On 16.08.2016 09:18, Suraj Jitindar Singh wrote:
> It would be nice if we had a generic sleep function which could be used
> in unit tests, add one.
>
> Add the variable tb_hz used to store the time base frequency which is read
> from the device tree on setup.
>
> Add functions msleep, usleep and sleep in processor.c to sleep for a given
> number of milliseconds, microseconds and time base ticks respectively.
You finally called them mdelay, udelay and delay instead, so in case you
respin, please adjust the commit message.
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> ---
>
> Change Log:
>
> V2 -> V3:
> - Add patch to series
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> ---
> lib/powerpc/asm/processor.h | 19 +++++++++++++++++++
> lib/powerpc/asm/setup.h | 2 ++
> lib/powerpc/processor.c | 13 +++++++++++++
> lib/powerpc/setup.c | 12 ++++++++++++
> 4 files changed, 46 insertions(+)
>
> diff --git a/lib/powerpc/asm/processor.h b/lib/powerpc/asm/processor.h
> index 09692bd..9554e08 100644
> --- a/lib/powerpc/asm/processor.h
> +++ b/lib/powerpc/asm/processor.h
> @@ -1,11 +1,30 @@
> #ifndef _ASMPOWERPC_PROCESSOR_H_
> #define _ASMPOWERPC_PROCESSOR_H_
>
> +#include <libcflat.h>
> #include <asm/ptrace.h>
>
> +#define cpu_relax() asm volatile ("" : : : "memory")
I'd maybe add a "nop" instruction in there ... just in case?
> #ifndef __ASSEMBLY__
> void handle_exception(int trap, void (*func)(struct pt_regs *, void *), void *);
> void do_handle_exception(struct pt_regs *regs);
> #endif /* __ASSEMBLY__ */
>
> +static inline uint64_t get_tb(void)
> +{
> + uint64_t tb;
> + asm volatile ("mfspr %[tb],268" : [tb] "=r" (tb));
> + return tb;
> +}
> +
> +extern void delay(uint64_t cycles);
> +extern void udelay(uint64_t us);
> +
> +static inline void mdelay(uint64_t ms)
> +{
> + while (ms--)
> + udelay(1000);
> +}
> +
> #endif /* _ASMPOWERPC_PROCESSOR_H_ */
> diff --git a/lib/powerpc/asm/setup.h b/lib/powerpc/asm/setup.h
> index b1e1e5a..23b4156 100644
> --- a/lib/powerpc/asm/setup.h
> +++ b/lib/powerpc/asm/setup.h
> @@ -11,6 +11,8 @@
> extern u32 cpus[NR_CPUS];
> extern int nr_cpus;
>
> +extern uint64_t tb_hz;
> +
> #define NR_MEM_REGIONS 8
> #define MR_F_PRIMARY (1U << 0)
> struct mem_region {
> diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c
> index a78bc3c..c84bae5 100644
> --- a/lib/powerpc/processor.c
> +++ b/lib/powerpc/processor.c
> @@ -5,6 +5,7 @@
> #include <libcflat.h>
> #include <asm/processor.h>
> #include <asm/ptrace.h>
> +#include <asm/setup.h>
>
> static struct {
> void (*func)(struct pt_regs *, void *data);
> @@ -36,3 +37,15 @@ void do_handle_exception(struct pt_regs *regs)
> printf("unhandled cpu exception 0x%lx\n", regs->trap);
> abort();
> }
> +
> +void delay(uint64_t cycles)
> +{
> + uint64_t start = get_tb();
> + while((get_tb() - start) < cycles)
> + cpu_relax();
Shouldn't there be some kind of wrap-around detection, like you had it
in v2 for the decrementer based sleep function?
> +}
> +
> +void udelay(uint64_t us)
> +{
> + delay((us * tb_hz) / 1000000);
> +}
> diff --git a/lib/powerpc/setup.c b/lib/powerpc/setup.c
> index e3d2afa..e7fa525 100644
> --- a/lib/powerpc/setup.c
> +++ b/lib/powerpc/setup.c
> @@ -24,6 +24,7 @@ extern void setup_args_progname(const char *args);
>
> u32 cpus[NR_CPUS] = { [0 ... NR_CPUS-1] = (~0U) };
> int nr_cpus;
> +uint64_t tb_hz;
>
> struct mem_region mem_regions[NR_MEM_REGIONS];
> phys_addr_t __physical_start, __physical_end;
> @@ -51,6 +52,17 @@ static void cpu_set(int fdtnode, u32 regval, void *info)
> }
> cpus[cpu] = regval;
>
> + /* set timebase frequency */
> + if (!tb_hz) {
> + const struct fdt_property *prop;
> + u32 *data;
> + prop = fdt_get_property(dt_fdt(), fdtnode,
> + "timebase-frequency", NULL);
> + assert(prop != NULL);
> + data = (u32 *)prop->data;
> + tb_hz = fdt32_to_cpu(*data);
You could short-cut that to fdt32_to_cpu(*(u32 *)prop->data) and get rid
of the "data" variable.
> + }
> +
> /* set exception stack address for this CPU (in SPGR0) */
>
> asm volatile ("mtsprg0 %[addr]" ::
>
Thomas
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