Ryan Malloy
0d6facb321
One-off diagnostic scripts from experiments 0xD7-0xDB investigating the I2C BERR deadlock. Documents the systematic elimination of software-only recovery approaches: - i2c_host_test.py: Proved 0xA0 register writes cannot drive I2C bus - i2c_register_test.py: Tested I2C register writability from host - i2c_recovery_boot.py: Attempted I2C state machine recovery via boot - eeprom_flash_a0.py: Host-side EEPROM flash attempt (failed) - boot_ab_test.py / boot_test.py: EEPROM boot reliability testing - a8_autoclear_test.py: BCM4500 command register auto-clear behavior - addr_gateway_test.py: BCM3440 gateway address routing analysis - stock_fw_compare.py / stock_fw_test.py: Stock vs custom fw analysis
96 lines
3.5 KiB
Python
96 lines
3.5 KiB
Python
#!/usr/bin/env python3
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"""Test whether BCM4500 register A8 auto-clears after write commands.
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If A8 auto-clears to 0x00 (or 0x02) after writing 0x03, then
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bcm_poll_ready() would always return TRUE, masking the fact that
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the DSP isn't processing commands.
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Uses enhanced 0xB6 diagnostic:
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wValue = page, wIndex = A8 command (0 = default READ)
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Returns 8 bytes:
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[0] write_A6_ok
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[1] A6 readback
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[2] write_A8_ok
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[3] A8 IMMEDIATE readback (no delay)
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[4] A8 after 2ms delay
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[5] A7 data result
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[6] A6 final state
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[7] echo: command sent
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"""
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import sys
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import time
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sys.path.insert(0, 'tools')
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from skywalker_lib import SkyWalker1
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CMD_I2C_DIAG = 0xB6
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CMD_I2C_RAW_READ = 0xB5
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BCM4500_ADDR = 0x08
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sw = SkyWalker1()
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sw.open()
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print('=== A8 Auto-Clear Test ===')
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print(f'Firmware: {sw.get_fw_version()}')
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# Boot with full sequence
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print('\n--- Booting BCM4500 (full boot) ---')
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result = sw._vendor_in(0x89, value=1, index=0, length=3)
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cfg, stage = result[0], result[1]
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print(f' Config: 0x{cfg:02X}, Stage: 0x{stage:02X}')
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# Read A8 default state before any commands
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print('\n--- A8 default state (after boot, before diagnostic) ---')
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a8_default = sw._vendor_in(CMD_I2C_RAW_READ, value=BCM4500_ADDR,
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index=0xA8, length=1)
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print(f' A8 default: 0x{a8_default[0]:02X} (bit0={a8_default[0] & 0x01})')
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# Test 1: READ command (0x01) — this was the previous behavior
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print('\n=== Test 1: A8 with READ command (0x01) ===')
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diag1 = sw._vendor_in(CMD_I2C_DIAG, value=0x06, index=0x01, length=8)
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print(f' A6 write ok: {diag1[0]}')
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print(f' A6 readback: 0x{diag1[1]:02X}')
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print(f' A8 write ok: {diag1[2]}')
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print(f' A8 IMMEDIATE: 0x{diag1[3]:02X} (bit0={diag1[3] & 0x01})')
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print(f' A8 after 2ms: 0x{diag1[4]:02X} (bit0={diag1[4] & 0x01})')
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print(f' A7 data: 0x{diag1[5]:02X}')
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print(f' A6 final: 0x{diag1[6]:02X}')
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print(f' Command sent: 0x{diag1[7]:02X}')
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# Reset A8 back to default by reading
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time.sleep(0.01)
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# Test 2: WRITE command (0x03) — the one used by init blocks
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print('\n=== Test 2: A8 with WRITE command (0x03) ===')
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diag2 = sw._vendor_in(CMD_I2C_DIAG, value=0x06, index=0x03, length=8)
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print(f' A6 write ok: {diag2[0]}')
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print(f' A6 readback: 0x{diag2[1]:02X}')
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print(f' A8 write ok: {diag2[2]}')
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print(f' A8 IMMEDIATE: 0x{diag2[3]:02X} (bit0={diag2[3] & 0x01})')
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print(f' A8 after 2ms: 0x{diag2[4]:02X} (bit0={diag2[4] & 0x01})')
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print(f' A7 data: 0x{diag2[5]:02X}')
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print(f' A6 final: 0x{diag2[6]:02X}')
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print(f' Command sent: 0x{diag2[7]:02X}')
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# Test 3: Try other A8 values
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print('\n=== Test 3: Various A8 values ===')
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for cmd in [0x00, 0x02, 0x04, 0xFF]:
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time.sleep(0.01)
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diag = sw._vendor_in(CMD_I2C_DIAG, value=0x00, index=cmd, length=8)
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print(f' CMD=0x{cmd:02X}: A8_imm=0x{diag[3]:02X} A8_2ms=0x{diag[4]:02X} '
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f'A7=0x{diag[5]:02X}')
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# Analysis
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print('\n=== Analysis ===')
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if diag2[3] != 0x03 or diag2[4] != 0x03:
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print(f' !! A8 AUTO-CLEARS after WRITE command!')
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print(f' Wrote 0x03, immediate={diag2[3]:02X}, after_2ms={diag2[4]:02X}')
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if (diag2[3] & 0x01) == 0 or (diag2[4] & 0x01) == 0:
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print(f' bcm_poll_ready() sees bit0=0 → always returns TRUE')
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print(f' Init blocks appear to succeed but DSP never processes them!')
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else:
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print(f' A8 retains WRITE command (0x03). No auto-clear.')
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if (diag1[3] == 0x01) and (diag2[3] == 0x03):
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print(f' Both READ and WRITE commands stick. DSP is genuinely not processing.')
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sw.close()
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print('\n=== Done ===')
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