2009-06-24 09:22:38 l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76242

hi, all

I'm moving my project from 2008R1.5 to 2009R1. But when I doing this job, My kernel will halt if I use l1.data in the kenerl driver like below,

char test2[4] __attribute__((section(".l1.data"))) = {0, 0, 0, 0};

But the same code in 2008R1.5 has no problem.

I enabled I-Cache and D-Cache - only half of Bank A.

Does anyone know what's the problem? Thanks!

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2009-06-24 09:34:07 Re: l1.data can't be used in 2009R1

Mike Frysinger (UNITED STATES)

Message: 76244

you should never use section("..."). use attribute((l1_data)).

saying "will halt" doesnt really provide any information at all. you need to post real details in your questions. what is the exact output when you boot the kernel ? if you are getting no output, then use the post_mortem debug method to dump the kernel log buffer from u-boot.

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2009-06-24 09:46:53 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76247

Hi, Mike

I've tried all other section param, like .l1.text, .l1.data.B, .l1.bss, .l1.bss.B . they are ok, only the .l1.data not work. But if I disable the D-Cache, event the .l1.data works. So I doubt the BFIN_DCACHE_BANKA not correct.

Btw, I think the BFIN_DCACHE_BANKA means only use half of Bank A to be data cache, and left the other half to be sram. So we have 16KB + 32 KB = 48 KB sram if we enable the option Am I right?

//below is the dump when startup

## Booting image at 01000000 ...

Image Name: Linux-2.6.28.10-ADI-2009R1-svn68

Image Type: Blackfin Linux Kernel Image (gzip compressed)

Data Size: 3106938 Bytes = 3 MB

Load Address: 00100000

Entry Point: 0038f6e4

Verifying Checksum ... OK

Uncompressing Kernel Image ... OK

Starting Kernel at = 38f6e4 <--------------------------------------------------halt here

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2009-06-24 09:57:53 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76248

BTW,

the same result with __attribute__((l1_data)).

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2009-06-24 09:59:07 Re: l1.data can't be used in 2009R1

Mike Frysinger (UNITED STATES)

Message: 76249

like i said, use the post mortem method:

docs.blackfin.uclinux.org/doku.php?id=linux-kernel:debug:post_mortem

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2009-06-24 10:28:05 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76254

Hi, Mike

It's unlucky that we don't have a reset buttom on the board. and I did things like "set bootargs $(bootargs) panic=3", but nothing happen after the board halt. So I can't get the kernel message in u-boot. What shall I do?

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2009-06-24 10:40:55 Re: l1.data can't be used in 2009R1

Mike Frysinger (UNITED STATES)

Message: 76255

then wire up a reset button. or use JTAG. or setup the watchdog to automatically reboot.

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2009-06-24 23:29:56 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76284

Hi, Mike

Our hardware engineer told me it's impossible to add a reset buttom to the current board. So would you pls try my sample code? It's very simple,

//add below codes to anywhere of the kernel and compile, the run ramboot by tftp

int test1[4] __attribute__((l1_data)) = {0, 1, 2, 3};

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2009-06-24 23:31:29 Re: l1.data can't be used in 2009R1

Mike Frysinger (UNITED STATES)

Message: 76285

we already know the l1 data attributes work

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2009-06-24 23:40:49 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76287

Hi, Mike

Did you test the sample under 2009R1 branch and what's the option configuration for D-Cache? When I disable the D-Cache, l1 data works. But if I enable D-Cache and Enable only 16KB of Bank A to be D-cache option, my board would not startup.

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2009-06-25 01:34:30 Re: l1.data can't be used in 2009R1

Mike Frysinger (UNITED STATES)

Message: 76289

then you probably have too much stuff in L1. remove some of it.

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2009-06-25 02:23:23 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76293

Hi, Mike

The problem is,

1) l1_data doesn't work but the l1.bss does.

2) l1.bss can't initial the buffer on compiling. like int test[4] __attribute__(section("l1.bss"))= {0,1,2,3};

3) I don't put any data into L1 except the test buffer. when I use section(".l1.bss") instead l1_data, the buffer is allocated at address of 0xff800000 which is the start address of L1. But I need to initial the global data at compile time, so I don't want to use l1.bss.

4) The same code in 2008R1.5 works.

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2009-06-25 04:11:42 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76301

I did a new test, when I build the test codes into module and inmod after system startup, it is ok.

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2009-06-25 05:18:19 Re: l1.data can't be used in 2009R1

david wang (CHINA)

Message: 76317

Hi, Mike

Pls tell me how to check which modules has used the l1 buffer?