From: Yuantian Tang <Yuantian.Tang@freescale.com>
To: Kumar Gala <galak@kernel.crashing.org>
CC: "rjw@rjwysocki.net" <rjw@rjwysocki.net>,
        "viresh.kumar@linaro.org" <viresh.kumar@linaro.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>
Subject: RE: [PATCH] cpufreq: qoriq: Make the driver usable on all QorIQ
 platforms
Thread-Topic: [PATCH] cpufreq: qoriq: Make the driver usable on all QorIQ
 platforms
Thread-Index: AQHP6bh2NIuvlhOTzUyj6ABxjLiyN5wz7kgAgAAOlgA=
Date: Mon, 20 Oct 2014 02:20:12 +0000
Message-ID: <8b12e15ad9634583b6985aea5e5fa077@DM2PR03MB574.namprd03.prod.outlook.com>
References: <1413515616-15874-1-git-send-email-B29983@freescale.com>
 <8F5E4DA7-8A64-4614-91E7-BFB28D91C737@kernel.crashing.org>
In-Reply-To: <8F5E4DA7-8A64-4614-91E7-BFB28D91C737@kernel.crashing.org>
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Thanks for your comments.  Will address them in next version.
Also some explanations inline for your comments.

Thanks,
Yuantian

> -----Original Message-----
> From: Kumar Gala [mailto:galak@kernel.crashing.org]
> Sent: Friday, October 17, 2014 4:04 PM
> To: Tang Yuantian-B29983
> Cc: rjw@rjwysocki.net; viresh.kumar@linaro.org; linux-kernel@vger.kernel.org;
> linux-pm@vger.kernel.org; linuxppc-dev@ozlabs.org; Tang Yuantian-B29983
> Subject: Re: [PATCH] cpufreq: qoriq: Make the driver usable on all QorIQ
> platforms
> 
> 
> On Oct 17, 2014, at 5:13 AM, b29983@freescale.com wrote:
> 
> > From: Tang Yuantian <Yuantian.Tang@freescale.com>
> >
> > Freescale introduced new ARM core-based SoCs which support dynamic
> > frequency switch feature. DFS on new SoCs are compatible with current
> > PowerPC CoreNet platforms. In order to support those new platforms,
> > this driver needs to be slightly adjusted. The main changes include:
> >
> > 1. Changed the names of driver and functions in driver.
> 
> split the name changes/renaming into a separate patch from the other changes.
> 
> > 2. Added two new functions get_cpu_physical_id() and get_bus_freq().
> > 3. Used a new way to get all the CPUs which sharing clock wire.
> >
> > Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
> > ---
> > drivers/cpufreq/Kconfig.arm                        |   8 ++
> > drivers/cpufreq/Kconfig.powerpc                    |  11 +-
> > drivers/cpufreq/Makefile                           |   2 +-
> > .../{ppc-corenet-cpufreq.c => qoriq-cpufreq.c}     | 150 ++++++++++++++-------
> > 4 files changed, 114 insertions(+), 57 deletions(-) rename
> > drivers/cpufreq/{ppc-corenet-cpufreq.c => qoriq-cpufreq.c} (72%)
> >
> > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> > index 83a75dc..1925ae94 100644
> > --- a/drivers/cpufreq/Kconfig.arm
> > +++ b/drivers/cpufreq/Kconfig.arm
> > @@ -247,3 +247,11 @@ config ARM_TEGRA_CPUFREQ
> > 	default y
> > 	help
> > 	  This adds the CPUFreq driver support for TEGRA SOCs.
> > +
> > +config QORIQ_CPUFREQ
> > +	tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
> > +	depends on OF && COMMON_CLK
> > +	select CLK_PPC_CORENET
> 
> Why are you not also renaming 'CLK_PPC_CORENET' to 'CLK_QORIQ' or
> something like that?  Seems rather odd to select a PPC CLK support on ARM ;)
> 
Yes, someone else is working on that.

> > +	help
> > +	  This adds the CPUFreq driver support for Freescale QorIQ SoCs
> > +	  which are capable of changing the CPU's frequency dynamically.
> > diff --git a/drivers/cpufreq/Kconfig.powerpc
> > b/drivers/cpufreq/Kconfig.powerpc index 72564b7..3a34248 100644
> > --- a/drivers/cpufreq/Kconfig.powerpc
> > +++ b/drivers/cpufreq/Kconfig.powerpc
> > @@ -23,14 +23,13 @@ config CPU_FREQ_MAPLE
> > 	  This adds support for frequency switching on Maple 970FX
> > 	  Evaluation Board and compatible boards (IBM JS2x blades).
> >
> > -config PPC_CORENET_CPUFREQ
> > -	tristate "CPU frequency scaling driver for Freescale E500MC SoCs"
> > -	depends on PPC_E500MC && OF && COMMON_CLK
> > +config QORIQ_CPUFREQ
> > +	tristate "CPU frequency scaling driver for Freescale QorIQ SoCs"
> > +	depends on OF && COMMON_CLK
> > 	select CLK_PPC_CORENET
> > 	help
> > -	  This adds the CPUFreq driver support for Freescale e500mc,
> > -	  e5500 and e6500 series SoCs which are capable of changing
> > -	  the CPU's frequency dynamically.
> > +	  This adds the CPUFreq driver support for Freescale QorIQ SoCs
> > +	  which are capable of changing the CPU's frequency dynamically.
> >
> > config CPU_FREQ_PMAC
> > 	bool "Support for Apple PowerBooks"
> > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index
> > 40c53dc..0020049 100644
> > --- a/drivers/cpufreq/Makefile
> > +++ b/drivers/cpufreq/Makefile
> > @@ -84,7 +84,7 @@ obj-$(CONFIG_CPU_FREQ_CBE)		+=
> ppc-cbe-cpufreq.o
> > ppc-cbe-cpufreq-y			+= ppc_cbe_cpufreq_pervasive.o
> ppc_cbe_cpufreq.o
> > obj-$(CONFIG_CPU_FREQ_CBE_PMI)		+= ppc_cbe_cpufreq_pmi.o
> > obj-$(CONFIG_CPU_FREQ_MAPLE)		+= maple-cpufreq.o
> > -obj-$(CONFIG_PPC_CORENET_CPUFREQ)   += ppc-corenet-cpufreq.o
> > +obj-$(CONFIG_QORIQ_CPUFREQ)   		+= qoriq-cpufreq.o
> > obj-$(CONFIG_CPU_FREQ_PMAC)		+= pmac32-cpufreq.o
> > obj-$(CONFIG_CPU_FREQ_PMAC64)		+= pmac64-cpufreq.o
> > obj-$(CONFIG_PPC_PASEMI_CPUFREQ)	+= pasemi-cpufreq.o
> > diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c
> > b/drivers/cpufreq/qoriq-cpufreq.c similarity index 72% rename from
> > drivers/cpufreq/ppc-corenet-cpufreq.c
> > rename to drivers/cpufreq/qoriq-cpufreq.c index bee5df7..80def0c
> > 100644
> > --- a/drivers/cpufreq/ppc-corenet-cpufreq.c
> > +++ b/drivers/cpufreq/qoriq-cpufreq.c
> > @@ -1,7 +1,7 @@
> > /*
> >  * Copyright 2013 Freescale Semiconductor, Inc.
> >  *
> > - * CPU Frequency Scaling driver for Freescale PowerPC corenet SoCs.
> > + * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
> >  *
> >  * This program is free software; you can redistribute it and/or
> > modify
> >  * it under the terms of the GNU General Public License version 2 as
> > @@ -20,7 +20,6 @@ #include <linux/of.h> #include <linux/slab.h>
> > #include <linux/smp.h> -#include <sysdev/fsl_soc.h>
> >
> > /**
> >  * struct cpu_data - per CPU data struct @@ -69,9 +68,6 @@ static
> > const u32 *fmask;
> >
> > static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
> >
> > -/* cpumask in a cluster */
> > -static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
> > -
> > #ifndef CONFIG_SMP
> > static inline const struct cpumask *cpu_core_mask(int cpu) { @@ -79,6
> > +75,79 @@ static inline const struct cpumask *cpu_core_mask(int cpu) }
> > #endif
> >
> > +#if defined(CONFIG_PPC_E500MC)
> 
> Probably should just be CONFIG_PPC, but do we need this at all.  Can't we just
> use topology_core_id() on both ARM & PPC?
> 
I will investigate if topology_core_id() works for PPC.

Regards,
Yuantian

> > +static int get_cpu_physical_id(int cpu) {
> > +	return get_hard_smp_processor_id(cpu); } #elif defined(CONFIG_ARM)
> > +static int get_cpu_physical_id(int cpu) {
> > +	return topology_core_id(cpu);
> > +}
> > +#endif
> > +
> > +static u32 get_bus_freq(void)
> > +{
> > +	struct device_node *soc;
> > +	u32 sysfreq;
> > +
> > +	soc = of_find_node_by_type(NULL, "soc");
> > +	if (!soc)
> > +		return 0;
> > +
> > +	if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
> > +		sysfreq = 0;
> > +
> > +	of_node_put(soc);
> > +
> > +	return sysfreq;
> > +}
> > +
> > +static struct device_node *cpu_to_clk_node(int cpu) {
> > +	struct device_node *np, *clk_np;
> > +
> > +	if (!cpu_present(cpu))
> > +		return NULL;
> > +
> > +	np = of_get_cpu_node(cpu, NULL);
> > +	if (!np)
> > +		return NULL;
> > +
> > +	clk_np = of_parse_phandle(np, "clocks", 0);
> > +	if (!clk_np)
> > +		return NULL;
> > +
> > +	of_node_put(np);
> > +
> > +	return clk_np;
> > +}
> > +
> > +/* traverse cpu nodes to get cpu mask of sharing clock wire */ static
> > +void set_affected_cpus(struct cpufreq_policy *policy) {
> > +	struct device_node *np, *clk_np;
> > +	struct cpumask *dstp = policy->cpus;
> > +	int i;
> > +
> > +	np = cpu_to_clk_node(policy->cpu);
> > +	if (!np)
> > +		return;
> > +
> > +	for_each_present_cpu(i) {
> > +		clk_np = cpu_to_clk_node(i);
> > +		if (!clk_np)
> > +			continue;
> > +
> > +		if (clk_np == np)
> > +			cpumask_set_cpu(i, dstp);
> > +
> > +		of_node_put(clk_np);
> > +	}
> > +	of_node_put(np);
> > +}
> > +
> > /* reduce the duplicated frequencies in frequency table */ static void
> > freq_table_redup(struct cpufreq_frequency_table *freq_table,
> > 		int count)
> > @@ -105,6 +174,7 @@ static void freq_table_sort(struct
> cpufreq_frequency_table *freq_table,
> > 	int i, j, ind;
> > 	unsigned int freq, max_freq;
> > 	struct cpufreq_frequency_table table;
> > +
> > 	for (i = 0; i < count - 1; i++) {
> > 		max_freq = freq_table[i].frequency;
> > 		ind = i;
> > @@ -129,7 +199,7 @@ static void freq_table_sort(struct
> cpufreq_frequency_table *freq_table,
> > 	}
> > }
> >
> > -static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
> > +static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
> > {
> > 	struct device_node *np;
> > 	int i, count, ret;
> > @@ -145,10 +215,8 @@ static int corenet_cpufreq_cpu_init(struct
> cpufreq_policy *policy)
> > 		return -ENODEV;
> >
> > 	data = kzalloc(sizeof(*data), GFP_KERNEL);
> > -	if (!data) {
> > -		pr_err("%s: no memory\n", __func__);
> > +	if (!data)
> > 		goto err_np;
> > -	}
> >
> > 	policy->clk = of_clk_get(np, 0);
> > 	if (IS_ERR(policy->clk)) {
> > @@ -170,7 +238,7 @@ static int corenet_cpufreq_cpu_init(struct
> cpufreq_policy *policy)
> > 	}
> >
> > 	if (fmask)
> > -		mask = fmask[get_hard_smp_processor_id(cpu)];
> > +		mask = fmask[get_cpu_physical_id(cpu)];
> > 	else
> > 		mask = 0x0;
> >
> > @@ -201,13 +269,13 @@ static int corenet_cpufreq_cpu_init(struct
> cpufreq_policy *policy)
> > 	data->table = table;
> >
> > 	/* update ->cpus if we have cluster, no harm if not */
> > -	cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
> > -	for_each_cpu(i, per_cpu(cpu_mask, cpu))
> > +	set_affected_cpus(policy);
> > +	for_each_cpu(i, policy->cpus)
> > 		per_cpu(cpu_data, i) = data;
> >
> > 	/* Minimum transition latency is 12 platform clocks */
> > 	u64temp = 12ULL * NSEC_PER_SEC;
> > -	do_div(u64temp, fsl_get_sys_freq());
> > +	do_div(u64temp, get_bus_freq());
> > 	policy->cpuinfo.transition_latency = u64temp + 1;
> >
> > 	of_node_put(np);
> > @@ -227,7 +295,7 @@ err_np:
> > 	return -ENODEV;
> > }
> >
> > -static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy
> > *policy)
> > +static int __exit qoriq_cpufreq_cpu_exit(struct cpufreq_policy
> > +*policy)
> > {
> > 	struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
> > 	unsigned int cpu;
> > @@ -236,13 +304,13 @@ static int __exit corenet_cpufreq_cpu_exit(struct
> cpufreq_policy *policy)
> > 	kfree(data->table);
> > 	kfree(data);
> >
> > -	for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
> > +	for_each_cpu(cpu, policy->cpus)
> > 		per_cpu(cpu_data, cpu) = NULL;
> >
> > 	return 0;
> > }
> >
> > -static int corenet_cpufreq_target(struct cpufreq_policy *policy,
> > +static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
> > 		unsigned int index)
> > {
> > 	struct clk *parent;
> > @@ -252,18 +320,18 @@ static int corenet_cpufreq_target(struct
> cpufreq_policy *policy,
> > 	return clk_set_parent(policy->clk, parent); }
> >
> > -static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
> > -	.name		= "ppc_cpufreq",
> > +static struct cpufreq_driver qoriq_cpufreq_driver = {
> > +	.name		= "qoriq_cpufreq",
> > 	.flags		= CPUFREQ_CONST_LOOPS,
> > -	.init		= corenet_cpufreq_cpu_init,
> > -	.exit		= __exit_p(corenet_cpufreq_cpu_exit),
> > +	.init		= qoriq_cpufreq_cpu_init,
> > +	.exit		= __exit_p(qoriq_cpufreq_cpu_exit),
> > 	.verify		= cpufreq_generic_frequency_table_verify,
> > -	.target_index	= corenet_cpufreq_target,
> > +	.target_index	= qoriq_cpufreq_target,
> > 	.get		= cpufreq_generic_get,
> > 	.attr		= cpufreq_generic_attr,
> > };
> >
> > -static const struct of_device_id node_matches[] __initdata = {
> > +static const struct of_device_id node_matches[] __initconst = {
> > 	{ .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
> > 	{ .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
> > 	{ .compatible = "fsl,p5020-clockgen", .data = &sdata[1], }, @@
> > -273,61 +341,43 @@ static const struct of_device_id node_matches[]
> __initdata = {
> > 	{}
> > };
> >
> > -static int __init ppc_corenet_cpufreq_init(void)
> > +static int __init qoriq_cpufreq_init(void)
> > {
> > 	int ret;
> > 	struct device_node  *np;
> > 	const struct of_device_id *match;
> > 	const struct soc_data *data;
> > -	unsigned int cpu;
> >
> > 	np = of_find_matching_node(NULL, node_matches);
> > 	if (!np)
> > 		return -ENODEV;
> >
> > -	for_each_possible_cpu(cpu) {
> > -		if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
> > -			goto err_mask;
> > -		cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
> > -	}
> > -
> > 	match = of_match_node(node_matches, np);
> > 	data = match->data;
> > 	if (data) {
> > 		if (data->flag)
> > 			fmask = data->freq_mask;
> > -		min_cpufreq = fsl_get_sys_freq();
> > +		min_cpufreq = get_bus_freq();
> > 	} else {
> > -		min_cpufreq = fsl_get_sys_freq() / 2;
> > +		min_cpufreq = get_bus_freq() / 2;
> > 	}
> >
> > 	of_node_put(np);
> >
> > -	ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
> > +	ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
> > 	if (!ret)
> > -		pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
> > +		pr_info("Freescale QorIQ CPU frequency scaling driver\n");
> >
> > 	return ret;
> > -
> > -err_mask:
> > -	for_each_possible_cpu(cpu)
> > -		free_cpumask_var(per_cpu(cpu_mask, cpu));
> > -
> > -	return -ENOMEM;
> > }
> > -module_init(ppc_corenet_cpufreq_init);
> > +module_init(qoriq_cpufreq_init);
> >
> > -static void __exit ppc_corenet_cpufreq_exit(void)
> > +static void __exit qoriq_cpufreq_exit(void)
> > {
> > -	unsigned int cpu;
> > -
> > -	for_each_possible_cpu(cpu)
> > -		free_cpumask_var(per_cpu(cpu_mask, cpu));
> > -
> > -	cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
> > +	cpufreq_unregister_driver(&qoriq_cpufreq_driver);
> > }
> > -module_exit(ppc_corenet_cpufreq_exit);
> > +module_exit(qoriq_cpufreq_exit);
> >
> > MODULE_LICENSE("GPL");
> > MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
> > -MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series
> > SoCs");
> > +MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");
> > --
> > 2.1.0.27.g96db324
> >
> > --
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