Re: [Xenomai-help] Blackfin BF-536 w/ Xenomai I-pipe Timer Issue

[Philippe Gerum <rpm@xenomai.org>]

Michael wrote:
> Soon after posting the last post, I read it and saw that I was using TIMIL6 
> instead of TIMIL7 in arch/blackfin/mach-common/ints-priority-sc.c
> 
> After changing this the board booted and everything worked and desired. 
> 
> I may be useful to make the timer used configurable in future builds to handle 
> situations like this.  I will test this further and come back if I have any 
> further problems.

Makes sense. I would merge such patch.

> 
> Thanks.
> 
> On Tuesday 17 June 2008 15:21, Michael wrote:
>> I have run into a problem with reconfiguring the i-pipe timer on the a
>> Blackfin BF-536 processor. The problem stems from having allocated TIMER0
>> to a be used as a PWM on a BF-536 based board. With this in mind I tried to
>> modify the Linux kernel to use a different timer (TIMER7) for the i-pipe
>> timer. Now when the board tries to boot the kernel it fails almost
>> immediately. Here is a shot of the boot sequence.
>>
>> CPU:   ADSP BF536 Rev.: 0.2
>> Board: Kryptic GCMB
>> Clock: VCO: 400 MHz, Core: 400 MHz, System: 80 MHz
>> SDRAM: 16 MB
>> FLASH:   4 MB
>> In:    serial
>> Out:   serial
>> Err:   serial
>> Using MAC Address 00:50:C2:0E:0D:9E
>> Net:    ADI BF53X EMAC
>> I2C:   ready
>> Hit any key to stop autoboot:  0
>> Using MAC Address 00:50:C2:0E:0D:9E
>> TFTP from server 10.0.2.131; our IP address is 10.0.2.75
>> Filename 'gcmb-vmImage'.
>> Load address: 0xa00000
>> Loading: #################################################################
>>          #################################################################
>>          ###########################################################
>> done
>> Bytes transferred = 967269 (ec265 hex)
>> ## Booting image at 00a00000 ...
>>    Image Name:   Linux-2.6.19.3-ADI-2007R1-svn598
>>    Created:      2008-06-17  17:18:18 UTC
>>    Image Type:   Blackfin Linux Kernel Image (gzip compressed)
>>    Data Size:    967205 Bytes = 944.5 kB
>>    Load Address: 00001000
>>    Entry Point:  00001000
>>    Verifying Checksum ... OK
>>    Uncompressing Kernel Image ... OK
>> Starting Kernel at = 1000
>> Linux version 2.6.19.3-
>>
>> It fails here and have not been able to get past this point. It looks as if
>> the interrupt is not being handled properly.
>>
>> The patches for modified files are shown below:
>> Index: arch/blackfin/mach-common/ints-priority-sc.c
>> ===================================================================
>> --- arch/blackfin/mach-common/ints-priority-sc.c        (revision 598)
>> +++ arch/blackfin/mach-common/ints-priority-sc.c        (working copy)
>> @@ -839,8 +839,8 @@
>>         ipipe_load_cpuid();
>>
>>         if (irq == IRQ_SYSTMR)
>> -           bfin_write_TIMER_STATUS(1); /* Latch TIMIL0 */
>> -
>> +           bfin_write_TIMER_STATUS(TIMIL6); /* Latch TIMIL6 */
>> +//         bfin_write_TIMER_STATUS(1); /* Latch TIMIL0 */
>>         /* This is basically what we need from the register frame. */
>>         __ipipe_irq_regs[cpuid].ipend = regs->ipend;
>>         __ipipe_irq_regs[cpuid].pc = regs->pc;
>> Index: include/asm-blackfin/ipipe.h
>> ===================================================================
>> --- include/asm-blackfin/ipipe.h        (revision 598)
>> +++ include/asm-blackfin/ipipe.h        (working copy)
>> @@ -199,14 +199,17 @@
>>
>>  #define IPIPE_TIMER_IRQ  IRQ_CORETMR
>>
>> -#define IRQ_SYSTMR       IRQ_TMR0
>> +#define IRQ_SYSTMR       IRQ_TMR7
>> Index: arch/blackfin/kernel/time.c
>> ===================================================================
>> --- arch/blackfin/kernel/time.c (revision 598)
>> +++ arch/blackfin/kernel/time.c (working copy)
>> @@ -149,15 +149,25 @@
>>         bfin_write_TCNTL(0);
>>         __builtin_bfin_csync();
>>         /* We use TIMER0 in PWM_OUT, periodic mode. */
>> -       bfin_write_TIMER_DISABLE(1);    /* Disable TIMER0 for now. */
>> +       //bfin_write_TIMER_DISABLE(1);    /* Disable TIMER0 for now. */
>> +       bfin_write_TIMER_DISABLE(1<<7);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER0_CONFIG(0x59); /* IRQ enable, periodic, PWM_OUT,
>> SCLKed, OUT PAD disabled */
>> +       //bfin_write_TIMER0_CONFIG(0x59); /* IRQ enable, periodic, PWM_OUT,
>> SCLKed, OUT PAD disabled */
>> +       bfin_write_TIMER7_CONFIG(0x59);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER0_PERIOD(get_sclk() / HZ);
>> +       //bfin_write_TIMER0_PERIOD(get_sclk() / HZ);
>> +       bfin_write_TIMER7_PERIOD(get_sclk() / HZ);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER0_WIDTH(1);
>> +       //bfin_write_TIMER0_WIDTH(1);
>> +       bfin_write_TIMER7_WIDTH(1);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER_ENABLE(1);     /* Enable TIMER0. */
>> +       //bfin_write_TIMER_ENABLE(1);     /* Enable TIMER0. */
>> +       bfin_write_TIMER_ENABLE(1<<7);
>> +
>>         __builtin_bfin_ssync();
>>  #else /* !CONFIG_IPIPE */
>>         u32 tcount;
>> @@ -201,8 +211,12 @@
>>         /* When the I-pipe is active, Linux uses TMR0 and not the core
>>            timer, which is then reserved to any real-time subsystem
>>            that may rely on Adeos for interrupt virtualization. */
>> -       clocks_per_jiffy =  bfin_read_TIMER0_PERIOD();
>> -       offset =  bfin_read_TIMER0_COUNTER() / (((clocks_per_jiffy + 1) *
>> HZ) / USEC_PER_SEC);
>> +       //clocks_per_jiffy =  bfin_read_TIMER0_PERIOD();
>> +       clocks_per_jiffy =  bfin_read_TIMER7_PERIOD();
>> +
>> +       //offset =  bfin_read_TIMER0_COUNTER() / (((clocks_per_jiffy + 1) *
>> HZ) / USEC_PER_SEC);
>> +       offset =  bfin_read_TIMER7_COUNTER() / (((clocks_per_jiffy + 1) *
>> HZ) / USEC_PER_SEC);
>> +
>>  #else /* !CONFIG_IPIPE */
>>         clocks_per_jiffy = bfin_read_TPERIOD();
>>         offset =
>> Index: arch/blackfin/kernel/ipipe.c
>> ===================================================================
>> --- arch/blackfin/kernel/ipipe.c        (revision 598)
>> +++ arch/blackfin/kernel/ipipe.c        (working copy)
>> @@ -415,16 +415,26 @@
>>
>>         x = ipipe_critical_enter(NULL);
>>
>> -       bfin_write_TIMER_DISABLE(1);
>> +       //bfin_write_TIMER_DISABLE(1);
>> +       bfin_write_TIMER_DISABLE(1<<7);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER0_CONFIG(0x59); /* IRQ enable, periodic, PWM_OUT,
>> SCLKed, OUT PAD disabled */
>> +       //bfin_write_TIMER0_CONFIG(0x59);       /* IRQ enable, periodic,
>> PWM_OUT, SCLKed, OUT PAD disabled */
>> +       bfin_write_TIMER7_CONFIG(0x59);
>> +
>>         __builtin_bfin_ssync();
>>         hz = (flags & IPIPE_RESET_TIMER) ? HZ : 1000000000L / ns;
>> -       bfin_write_TIMER0_PERIOD(get_sclk() / hz);
>> +       //bfin_write_TIMER0_PERIOD(get_sclk() / hz);
>> +       bfin_write_TIMER7_PERIOD(get_sclk() / hz);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER0_WIDTH(1);
>> +       //bfin_write_TIMER0_WIDTH(1);
>> +       bfin_write_TIMER7_WIDTH(1);
>> +
>>         __builtin_bfin_ssync();
>> -       bfin_write_TIMER_ENABLE(1);
>> +       //bfin_write_TIMER_ENABLE(1);
>> +       bfin_write_TIMER_ENABLE(1<<7);
>> +
>>         __builtin_bfin_ssync();
>>
>>         ipipe_critical_exit(x);
>>
>>
>> Is there anything obvious that I am missing? Has this ever been attempted?
>>
>> FYI
>> The ucLinux kernel is version 2.6.19.3-ADI-2007R1-svn598 patched with
>> xenomai-2.3.1.
>>
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-- 
Philippe.