Hello Matthias, On 11/22/2018 12:11 AM, Matthias Kaehlcke wrote:
Hi Taniya,thanks for respinning, a few nits inline. On Wed, Nov 21, 2018 at 04:12:47PM +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 <skan...@codeaurora.org> Signed-off-by: Taniya Das <t...@codeaurora.org> --- drivers/cpufreq/Kconfig.arm | 11 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/qcom-cpufreq-hw.c | 346 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 358 insertions(+) create mode 100644 drivers/cpufreq/qcom-cpufreq-hw.c diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 4e1131e..688f102 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -114,6 +114,17 @@ config ARM_QCOM_CPUFREQ_KRYO If in doubt, say N. +config ARM_QCOM_CPUFREQ_HW + tristate "QCOM CPUFreq HW driver" + 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/Makefile b/drivers/cpufreq/Makefile index d5ee456..789b2e0 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -62,6 +62,7 @@ obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o obj-$(CONFIG_ARM_QCOM_CPUFREQ_KRYO) += qcom-cpufreq-kryo.o +obj-$(CONFIG_ARM_QCOM_CPUFREQ_HW) += qcom-cpufreq-hw.o obj-$(CONFIG_ARM_S3C2410_CPUFREQ) += s3c2410-cpufreq.o obj-$(CONFIG_ARM_S3C2412_CPUFREQ) += s3c2412-cpufreq.o obj-$(CONFIG_ARM_S3C2416_CPUFREQ) += s3c2416-cpufreq.o diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c new file mode 100644 index 0000000..6390e85 --- /dev/null +++ b/drivers/cpufreq/qcom-cpufreq-hw.c @@ -0,0 +1,346 @@ +// 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 LUT_MAX_ENTRIES 40U +#define CORE_COUNT_VAL(val) (((val) & (GENMASK(18, 16))) >> 16) +#define LUT_ROW_SIZE 32 +#define CLK_HW_DIV 2 + +/* Register offsets */ +#define REG_ENABLE 0x0 +#define REG_LUT_TABLE 0x110 +#define REG_PERF_STATE 0x920 + +struct cpufreq_qcom { + struct cpufreq_frequency_table *table; + void __iomem *perf_base;nit: is this really a base address? It's the address of the perf state register, right? Better name it 'perf_state_reg'/'reg_perf_state' or similar (just 'perf_state' might be confusing, I'd expect a variable with this name to hold a state, not an address).
I have updated the name to "perf_state_reg".
+ cpumask_t related_cpus; + unsigned int max_cores; + unsigned long xo_rate; + unsigned long cpu_hw_rate; +}; + +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->perf_base); + + return 0; +} + +static unsigned int qcom_cpufreq_hw_get(unsigned int cpu) +{ + struct cpufreq_qcom *c; + struct cpufreq_policy *policy; + unsigned int index; + + policy = cpufreq_cpu_get_raw(cpu); + if (!policy) + return 0; + + c = policy->driver_data; + + index = readl_relaxed(c->perf_base); + index = min(index, LUT_MAX_ENTRIES - 1); + + return policy->freq_table[index].frequency; +} + +static unsigned int +qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy, + unsigned int target_freq) +{ + struct cpufreq_qcom *c = policy->driver_data; + int index; + + index = policy->cached_resolved_idx; + if (index < 0) + return 0; + + writel_relaxed(index, c->perf_base); + + return policy->freq_table[index].frequency; +} + +static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy) +{ + struct cpufreq_qcom *c; + + c = qcom_freq_domain_map[policy->cpu]; + if (!c) { + pr_err("No scaling support for CPU%d\n", policy->cpu); + return -ENODEV; + } + + cpumask_copy(policy->cpus, &c->related_cpus); + + policy->fast_switch_possible = true; + policy->freq_table = c->table; + policy->driver_data = c; + + return 0; +} + +static struct freq_attr *qcom_cpufreq_hw_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + &cpufreq_freq_attr_scaling_boost_freqs, + NULL +}; + +static struct cpufreq_driver cpufreq_qcom_hw_driver = { + .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK | + CPUFREQ_HAVE_GOVERNOR_PER_POLICY, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = qcom_cpufreq_hw_target_index, + .get = qcom_cpufreq_hw_get, + .init = qcom_cpufreq_hw_cpu_init, + .fast_switch = qcom_cpufreq_hw_fast_switch, + .name = "qcom-cpufreq-hw", + .attr = qcom_cpufreq_hw_attr, + .boost_enabled = true, +}; + +static int qcom_cpufreq_hw_read_lut(struct platform_device *pdev, + struct cpufreq_qcom *c, void __iomem *base) +{ + 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(base + REG_LUT_TABLE + 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 = c->xo_rate * lval / 1000; + else + c->table[i].frequency = c->cpu_hw_rate / 1000; + + cur_freq = c->table[i].frequency; + + dev_dbg(dev, "index=%d freq=%d, core_count %d\n", + i, c->table[i].frequency, core_count); + + if (core_count != c->max_cores) + cur_freq = CPUFREQ_ENTRY_INVALID; + + /* + * Two of the same frequencies with the same core counts means + * end of table. + */ + if (i > 0 && c->table[i - 1].frequency == + c->table[i].frequency && prev_cc == core_count) { + struct cpufreq_frequency_table *prev = &c->table[i - 1]; + + if (prev_freq == CPUFREQ_ENTRY_INVALID) + prev->flags = CPUFREQ_BOOST_FREQ; + break; + } + prev_cc = core_count; + prev_freq = cur_freq; + } + + c->table[i].frequency = CPUFREQ_TABLE_END; + + return 0; +} + +static int qcom_get_related_cpus(int index, struct cpumask *m) +{ + struct device_node *cpu_np; + struct of_phandle_args args; + int cpu, ret; + + for_each_possible_cpu(cpu) { + cpu_np = of_cpu_device_node_get(cpu); + if (!cpu_np) + continue; + + ret = of_parse_phandle_with_args(cpu_np, "qcom,freq-domain", + "#freq-domain-cells", 0, + &args); + of_node_put(cpu_np); + if (ret < 0) + continue; + + if (index == args.args[0]) + cpumask_set_cpu(cpu, m); + } + + return 0; +} + +static int qcom_cpu_resources_init(struct platform_device *pdev, + unsigned int cpu, int index, + unsigned long xo_rate, + unsigned long cpu_hw_rate) +{ + struct cpufreq_qcom *c; + struct resource *res; + struct device *dev = &pdev->dev; + void __iomem *base; + int ret, cpu_r; + + if (qcom_freq_domain_map[cpu]) + return 0; + + c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL); + if (!c) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, index); + base = devm_ioremap_resource(dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + /* HW should be in enabled state to proceed */ + if (!(readl_relaxed(base + REG_ENABLE) & 0x1)) { + dev_err(dev, "Domain-%d cpufreq hardware not enabled\n", index); + return -ENODEV; + } + + ret = qcom_get_related_cpus(index, &c->related_cpus); + if (ret) { + dev_err(dev, "Domain-%d failed to get related CPUs\n", index); + return ret; + } + + c->max_cores = cpumask_weight(&c->related_cpus); + if (!c->max_cores) + return -ENOENT; + + c->xo_rate = xo_rate; + c->cpu_hw_rate = cpu_hw_rate; + c->perf_base = base + REG_PERF_STATE; + + ret = qcom_cpufreq_hw_read_lut(pdev, c, base); + if (ret) { + dev_err(dev, "Domain-%d failed to read LUT\n", index); + return ret; + } + + for_each_cpu(cpu_r, &c->related_cpus) + qcom_freq_domain_map[cpu_r] = c; + + 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, "gcc_cpuss_gpll0_clk_src");As commented on the binding patch, I'm not sure if this is the correct name for this clock input from the POV of this IP block. Just a doubt at this point, I don't have/find the hardware documentation to suggest something better.
The clock name used in the latest series is "alternate".
+ if (IS_ERR(clk)) + return PTR_ERR(clk); + + cpu_hw_rate = clk_get_rate(clk) / CLK_HW_DIV; + + clk_put(clk); + + for_each_possible_cpu(cpu) { + cpu_np = of_cpu_device_node_get(cpu); + if (!cpu_np) { + dev_dbg(&pdev->dev, "Failed to get cpu %d device\n", + cpu); + continue; + } + + ret = of_parse_phandle_with_args(cpu_np, "qcom,freq-domain", + "#freq-domain-cells", 0, + &args); + of_node_put(cpu_np); + if (ret < 0) + return ret; + + ret = qcom_cpu_resources_init(pdev, cpu, args.args[0], + xo_rate, cpu_hw_rate); + if (ret) + return ret; + } + + return 0; +} + +static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev) +{ + int rc; + + /* Get the bases of cpufreq for domains */ + rc = qcom_resources_init(pdev); + if (rc) { + dev_err(&pdev->dev, "CPUFreq resource init failed\n"); + return rc; + } + + rc = cpufreq_register_driver(&cpufreq_qcom_hw_driver); + if (rc) { + dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n"); + return rc; + } + + dev_dbg(&pdev->dev, "QCOM CPUFreq HW driver initialized\n"); + + return 0; +} + +static const struct of_device_id qcom_cpufreq_hw_match[] = { + { .compatible = "qcom,cpufreq-hw" }, + {} +}; + +static struct platform_driver qcom_cpufreq_hw_driver = { + .probe = qcom_cpufreq_hw_driver_probe, + .driver = { + .name = "qcom-cpufreq-hw", + .of_match_table = qcom_cpufreq_hw_match, + }, +}; + +static int __init qcom_cpufreq_hw_init(void) +{ + return platform_driver_register(&qcom_cpufreq_hw_driver); +} +subsys_initcall(qcom_cpufreq_hw_init);I'm still not convinced that a subsys_initcall is needed (instead of module_init or device_initcall), as mentioned in the review of v7 it causes problems when registering CPU cooling devices, but we can also fix this when support for cooling devices is added ;-)
Yes, sure, we could revisit this.
+static void __exit qcom_cpufreq_hw_exit(void) +{ + cpufreq_unregister_driver(&cpufreq_qcom_hw_driver); + platform_driver_unregister(&qcom_cpufreq_hw_driver); +} +module_exit(qcom_cpufreq_hw_exit); + +MODULE_DESCRIPTION("QTI CPUFREQ HW Driver");nit: make it 'QCOM CPUFreq HW driver' for consistency?
Thanks, have taken care in the latest patch.
Cheers Matthias
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