Re: [Qemu-devel] [PATCH arm-ccnt v2 1/1] ARM-CCNT: Implements the ARM PMCCNTR register

[Alistair Francis <alistair.francis@xilinx.com>]

I have worked through this some more and have found some issues that I
have fixed in V3, which is now on the list

On Mon, Jan 20, 2014 at 11:11 AM, Alistair Francis
<alistair.francis@xilinx.com> wrote:
> This patch implements the ARM PMCCNTR register including
> the disable and reset components of the PMCR register.
>
> Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> ---
> This patch assumes that non-invasive debugging is not permitted
> when determing if the counter is disabled
> V2: Incorperated the comments that Peter Maydell and Peter
> Crosthwaite had. Now the implementation only required one
> CPU state
>
>  target-arm/cpu.h    |    3 +++
>  target-arm/helper.c |   46 ++++++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 47 insertions(+), 2 deletions(-)
>
> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
> index 198b6b8..2fdab58 100644
> --- a/target-arm/cpu.h
> +++ b/target-arm/cpu.h
> @@ -215,6 +215,9 @@ typedef struct CPUARMState {
>          uint32_t c15_diagnostic; /* diagnostic register */
>          uint32_t c15_power_diagnostic;
>          uint32_t c15_power_control; /* power control */
> +        /* If the counter is enabled, this stores the last time the counter
> +         * was reset. Otherwise it stores the counter value */
> +        uint32_t c15_ccnt;
>      } cp15;
>
>      /* System registers (AArch64) */
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index c708f15..8aee764 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -13,6 +13,12 @@ static inline int get_phys_addr(CPUARMState *env, uint32_t address,
>                                  target_ulong *page_size);
>  #endif
>
> +/* Definitions for the PMCCNTR and PMCR registers */
> +#define PMCRDP  0x20
> +#define PMCRD   0x8
> +#define PMCRC   0x4
> +#define PMCRE   0x1
> +
>  static int vfp_gdb_get_reg(CPUARMState *env, uint8_t *buf, int reg)
>  {
>      int nregs;
> @@ -508,6 +514,15 @@ static int pmcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
>      /* only the DP, X, D and E bits are writable */
>      env->cp15.c9_pmcr &= ~0x39;
>      env->cp15.c9_pmcr |= (value & 0x39);
> +
> +    if (value & PMCRC || env->cp15.c9_pmcr & PMCRDP ||
> +        !(env->cp15.c9_pmcr & PMCRE)) {
> +        /* Store the value of when the reset or disable occured */
> +        env->cp15.c15_ccnt = ((((qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) *
> +                                 get_ticks_per_sec())/1000000000) >> 8) &
> +                                 0xFFFFFFFF);
> +    }
> +
>      return 0;
>  }
>
> @@ -584,6 +599,32 @@ static int vbar_write(CPUARMState *env, const ARMCPRegInfo *ri,
>      return 0;
>  }
>
> +static int pmccntr_read(CPUARMState *env, const ARMCPRegInfo *ri,
> +                       uint64_t *value)
> +{
> +    int64_t total_ticks;
> +
> +    /* This assumes that non-invasive debugging is not permitted */
> +    if (env->cp15.c9_pmcr & PMCRDP ||
> +       !(env->cp15.c9_pmcr & PMCRE)) {
> +        /* Counter is disabled, do not change value */
> +        *value = env->cp15.c15_ccnt;
> +        return 0;
> +    }
> +
> +    total_ticks = ((((qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) *
> +                      get_ticks_per_sec())/1000000000) >> 8) & 0xFFFFFFFF);
> +
> +    if (env->cp15.c9_pmcr & PMCRDP) {
> +        /* Increment once every 64 processor clock cycles */
> +        *value = (uint32_t) (total_ticks - env->cp15.c15_ccnt)/64;
> +    } else {
> +        *value = (uint32_t) (total_ticks - env->cp15.c15_ccnt);
> +    }
> +
> +    return 0;
> +}
> +
>  static int ccsidr_read(CPUARMState *env, const ARMCPRegInfo *ri,
>                         uint64_t *value)
>  {
> @@ -644,9 +685,10 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
>       */
>      { .name = "PMSELR", .cp = 15, .crn = 9, .crm = 12, .opc1 = 0, .opc2 = 5,
>        .access = PL0_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
> -    /* Unimplemented, RAZ/WI. XXX PMUSERENR */
>      { .name = "PMCCNTR", .cp = 15, .crn = 9, .crm = 13, .opc1 = 0, .opc2 = 0,
> -      .access = PL0_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
> +      .access = PL1_RW, .readfn = pmccntr_read,
> +      .fieldoffset = offsetof(CPUARMState, cp15.c15_ccnt),
> +      .resetvalue = 0, .type = ARM_CP_IO },
>      { .name = "PMXEVTYPER", .cp = 15, .crn = 9, .crm = 13, .opc1 = 0, .opc2 = 1,
>        .access = PL0_RW,
>        .fieldoffset = offsetof(CPUARMState, cp15.c9_pmxevtyper),
> --
> 1.7.1
>