[PR 05] LEON3: CPU index intialization moved to bspstart.c

[Daniel Hellstrom]

On 02/02/2012 04:45 PM, Gedare Bloom wrote:
> On Thu, Feb 2, 2012 at 9:46 AM, Daniel Hellstrom<daniel at gaisler.com>  wrote:
>> All LEON3/4 systems have a CPU-id, if on a single-CPU system the
>> ID is always zero. On a multicore system it ranges from 0 to 15.
>>
>> The CPU index should always by updated even in a non-MP RTEMS OS
>> since the CPU running RTEMS may not always be CPU0. For example
>> when RTEMS runs on CPU1 and Linux on CPU0 in a mixed ASMP system.
>>
>> The old code executed within the IRQ controller initialization code
>> makes no sense since the ASR register is a CPU register, it has
>> nothing to do with AMBA initialization either.
>>
>> Signed-off-by: Daniel Hellstrom<daniel at gaisler.com>
>> ---
>>   c/src/lib/libbsp/sparc/leon3/amba/amba.c        |   18 ------------------
>>   c/src/lib/libbsp/sparc/leon3/startup/bspstart.c |   18 ++++++++++++++++++
>>   2 files changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/c/src/lib/libbsp/sparc/leon3/amba/amba.c b/c/src/lib/libbsp/sparc/leon3/amba/amba.c
>> index 1932cee..b0a43f9 100644
>> --- a/c/src/lib/libbsp/sparc/leon3/amba/amba.c
>> +++ b/c/src/lib/libbsp/sparc/leon3/amba/amba.c
>> @@ -21,8 +21,6 @@ amba_confarea_type amba_conf;
>>   /* Pointers to Interrupt Controller configuration registers */
>>   volatile LEON3_IrqCtrl_Regs_Map *LEON3_IrqCtrl_Regs;
>>
>> -int LEON3_Cpu_Index = 0;
>> -
>>   /*
>>   *  amba_initialize
>>   *
>> @@ -33,16 +31,6 @@ int LEON3_Cpu_Index = 0;
>>   *  amba_ahb_masters, amba_ahb_slaves and amba.
>>   */
>>
>> -unsigned int getasr17(void);
>> -
>> -__asm__ (" .text  \n"
>> -    "getasr17:   \n"
>> -    "retl \n"
>> -    "mov %asr17, %o0\n"
>> -);
>> -
>> -
>> -extern rtems_configuration_table Configuration;
>>   extern int scan_uarts(void);
>>
>>   void amba_initialize(void)
>> @@ -58,12 +46,6 @@ void amba_initialize(void)
>>    if ( i>  0 ){
>>      /* Found APB IRQ_MP Interrupt Controller */
>>      LEON3_IrqCtrl_Regs = (volatile LEON3_IrqCtrl_Regs_Map *) dev.start;
>> -#if defined(RTEMS_MULTIPROCESSING)
>> -      if (rtems_configuration_get_user_multiprocessing_table() != NULL) {
>> -        unsigned int tmp = getasr17();
>> -        LEON3_Cpu_Index = (tmp>>  28)&  3;
>> -      }
>> -#endif
>>    }
>>
>>    /* find GP Timer */
>> diff --git a/c/src/lib/libbsp/sparc/leon3/startup/bspstart.c b/c/src/lib/libbsp/sparc/leon3/startup/bspstart.c
>> index a4b9ffa..82054e8 100644
>> --- a/c/src/lib/libbsp/sparc/leon3/startup/bspstart.c
>> +++ b/c/src/lib/libbsp/sparc/leon3/startup/bspstart.c
>> @@ -27,6 +27,9 @@
>>   */
>>   int CPU_SPARC_HAS_SNOOPING;
>>
>> +/* Index of CPU, in an AMP system CPU-index may be non-zero */
>> +int LEON3_Cpu_Index = 0;
>> +
>>   extern void amba_initialize(void);
>>
>>   /*
>> @@ -48,6 +51,14 @@ static inline int set_snooping(void)
>>    return (tmp>>  27)&  1;
>>   }
>>
>> +/* ASM-function used to get the CPU-Index on calling LEON3 CPUs */
>> +static inline unsigned int get_asr17(void)
>> +{
>> +  unsigned int reg;
>> +  __asm__ (" mov %%asr17, %0 " : "=r"(reg) :);
>> +  return reg;
>> +}
> Might get_asr17 make sense as a function defined by
> cpukit/score/cpu/sparc/rtems/score/sparc.h? Or is it really only
> useful for getting the cpu index as used below?
>
>> +
>>   /*
>>   *  bsp_start
>>   *
>> @@ -57,6 +68,13 @@ void bsp_start( void )
>>   {
>>    CPU_SPARC_HAS_SNOOPING = set_snooping();
>>
>> +  /* Get the LEON3 CPU index, normally 0, but for MP systems we do
>> +   * _not_ assume that this is CPU0. One may run another OS on CPU0
>> +   * and RTEMS on this CPU, and AMP system with mixed operating
>> +   * systems
>> +   */
>> +  LEON3_Cpu_Index = (get_asr17()>>  28)&  3;
> Would it make sense to also define something like
> sparc_get_cpu_index()? Or does it only ever need to be done during bsp
> initialization?
Yes, that makes sens, but perhaps in a separate "clean patch" for HEAD? This is the way the code was code first time:

-      if (rtems_configuration_get_user_multiprocessing_table() != NULL) {
-        unsigned int tmp = getasr17();
-        LEON3_Cpu_Index = (tmp>>  28)&  3;
-      }


>> +
>>    /* Find UARTs */
>>    amba_initialize();
>>   }
>> --
>> 1.7.0.4
>>
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>