customizing_u-boot_for_your_own_board.html

ADI 公司blackfin系列的用户使用文挡。

SOBJS   =
 
$(LIB): .depend $(OBJS)
        $(AR) crv $@ $(OBJS)
&nbsp;</pre><ul>
<li class="level1"><div class="li"> Modify config.mk to suit your memory layout. This file contains the start address of uboot. Typically the image will be built to reside at the upper part of memory.</div>
</li>
</ul>
<pre class="code text"># TEXT_BASE should be defined as the MAX_SDRAM Address - 256k bytes
#  256k is defined as CFG_MONITOR_LEN in ./include/configs/&lt;board&gt;.h
# TEXT_BASE was 0X07FC0000  for the stamp
TEXT_BASE = 0x03FC0000
PLATFORM_CPPFLAGS += -I$(TOPDIR)
&nbsp;</pre>
</div>

<h4><a name="additional_considerations" id="additional_considerations">Additional Considerations</a></h4>
<div class="level4">

<p>
 You may need to adjust some other files to suit your board hardware. 
</p>
<ul>
<li class="level1"><div class="li"> Flash Access</div>
<ul>
<li class="level2"><div class="li"> Flash access is modified in a common file <strong>common/flash.c</strong></div>
</li>
<li class="level2"><div class="li"> This uses the <strong>flash_info_t *info</strong> structure</div>
</li>
</ul>
</li>
</ul>
<ul>
<li class="level1"><div class="li"> Memory Access and CPLD&rsquo;s </div>
<ul>
<li class="level2"><div class="li"> These are set up in a file in the <strong>cpu/bf533</strong> directory.</div>
</li>
<li class="level2"><div class="li"> The file  <strong>cpu/bf533/cpu.c</strong> defines Data and instruction CPLD&rsquo;s</div>
</li>
</ul>
</li>
</ul>
<pre class="code text">#define SDRAM_EBIU              
(PAGE_SIZE_4MB 
| CPLB_WT 
| CPLB_L1_AOW 
| CPLB_USER_RD 
| CPLB_USER_WR 
| CPLB_SUPV_WR 
| CPLB_VALID 
| ANOMALY_05000158
)
#define SDRAM_IKERNEL           
(PAGE_SIZE_4MB 
| CPLB_L1_CHBL 
| CPLB_USER_RD 
| CPLB_VALID 
| CPLB_LOCK)
&nbsp;
#define L1_DMEMORY              
(PAGE_SIZE_4KB 
| CPLB_L1_CHBL 
| CPLB_L1_AOW 
| CPLB_WT 
| CPLB_SUPV_WR 
| CPLB_USER_WR 
| CPLB_VALID 
| ANOMALY_05000158)
&nbsp;
#define L1_IMEMORY              
(PAGE_SIZE_1MB 
| CPLB_L1_CHBL 
| CPLB_USER_RD 
| CPLB_VALID 
| CPLB_LOCK)
&nbsp;
#define SDRAM_IGENERIC          
(PAGE_SIZE_4MB 
| CPLB_L1_CHBL 
| CPLB_USER_RD 
| CPLB_VALID)
&nbsp;
&nbsp;
icplb_table[16][2]={
{0xFFA00000, L1_IMEMORY},
{0x00000000, SDRAM_IKERNEL},    /*SDRAM_Page1*/
{0x00400000, SDRAM_IKERNEL},    /*SDRAM_Page1*/
#ifdef CONFIG_STAMP
{0x07C00000, SDRAM_IKERNEL},    /*SDRAM_Page14*/
#else
{0x03C00000, SDRAM_IKERNEL},    /*SDRAM_Page14*/
#endif
&nbsp;
{0x00800000, SDRAM_IGENERIC},   /*SDRAM_Page2*/
{0x00C00000, SDRAM_IGENERIC},   /*SDRAM_Page2*/
{0x01000000, SDRAM_IGENERIC},   /*SDRAM_Page4*/
{0x01400000, SDRAM_IGENERIC},   /*SDRAM_Page5*/
{0x01800000, SDRAM_IGENERIC},   /*SDRAM_Page6*/
{0x01C00000, SDRAM_IGENERIC},   /*SDRAM_Page7*/
{0x02000000, SDRAM_IGENERIC},   /*SDRAM_Page8*/
{0x02400000, SDRAM_IGENERIC},   /*SDRAM_Page9*/
{0x02800000, SDRAM_IGENERIC},   /*SDRAM_Page10*/
{0x02C00000, SDRAM_IGENERIC},   /*SDRAM_Page11*/
{0x03000000, SDRAM_IGENERIC},   /*SDRAM_Page12*/
{0x03400000, SDRAM_IGENERIC},   /*SDRAM_Page13*/
&nbsp;</pre>
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<!-- SECTION [3473-7726] -->
<h2><a name="u_boot_startup_sequence" id="u_boot_startup_sequence">U Boot Startup Sequence</a></h2>
<div class="level2">

<p>
The following sequence of files defines the startup sequence for U-boot
</p>

<p>
 The start up sequence for the BF533 is as follows
</p>
<pre class="code text">cpu/bf533/start.S : inits pll / sdram and relocates from flash to Ram
                    enabled icache and dcache, sets up stack
                    jumps to _start1
&nbsp;
cpu/bf533/start1.S : completes init after relocate to ram
                     calls    board_init_f;
&nbsp;
lib_blackfin/board.c: runs **board_init_f** **board_init_r** to initialize the whole
                      system and finally calls **main_loop** to run the boot 
                      command line parser
&nbsp;</pre><pre class="code"> Specific Init functions and the files associated with them</pre>
<pre class="code text">init_IRQ()              cpu/bf533/ints.c 
flash_init()            drivers/cfi_flash.c
env_init()              common/env_flash.c
init_baudrate()         lib_blackfin/board.c
serial_init()           cpu/bf533/serial.c
console_init_f()        common/console.c 
display_banner()        lib_blackfin/board.c
checkboard()            board/stamp/stamp.c
timer_init()            cpu/bf533/interrupts.c
&nbsp;</pre>
</div>

<h4><a name="checking_the_startup_sequence" id="checking_the_startup_sequence">Checking the Startup Sequence</a></h4>
<div class="level4">

<p>
 You can check this sequence using <strong>bfin-uclinux-objdump</strong> to disassemble object files
</p>
<pre class="code text">__Check a particular file__
&nbsp;
$ bfin-uclinux-objdump -D cpu/bf533/start.o | more  
&nbsp;
Disassembly of section .text:
&nbsp;
00000000 &lt;_start&gt;:
   0:   20 e1 61 00     R0=0x61 (X);
   4:   ff e3 fe ff     CALL  0 &lt;_start&gt;;
   8:   90 61           R0=0x32(x);
   a:   10 3e           SYSCFG=R0;
   c:   24 00           SSYNC;
   e:   01 60           R1=0x0(x);
  10:   02 60           R2=0x0(x);
  12:   03 60           R3=0x0(x);
  14:   04 60           R4=0x0(x);
  16:   05 60           R5=0x0(x);
  18:   06 60           R6=0x0(x);
  1a:   07 60           R7=0x0(x);
&nbsp;
&nbsp;
__Check the u-boot elf image__
&nbsp;
$ bfin-uclinux-objdump -D u-boot | more              
&nbsp;
Disassembly of section .text:
&nbsp;
03fc0000 &lt;_start&gt;:
 3fc0000:       20 e1 61 00     R0=0x61 (X);
 3fc0004:       00 e3 b2 06     CALL  3fc0d68 &lt;putch&gt;;
 3fc0008:       90 61           R0=0x32(x);
 3fc000a:       10 3e           SYSCFG=R0;
 3fc000c:       24 00           SSYNC;
 3fc000e:       01 60           R1=0x0(x);
 3fc0010:       02 60           R2=0x0(x);
 3fc0012:       03 60           R3=0x0(x);
 3fc0014:       04 60           R4=0x0(x);
 3fc0016:       05 60           R5=0x0(x);
&nbsp;</pre>
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<!-- SECTION [7727-10154] -->
<h2><a name="adding_u-boot_commands" id="adding_u-boot_commands">Adding U-boot commands</a></h2>
<div class="level2">

<p>
 You can  create your own uboot commands.
</p>

<p>
The directory  <strong>common</strong> contains the sources for many commands
</p>

<p>
 Add the name of the new command file  cmd_xxx.o file to the list of COBJS in <strong>common/Makefile</strong> to include additional objects in the u-boot image.
</p>

<p>
 A command is added to the system at link time by adding some special code to a  regular &ldquo;C&rdquo; file. You can specify a max number of arguments and if the  command can be repeated or remembered by the system.
</p>

<p>
A remembered command will be repeated if a blank command is issued after the first instance of the command.
</p>
<pre class="code c"><span class="co2">#include &lt;common.h&gt;</span>
<span class="co2">#include &lt;asm/blackfin.h&gt;</span>
<span class="co2">#include &lt;command.h&gt;</span>
&nbsp;
U_BOOT_CMD<span class="br0">&#40;</span>
        mycmd,                               <span class="co1">// name </span>
	<span class="nu0">2</span>,                                   <span class="co1">// max args</span>
	<span class="nu0">1</span>,                                   <span class="co1">// rep </span>
	do_mycmd,                            <span class="co1">// command function</span>
        <span class="st0">"mycmd - my test command   <span class="es0">\n</span>"</span>,      <span class="co1">// command usage</span>
        <span class="st0">"      A test command example <span class="es0">\n</span>"</span>    <span class="co1">// command help</span>
<span class="br0">&#41;</span>;</pre>
<p>
A typical command function is shown below. You will need to add code to interpret the command arguments.
</p>
<pre class="code c"><span class="kw4">int</span> do_mycmd<span class="br0">&#40;</span>cmd_tbl_t *cmdtp, <span class="kw4">int</span> flag, <span class="kw4">int</span> argc, <span class="kw4">char</span> *argv<span class="br0">&#91;</span><span class="br0">&#93;</span><span class="br0">&#41;</span>
<span class="br0">&#123;</span>
    <span class="co1">// flag used to hold system information ( not normally used )</span>
    <span class="co1">// argc  = count of additional args</span>
    <span class="co1">// argv = list of commands</span>
    <span class="co1">//... add command code as required...</span>
&nbsp;
    <span class="kw1">return</span> <span class="nu0">0</span>;       <span class="co1">// if the command is OK</span>
<span class="br0">&#125;</span></pre>
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