Difference between revisions of "Unit BootRPi"

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----
  
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''To be documented''
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'''Ultibo Initialization code for Raspberry Pi unit'''
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'''Raspberry Pi'''
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SoC: Broadcom BCM2835
 +
 +
CPU: ARM1176 (ARMv6) (1 @ 700MHz)
 +
 +
Cache: L1 16KB/L2 128KB (Shared with GPU)
 +
 +
FPU: VFPV2
 +
 +
GPU: Broadcom VideoCore IV (VC4)
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 +
RAM: 512MB (256MB on Model A/A+)
 +
 +
USB: Synopsys DesignWare Hi-Speed USB 2.0 On-The-Go Controller (DWCOTG)
 +
 +
LAN: SMSC LAN9512 (SMSC LAN9514 on Model B+/No LAN on Model A/A+/Zero) (SMSC95XX)
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SD/MMC: Arasan (BCM2708)
 +
 +
WiFi: (None)
 +
 +
Bluetooth: (None)
 +
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Other: GPIO/SPI/I2C/I2S/PL011 (UART)/PWM/SMI/Watchdog (PM)/Random (RNG)/Timer
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'''Boot RPi'''
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The boot loader on the Raspberry Pi will load this code at address 0x00008000 onwards and set the following registers before jumping to this code.
 +
 
 +
R0 - Zero
 +
 
 +
R1 - Machine Type (Raspberry Pi or BCM2708 = 0x0c42)
 +
 +
R2 - Address of the ARM Tags structure (Normally 0x0100)
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 +
On entry to this code the processor will be in the following state:
 +
 
 +
World - Secure
 +
 
 +
Mode - Supervisor (ARM_MODE_SVC)
 +
 
 +
MMU - Disabled
 +
 
 +
FPU - Disabled
 +
 
 +
L1 Data Cache - Disabled
 +
 
 +
L1 Instruction Cache - Disabled
 +
 
 +
Branch Predication - Disabled
 +
 
 +
Unaligned Data Access - Disabled
 +
 
 +
 
 +
Ultibo switches the processor to System mode for all operations and remains in the Secure world.
 +
 
 +
The initialization process enables the MMU, FPU, L1 Cache and other performance optimizations.
  
 
=== Constants ===
 
=== Constants ===
 
----
 
----
  
−
''To be documented''
+
''None defined''
  
 
=== Type definitions ===
 
=== Type definitions ===
 
----
 
----
  
−
''To be documented''
+
''None defined''
  
 
=== Public variables ===
 
=== Public variables ===
 
----
 
----
  
−
''To be documented''
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''None defined''
  
 
=== Function declarations ===
 
=== Function declarations ===
 
----
 
----
  
−
''To be documented''
 
  
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'''Boot functions'''
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
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<pre style="border: 0; padding-bottom:0px;">procedure Startup; assembler; nostackframe; public name '_START';</pre>
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Entry point of Ultibo on Raspberry Pi, this will be the very first byte executed and will be loaded by the GPU at address 0x00008000</div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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! Note
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| None documented
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
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<pre style="border: 0; padding-bottom:0px;">procedure Vectors; assembler; nostackframe;</pre>
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' ARM exception vector table which is copied to address 0 by the StartupHandler</div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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! Note
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| See A2.6 "Exceptions" of the ARM Architecture Reference Manual
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
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<pre style="border: 0; padding-bottom:0px;">procedure StartupHandler; assembler; nostackframe;</pre>
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Startup handler routine executed to start the Ultibo kernel</div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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! Note
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| None documented
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|-
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|}
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</div></div>
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<br />
  
 
Return to [[Unit_Reference|Unit Reference]]
 
Return to [[Unit_Reference|Unit Reference]]

Latest revision as of 01:19, 22 April 2022

Return to Unit Reference


Description

Ultibo Initialization code for Raspberry Pi unit

Raspberry Pi

SoC: Broadcom BCM2835

CPU: ARM1176 (ARMv6) (1 @ 700MHz)

Cache: L1 16KB/L2 128KB (Shared with GPU)

FPU: VFPV2

GPU: Broadcom VideoCore IV (VC4)

RAM: 512MB (256MB on Model A/A+)

USB: Synopsys DesignWare Hi-Speed USB 2.0 On-The-Go Controller (DWCOTG)

LAN: SMSC LAN9512 (SMSC LAN9514 on Model B+/No LAN on Model A/A+/Zero) (SMSC95XX)

SD/MMC: Arasan (BCM2708)

WiFi: (None)

Bluetooth: (None)

Other: GPIO/SPI/I2C/I2S/PL011 (UART)/PWM/SMI/Watchdog (PM)/Random (RNG)/Timer


Boot RPi

The boot loader on the Raspberry Pi will load this code at address 0x00008000 onwards and set the following registers before jumping to this code.

R0 - Zero

R1 - Machine Type (Raspberry Pi or BCM2708 = 0x0c42)

R2 - Address of the ARM Tags structure (Normally 0x0100)

On entry to this code the processor will be in the following state:

World - Secure

Mode - Supervisor (ARM_MODE_SVC)

MMU - Disabled

FPU - Disabled

L1 Data Cache - Disabled

L1 Instruction Cache - Disabled

Branch Predication - Disabled

Unaligned Data Access - Disabled


Ultibo switches the processor to System mode for all operations and remains in the Secure world.

The initialization process enables the MMU, FPU, L1 Cache and other performance optimizations.

Constants

None defined

Type definitions

None defined

Public variables

None defined

Function declarations


Boot functions 

procedure Startup; assembler; nostackframe; public name '_START';
Description: Entry point of Ultibo on Raspberry Pi, this will be the very first byte executed and will be loaded by the GPU at address 0x00008000
Note None documented 


procedure Vectors; assembler; nostackframe;
Description: ARM exception vector table which is copied to address 0 by the StartupHandler
Note See A2.6 "Exceptions" of the ARM Architecture Reference Manual 


procedure StartupHandler; assembler; nostackframe;
Description: Startup handler routine executed to start the Ultibo kernel
Note None documented


Return to Unit Reference

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