Re: Resend: [PATCH V5 2/4] pseries/drc-info: Search DRC properties for CPU indexes

[Nathan Fontenot <nfont@linux.vnet.ibm.com>]

On 11/28/2017 05:07 PM, Michael Bringmann wrote:
> pseries/drc-info: Provide parallel routines to convert between
> drc_index and CPU numbers at runtime, using the older device-tree
> properties ("ibm,drc-indexes", "ibm,drc-names", "ibm,drc-types"
> and "ibm,drc-power-domains"), or the new property "ibm,drc-info".
> 
> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> ---
> Changes in V5:
>   -- Simplify of_prop_next_u32 invocation
>   -- Remove unnecessary WARN_ON() tests

I'm not sure the WARN_ON()'s that you removed are unnecessary, I had just asked
that they get moved to read_drc_info_cell(). If you think they are not needed
perhaps making them pr_debug() instead.
 
> ---
>  arch/powerpc/include/asm/prom.h                 |   15 +++
>  arch/powerpc/platforms/pseries/of_helpers.c     |   60 +++++++++++
>  arch/powerpc/platforms/pseries/pseries_energy.c |  126 ++++++++++++++++++-----
>  3 files changed, 173 insertions(+), 28 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
> index 3243455..0ef41b1 100644
> --- a/arch/powerpc/include/asm/prom.h
> +++ b/arch/powerpc/include/asm/prom.h
> @@ -96,6 +96,21 @@ struct of_drconf_cell {
>  #define DRCONF_MEM_AI_INVALID	0x00000040
>  #define DRCONF_MEM_RESERVED	0x00000080
> 
> +struct of_drc_info {
> +	char *drc_type;
> +	char *drc_name_prefix;
> +	u32 drc_index_start;
> +	u32 drc_name_suffix_start;
> +	u32 num_sequential_elems;
> +	u32 sequential_inc;
> +	u32 drc_power_domain;
> +	u32 last_drc_index;
> +};
> +
> +extern int of_read_drc_info_cell(struct property **prop,
> +			const __be32 **curval, struct of_drc_info *data);
> +
> +
>  /*
>   * There are two methods for telling firmware what our capabilities are.
>   * Newer machines have an "ibm,client-architecture-support" method on the
> diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
> index 7e75101..6df192f 100644
> --- a/arch/powerpc/platforms/pseries/of_helpers.c
> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
> @@ -3,6 +3,7 @@
>  #include <linux/err.h>
>  #include <linux/slab.h>
>  #include <linux/of.h>
> +#include <asm/prom.h>
> 
>  #include "of_helpers.h"
> 
> @@ -37,3 +38,62 @@ struct device_node *pseries_of_derive_parent(const char *path)
>  		kfree(parent_path);
>  	return parent ? parent : ERR_PTR(-EINVAL);
>  }
> +
> +
> +/* Helper Routines to convert between drc_index to cpu numbers */
> +
> +int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
> +			struct of_drc_info *data)
> +{
> +	const char *p;
> +	const __be32 *p2;
> +
> +	if (!data)
> +		return -EINVAL;
> +
> +	/* Get drc-type:encode-string */
> +	p = data->drc_type = (char*) (*curval);
> +	p = of_prop_next_string(*prop, p);
> +	if (!p)
> +		return -EINVAL;
> +
> +	/* Get drc-name-prefix:encode-string */
> +	data->drc_name_prefix = (char *)p;
> +	p = of_prop_next_string(*prop, p);
> +	if (!p)
> +		return -EINVAL;
> +
> +	/* Get drc-index-start:encode-int */
> +	p2 = (const __be32 *)p;
> +	p2 = of_prop_next_u32(*prop, p2, &data->drc_index_start);
> +	if (!p2)
> +		return -EINVAL;
> +
> +	/* Get drc-name-suffix-start:encode-int */
> +	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
> +	if (!p2)
> +		return -EINVAL;
> +
> +	/* Get number-sequential-elements:encode-int */
> +	p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
> +	if (!p2)
> +		return -EINVAL;
> +
> +	/* Get sequential-increment:encode-int */
> +	p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
> +	if (!p2)
> +		return -EINVAL;
> +
> +	/* Get drc-power-domain:encode-int */
> +	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
> +	if (!p2)
> +		return -EINVAL;
> +
> +	/* Should now know end of current entry */
> +	(*curval) = (void *)p2;
> +	data->last_drc_index = data->drc_index_start +
> +		((data->num_sequential_elems - 1) * data->sequential_inc);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(of_read_drc_info_cell);
> diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
> index 35c891a..f96677b 100644
> --- a/arch/powerpc/platforms/pseries/pseries_energy.c
> +++ b/arch/powerpc/platforms/pseries/pseries_energy.c
> @@ -22,6 +22,7 @@
>  #include <asm/page.h>
>  #include <asm/hvcall.h>
>  #include <asm/firmware.h>
> +#include <asm/prom.h>
> 
> 
>  #define MODULE_VERS "1.0"
> @@ -38,26 +39,58 @@
>  static u32 cpu_to_drc_index(int cpu)
>  {
>  	struct device_node *dn = NULL;
> -	const int *indexes;
> -	int i;
> +	int thread_index;
>  	int rc = 1;
>  	u32 ret = 0;
> 
>  	dn = of_find_node_by_path("/cpus");
>  	if (dn == NULL)
>  		goto err;
> -	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
> -	if (indexes == NULL)
> -		goto err_of_node_put;
> +
>  	/* Convert logical cpu number to core number */
> -	i = cpu_core_index_of_thread(cpu);
> -	/*
> -	 * The first element indexes[0] is the number of drc_indexes
> -	 * returned in the list.  Hence i+1 will get the drc_index
> -	 * corresponding to core number i.
> -	 */
> -	WARN_ON(i > indexes[0]);
> -	ret = indexes[i + 1];
> +	thread_index = cpu_core_index_of_thread(cpu);
> +
> +	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
> +		struct property *info = NULL;
> +		struct of_drc_info drc;
> +		int j;
> +		u32 num_set_entries;
> +		const __be32 *value;
> +
> +		info = of_find_property(dn, "ibm,drc-info", NULL);
> +		if (info == NULL)
> +			goto err_of_node_put;
> +
> +		value = (void *)of_prop_next_u32(info, NULL, &num_set_entries);

Shouldn't need to cast the return value to void *.

> +		if (!value)
> +			goto err_of_node_put;
> +
> +		for (j = 0; j < num_set_entries; j++) {
> +
> +			of_read_drc_info_cell(&info, &value, &drc);
> +			if (strncmp(drc.drc_type, "CPU", 3))
> +				goto err;
> +
> +			if (thread_index < drc.last_drc_index)
> +				break;
> +		}
> +
> +		ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
> +	} else {
> +		const __be32 *indexes;
> +
> +		indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
> +		if (indexes == NULL)
> +			goto err_of_node_put;
> +
> +		/*
> +		 * The first element indexes[0] is the number of drc_indexes
> +		 * returned in the list.  Hence thread_index+1 will get the
> +		 * drc_index corresponding to core number thread_index.
> +		 */
> +		ret = indexes[thread_index + 1];
> +	}
> +
>  	rc = 0;
> 
>  err_of_node_put:
> @@ -72,34 +105,71 @@ static int drc_index_to_cpu(u32 drc_index)
>  {
>  	struct device_node *dn = NULL;
>  	const int *indexes;
> -	int i, cpu = 0;
> +	int thread_index = 0, cpu = 0;
>  	int rc = 1;
> 
>  	dn = of_find_node_by_path("/cpus");
>  	if (dn == NULL)
>  		goto err;
> -	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
> -	if (indexes == NULL)
> -		goto err_of_node_put;
> -	/*
> -	 * First element in the array is the number of drc_indexes
> -	 * returned.  Search through the list to find the matching
> -	 * drc_index and get the core number
> -	 */
> -	for (i = 0; i < indexes[0]; i++) {
> -		if (indexes[i + 1] == drc_index)
> +
> +	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
> +		struct property *info = NULL;
> +		struct of_drc_info drc;
> +		int j;
> +		u32 num_set_entries;
> +		const __be32 *value;
> +
> +		info = of_find_property(dn, "ibm,drc-info", NULL);
> +		if (info == NULL)
> +			goto err_of_node_put;
> +
> +		value = (void *)of_prop_next_u32(info, NULL, &num_set_entries);

Same here.

-Nathan

> +		if (!value)
> +			goto err_of_node_put;
> +
> +		for (j = 0; j < num_set_entries; j++) {
> +
> +			of_read_drc_info_cell(&info, &value, &drc);
> +			if (strncmp(drc.drc_type, "CPU", 3))
> +				goto err;
> +
> +			if (drc_index > drc.last_drc_index) {
> +				cpu += drc.num_sequential_elems;
> +				continue;
> +			}
> +			cpu += ((drc_index - drc.drc_index_start) /
> +				drc.sequential_inc);
> +
> +			thread_index = cpu_first_thread_of_core(cpu);
> +			rc = 0;
>  			break;
> +		}
> +	} else {
> +		unsigned long int i;
> +
> +		indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
> +		if (indexes == NULL)
> +			goto err_of_node_put;
> +		/*
> +		 * First element in the array is the number of drc_indexes
> +		 * returned.  Search through the list to find the matching
> +		 * drc_index and get the core number
> +		 */
> +		for (i = 0; i < indexes[0]; i++) {
> +			if (indexes[i + 1] == drc_index)
> +				break;
> +		}
> +		/* Convert core number to logical cpu number */
> +		thread_index = cpu_first_thread_of_core(i);
> +		rc = 0;
>  	}
> -	/* Convert core number to logical cpu number */
> -	cpu = cpu_first_thread_of_core(i);
> -	rc = 0;
> 
>  err_of_node_put:
>  	of_node_put(dn);
>  err:
>  	if (rc)
>  		printk(KERN_WARNING "drc_index_to_cpu(%d) failed", drc_index);
> -	return cpu;
> +	return thread_index;
>  }
> 
>  /*
>