On Thu, 2014-02-06 at 12:11 +0100, Alexander Graf wrote:
> 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;
> }
What did you set CONFIG_SYS_FSL_TBCLK_DIV to?
-Scott
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
