From mboxrd@z Thu Jan 1 00:00:00 1970 From: Taniya Das Subject: Re: [PATCH 2/2] cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver Date: Sat, 3 Nov 2018 08:36:00 +0530 Message-ID: <0c51a12e-38d3-2df5-4f5f-6a687727e9bf@codeaurora.org> References: <1539257761-23023-1-git-send-email-tdas@codeaurora.org> <1539257761-23023-3-git-send-email-tdas@codeaurora.org> <153981915373.5275.15971019914218464179@swboyd.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <153981915373.5275.15971019914218464179@swboyd.mtv.corp.google.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Stephen Boyd , "Rafael J. Wysocki" , Viresh Kumar , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Rajendra Nayak , devicetree@vger.kernel.org, robh@kernel.org, skannan@codeaurora.org, linux-arm-msm@vger.kernel.org, amit.kucheria@linaro.org, evgreen@google.com List-Id: devicetree@vger.kernel.org Hello Stephen, On 10/18/2018 5:02 AM, Stephen Boyd wrote: > Quoting Taniya Das (2018-10-11 04:36:01) >> --- a/drivers/cpufreq/Kconfig.arm >> +++ b/drivers/cpufreq/Kconfig.arm >> @@ -121,6 +121,17 @@ config ARM_QCOM_CPUFREQ_KRYO >> >> If in doubt, say N. >> >> +config ARM_QCOM_CPUFREQ_HW >> + bool "QCOM CPUFreq HW driver" > > Is there any reason this can't be a module? > We do not have any use cases where we need to support it as module. >> + depends on ARCH_QCOM || COMPILE_TEST >> + 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. >> + >> config ARM_S3C_CPUFREQ >> bool >> help >> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c >> new file mode 100644 >> index 0000000..fe1c264 >> --- /dev/null >> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c >> @@ -0,0 +1,354 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Copyright (c) 2018, The Linux Foundation. All rights reserved. >> + */ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#define LUT_MAX_ENTRIES 40U >> +#define CORE_COUNT_VAL(val) (((val) & (GENMASK(18, 16))) >> 16) >> +#define LUT_ROW_SIZE 32 >> +#define CLK_HW_DIV 2 >> + >> +enum { >> + REG_ENABLE, >> + REG_LUT_TABLE, >> + REG_PERF_STATE, >> + >> + REG_ARRAY_SIZE, >> +}; >> + >> +struct cpufreq_qcom { >> + struct cpufreq_frequency_table *table; >> + void __iomem *reg_bases[REG_ARRAY_SIZE]; >> + cpumask_t related_cpus; >> + unsigned int max_cores; >> + unsigned long xo_rate; >> + unsigned long cpu_hw_rate; >> +}; >> + >> +static const u16 cpufreq_qcom_std_offsets[REG_ARRAY_SIZE] = { > > Is this going to change in the future? > Yes, they could change and that was the reason to introduce the offsets. This was discussed earlier too with Sudeep and was to add them. >> + [REG_ENABLE] = 0x0, >> + [REG_LUT_TABLE] = 0x110, >> + [REG_PERF_STATE] = 0x920, >> +}; >> + >> +static struct cpufreq_qcom *qcom_freq_domain_map[NR_CPUS]; >> + >> +static int >> +qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy, >> + unsigned int index) >> +{ >> + struct cpufreq_qcom *c = policy->driver_data; >> + >> + writel_relaxed(index, c->reg_bases[REG_PERF_STATE]); > > Why can't we avoid the indirection here and store the perf_state pointer > in probe? Then we don't have to indirect through a table to perform the > register write. > As the offsets could change and that was the reason to add this. >> + >> + return 0; >> +} >> + > [..] >> +static int qcom_resources_init(struct platform_device *pdev) >> +{ >> + struct device_node *cpu_np; >> + struct of_phandle_args args; >> + struct clk *clk; >> + unsigned int cpu; >> + unsigned long xo_rate, cpu_hw_rate; >> + int ret; >> + >> + clk = clk_get(&pdev->dev, "xo"); >> + if (IS_ERR(clk)) >> + return PTR_ERR(clk); >> + >> + xo_rate = clk_get_rate(clk); >> + >> + clk_put(clk); >> + >> + clk = clk_get(&pdev->dev, "cpu_clk"); > > Sad that the name is cpu_clk, instead of something like 'backup' or > whatever the name really is in hardware. > Sure, would update it. -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation. --