Porting Linux kernel on ARM from scratch

Create new directory mach-PuppyBeagle  under arch/arm.
Create include/mach/ folder under PuppyBeagle

 Following header files created under this directory:

• hardware.h -Nothing added yet
• io.h -
• Following lines copied and added from other mach directory
• #define IO_SPACE_LIMIT 0xffffffff
  
  /*
   * We don't actually have real ISA nor PCI buses, but there is so many
   * drivers out there that might just work if we fake them...
   */
  #define __io(a)        __typesafe_io(a)
  #define __mem_pci(a)    (a)
• irqs.h -
• /*TODO: Temporary declaration, to be corrected*/
  #define NR_IRQS        96
• memory.h -
• #define PHYS_OFFSET    0x80000000
• system.h -
• void arch_reset(char mode, const char *cmd);
  void arch_idle(void);
• timex.h -
• #define CLOCK_TICK_RATE        32768 (Copied from other mach directory)
• uncompress.h -
• Added UART3 physical addr pointer to get decompress message from early compressed kernel
• #define UART3_TX_REG    0x49020000
  
  inline void arch_decomp_setup(void)
  {
  }
  
  inline void putc (char c)
  {
      u32 *reg_uart_tx = (u32 *)UART3_TX_REG;
      *reg_uart_tx = c;
  }
  
  inline void flush (void)
  {
  }
• vmalloc.h -
• #define VMALLOC_END    0xFF000000  (Copied from other mach directory)

 You also need to add a assembly file under this same include/mach directory:

• entry-macro.S -
• (Copied from other mach directory)
•     .macro    get_irqnr_preamble , base, tmp
      .endm
  
      .macro  arch_ret_to_user, tmp1, tmp2
      .endm
  
      .macro    get_irqnr_and_base, irqnr, irqstat, base, tmp
      .endm
  
      .macro    disable_fiq
      .endm

Create a Kconfig file under mach-PuppyBeagle directory to provide additional configuration options while preparing for building the image (to get options under menuconfig)

You need to add a  Makefile for any source files to be compiled under this directory.
You also need to add an additional file named Makefile.boot  to include zreladdr value.

Add a new entry in arch/arm/KConfig for PuppyBeagle:

config ARCH_PUPPYBEAGLE
    bool "Puppy Beagle"
    select GENERIC_GPIO
    select HAVE_CLK
    select CPU_V7
    help
      Puppy Beagle series based systems

Also add


source "arch/arm/mach-puppybeagle/Kconfig"

to source additional configuration file from above PATH