On 04.02.2014, at 03:52, Scott Wood <scottw...@freescale.com> wrote:
> On Fri, 2014-01-31 at 12:16 +0100, Alexander Graf wrote:
>> The only thing we know in our PV machine through device tree is the clock
>> speed of the CPUs. Take that as CPU speed, system speed and ddr speed so that
>> we have some meaningful values there at all.
>>
>> The CPU speed is important because our timing loops get determined based on
>> it.
>>
>> Signed-off-by: Alexander Graf <ag...@suse.de>
>> ---
>> arch/powerpc/cpu/mpc85xx/Makefile | 2 ++
>> board/freescale/qemu-ppce500/qemu-ppce500.c | 43
>> +++++++++++++++++++++++++++
>> 2 files changed, 45 insertions(+)
>>
>> diff --git a/arch/powerpc/cpu/mpc85xx/Makefile
>> b/arch/powerpc/cpu/mpc85xx/Makefile
>> index ef7637a..4094785 100644
>> --- a/arch/powerpc/cpu/mpc85xx/Makefile
>> +++ b/arch/powerpc/cpu/mpc85xx/Makefile
>> @@ -102,7 +102,9 @@ obj-y += cpu.o
>> obj-y += cpu_init.o
>> obj-y += cpu_init_early.o
>> obj-y += interrupts.o
>> +ifneq ($(CONFIG_QEMU_E500),y)
>> obj-y += speed.o
>> +endif
>> obj-y += tlb.o
>> obj-y += traps.o
>>
>> diff --git a/board/freescale/qemu-ppce500/qemu-ppce500.c
>> b/board/freescale/qemu-ppce500/qemu-ppce500.c
>> index 5d4dd64..9e9d688 100644
>> --- a/board/freescale/qemu-ppce500/qemu-ppce500.c
>> +++ b/board/freescale/qemu-ppce500/qemu-ppce500.c
>> @@ -407,3 +407,46 @@ void init_laws(void)
>> {
>> /* We don't emulate LAWs yet */
>> }
>> +
>> +static uint32_t get_cpu_freq(void)
>> +{
>> + const void *fdt = get_fdt();
>> + int cpus_node = fdt_path_offset(fdt, "/cpus");
>> + int cpu_node = fdt_first_subnode(fdt, cpus_node);
>> + return myfdt_one_cell(fdt, cpu_node, "clock-frequency", 0);
>> +}
>> +
>> +void get_sys_info(sys_info_t *sys_info)
>> +{
>> + int freq = get_cpu_freq();
>> +
>> + memset(sys_info, 0, sizeof(sys_info_t));
>> + sys_info->freq_systembus = freq;
>> + sys_info->freq_ddrbus = freq;
>> + sys_info->freq_processor[0] = freq;
>> +}
>> +
>> +int get_clocks (void)
>> +{
>> + sys_info_t sys_info;
>> +
>> + get_sys_info(&sys_info);
>> +
>> + gd->cpu_clk = sys_info.freq_processor[0];
>> + gd->bus_clk = sys_info.freq_systembus;
>> + gd->mem_clk = sys_info.freq_ddrbus;
>> + gd->arch.lbc_clk = sys_info.freq_ddrbus;
>> +
>> + return 0;
>> +}
>
> This probably decreases the accuracy of the timebase frequency, since
> you'll be basing it on the CPU frequency rather than the bus frequency.
>
> If you're doing this, why not override get_tbclk() as well?
That one only uses variables I already control, no?
unsigned long get_tbclk (void)
{
unsigned long tbclk_div = CONFIG_SYS_FSL_TBCLK_DIV;
return (gd->bus_clk + (tbclk_div >> 1)) / tbclk_div;
}
Alex
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