uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(66)：_ebss_l1

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ADI bf561 DSP

优视BF561EVB开发板

uclinux-2008r1.5-rc3(smp patch)

Visual DSP++ 5.0(update 5)

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有几个链接错误：

[Error li1021] The following symbols referenced in processor 'p1' could not be resolved:

'_ebss_l1 [__ebss_l1]' referenced from 'arch-kernel.dlb[setup.doj]'

'_ebss_l1 [__ebss_l1]' referenced from 'arch-mm.dlb[blackfin_sram.doj]'

'_etext_l1 [__etext_l1]' referenced from 'arch-kernel.dlb[setup.doj]'

'_etext_l1 [__etext_l1]' referenced from 'arch-mm.dlb[blackfin_sram.doj]'

'_sdata_l1 [__sdata_l1]' referenced from 'arch-kernel.dlb[setup.doj]'

'_sdata_l1 [__sdata_l1]' referenced from 'arch-mm.dlb[blackfin_sram.doj]'

'_stext_l1 [__stext_l1]' referenced from 'arch-kernel.dlb[setup.doj]'

'_stext_l1 [__stext_l1]' referenced from 'arch-mm.dlb[blackfin_sram.doj]'

这里出现的几个符号均定义在vmlinux.lds.s中：

.text_l1 L1_CODE_START : AT(LOADADDR(.init.ramfs) + SIZEOF(.init.ramfs))

{

. = ALIGN(4);

__stext_l1 = .;

LDS_L1_CODE

. = ALIGN(4);

__etext_l1 = .;

}

.data_l1 L1_DATA_A_START : AT(LOADADDR(.text_l1) + SIZEOF(.text_l1))

{

. = ALIGN(4);

__sdata_l1 = .;

LDS_L1_A_DATA

__edata_l1 = .;

. = ALIGN(4);

__sbss_l1 = .;

LDS_L1_A_BSS

. = ALIGN(32);

LDS_L1_A_CACHE

. = ALIGN(4);

__ebss_l1 = .;

}

也就是说，这几个符号将指向A核中l1 memory被内核使用的部分的起始位置和结束位置。

再看看使用这两个符号的地方，第一个在arch\blackfin\kernel\setup.c(161)文件中

void __init bf53x_relocate_l1_mem(void)

{

unsigned long l1_code_length;

unsigned long l1_data_a_length;

unsigned long l1_data_b_length;

l1_code_length = _etext_l1 - _stext_l1;

if (l1_code_length > L1_CODE_LENGTH)

panic("L1 Instruction SRAM Overflow\n");

/* cannot complain as printk is not available as yet.

* But we can continue booting and complain later!

*/

/* Copy _stext_l1 to _etext_l1 to L1 instruction SRAM */

dma_memcpy(_stext_l1, _l1_lma_start, l1_code_length);

l1_data_a_length = _ebss_l1 - _sdata_l1;

if (l1_data_a_length > L1_DATA_A_LENGTH)

panic("L1 Data SRAM Bank A Overflow\n");

/* Copy _sdata_l1 to _ebss_l1 to L1 data bank A SRAM */

dma_memcpy(_sdata_l1, _l1_lma_start + l1_code_length, l1_data_a_length);

l1_data_b_length = _ebss_b_l1 - _sdata_b_l1;

if (l1_data_b_length > L1_DATA_B_LENGTH)

panic("L1 Data SRAM Bank B Overflow\n");

/* Copy _sdata_b_l1 to _ebss_b_l1 to L1 data bank B SRAM */

dma_memcpy(_sdata_b_l1, _l1_lma_start + l1_code_length +

l1_data_a_length, l1_data_b_length);

}

这个函数用于将代码复制到L1的相应区域，但是在VDSP下可以通过ldf文件直接将代码或者数据放置在相应的地方，因此这个函数可以略过，不调用它。

第二个地方在arch\blackfin\kernel\setup.c(475)文件中：

void __init setup_arch(char **cmdline_p)

{

………………………………

/* check the size of the l1 area */

l1_length = _etext_l1 - _stext_l1;

if (l1_length > L1_CODE_LENGTH)

panic("L1 code memory overflow\n");

l1_length = _ebss_l1 - _sdata_l1;

if (l1_length > L1_DATA_A_LENGTH)

panic("L1 data memory overflow\n");

……………………………….

}

仅仅是一个简单的条件判断，因为这个检验将由vdsp的链接器来完成，所以直接略过这里的条件判断。

第三个地方在arch\blackfin\mm\blackfin_sram.c(133)文件中：

void __init l1_data_sram_init(void)

{

unsigned int cpu;

#if L1_DATA_A_LENGTH != 0

printk(KERN_INFO "Blackfin DATA_A SRAM: %d KB\n",

L1_DATA_A_LENGTH >> 10);

for (cpu = 0; cpu < NR_CPUS; ++cpu) {

memset(&per_cpu(l1sram, cpu).l1_data_A_sram, 0x00,

sizeof(per_cpu(l1sram, cpu).l1_data_A_sram));

per_cpu(l1sram, cpu).l1_data_A_sram[0].paddr = (void *)get_l1_data_a_start_cpu(cpu) +

(_ebss_l1 - _sdata_l1);

per_cpu(l1sram, cpu).l1_data_A_sram[0].size = L1_DATA_A_LENGTH - (_ebss_l1 - _sdata_l1);

per_cpu(l1sram, cpu).l1_data_A_sram[0].flag = SRAM_SLT_FREE;

}

#endif

#if L1_DATA_B_LENGTH != 0

printk(KERN_INFO "Blackfin DATA_B SRAM: %d KB\n",

L1_DATA_B_LENGTH >> 10);

for (cpu = 0; cpu < NR_CPUS; ++cpu) {

memset(&per_cpu(l1sram, cpu).l1_data_B_sram, 0x00, sizeof(per_cpu(l1sram, cpu).l1_data_B_sram));

per_cpu(l1sram, cpu).l1_data_B_sram[0].paddr = (void *)get_l1_data_b_start_cpu(cpu)/*+(_ebss_b_l1 - _sdata_b_l1)*/;

per_cpu(l1sram, cpu).l1_data_B_sram[0].size = L1_DATA_B_LENGTH/*-(_ebss_b_l1 - _sdata_b_l1)*/;

per_cpu(l1sram, cpu).l1_data_B_sram[0].flag = SRAM_SLT_FREE;

}

#endif

/* mutex initialize */

spin_lock_init(&per_cpu(l1sram, cpu).l1_data_sram_lock);

}

这段代码主要用于注册l1中的可用存储空间。它用_ebss_l1 - _sdata_l1来表示内核已经使用的空间大小，在此直接预留4K的空间出来，同时在LDF文件中将这个预留段的大小限制为4K。

修改后的代码：

void __init l1_data_sram_init(void)

{

unsigned int cpu;

#if L1_DATA_A_LENGTH != 0

printk(KERN_INFO "Blackfin DATA_A SRAM: %d KB\n",

L1_DATA_A_LENGTH >> 10);

for (cpu = 0; cpu < NR_CPUS; ++cpu) {

memset(&per_cpu(l1sram, cpu).l1_data_A_sram, 0x00,

sizeof(per_cpu(l1sram, cpu).l1_data_A_sram));

per_cpu(l1sram, cpu).l1_data_A_sram[0].paddr = (void *)get_l1_data_a_start_cpu(cpu) + 0x1000 /*(_ebss_l1 - _sdata_l1)*/;

per_cpu(l1sram, cpu).l1_data_A_sram[0].size = L1_DATA_A_LENGTH - 0x1000/*(_ebss_l1 - _sdata_l1)*/;

per_cpu(l1sram, cpu).l1_data_A_sram[0].flag = SRAM_SLT_FREE;

}

#endif

#if L1_DATA_B_LENGTH != 0

printk(KERN_INFO "Blackfin DATA_B SRAM: %d KB\n",

L1_DATA_B_LENGTH >> 10);

for (cpu = 0; cpu < NR_CPUS; ++cpu) {

memset(&per_cpu(l1sram, cpu).l1_data_B_sram, 0x00, sizeof(per_cpu(l1sram, cpu).l1_data_B_sram));

per_cpu(l1sram, cpu).l1_data_B_sram[0].paddr = (void *)get_l1_data_b_start_cpu(cpu) + 0x1000/*(_ebss_b_l1 - _sdata_b_l1)*/;

per_cpu(l1sram, cpu).l1_data_B_sram[0].size = L1_DATA_B_LENGTH - 0x1000/*(_ebss_b_l1 - _sdata_b_l1)*/;

per_cpu(l1sram, cpu).l1_data_B_sram[0].flag = SRAM_SLT_FREE;

}

#endif

/* mutex initialize */

spin_lock_init(&per_cpu(l1sram, cpu).l1_data_sram_lock);

}

LDF文件中的修改：

MEM_A_L1_DATA_B { TYPE(RAM) START(0xFF900000) END(0xFF900FFF) WIDTH(8) }

MEM_A_L1_DATA_A { TYPE(RAM) START(0xFF800000) END(0xFF800FFF) WIDTH(8) }

MEM_B_L1_DATA_B { TYPE(RAM) START(0xFF500000) END(0xFF500FFF) WIDTH(8) }

MEM_B_L1_DATA_A { TYPE(RAM) START(0xFF400000) END(0xFF400FFF) WIDTH(8) }

1 参考资料

uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(62)：__builtin_return_address(2009-2-11)

uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(63)：_NSIG_WORDS_is_unsupported_size(2009-2-11)

uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(64)：__ebss_b_l1(2009-02-12)

uclinux-2008R1.5-RC3(bf561)到VDSP5的移植(65)：B核启动(2009-2-13)