hal-porting-platform.html

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    description   "
        Enable this option if this program is to be used as a ROM monitor,
        i.e. applications will be loaded into RAM on the board, and this
        ROM monitor may process exceptions or interrupts generated from the
        application. This enables features such as utilizing a separate
        interrupt stack when exceptions are generated."
}</PRE
></TD
></TR
></TABLE
><P
>The latter option is accompanied by a special build rule that
extends the generic ROM monitor build rule in the common HAL:</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>cdl_option CYGBLD_BUILD_GDB_STUBS {
    display "Build GDB stub ROM image"
    default_value 0
    requires { CYG_HAL_STARTUP == "ROM" }
    requires CYGSEM_HAL_ROM_MONITOR
    requires CYGBLD_BUILD_COMMON_GDB_STUBS
    requires CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
    requires ! CYGDBG_HAL_DEBUG_GDB_BREAK_SUPPORT
    requires ! CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT
    requires ! CYGDBG_HAL_COMMON_INTERRUPTS_SAVE_MINIMUM_CONTEXT
    requires ! CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
    no_define
    description "
        This option enables the building of the GDB stubs for the
        board. The common HAL controls takes care of most of the
        build process, but the final conversion from ELF image to
        binary data is handled by the platform CDL, allowing
        relocation of the data if necessary."

    make -priority 320 {
        &lt;PREFIX&gt;/bin/gdb_module.bin : &lt;PREFIX&gt;/bin/gdb_module.img
        $(OBJCOPY) -O binary $&#60; $@
    }
}</PRE
></TD
></TR
></TABLE
><P
>Most platforms support RedBoot, and some options are needed to
configure for RedBoot.</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>    cdl_component CYGPKG_REDBOOT_HAL_OPTIONS {
        display       "Redboot HAL options"
        flavor        none
        no_define
        parent        CYGPKG_REDBOOT
        active_if     CYGPKG_REDBOOT
        description   "
            This option lists the target's requirements for a valid Redboot
            configuration."
    
        cdl_option CYGBLD_BUILD_REDBOOT_BIN {
            display       "Build Redboot ROM binary image"
            active_if     CYGBLD_BUILD_REDBOOT
            default_value 1
            no_define
            description "This option enables the conversion of the Redboot ELF
                         image to a binary image suitable for ROM programming."
    
            make -priority 325 {
                &lt;PREFIX&gt;/bin/redboot.bin : &lt;PREFIX&gt;/bin/redboot.elf
                $(OBJCOPY) --strip-debug $&#60; $(@:.bin=.img) 
                $(OBJCOPY) -O srec $&#60; $(@:.bin=.srec)
                $(OBJCOPY) -O binary $&#60; $@
            }
        }
    }</PRE
></TD
></TR
></TABLE
><P
>The important part here is the <TT
CLASS="LITERAL"
>make</TT
> command in the
<TT
CLASS="LITERAL"
>CYGBLD_BUILD_REDBOOT_BIN</TT
> option which emits
makefile commands to translate the <TT
CLASS="FILENAME"
>.elf</TT
> file
generated by the link phase into both a binary file and an S-Record
file. If a different format is required by a PROM programmer or ROM
monitor, then different output formats would need to be generated here.</P
></DIV
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="HAL-PORTING-PLATFORM-MEMORY-LAYOUT">Platform Memory Layout</H2
><P
>The platform memory layout is defined using the Memory
Configuration Window  in the Configuration Tool.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>If you do not have access to a Windows machine, you can
hand edit the <TT
CLASS="FILENAME"
>.h</TT
> and <TT
CLASS="FILENAME"
>.ldi</TT
> files to match the
properties of your platform. If you want to contribute your port back
to the eCos community, ask someone on the list to make proper memory
map files for you.</P
></BLOCKQUOTE
></DIV
><DIV
CLASS="SECTION"
><H3
CLASS="SECTION"
><A
NAME="AEN9615">Layout Files</H3
><P
>The memory configuration details are saved in three files:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="FILENAME"
>.mlt</TT
></DT
><DD
><P
>This is the Configuration Tool save-file. It is only used
	by the Configuration Tool.</P
></DD
><DT
><TT
CLASS="FILENAME"
>.ldi</TT
></DT
><DD
><P
>This is the linker script fragment. It defines the memory
	and location of sections by way of macros defined in the
	architecture or variant linker script.</P
></DD
><DT
><TT
CLASS="FILENAME"
>.h</TT
></DT
><DD
><P
>This file describes some of the memory region details as C
	macros, allowing eCos or the application adapt the memory
	layout of a specific configuration.</P
></DD
></DL
></DIV
><P
>These three files are generated for each startup-type, since the
memory details usually differ.</P
></DIV
><DIV
CLASS="SECTION"
><H3
CLASS="SECTION"
><A
NAME="AEN9635">Reserved Regions</H3
><P
>Some areas of the memory space are reserved for specific
purposes, making room for exception vectors and various tables. RAM
startup configurations also need to reserve some space at the bottom
of the memory map for the ROM monitor.</P
><P
>These reserved areas are named with the prefix "reserved_" which is
handled specially by the Configuration Tool: instead of referring to a
linker macro, the start of the area is labeled and a gap left in the
memory map.</P
></DIV
></DIV
><DIV
CLASS="SECTION"
><H2
CLASS="SECTION"
><A
NAME="AEN9639">Platform Serial Device Support</H2
><P
>The first step is to set up the CDL definitions. The configuration
options that need to be set are the following:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_COMM_CHANNELS</TT
></DT
><DD
><P
>The number of channels, usually 0, 1 or 2.</P
></DD
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_DEBUG_CHANNEL</TT
></DT
><DD
><P
>The channel to use for GDB.</P
></DD
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_DEBUG_CHANNEL_BAUD</TT
></DT
><DD
><P
>Initial baud rate for debug channel.</P
></DD
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_CONSOLE_CHANNEL</TT
></DT
><DD
><P
>The channel to use for the
    console.</P
></DD
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_CONSOLE_CHANNEL_BAUD</TT
></DT
><DD
><P
>The initial baud rate for the console
    channel.</P
></DD
><DT
><TT
CLASS="LITERAL"
>CYGNUM_HAL_VIRTUAL_VECTOR_CONSOLE_CHANNEL_DEFAULT</TT
></DT
><DD
><P
>The default console channel.</P
></DD
></DL
></DIV
><P
>The code in <TT
CLASS="FILENAME"
>hal_diag.c</TT
> need to be converted to
support the new serial device.
If this the same as a device already supported, copy that.</P
><P
>The following functions and types need to be rewritten to support a new serial
device.</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="LITERAL"
>struct channel_data_t;</TT
></DT
><DD
><P
>      Structure containing base address, timeout and ISR vector number
      for each serial device supported. Extra fields my be added if
      necessary for the device. For example some devices have
      write-only control registers, so keeping a shadow of the last
      value written here can be useful.
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>xxxx_ser_channels[];</TT
></DT
><DD
><P
>	Array of <TT
CLASS="LITERAL"
>channel_data_t</TT
>, initialized with parameters of each
	channel. The index into this array is the channel number used
	in the CDL options above and is used by the virtual vector
	mechanism to refer to each channel.
        </P
></DD
><DT
><TT
CLASS="LITERAL"
>void cyg_hal_plf_serial_init_channel(void
           *__ch_data)</TT
></DT
><DD
><P
>	Initialize the serial device. The parameter is actually a pointer to a
	<TT
CLASS="LITERAL"
>channel_data_t</TT
> and should be cast back to
	this type before use. This function should use the CDL
	definition for the baud rate for the channel it is initializing.
        </P
></DD
><DT
><TT
CLASS="LITERAL"
>void cyg_hal_plf_serial_putc(void * __ch_data,
                    char *c)</TT
></DT
><DD
><P
>        Send a character to the serial device. This function should
	poll for the device being ready to send and then write the character.
        Since this is intended to be a diagnostic/debug channel, it is
	often also a good idea to poll for end of transmission
	too. This ensures that as much data gets out of the system as
	possible.
        </P
></DD
><DT
><TT
CLASS="LITERAL"
>bool cyg_hal_plf_serial_getc_nonblock(void*
                    __ch_data, cyg_uint8* ch)</TT
></DT
><DD
><P
>        This function tests the device and if a character is
	available, places it in <TT
CLASS="PARAMETER"
><I
>*ch</I
></TT
> and returns
	<TT
CLASS="LITERAL"
>TRUE</TT
>. If no character is available, then
	the function returns <TT
CLASS="LITERAL"
>FALSE</TT
> immediately.
        </P
></DD
><DT
><TT
CLASS="LITERAL"
>int cyg_hal_plf_serial_control(void *__ch_data,
                    __comm_control_cmd_t __func,
                    ...)</TT
></DT
><DD
><P
>        This is an IOCTL-like function for controlling various aspects
	of the serial device. The only part in which you may need to
	do some work initially is in the
	<TT
CLASS="LITERAL"
>__COMMCTL_IRQ_ENABLE</TT
> and
	<TT
CLASS="LITERAL"
>__COMMCTL_IRQ_DISABLE</TT
> cases to
	enable/disable interrupts.
        </P
></DD
><DT
><TT
CLASS="LITERAL"
>int cyg_hal_plf_serial_isr(void *__ch_data, int* __ctrlc, 
                       CYG_ADDRWORD __vector, CYG_ADDRWORD
                       __data)</TT
></DT
><DD
><P
>        This interrupt handler, called from the spurious interrupt
        vector, is specifically for dealing with
        <TT
CLASS="LITERAL"
>Ctrl-C</TT
> interrupts from GDB. When called
        this function should do the following:
        <P
></P
><OL
TYPE="1"
><LI
><P
>Check for an incoming character. The code here is very
          similar to that in
          <TT
CLASS="FUNCTION"
>cyg_hal_plf_serial_getc_nonblock()</TT
>.
          </P
></LI
><LI
><P
>	  Read the character and call
	  <TT
CLASS="FUNCTION"
>cyg_hal_is_break()</TT
>.
          </P
></LI
><LI
><P
>	  If result is true, set <TT
CLASS="PARAMETER"
><I
>*__ctrlc</I
></TT
> to
	  <TT
CLASS="LITERAL"
>1</TT
>.
          </P
></LI
><LI
><P
>	  Return <TT
CLASS="LITERAL"
>CYG_ISR_HANDLED</TT
>.
          </P
></LI
></OL
>
      </P
></DD
><DT
><TT
CLASS="LITERAL"
>void cyg_hal_plf_serial_init()</TT
></DT
><DD
><P
>        Initialize each of the serial channels.
	First call <TT
CLASS="FUNCTION"
>cyg_hal_plf_serial_init_channel()</TT
> for each channel.
	Then call the <TT
CLASS="LITERAL"
>CYGACC_COMM_IF_*</TT
> macros for
	each channel. This latter set of calls are identical for all
	channels, so the best way to do this is to copy and edit an
	existing example.
        </P
></DD
></DL
></DIV
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