From mboxrd@z Thu Jan 1 00:00:00 1970 From: Taniya Das Subject: Re: [PATCH v7 2/2] cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver Date: Sun, 23 Sep 2018 15:10:55 +0530 Message-ID: <8c19c840-292c-a5c4-f3d3-0c6fb14b15fb@codeaurora.org> References: <1532428970-18122-1-git-send-email-tdas@codeaurora.org> <1532428970-18122-3-git-send-email-tdas@codeaurora.org> <20180829180122.GC10879@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180829180122.GC10879@google.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Matthias Kaehlcke Cc: "Rafael J. Wysocki" , Viresh Kumar , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Stephen Boyd , Rajendra Nayak , Amit Nischal , devicetree@vger.kernel.org, robh@kernel.org, skannan@codeaurora.org, amit.kucheria@linaro.org, evgreen@google.com List-Id: devicetree@vger.kernel.org Hello Matthias, Thanks for your review comments. On 8/29/2018 11:31 PM, Matthias Kaehlcke wrote: > Hi Taniya, > > On Tue, Jul 24, 2018 at 04:12:50PM +0530, Taniya Das wrote: >> The CPUfreq HW present in some QCOM chipsets offloads the steps necessary >> for changing the frequency of CPUs. The driver implements the cpufreq >> driver interface for this hardware engine. >> >> Signed-off-by: Saravana Kannan >> Signed-off-by: Taniya Das >> --- >> drivers/cpufreq/Kconfig.arm | 11 ++ >> drivers/cpufreq/Makefile | 1 + >> drivers/cpufreq/qcom-cpufreq-hw.c | 348 ++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 360 insertions(+) >> create mode 100644 drivers/cpufreq/qcom-cpufreq-hw.c >> >> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm >> index 0cd8eb7..93a9d72 100644 >> --- a/drivers/cpufreq/Kconfig.arm >> +++ b/drivers/cpufreq/Kconfig.arm >> @@ -298,3 +298,14 @@ config ARM_PXA2xx_CPUFREQ >> This add the CPUFreq driver support for Intel PXA2xx SOCs. >> >> If in doubt, say N. >> + >> +config ARM_QCOM_CPUFREQ_HW >> + bool "QCOM CPUFreq HW driver" >> + depends on ARCH_QCOM >> + help >> + Support for the CPUFreq HW driver. >> + Some QCOM chipsets have a HW engine to offload the steps >> + necessary for changing the frequency of the CPUs. Firmware loaded >> + in this engine exposes a programming interface to the OS. >> + The driver implements the cpufreq interface for this HW engine. >> + Say Y if you want to support CPUFreq HW. >> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile >> index c1ffeab..ca48a1d 100644 >> --- a/drivers/cpufreq/Makefile >> +++ b/drivers/cpufreq/Makefile >> @@ -85,6 +85,7 @@ 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_HW) += qcom-cpufreq-hw.o >> >> >> ################################################################################## >> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c >> new file mode 100644 >> index 0000000..ea8f7d1 >> --- /dev/null >> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c >> @@ -0,0 +1,348 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (c) 2018, The Linux Foundation. All rights reserved. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#define INIT_RATE 300000000UL >> +#define LUT_MAX_ENTRIES 40U >> +#define CORE_COUNT_VAL(val) (((val) & (GENMASK(18, 16))) >> 16) >> +#define LUT_ROW_SIZE 32 >> + >> +enum { >> + REG_ENABLE, >> + REG_LUT_TABLE, >> + REG_PERF_STATE, >> + >> + REG_ARRAY_SIZE, >> +}; >> + >> +struct cpufreq_qcom { >> + struct cpufreq_frequency_table *table; >> + struct device *dev; > > 'dev' is not used and can be removed. > Thanks, would remove in the next patch. >> ... >> >> +static int qcom_cpu_resources_init(struct platform_device *pdev, >> + struct device_node *np, unsigned int cpu, >> + unsigned long xo_rate) >> +{ >> + struct cpufreq_qcom *c; >> + struct resource res; >> + struct device *dev = &pdev->dev; >> + const u16 *offsets; >> + int ret, i, cpu_first, cpu_r; >> + void __iomem *base; >> + >> + if (qcom_freq_domain_map[cpu]) >> + return 0; >> + >> + c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL); >> + if (!c) >> + return -ENOMEM; >> + >> + offsets = of_device_get_match_data(&pdev->dev); >> + if (!offsets) >> + return -EINVAL; >> + >> + if (of_address_to_resource(np, 0, &res)) >> + return -ENOMEM; >> + >> + base = devm_ioremap_resource(dev, &res); >> + if (!base) >> + return -ENOMEM; >> + >> + for (i = REG_ENABLE; i < REG_ARRAY_SIZE; i++) >> + c->reg_bases[i] = base + offsets[i]; >> + >> + /* HW should be in enabled state to proceed */ >> + if (!(readl_relaxed(c->reg_bases[REG_ENABLE]) & 0x1)) { >> + dev_err(dev, "%s cpufreq hardware not enabled\n", np->name); >> + return -ENODEV; >> + } >> + >> + ret = qcom_get_related_cpus(np, &c->related_cpus); >> + if (ret) { >> + dev_err(dev, "%s failed to get related CPUs\n", np->name); >> + return ret; >> + } >> + >> + c->max_cores = cpumask_weight(&c->related_cpus); >> + if (!c->max_cores) >> + return -ENOENT; >> + >> + c->xo_rate = xo_rate; >> + >> + ret = qcom_cpufreq_hw_read_lut(pdev, c); >> + if (ret) { >> + dev_err(dev, "%s failed to read LUT\n", np->name); >> + return ret; >> + } >> + >> + qcom_freq_domain_map[cpu] = c; >> + >> + /* Related CPUs */ >> + cpu_first = cpumask_first(&c->related_cpus); >> + >> + for_each_cpu(cpu_r, &c->related_cpus) { >> + if (cpu_r != cpu_first) >> + qcom_freq_domain_map[cpu_r] = >> + qcom_freq_domain_map[cpu_first]; >> + } > > The above ten lines could be simplified to: > > for_each_cpu(cpu_r, &c->related_cpus) > qcom_freq_domain_map[cpu_r] = c; > Would clean it up in the next patch. >> ... >> >> +static int __init qcom_cpufreq_hw_init(void) >> +{ >> + return platform_driver_register(&qcom_cpufreq_hw_driver); >> +} >> +subsys_initcall(qcom_cpufreq_hw_init); > > Is subsys_initcall used for a particular reason? It will cause > problems when registering cooling devices, since the thermal device > class is initialized through an fs_initcall, which are executed > later. > > Most cpufreq drivers use module_init, device_initcall or > late_initcall, can't this driver use one of those? > We want the CPU to be scaling to the highest frequency at the earliest. > Cheers > > Matthias > -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation. --