Subject: [PATCH 1/2] ARM64: kernel: make cpu_ops hooks DT agnostic

From: [email-masked] (Hanjun Guo)
Date: Tue, 12 May 2015 21:43:45 +0800

On 2015?05?08? 01:34, Lorenzo Pieralisi wrote:
> ARM64 CPU operations such as cpu_init and cpu_init_idle take
> a struct device_node pointer as a parameter, which corresponds to
> the device tree node of the logical cpu on which the operation
> has to be applied.
>
> With the advent of ACPI on arm64, where MADT static table entries
> are used to initialize cpus, the device tree node parameter
> in cpu_ops hooks become useless when booting with ACPI, since
> in that case cpu device tree nodes are not present and can not be
> used for cpu initialization.
>
> The current cpu_init hook requires a struct device_node pointer
> parameter because it is called while parsing the device tree to
> initialize CPUs, when the cpu_logical_map (that is used to match
> a cpu node reg property to a device tree node) for a given logical
> cpu id is not set up yet. This means that the cpu_init hook cannot
> rely on the of_get_cpu_node function to retrieve the device tree
> node corresponding to the logical cpu id passed in as parameter,
> so the cpu device tree node must be passed in as a parameter to fix
> this catch-22 dependency cycle.
>
> This patch reshuffles the cpu_logical_map initialization code so
> that the cpu_init cpu_ops hook can safely use the of_get_cpu_node
> function to retrieve the cpu device tree node, removing the need for
> the device tree node pointer parameter.
>
> In the process, the patch removes device tree node parameters
> from all cpu_ops hooks, in preparation for SMP DT/ACPI cpus
> initialization consolidation.
>
> Signed-off-by: Lorenzo Pieralisi <[email-masked]>
> Acked-by: Sudeep Holla <[email-masked]>
> Cc: Will Deacon <[email-masked]>
> Cc: Hanjun Guo <[email-masked]>
> Cc: Catalin Marinas <[email-masked]>
> Cc: Mark Rutland <[email-masked]>
> ---

I tested this patch set, and it boot smp OK on
ACPI based system, and this patch set addressed
the comment raised by Sudeep in ARM64 ACPI core patch
set, also address part of cleanup suggestions from
Olof, for both two patches:

Tested-by: Hanjun Guo <[email-masked]>
Acked-by: Hanjun Guo <[email-masked]>

Thanks
Hanjun

>   arch/arm64/include/asm/cpu_ops.h   | 25 ++++++++++++------------
>   arch/arm64/kernel/acpi.c           |  2 +-
>   arch/arm64/kernel/cpu_ops.c        | 23 +++++++++++-----------
>   arch/arm64/kernel/cpuidle.c        |  7 +------
>   arch/arm64/kernel/psci.c           | 11 +++++++----
>   arch/arm64/kernel/smp.c            | 39 +++++++++++++++++++++++++++-----------
>   arch/arm64/kernel/smp_spin_table.c |  8 +++++++-
>   7 files changed, 68 insertions(+), 47 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h
> index 5a31d67..53d4555 100644
> --- a/arch/arm64/include/asm/cpu_ops.h
> +++ b/arch/arm64/include/asm/cpu_ops.h
> @@ -19,15 +19,12 @@
>   #include <linux/init.h>
>   #include <linux/threads.h>
>
> -struct device_node;
> -
>   /**
>    * struct cpu_operations - Callback operations for hotplugging CPUs.
>    *
> - * @name:	Name of the property as appears in a devicetree cpu node's
> - *		enable-method property.
> - * @cpu_init:	Reads any data necessary for a specific enable-method from the
> - *		devicetree, for a given cpu node and proposed logical id.
> + * @name:	Name of the enable-method.
> + * @cpu_init:	Reads any data necessary for a specific enable-method for a
> + *		proposed logical id.
>    * @cpu_prepare: Early one-time preparation step for a cpu. If there is a
>    *		mechanism for doing so, tests whether it is possible to boot
>    *		the given CPU.
> @@ -40,15 +37,15 @@ struct device_node;
>    * @cpu_die:	Makes a cpu leave the kernel. Must not fail. Called from the
>    *		cpu being killed.
>    * @cpu_kill:  Ensures a cpu has left the kernel. Called from another cpu.
> - * @cpu_init_idle: Reads any data necessary to initialize CPU idle states from
> - *		devicetree, for a given cpu node and proposed logical id.
> + * @cpu_init_idle: Reads any data necessary to initialize CPU idle states for
> + *		   a proposed logical id.
>    * @cpu_suspend: Suspends a cpu and saves the required context. May fail owing
>    *               to wrong parameters or error conditions. Called from the
>    *               CPU being suspended. Must be called with IRQs disabled.
>    */
>   struct cpu_operations {
>   	const char	*name;
> -	int		(*cpu_init)(struct device_node *, unsigned int);
> +	int		(*cpu_init)(unsigned int);
>   	int		(*cpu_prepare)(unsigned int);
>   	int		(*cpu_boot)(unsigned int);
>   	void		(*cpu_postboot)(void);
> @@ -58,14 +55,18 @@ struct cpu_operations {
>   	int		(*cpu_kill)(unsigned int cpu);
>   #endif
>   #ifdef CONFIG_CPU_IDLE
> -	int		(*cpu_init_idle)(struct device_node *, unsigned int);
> +	int		(*cpu_init_idle)(unsigned int);
>   	int		(*cpu_suspend)(unsigned long);
>   #endif
>   };
>
>   extern const struct cpu_operations *cpu_ops[NR_CPUS];
> -int __init cpu_read_ops(struct device_node *dn, int cpu);
> -void __init cpu_read_bootcpu_ops(void);
> +int __init cpu_read_ops(int cpu);
>   const struct cpu_operations *cpu_get_ops(const char *name);
>
> +static inline void __init cpu_read_bootcpu_ops(void)
> +{
> +	cpu_read_ops(0);
> +}
> +
>   #endif /* ifndef __ASM_CPU_OPS_H */
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index 8b83955..945cc1f 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -154,7 +154,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
>   		if (!cpu_ops[enabled_cpus])
>   			return;
>
> -		if (cpu_ops[enabled_cpus]->cpu_init(NULL, enabled_cpus))
> +		if (cpu_ops[enabled_cpus]->cpu_init(enabled_cpus))
>   			return;
>
>   		/* map the logical cpu id to cpu MPIDR */
> diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
> index fb8ff9b..bbda2d2 100644
> --- a/arch/arm64/kernel/cpu_ops.c
> +++ b/arch/arm64/kernel/cpu_ops.c
> @@ -52,9 +52,18 @@ const struct cpu_operations * __init cpu_get_ops(const char *name)
>   /*
>    * Read a cpu's enable method from the device tree and record it in cpu_ops.
>    */
> -int __init cpu_read_ops(struct device_node *dn, int cpu)
> +int __init cpu_read_ops(int cpu)
>   {
> -	const char *enable_method = of_get_property(dn, "enable-method", NULL);
> +	const char *enable_method;
> +	struct device_node *dn = of_get_cpu_node(cpu, NULL);
> +
> +	if (!dn) {
> +		if (!cpu)
> +			pr_err("Failed to find device node for boot cpu\n");
> +		return -ENODEV;
> +	}
> +
> +	enable_method = of_get_property(dn, "enable-method", NULL);
>   	if (!enable_method) {
>   		/*
>   		 * The boot CPU may not have an enable method (e.g. when
> @@ -75,13 +84,3 @@ int __init cpu_read_ops(struct device_node *dn, int cpu)
>
>   	return 0;
>   }
> -
> -void __init cpu_read_bootcpu_ops(void)
> -{
> -	struct device_node *dn = of_get_cpu_node(0, NULL);
> -	if (!dn) {
> -		pr_err("Failed to find device node for boot cpu\n");
> -		return;
> -	}
> -	cpu_read_ops(dn, 0);
> -}
> diff --git a/arch/arm64/kernel/cpuidle.c b/arch/arm64/kernel/cpuidle.c
> index a78143a..f8aa169 100644
> --- a/arch/arm64/kernel/cpuidle.c
> +++ b/arch/arm64/kernel/cpuidle.c
> @@ -18,15 +18,10 @@
>   int arm_cpuidle_init(unsigned int cpu)
>   {
>   	int ret = -EOPNOTSUPP;
> -	struct device_node *cpu_node = of_cpu_device_node_get(cpu);
> -
> -	if (!cpu_node)
> -		return -ENODEV;
>
>   	if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_init_idle)
> -		ret = cpu_ops[cpu]->cpu_init_idle(cpu_node, cpu);
> +		ret = cpu_ops[cpu]->cpu_init_idle(cpu);
>
> -	of_node_put(cpu_node);
>   	return ret;
>   }
>
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index ea18cb5..efe3480 100644
> --- a/arch/arm64/kernel/psci.c
> +++ b/arch/arm64/kernel/psci.c
> @@ -186,12 +186,15 @@ static int psci_migrate_info_type(void)
>   	return err;
>   }
>
> -static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node,
> -						 unsigned int cpu)
> +static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
>   {
>   	int i, ret, count = 0;
>   	struct psci_power_state *psci_states;
> -	struct device_node *state_node;
> +	struct device_node *state_node, *cpu_node;
> +
> +	cpu_node = of_get_cpu_node(cpu, NULL);
> +	if (!cpu_node)
> +		return -ENODEV;
>
>   	/*
>   	 * If the PSCI cpu_suspend function hook has not been initialized
> @@ -444,7 +447,7 @@ int __init psci_acpi_init(void)
>
>   #ifdef CONFIG_SMP
>
> -static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
> +static int __init cpu_psci_cpu_init(unsigned int cpu)
>   {
>   	return 0;
>   }
> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> index 2cb0081..98eb68b 100644
> --- a/arch/arm64/kernel/smp.c
> +++ b/arch/arm64/kernel/smp.c
> @@ -319,6 +319,23 @@ void __init smp_prepare_boot_cpu(void)
>   }
>
>   /*
> + * Initialize cpu operations for a logical cpu and
> + * set it in the possible mask on success
> + */
> +static int __init smp_cpu_setup(int cpu)
> +{
> +	if (cpu_read_ops(cpu))
> +		return -ENODEV;
> +
> +	if (cpu_ops[cpu]->cpu_init(cpu))
> +		return -ENODEV;
> +
> +	set_cpu_possible(cpu, true);
> +
> +	return 0;
> +}
> +
> +/*
>    * Enumerate the possible CPU set from the device tree and build the
>    * cpu logical map array containing MPIDR values related to logical
>    * cpus. Assumes that cpu_logical_map(0) has already been initialized.
> @@ -395,12 +412,6 @@ void __init of_smp_init_cpus(void)
>   		if (cpu >= NR_CPUS)
>   			goto next;
>
> -		if (cpu_read_ops(dn, cpu) != 0)
> -			goto next;
> -
> -		if (cpu_ops[cpu]->cpu_init(dn, cpu))
> -			goto next;
> -
>   		pr_debug("cpu logical map 0x%llx\n", hwid);
>   		cpu_logical_map(cpu) = hwid;
>   next:
> @@ -418,12 +429,18 @@ next:
>   	}
>
>   	/*
> -	 * All the cpus that made it to the cpu_logical_map have been
> -	 * validated so set them as possible cpus.
> +	 * We need to set the cpu_logical_map entries before enabling
> +	 * the cpus so that cpu processor description entries (DT cpu nodes
> +	 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
> +	 * with entries in cpu_logical_map while initializing the cpus.
> +	 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
>   	 */
> -	for (i = 0; i < NR_CPUS; i++)
> -		if (cpu_logical_map(i) != INVALID_HWID)
> -			set_cpu_possible(i, true);
> +	for (i = 1; i < NR_CPUS; i++) {
> +		if (cpu_logical_map(i) != INVALID_HWID) {
> +			if (smp_cpu_setup(i))
> +				cpu_logical_map(i) = INVALID_HWID;
> +		}
> +	}
>   }
>
>   void __init smp_prepare_cpus(unsigned int max_cpus)
> diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
> index 14944e5..aef3605 100644
> --- a/arch/arm64/kernel/smp_spin_table.c
> +++ b/arch/arm64/kernel/smp_spin_table.c
> @@ -49,8 +49,14 @@ static void write_pen_release(u64 val)
>   }
>
>
> -static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)
> +static int smp_spin_table_cpu_init(unsigned int cpu)
>   {
> +	struct device_node *dn;
> +
> +	dn = of_get_cpu_node(cpu, NULL);
> +	if (!dn)
> +		return -ENODEV;
> +
>   	/*
>   	 * Determine the address from which the CPU is polling.
>   	 */
>