Hisilicon chips do not support delivered performance counter register
and reference performance counter register. But the platform can
calculate the real performance using its own method. This patch provide
a workaround for this problem, and other platforms can also use this
workaround framework. We reuse the desired performance register to
store the real performance calculated by the platform. After the
platform finished the frequency adjust, it gets the real performance and
writes it into desired performance register. OS can use it to calculate
the real frequency.
Changlog:
v2 -> v3:
Recontruct 'cppc_get_desired_perf'.
Rename 'cppc_workaround_info' to 'cppc_workaround_oem_info'
Drop 'get_rate' member from struct cppc_workaround_oem_info
Change 'cppc_wa_get_rate' pointer to a flag to indicate whether
we need to aplly the workaround.
Move the new functions to the beginning of cppc-cpufreq.c
Xiongfeng Wang (2):
ACPI / CPPC: Add a helper to get desired performance
cpufreq / cppc: Work around for Hisilicon CPPC cpufreq
drivers/acpi/cppc_acpi.c | 39 +++++++++++++++++++++++++
drivers/cpufreq/cppc_cpufreq.c | 66 ++++++++++++++++++++++++++++++++++++++++++
include/acpi/cppc_acpi.h | 1 +
3 files changed, 106 insertions(+)
--
1.7.12.4
This patch add a helper to get the value of desired performance
register.
Signed-off-by: Xiongfeng Wang <[email protected]>
---
drivers/acpi/cppc_acpi.c | 39 +++++++++++++++++++++++++++++++++++++++
include/acpi/cppc_acpi.h | 1 +
2 files changed, 40 insertions(+)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 217a782..231d447 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1051,6 +1051,45 @@ 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;
+
+ 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;
+ }
+
+ cpc_read(cpunum, desired_reg, desired_perf);
+
+ 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
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 4f34734..ba6fd72 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -137,6 +137,7 @@ struct cppc_cpudata {
cpumask_var_t shared_cpu_map;
};
+extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
--
1.7.12.4
Hisilicon chips do not support delivered performance counter register
and reference performance counter register. But the platform can
calculate the real performance using its own method. We reuse the
desired performance register to store the real performance calculated by
the platform. After the platform finished the frequency adjust, it gets
the real performance and writes it into desired performance register. Os
can use it to calculate the real frequency.
Signed-off-by: Xiongfeng Wang <[email protected]>
---
drivers/cpufreq/cppc_cpufreq.c | 66 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index fd25c21c..efc0298 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -42,6 +42,67 @@
*/
static struct cppc_cpudata **all_cpu_data;
+struct cppc_workaround_oem_info {
+ char oem_id[ACPI_OEM_ID_SIZE +1];
+ char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
+ u32 oem_revision;
+};
+
+static bool apply_hisi_workaround;
+
+static struct cppc_workaround_oem_info wa_info[] = {
+ {
+ .oem_id = "HISI ",
+ .oem_table_id = "HIP07 ",
+ .oem_revision = 0,
+ }, {
+ .oem_id = "HISI ",
+ .oem_table_id = "HIP08 ",
+ .oem_revision = 0,
+ }
+};
+
+static unsigned int cppc_cpufreq_perf_to_khz(struct cppc_cpudata *cpu,
+ unsigned int perf);
+
+/*
+ * HISI platform does not support delivered performance counter and
+ * reference performance counter. It can calculate the performance using the
+ * platform specific mechanism. We reuse the desired performance register to
+ * store the real performance calculated by the platform.
+ */
+static unsigned int hisi_cppc_cpufreq_get_rate(unsigned int cpunum)
+{
+ struct cppc_cpudata *cpudata = all_cpu_data[cpunum];
+ u64 desired_perf;
+ int ret;
+
+ ret = cppc_get_desired_perf(cpunum, &desired_perf);
+ if (ret < 0)
+ return -EIO;
+
+ return cppc_cpufreq_perf_to_khz(cpudata, desired_perf);
+}
+
+static void cppc_check_hisi_workaround(void)
+{
+ struct acpi_table_header *tbl;
+ acpi_status status = AE_OK;
+ int i;
+
+ status = acpi_get_table(ACPI_SIG_PCCT, 0, &tbl);
+ if (ACPI_FAILURE(status) || !tbl)
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(wa_info); i++) {
+ if (!memcmp(wa_info[i].oem_id, tbl->oem_id, ACPI_OEM_ID_SIZE) &&
+ !memcmp(wa_info[i].oem_table_id, tbl->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) &&
+ wa_info[i].oem_revision == tbl->oem_revision) {
+ apply_hisi_workaround = true;
+ }
+ }
+}
+
/* Callback function used to retrieve the max frequency from DMI */
static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
{
@@ -334,6 +395,9 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpunum)
struct cppc_cpudata *cpu = all_cpu_data[cpunum];
int ret;
+ if (apply_hisi_workaround)
+ return hisi_cppc_cpufreq_get_rate(cpunum);
+
ret = cppc_get_perf_ctrs(cpunum, &fb_ctrs_t0);
if (ret)
return ret;
@@ -386,6 +450,8 @@ static int __init cppc_cpufreq_init(void)
goto out;
}
+ cppc_check_hisi_workaround();
+
ret = cpufreq_register_driver(&cppc_cpufreq_driver);
if (ret)
goto out;
--
1.7.12.4
On Sunday, February 17, 2019 4:54:13 AM CET Xiongfeng Wang wrote:
> Hisilicon chips do not support delivered performance counter register
> and reference performance counter register. But the platform can
> calculate the real performance using its own method. This patch provide
> a workaround for this problem, and other platforms can also use this
> workaround framework. We reuse the desired performance register to
> store the real performance calculated by the platform. After the
> platform finished the frequency adjust, it gets the real performance and
> writes it into desired performance register. OS can use it to calculate
> the real frequency.
>
> Changlog:
>
> v2 -> v3:
> Recontruct 'cppc_get_desired_perf'.
> Rename 'cppc_workaround_info' to 'cppc_workaround_oem_info'
> Drop 'get_rate' member from struct cppc_workaround_oem_info
> Change 'cppc_wa_get_rate' pointer to a flag to indicate whether
> we need to aplly the workaround.
> Move the new functions to the beginning of cppc-cpufreq.c
>
>
> Xiongfeng Wang (2):
> ACPI / CPPC: Add a helper to get desired performance
> cpufreq / cppc: Work around for Hisilicon CPPC cpufreq
>
> drivers/acpi/cppc_acpi.c | 39 +++++++++++++++++++++++++
> drivers/cpufreq/cppc_cpufreq.c | 66 ++++++++++++++++++++++++++++++++++++++++++
> include/acpi/cppc_acpi.h | 1 +
> 3 files changed, 106 insertions(+)
>
>
Both patches applied, thanks!