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Date: Tue, 8 Sep 2020 10:39:11 -0500
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: rjw@...ysocki.net, viresh.kumar@...aro.org, robh+dt@...nel.org,
agross@...nel.org, amitk@...nel.org, linux-pm@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, dmitry.baryshkov@...aro.org,
tdas@...eaurora.org
Subject: Re: [PATCH 5/7] cpufreq: qcom-hw: Use regmap for accessing hardware
registers
On Tue 08 Sep 02:57 CDT 2020, Manivannan Sadhasivam wrote:
> Use regmap for accessing cpufreq registers in hardware.
>
The content of the patch looks good, but in itself I don't see the
reason for migrating to regmap.
If you have subsequent patches, that would benefit from describing the
hardware differences using reg_fields then it might be a good idea, but
I would suggest that you postpone this patch until there's an actual
beneficiary.
Regards,
Bjorn
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> ---
> drivers/cpufreq/qcom-cpufreq-hw.c | 55 ++++++++++++++++++++++++++-----
> 1 file changed, 47 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 41853db7c9b8..de816bcafd33 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -12,6 +12,7 @@
> #include <linux/of_address.h>
> #include <linux/of_platform.h>
> #include <linux/pm_opp.h>
> +#include <linux/regmap.h>
> #include <linux/slab.h>
>
> #define LUT_MAX_ENTRIES 40U
> @@ -32,6 +33,7 @@ struct qcom_cpufreq_soc_data {
>
> struct qcom_cpufreq_data {
> void __iomem *base;
> + struct regmap *regmap;
> const struct qcom_cpufreq_soc_data *soc_data;
> };
>
> @@ -85,8 +87,11 @@ static int qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
> struct qcom_cpufreq_data *data = policy->driver_data;
> const struct qcom_cpufreq_soc_data *soc_data = data->soc_data;
> unsigned long freq = policy->freq_table[index].frequency;
> + int ret;
>
> - writel_relaxed(index, data->base + soc_data->reg_perf_state);
> + ret = regmap_write(data->regmap, soc_data->reg_perf_state, index);
> + if (ret)
> + return ret;
>
> if (icc_scaling_enabled)
> qcom_cpufreq_set_bw(policy, freq);
> @@ -102,6 +107,7 @@ static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
> const struct qcom_cpufreq_soc_data *soc_data;
> struct cpufreq_policy *policy;
> unsigned int index;
> + int ret;
>
> policy = cpufreq_cpu_get_raw(cpu);
> if (!policy)
> @@ -110,7 +116,10 @@ static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
> data = policy->driver_data;
> soc_data = data->soc_data;
>
> - index = readl_relaxed(data->base + soc_data->reg_perf_state);
> + ret = regmap_read(data->regmap, soc_data->reg_perf_state, &index);
> + if (ret)
> + return 0;
> +
> index = min(index, LUT_MAX_ENTRIES - 1);
>
> return policy->freq_table[index].frequency;
> @@ -123,9 +132,12 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
> const struct qcom_cpufreq_soc_data *soc_data = data->soc_data;
> unsigned int index;
> unsigned long freq;
> + int ret;
>
> index = policy->cached_resolved_idx;
> - writel_relaxed(index, data->base + soc_data->reg_perf_state);
> + ret = regmap_write(data->regmap, soc_data->reg_perf_state, index);
> + if (ret)
> + return 0;
>
> freq = policy->freq_table[index].frequency;
> arch_set_freq_scale(policy->related_cpus, freq,
> @@ -171,14 +183,24 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
> }
>
> for (i = 0; i < LUT_MAX_ENTRIES; i++) {
> - data = readl_relaxed(drv_data->base + soc_data->reg_freq_lut +
> - i * soc_data->lut_row_size);
> + ret = regmap_read(drv_data->regmap, soc_data->reg_freq_lut +
> + i * soc_data->lut_row_size, &data);
> + if (ret) {
> + kfree(table);
> + return ret;
> + }
> +
> src = FIELD_GET(LUT_SRC, data);
> lval = FIELD_GET(LUT_L_VAL, data);
> core_count = FIELD_GET(LUT_CORE_COUNT, data);
>
> - data = readl_relaxed(drv_data->base + soc_data->reg_volt_lut +
> - i * soc_data->lut_row_size);
> + ret = regmap_read(drv_data->regmap, soc_data->reg_volt_lut +
> + i * soc_data->lut_row_size, &data);
> + if (ret) {
> + kfree(table);
> + return ret;
> + }
> +
> volt = FIELD_GET(LUT_VOLT, data) * 1000;
>
> if (src)
> @@ -248,6 +270,13 @@ static void qcom_get_related_cpus(int index, struct cpumask *m)
> }
> }
>
> +static struct regmap_config qcom_cpufreq_regmap = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + .fast_io = true,
> +};
> +
> static const struct qcom_cpufreq_soc_data qcom_soc_data = {
> .reg_enable = 0x0,
> .reg_freq_lut = 0x110,
> @@ -274,6 +303,7 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> struct qcom_cpufreq_data *data;
> const struct of_device_id *match;
> int ret, index;
> + u32 val;
>
> cpu_dev = get_cpu_device(policy->cpu);
> if (!cpu_dev) {
> @@ -316,9 +346,18 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>
> data->soc_data = match->data;
> data->base = base;
> + data->regmap = devm_regmap_init_mmio(dev, base, &qcom_cpufreq_regmap);
> + if (IS_ERR(data->regmap)) {
> + ret = PTR_ERR(data->regmap);
> + goto error;
> + }
>
> /* HW should be in enabled state to proceed */
> - if (!(readl_relaxed(base + data->soc_data->reg_enable) & 0x1)) {
> + ret = regmap_read(data->regmap, data->soc_data->reg_enable, &val);
> + if (ret)
> + goto error;
> +
> + if (!(val & 0x1)) {
> dev_err(dev, "Domain-%d cpufreq hardware not enabled\n", index);
> ret = -ENODEV;
> goto error;
> --
> 2.17.1
>
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