[U-Boot] [PATCH] driver/ddr: Fix DDR4 driver for ARM

[York Sun]

On 06/18/2014 07:57 AM, Jon Loeliger wrote:
> On Tue, Jun 17, 2014 at 5:07 PM, York Sun <yorksun at freescale.com> wrote:
>> Previously the driver was only tested on Power SoCs. Minor fix is needed
>> for ARM SoCs.
>>
>> Signed-off-by: York Sun <yorksun at freescale.com>
> 
> 
> Hi York!
> 
> 
>> --- a/drivers/ddr/fsl/fsl_ddr_gen4.c
>> +++ b/drivers/ddr/fsl/fsl_ddr_gen4.c
> 
>> @@ -183,12 +184,20 @@ step2:
>>          * we choose the max, that is 500 us for all of case.
>>          */
>>         udelay(500);
>> +#ifdef CONFIG_PPC
>>         asm volatile("sync;isync");
>> +#else
>> +       asm volatile("dsb sy;isb");
>> +#endif
>>
>>         /* Let the controller go */
>>         temp_sdram_cfg = ddr_in32(&ddr->sdram_cfg) & ~SDRAM_CFG_BI;
>>         ddr_out32(&ddr->sdram_cfg, temp_sdram_cfg | SDRAM_CFG_MEM_EN);
>> +#ifdef CONFIG_PPC
>>         asm volatile("sync;isync");
>> +#else
>> +       asm volatile("dsb sy;isb");
>> +#endif
>>
>>         total_gb_size_per_controller = 0;
>>         for (i = 0; i < CONFIG_CHIP_SELECTS_PER_CTRL; i++) {
> 
> This is a great example where we should try to introduce better abstractions
> in much the same way that Linux has.  Specifically, we (U-Boot) collective
> might work toward some common lower-level abstractions such as a
> memory_barrier() (and variants), and let those generic names get mapped
> into architecture-specific implementations via a linked binding.  Then this
> code would not need to change, nor would #ifdefs be needed.
> 

Jon,

Are you suggesting to pick arch/<arch>/include/asm/barrier.h from Linux, or part
of it?

York