[V4,2/4] pseries/drc-info: Search DRC properties for CPU indexes

Message ID 0c773d7c-d83e-b76c-41f7-82b8e0883e6d@linux.vnet.ibm.com
State New
Headers show
Series
  • powerpc/devtree: Add support for 'ibm,drc-info' property
Related show

Commit Message

Michael Bringmann Nov. 16, 2017, 8:11 p.m.
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 V4:
  -- Rename of_one_drc_info to of_read_drc_info_cell
  -- Fix some spacing within expressions
  -- Make some style corrections
---
 arch/powerpc/include/asm/prom.h                 |   15 +++
 arch/powerpc/platforms/pseries/of_helpers.c     |   60 ++++++++++
 arch/powerpc/platforms/pseries/pseries_energy.c |  138 ++++++++++++++++++-----
 3 files changed, 185 insertions(+), 28 deletions(-)

Comments

Nathan Fontenot Nov. 20, 2017, 3:35 p.m. | #1
On 11/16/2017 02:11 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 V4:
>   -- Rename of_one_drc_info to of_read_drc_info_cell
>   -- Fix some spacing within expressions
>   -- Make some style corrections
> ---
>  arch/powerpc/include/asm/prom.h                 |   15 +++
>  arch/powerpc/platforms/pseries/of_helpers.c     |   60 ++++++++++
>  arch/powerpc/platforms/pseries/pseries_energy.c |  138 ++++++++++++++++++-----
>  3 files changed, 185 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 2798933..b36f1ae 100644
> --- a/arch/powerpc/platforms/pseries/of_helpers.c
> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
> @@ -2,6 +2,7 @@
>  #include <linux/err.h>
>  #include <linux/slab.h>
>  #include <linux/of.h>
> +#include <asm/prom.h>
> 
>  #include "of_helpers.h"
> 
> @@ -36,3 +37,62 @@ 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..b8f6603 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 +39,64 @@
>  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 = info->value;
> +		value = (void *)of_prop_next_u32(info, value,
> +						&num_set_entries);

Missed this the first time, but setting value twice seems a bit odd.
This should be able to be collapsed into;

		value = (void *)of_prop_next_u32(info, NULL, &num_set_entries);

> +		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;
> +
> +			WARN_ON(((thread_index - drc.drc_index_start) %
> +					drc.sequential_inc) != 0);

The WARN_ON that you have here, and in the code below, really fell like they
should be in of_read_drc_info_cell. These are checks on reading the info in
the drc-info property.

> +		}
> +
> +		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.
> +		 */
> +		WARN_ON(thread_index > indexes[0]);
> +		ret = indexes[thread_index + 1];
> +	}
> +
>  	rc = 0;
> 
>  err_of_node_put:
> @@ -72,34 +111,77 @@ 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 = info->value;
> +		value = (void *)of_prop_next_u32(info, value,
> +						&num_set_entries);

Same here as mentioned above.

-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;
> +
> +			WARN_ON(drc_index < drc.drc_index_start);
> +			WARN_ON(((drc_index - drc.drc_index_start) %
> +					drc.sequential_inc) != 0);
> +
> +			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;
>  }
> 
>  /*
>
Michael Bringmann Nov. 27, 2017, 7 p.m. | #2
See below.

On 11/20/2017 09:35 AM, Nathan Fontenot wrote:
> On 11/16/2017 02:11 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 V4:
>>   -- Rename of_one_drc_info to of_read_drc_info_cell
>>   -- Fix some spacing within expressions
>>   -- Make some style corrections
>> ---
>>  arch/powerpc/include/asm/prom.h                 |   15 +++
>>  arch/powerpc/platforms/pseries/of_helpers.c     |   60 ++++++++++
>>  arch/powerpc/platforms/pseries/pseries_energy.c |  138 ++++++++++++++++++-----
>>  3 files changed, 185 insertions(+), 28 deletions(-)
>>

...

>> +
>> +		value = info->value;
>> +		value = (void *)of_prop_next_u32(info, value,
>> +						&num_set_entries);
> 
> Missed this the first time, but setting value twice seems a bit odd.
> This should be able to be collapsed into;
> 
> 		value = (void *)of_prop_next_u32(info, NULL, &num_set_entries);

Okay
> 
>> +		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;
>> +
>> +			WARN_ON(((thread_index - drc.drc_index_start) %
>> +					drc.sequential_inc) != 0);
> 
> The WARN_ON that you have here, and in the code below, really fell like they
> should be in of_read_drc_info_cell. These are checks on reading the info in
> the drc-info property.

Remove unnecessary WARN_ON() checks.

> 
>> +		}
>> +
>> +		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.
>> +		 */
>> +		WARN_ON(thread_index > indexes[0]);
>> +		ret = indexes[thread_index + 1];
>> +	}
>> +
>>  	rc = 0;
>>
>>  err_of_node_put:
>> @@ -72,34 +111,77 @@ 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 = info->value;
>> +		value = (void *)of_prop_next_u32(info, value,
>> +						&num_set_entries);

Okay.

> 
> Same here as mentioned above.
> 
> -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;
>> +
>> +			WARN_ON(drc_index < drc.drc_index_start);
>> +			WARN_ON(((drc_index - drc.drc_index_start) %
>> +					drc.sequential_inc) != 0);
>> +
>> +			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;
>>  }
>>
>>  /*
>>
> 
>

Patch

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 2798933..b36f1ae 100644
--- a/arch/powerpc/platforms/pseries/of_helpers.c
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -2,6 +2,7 @@ 
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <asm/prom.h>
 
 #include "of_helpers.h"
 
@@ -36,3 +37,62 @@  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..b8f6603 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 +39,64 @@ 
 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 = info->value;
+		value = (void *)of_prop_next_u32(info, value,
+						&num_set_entries);
+		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;
+
+			WARN_ON(((thread_index - drc.drc_index_start) %
+					drc.sequential_inc) != 0);
+		}
+
+		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.
+		 */
+		WARN_ON(thread_index > indexes[0]);
+		ret = indexes[thread_index + 1];
+	}
+
 	rc = 0;
 
 err_of_node_put:
@@ -72,34 +111,77 @@  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 = info->value;
+		value = (void *)of_prop_next_u32(info, value,
+						&num_set_entries);
+		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;
+
+			WARN_ON(drc_index < drc.drc_index_start);
+			WARN_ON(((drc_index - drc.drc_index_start) %
+					drc.sequential_inc) != 0);
+
+			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;
 }
 
 /*