On Thu, Feb 14, 2019 at 8:46 AM Xiongfeng Wang
<wangxiongfeng2@xxxxxxxxxx> wrote:
>
> This patch add a helper to get the value of desired performance
> register.
>
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
> ---
> drivers/acpi/cppc_acpi.c | 38 ++++++++++++++++++++++++++++++++++++++
> include/acpi/cppc_acpi.h | 1 +
> 2 files changed, 39 insertions(+)
>
> diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
> index 217a782..93588c5 100644
> --- a/drivers/acpi/cppc_acpi.c
> +++ b/drivers/acpi/cppc_acpi.c
> @@ -1051,6 +1051,44 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
> }
>
> /**
> + * cppc_get_desired_perf - Get the value of desired performance register.
> + * @cpunum: CPU from which to get desired performance.
> + * @desired_perf: address of a variable to store the returned desired performance
> + *
> + * Return: 0 for success, -EIO otherwise.
> + */
> +int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
> +{
> + struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
> + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
> + struct cpc_register_resource *desired_reg;
> + struct cppc_pcc_data *pcc_ss_data = NULL;
> + int regs_in_pcc = 0;
It would be better to use bool here, but it would be even better to
not try to avoid calling cpc_read() in two branches.
> +
> + desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
> +
> + if (CPC_IN_PCC(desired_reg)) {
int ret = 0;
> + if (pcc_ss_id < 0)
> + return -EIO;
> + pcc_ss_data = pcc_data[pcc_ss_id];
> + down_write(&pcc_ss_data->pcc_lock);
if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
cpc_read(cpunum, desired_reg, desired_perf);
else
ret = -EIO;
up_write(&pcc_ss_data->pcc_lock);
return ret;
> + regs_in_pcc = 1;
> + if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
> + up_write(&pcc_ss_data->pcc_lock);
> + return -EIO;
> + }
> + }
cpc_read(cpunum, desired_reg, desired_perf);
return 0;
> +
> + cpc_read(cpunum, desired_reg, desired_perf);
> +
> + if (regs_in_pcc)
> + up_write(&pcc_ss_data->pcc_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
> +
> +/**
> * cppc_get_perf_caps - Get a CPUs performance capabilities.
> * @cpunum: CPU from which to get capabilities info.
> * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
