[U-Boot] [PATCH 4/6] nand_spl: update udelay for Freescale boards

[McClintock Matthew-B29882]

On Mon, Aug 13, 2012 at 5:56 PM, Scott Wood <scottwood at freescale.com> wrote:
> On 08/13/2012 01:10 PM, Matthew McClintock wrote:
>> Let's use the more appropriate udelay for the nand_spl. While we
>> can't make use of u-boot's full udelay we can atl east use a for
>> loop that won't get optimized away .Since we have the bus clock
>> we can use the timebase to calculate wall time.
>>
>> Looked at reusing the u-boot udelay functions but it pulls in a lot
>> of code as well as depends on the gd struct and would require a lot
>> of rework
>
> What's wrong with depending on the gd struct?

Perhaps the wording is wrong a bit off. It's just pulling in other
stuff and as you know we are very space constrained.

>> +extern u32 bus_clk;
>
> Change to gd->bus_clk as mentioned in patch 5/6.

Yes, v2 was already sent: http://patchwork.ozlabs.org/patch/177047/

>> +void udelay(unsigned long usec) {
>> +     u32 ticks_per_usec = bus_clk / (8 * 1000000);
>> +     u32 ticks = ticks_per_usec * usec;
>> +     u32 s = mfspr(SPRN_TBRL);
>> +
>> +     while ((mfspr(SPRN_TBRL)-s) < ticks);
>> +}
>
> Opening brace goes on its own line for function definitions.  Use spaces
> around that '-'.

Will fix.

> Dividing the bus clock by 8 only works for e500v1/v2, but this isn't
> labelled as specific to those cores.

Updated to use CONFIG_SYS_FSL_TBCLK_DIV

>
>> diff --git a/nand_spl/board/freescale/p1010rdb/Makefile b/nand_spl/board/freescale/p1010rdb/Makefile
>> index 8d240ea..cdbd492 100644
>> --- a/nand_spl/board/freescale/p1010rdb/Makefile
>> +++ b/nand_spl/board/freescale/p1010rdb/Makefile
>> @@ -39,7 +39,8 @@ CFLAGS      += -DCONFIG_NAND_SPL
>>
>>  SOBJS        = start.o resetvec.o ticks.o
>>  COBJS        = cache.o cpu_init_early.o cpu_init_nand.o fsl_law.o law.o \
>> -       nand_boot.o nand_boot_fsl_ifc.o ns16550.o tlb.o tlb_table.o
>> +       nand_boot.o nand_boot_fsl_ifc.o ns16550.o tlb.o tlb_table.o \
>> +       ../common.o
>>
>>  SRCS := $(addprefix $(obj),$(SOBJS:.o=.S) $(COBJS:.o=.c))
>>  OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
>> @@ -123,6 +124,9 @@ ifneq ($(OBJTREE), $(SRCTREE))
>>  $(obj)nand_boot.c:
>>       @rm -f $(obj)nand_boot.c
>>       ln -s $(SRCTREE)/nand_spl/board/$(BOARDDIR)/nand_boot.c $(obj)nand_boot.c
>> +$(obj)../common.c:
>> +     @rm -f $(obj)../common.c
>> +     ln -s $(SRCTREE)/nand_spl/board/freescale/common.c $(obj)../common.c
>>  endif
>
> Why are you creating a link in the parent directory?

The typical build process picks out files needed for the build and
symlinks them to nand_spl folder - or if building out of tree then it
symlinks to the out of tree folder. This is true for all files in
nand_spl as it currently exists not just this new file.

-M