on_off

Test: aon_timer_alternating_enable_on_off

Run aon_timer_alternating_enable_on_off_vseq, which alternates each counter enable between ON/OFF as well as intr_test writes in order to ensure the TB can cope with non SW-like stimulus.

stress_all_with_rand_reset

Test: aon_timer_stress_all_with_rand_reset

This test runs 3 parallel threads - stress_all, tl_errors and random reset. After reset is asserted, the test will read and check all valid CSR registers.

Covergroups

regwen_val_when_new_value_written_cg

Cover each lockable reg field with these 2 cases:

  • When regwen = 1, a different value is written to the lockable CSR field, and a read occurs after that.
  • When regwen = 0, a different value is written to the lockable CSR field, and a read occurs after that.

This is only applicable if the block contains regwen and locakable CSRs.

timer_cfg_cg

Includes possible values of all registers of AON timer. For 32b registers, bins are introduced in order to simplfy coverage. Maximum and minimum values are collected in a separate bin to guarantee that they are checked. 32 separate bins are auto-generated in order to distrubute values evenly.

tl_errors_cg

Cover the following error cases on TL-UL bus:

  • TL-UL protocol error cases.
  • OpenTitan defined error cases, refer to testpoint tl_d_illegal_access.

tl_intg_err_cg

Cover all kinds of integrity errors (command, data or both) and cover number of error bits on each integrity check.

Cover the kinds of integrity errors with byte enabled write on memory if applicable: Some memories store the integrity values. When there is a subword write, design re-calculate the integrity with full word data and update integrity in the memory. This coverage ensures that memory byte write has been issued and the related design logic has been verfied.