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SubjectRe: [PATCH v4 2/2] cpufreq: qcom-fw: Add support for QCOM cpufreq FW driver
From
Date
Please help review of the new series[v5] which takes care of the below.

- Remove mapping different register regions of perf/lut/enable,
instead map the entire HW region.
- Add reg_offset/cpufreq_qcom_std_offsets to be supplied as device data.
- Check of src == 0 during lut read.
- Add of_node_put(cpu_np) in qcom_get_related_cpus
- Update the qcom_cpu_resources_init for register offset data,
and cleanup the related cpus to keep a single copy of CPUfreq.
- Replace FW with HW, update Kconfig, rename filename qcom-cpufreq-hw.c

On 7/12/2018 2:07 AM, Matthias Kaehlcke wrote:
> Hi,
>
> On Tue, Jun 12, 2018 at 04:32:35PM +0530, Taniya Das wrote:
>> The CPUfreq FW present in some QCOM chipsets offloads the steps necessary
>> for changing the frequency of CPUs. The driver implements the cpufreq
>> driver interface for this firmware.
>>
>> Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
>> Signed-off-by: Taniya Das <tdas@codeaurora.org>
>> ---
>> drivers/cpufreq/Kconfig.arm | 9 +
>> drivers/cpufreq/Makefile | 1 +
>> drivers/cpufreq/qcom-cpufreq-fw.c | 336 ++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 346 insertions(+)
>> create mode 100644 drivers/cpufreq/qcom-cpufreq-fw.c
>>
>> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
>> index 52f5f1a..2683716 100644
>> --- a/drivers/cpufreq/Kconfig.arm
>> +++ b/drivers/cpufreq/Kconfig.arm
>> @@ -312,3 +312,12 @@ config ARM_PXA2xx_CPUFREQ
>> This add the CPUFreq driver support for Intel PXA2xx SOCs.
>>
>> If in doubt, say N.
>> +
>> +config ARM_QCOM_CPUFREQ_FW
>> + bool "QCOM CPUFreq FW driver"
>> + help
>> + Support for the CPUFreq FW driver.
>> + The CPUfreq FW preset in some QCOM chipsets offloads the steps
>> + necessary for changing the frequency of CPUs. The driver
>> + implements the cpufreq driver interface for this firmware.
>> + Say Y if you want to support CPUFreq FW.
>> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
>> index fb4a2ec..34691a2 100644
>> --- a/drivers/cpufreq/Makefile
>> +++ b/drivers/cpufreq/Makefile
>> @@ -86,6 +86,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
>> obj-$(CONFIG_ARM_TEGRA186_CPUFREQ) += tegra186-cpufreq.o
>> obj-$(CONFIG_ARM_TI_CPUFREQ) += ti-cpufreq.o
>> obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
>> +obj-$(CONFIG_ARM_QCOM_CPUFREQ_FW) += qcom-cpufreq-fw.o
>>
>>
>> ##################################################################################
>> diff --git a/drivers/cpufreq/qcom-cpufreq-fw.c b/drivers/cpufreq/qcom-cpufreq-fw.c
>> new file mode 100644
>> index 0000000..62f4452
>> --- /dev/null
>> +++ b/drivers/cpufreq/qcom-cpufreq-fw.c
>> @@ -0,0 +1,336 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +#include <linux/cpufreq.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_platform.h>
>> +
>> +#define INIT_RATE 300000000UL
>> +#define XO_RATE 19200000UL
>> +#define LUT_MAX_ENTRIES 40U
>> +#define CORE_COUNT_VAL(val) (((val) & (GENMASK(18, 16))) >> 16)
>> +#define LUT_ROW_SIZE 32
>> +
>> +struct cpufreq_qcom {
>> + struct cpufreq_frequency_table *table;
>> + struct device *dev;
>> + void __iomem *perf_base;
>> + void __iomem *lut_base;
>> + cpumask_t related_cpus;
>> + unsigned int max_cores;
>
> Why *max*_cores? This seems to be the number of CPUs in a cluster and
> qcom_read_lut() expects the core count read from the LUT to match
> exactly.
>
>> +static int qcom_read_lut(struct platform_device *pdev,
>> + struct cpufreq_qcom *c)
>> +{
>> + struct device *dev = &pdev->dev;
>> + u32 data, src, lval, i, core_count, prev_cc, prev_freq, cur_freq;
>> +
>> + c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
>> + sizeof(*c->table), GFP_KERNEL);
>> + if (!c->table)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < LUT_MAX_ENTRIES; i++) {
>> + data = readl_relaxed(c->lut_base + i * LUT_ROW_SIZE);
>> + src = ((data & GENMASK(31, 30)) >> 30);
>> + lval = (data & GENMASK(7, 0));
>> + core_count = CORE_COUNT_VAL(data);
>> +
>> + if (!src)
>> + c->table[i].frequency = INIT_RATE / 1000;
>> + else
>> + c->table[i].frequency = XO_RATE * lval / 1000;
>
> nit: any particular reason to use negative logic here? Why not check
> for 'src[ != NULL]', which also seems to be the more common case.
>
>> +static int qcom_get_related_cpus(struct device_node *np, struct cpumask *m)
>> +{
>> + struct device_node *cpu_np, *freq_np;
>> + int cpu;
>> +
>> + for_each_possible_cpu(cpu) {
>> + cpu_np = of_cpu_device_node_get(cpu);
>> + if (!cpu_np)
>> + continue;
>> + freq_np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
>> + if (!freq_np)
>> + continue;
>> + if (freq_np == np)
>> + cpumask_set_cpu(cpu, m);
>
> missing 'of_node_put(cpu_np)'. You might want to do it at the end of
> the loop and use a 'goto' above instead of 'continue'.
>
>> +static int qcom_cpu_resources_init(struct platform_device *pdev,
>> + struct device_node *np, unsigned int cpu)
>> +{
>> + struct cpufreq_qcom *c;
>> + struct resource res;
>> + struct device *dev = &pdev->dev;
>> + void __iomem *en_base;
>> + int index, ret;
>> +
>> + c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
>> + if (!c)
>> + return -ENOMEM;
>> +
>> + index = of_property_match_string(np, "reg-names", "enable");
>> + if (index < 0)
>> + return index;
>> +
>> + if (of_address_to_resource(np, index, &res))
>> + return -ENOMEM;
>> +
>> + en_base = devm_ioremap(dev, res.start, resource_size(&res));
>> + if (!en_base) {
>> + dev_err(dev, "Unable to map %s enable-base\n", np->name);
>> + return -ENOMEM;
>> + }
>> +
>> + /* FW should be in enabled state to proceed */
>> + if (!(readl_relaxed(en_base) & 0x1)) {
>> + dev_err(dev, "%s firmware not enabled\n", np->name);
>> + return -ENODEV;
>> + }
>> + devm_iounmap(&pdev->dev, en_base);
>> +
>> + index = of_property_match_string(np, "reg-names", "perf");
>> + if (index < 0)
>> + return index;
>> +
>> + if (of_address_to_resource(np, index, &res))
>> + return -ENOMEM;
>> +
>> + c->perf_base = devm_ioremap(dev, res.start, resource_size(&res));
>> + if (!c->perf_base) {
>> + dev_err(dev, "Unable to map %s perf-base\n", np->name);
>> + return -ENOMEM;
>> + }
>> +
>> + index = of_property_match_string(np, "reg-names", "lut");
>> + if (index < 0)
>> + return index;
>> +
>> + if (of_address_to_resource(np, index, &res))
>> + return -ENOMEM;
>> +
>> + c->lut_base = devm_ioremap(dev, res.start, resource_size(&res));
>> + if (!c->lut_base) {
>> + dev_err(dev, "Unable to map %s lut-base\n", np->name);
>> + return -ENOMEM;
>> + }
>
> The of_property_match_string() - of_address_to_resource() -
> devm_ioremap() pattern is repeated 3x. In case the binding doesn't
> change (there is discussion on the DT patch) you might want to move
> this to a helper.
>
>> +static int qcom_resources_init(struct platform_device *pdev)
>> +{
>> + struct device_node *np, *cpu_np;
>> + unsigned int cpu;
>> + int ret;
>> +
>> + for_each_possible_cpu(cpu) {
>> + cpu_np = of_cpu_device_node_get(cpu);
>> + if (!cpu_np) {
>> + dev_err(&pdev->dev, "Failed to get cpu %d device\n",
>> + cpu);
>> + continue;
>> + }
>> +
>> + np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
>> + if (!np) {
>> + dev_err(&pdev->dev, "Failed to get freq-domain device\n");
> of_node_put(cpu_np);
>> + return -EINVAL;
>> + }
>> +
>> + of_node_put(cpu_np);
>> +
>> + ret = qcom_cpu_resources_init(pdev, np, cpu);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + return 0;
>
> Cheers
>
> Matthias
>

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