[RFC v3 0/4] powerpc/drcinfo: Fix bugs 'ibm,drc-info' property

[RFC v3 0/4] powerpc/drcinfo: Fix bugs 'ibm,drc-info' property

[Michael Bringmann]

This patch set corrects some errors and omissions in the previous
set of patches adding support for the "ibm,drc-info" property to
powerpc systems.

Unfortunately, some errors in the previous patch set break things
in some of the DLPAR operations.  In particular when attempting to
hot-add a new CPU or set of CPUs, the original patch failed to
properly calculate the available resources, and aborted the operation.
In addition, the original set missed several opportunities to compress
and reuse common code, especially, in the area of device processing.

Signed-off-by: Michael W. Bringmann <mwb@linux.vnet.ibm.com>
---
Changes in V3:
  -- Update code for latest kernel checkins.
  -- Fix bug with virtual devices.
  -- Rebase on top of 4.17-rc5 kernel

[RFC v3 1/4] powerpc/hotplug/drcinfo: Fix bugs parsing ibm,drc-info structs

[Michael Bringmann]

[Replace/withdraw previous patch submission to ensure that testing
of related patches on similar hardware progresses together.]

This patch fixes a memory parsing bug when using of_prop_next_u32
calls at the start of a structure.  Depending upon the value of
"cur" memory pointer argument to of_prop_next_u32, it will or it
won't advance the value of the returned memory pointer by the
size of one u32.  This patch corrects the code to deal with that
indexing feature when parsing the ibm,drc-info structs for CPUs.
Also, need to advance the pointer at the end of_read_drc_info_cell
for same reason.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmware feature" -- end of patch series applied to powerpc next)
---
Changes in V3:
  -- Rebased patch to 4.17-rc5 kernel
---
 arch/powerpc/platforms/pseries/of_helpers.c     |    5 ++---
 arch/powerpc/platforms/pseries/pseries_energy.c |    2 ++
 drivers/pci/hotplug/rpaphp_core.c               |    1 +
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
index 6df192f..20598b2 100644
--- a/arch/powerpc/platforms/pseries/of_helpers.c
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -65,9 +65,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
 
 	/* 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;
+	data->drc_index_start = of_read_number(p2, 1);
 
 	/* Get drc-name-suffix-start:encode-int */
 	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
@@ -88,6 +86,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
 	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
 	if (!p2)
 		return -EINVAL;
+	p2++;
 
 	/* Should now know end of current entry */
 	(*curval) = (void *)p2;
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
index 6ed2212..c7d84aa 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -64,6 +64,7 @@ static u32 cpu_to_drc_index(int cpu)
 		value = of_prop_next_u32(info, NULL, &num_set_entries);
 		if (!value)
 			goto err_of_node_put;
+		value++;
 
 		for (j = 0; j < num_set_entries; j++) {
 
@@ -126,6 +127,7 @@ static int drc_index_to_cpu(u32 drc_index)
 		value = of_prop_next_u32(info, NULL, &num_set_entries);
 		if (!value)
 			goto err_of_node_put;
+		value++;
 
 		for (j = 0; j < num_set_entries; j++) {
 
diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
index fb5e084..dccdf62 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -239,6 +239,7 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
 	value = of_prop_next_u32(info, NULL, &entries);
 	if (!value)
 		return -EINVAL;
+	value++;
 
 	for (j = 0; j < entries; j++) {
 		of_read_drc_info_cell(&info, &value, &drc);

Re: [RFC v3 1/4] powerpc/hotplug/drcinfo: Fix bugs parsing ibm,drc-info structs

[Nathan Fontenot]

On 05/17/2018 05:41 PM, Michael Bringmann wrote:
> [Replace/withdraw previous patch submission to ensure that testing
> of related patches on similar hardware progresses together.]
> 
> This patch fixes a memory parsing bug when using of_prop_next_u32
> calls at the start of a structure.  Depending upon the value of
> "cur" memory pointer argument to of_prop_next_u32, it will or it
> won't advance the value of the returned memory pointer by the
> size of one u32.  This patch corrects the code to deal with that
> indexing feature when parsing the ibm,drc-info structs for CPUs.
> Also, need to advance the pointer at the end of_read_drc_info_cell
> for same reason.
> 

I see that you provide an update for of_read_drc_info_cell to fix the
unexpected behavior you're seeing, but I'm not sure why you're updating
the code in pseries_energy.c and rpaphp_core.c? can you provide some
additional information as to why these functions also need to be updated.

> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmware feature" -- end of patch series applied to powerpc next)
> ---
> Changes in V3:
>   -- Rebased patch to 4.17-rc5 kernel
> ---
>  arch/powerpc/platforms/pseries/of_helpers.c     |    5 ++---
>  arch/powerpc/platforms/pseries/pseries_energy.c |    2 ++
>  drivers/pci/hotplug/rpaphp_core.c               |    1 +
>  3 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
> index 6df192f..20598b2 100644
> --- a/arch/powerpc/platforms/pseries/of_helpers.c
> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
> @@ -65,9 +65,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
> 
>  	/* 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;
> +	data->drc_index_start = of_read_number(p2, 1);

This appears to resolve advancing the pointer for the beginning of a struct.

> 
>  	/* Get drc-name-suffix-start:encode-int */
>  	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
> @@ -88,6 +86,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
>  	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
>  	if (!p2)
>  		return -EINVAL;
> +	p2++;

...but why is the advancement needed here? of_prop_next_u32 should have advanced it, correct?

-Nathan

> 
>  	/* Should now know end of current entry */
>  	(*curval) = (void *)p2;
> diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
> index 6ed2212..c7d84aa 100644
> --- a/arch/powerpc/platforms/pseries/pseries_energy.c
> +++ b/arch/powerpc/platforms/pseries/pseries_energy.c
> @@ -64,6 +64,7 @@ static u32 cpu_to_drc_index(int cpu)
>  		value = of_prop_next_u32(info, NULL, &num_set_entries);
>  		if (!value)
>  			goto err_of_node_put;
> +		value++;
> 
>  		for (j = 0; j < num_set_entries; j++) {
> 
> @@ -126,6 +127,7 @@ static int drc_index_to_cpu(u32 drc_index)
>  		value = of_prop_next_u32(info, NULL, &num_set_entries);
>  		if (!value)
>  			goto err_of_node_put;
> +		value++;
> 
>  		for (j = 0; j < num_set_entries; j++) {
> 
> diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
> index fb5e084..dccdf62 100644
> --- a/drivers/pci/hotplug/rpaphp_core.c
> +++ b/drivers/pci/hotplug/rpaphp_core.c
> @@ -239,6 +239,7 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
>  	value = of_prop_next_u32(info, NULL, &entries);
>  	if (!value)
>  		return -EINVAL;
> +	value++;
> 
>  	for (j = 0; j < entries; j++) {
>  		of_read_drc_info_cell(&info, &value, &drc);
> 

Re: [RFC v3 1/4] powerpc/hotplug/drcinfo: Fix bugs parsing ibm,drc-info structs

[Michael Bringmann]

See below.

On 05/18/2018 02:57 PM, Nathan Fontenot wrote:
> On 05/17/2018 05:41 PM, Michael Bringmann wrote:
>> [Replace/withdraw previous patch submission to ensure that testing
>> of related patches on similar hardware progresses together.]
>>
>> This patch fixes a memory parsing bug when using of_prop_next_u32
>> calls at the start of a structure.  Depending upon the value of
>> "cur" memory pointer argument to of_prop_next_u32, it will or it
>> won't advance the value of the returned memory pointer by the
>> size of one u32.  This patch corrects the code to deal with that
>> indexing feature when parsing the ibm,drc-info structs for CPUs.
>> Also, need to advance the pointer at the end of_read_drc_info_cell
>> for same reason.
>>
> 
> I see that you provide an update for of_read_drc_info_cell to fix the
> unexpected behavior you're seeing, but I'm not sure why you're updating
> the code in pseries_energy.c and rpaphp_core.c? can you provide some
> additional information as to why these functions also need to be updated.

The changes are related.

of_prop_next_u32() does not read a u32 and then advance the pointer.
It advances the pointer and then reads a u32.  It does an error check
to see whether the u32 read is within the boundary of the property
value, but it returns a pointer to the u32 that was read.

> 
>> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
>> Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmware feature" -- end of patch series applied to powerpc next)
>> ---
>> Changes in V3:
>>   -- Rebased patch to 4.17-rc5 kernel
>> ---
>>  arch/powerpc/platforms/pseries/of_helpers.c     |    5 ++---
>>  arch/powerpc/platforms/pseries/pseries_energy.c |    2 ++
>>  drivers/pci/hotplug/rpaphp_core.c               |    1 +
>>  3 files changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
>> index 6df192f..20598b2 100644
>> --- a/arch/powerpc/platforms/pseries/of_helpers.c
>> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
>> @@ -65,9 +65,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
>>
>>  	/* 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;
>> +	data->drc_index_start = of_read_number(p2, 1);
> 
> This appears to resolve advancing the pointer for the beginning of a struct.
> 
>>
>>  	/* Get drc-name-suffix-start:encode-int */
>>  	p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
>> @@ -88,6 +86,7 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
>>  	p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
>>  	if (!p2)
>>  		return -EINVAL;
>> +	p2++;
> 
> ...but why is the advancement needed here? of_prop_next_u32 should have advanced it, correct?
> 
> -Nathan
> 
>>
>>  	/* Should now know end of current entry */
>>  	(*curval) = (void *)p2;
>> diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
>> index 6ed2212..c7d84aa 100644
>> --- a/arch/powerpc/platforms/pseries/pseries_energy.c
>> +++ b/arch/powerpc/platforms/pseries/pseries_energy.c
>> @@ -64,6 +64,7 @@ static u32 cpu_to_drc_index(int cpu)
>>  		value = of_prop_next_u32(info, NULL, &num_set_entries);
>>  		if (!value)
>>  			goto err_of_node_put;
>> +		value++;
>>
>>  		for (j = 0; j < num_set_entries; j++) {
>>
>> @@ -126,6 +127,7 @@ static int drc_index_to_cpu(u32 drc_index)
>>  		value = of_prop_next_u32(info, NULL, &num_set_entries);
>>  		if (!value)
>>  			goto err_of_node_put;
>> +		value++;
>>
>>  		for (j = 0; j < num_set_entries; j++) {
>>
>> diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
>> index fb5e084..dccdf62 100644
>> --- a/drivers/pci/hotplug/rpaphp_core.c
>> +++ b/drivers/pci/hotplug/rpaphp_core.c
>> @@ -239,6 +239,7 @@ static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
>>  	value = of_prop_next_u32(info, NULL, &entries);
>>  	if (!value)
>>  		return -EINVAL;
>> +	value++;
>>
>>  	for (j = 0; j < entries; j++) {
>>  		of_read_drc_info_cell(&info, &value, &drc);
>>
> 
> 

-- 
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb@linux.vnet.ibm.com

[RFC v3 2/4] powerpc/hotplug/drcinfo: Provide common parser for ibm,drc-info

[Michael Bringmann]

This patch provides a common parse function for the ibm,drc-info
property that can be modified by a callback function.  The caller
provides a pointer to the function and a pointer to their unique
data, and the parser provides the current lmb set from the struct.
The callback function may return codes indicating that the parsing
is complete, or should continue, along with an error code that may
be returned to the caller.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmwar
e feature" -- end of patch series applied to powerpc next)
---
Changes in V3:
  -- Update code to account for latest kernel checkins.
  -- Rebased to 4.17-rc5 kernel
---
 arch/powerpc/include/asm/prom.h             |    7 +++
 arch/powerpc/platforms/pseries/Makefile     |    2 -
 arch/powerpc/platforms/pseries/drchelpers.c |   66 +++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/pseries/drchelpers.c

diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index b04c5ce..2e947b3 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -94,6 +94,13 @@ struct of_drc_info {
 extern int of_read_drc_info_cell(struct property **prop,
 			const __be32 **curval, struct of_drc_info *data);
 
+extern int drc_info_parser(struct device_node *dn,
+			int (*usercb)(struct of_drc_info *drc,
+					void *data,
+					void *optional_data,
+					int *ret_code),
+			char *opt_drc_type,
+			void *data);
 
 /*
  * There are two methods for telling firmware what our capabilities are.
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 13eede6..38c8547 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_PPC64)			:= $(NO_MINIMAL_TOC)
 ccflags-$(CONFIG_PPC_PSERIES_DEBUG)	+= -DDEBUG
 
 obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
-			   of_helpers.o \
+			   of_helpers.o drchelpers.o \
 			   setup.o iommu.o event_sources.o ras.o \
 			   firmware.o power.o dlpar.o mobility.o rng.o \
 			   pci.o pci_dlpar.o eeh_pseries.o msi.o
diff --git a/arch/powerpc/platforms/pseries/drchelpers.c b/arch/powerpc/platforms/pseries/drchelpers.c
new file mode 100644
index 0000000..556e05d
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/drchelpers.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2018 Michael Bringmann <mbringm@us.ibm.com>, IBM
+ *
+ * pSeries specific routines for device-tree properties.
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *    
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/string.h>
+
+#include <asm/prom.h>
+#include "pseries.h"
+
+#define	MAX_DRC_NAME_LEN 64
+
+int drc_info_parser(struct device_node *dn,
+		int (*usercb)(struct of_drc_info *drc,
+				void *data,
+				void *optional_data,
+				int *ret_code),
+		char *opt_drc_type,
+		void *data)
+{
+	struct property *info;
+	unsigned int entries;
+	struct of_drc_info drc;
+	const __be32 *value;
+	int j, done = 0, ret_code = -EINVAL;
+
+	info = of_find_property(dn, "ibm,drc-info", NULL);
+	if (info == NULL)
+		return -EINVAL;
+
+	value = of_prop_next_u32(info, NULL, &entries);
+	if (!value)
+		return -EINVAL;
+	value++;
+
+	for (j = 0, done = 0; (j < entries) && (!done); j++) {
+		of_read_drc_info_cell(&info, &value, &drc);
+
+		if (opt_drc_type && strcmp(opt_drc_type, drc.drc_type))
+			continue;
+
+		done = usercb(&drc, data, NULL, &ret_code);
+	}
+
+	return ret_code;
+}
+EXPORT_SYMBOL(drc_info_parser);

[RFC v3 3/4] powerpc/hotplug/drcinfo: Fix hot-add CPU issues

[Michael Bringmann]

This patch applies a common parse function for the ibm,drc-info
property that can be modified by a callback function to the
hot-add CPU code.  Candidate code is replaced by a call to the
parser including a pointer to a local context-specific functions,
and local data.

In addition, a bug in the release of the previous patch set may
break things in some of the CPU DLPAR operations.  For instance,
when attempting to hot-add a new CPU or set of CPUs, the original
patch failed to always properly calculate the available resources,
and aborted the operation.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmwar
e feature" -- end of patch series applied to powerpc next)
---
Changes in V3:
  -- Update code to account for latest kernel checkins.
  -- Rebased to 4.17-rc5 kernel
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c    |  129 +++++++++++++++++------
 arch/powerpc/platforms/pseries/pseries_energy.c |  112 ++++++++++----------
 2 files changed, 154 insertions(+), 87 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 6ef77ca..a408217 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -411,25 +411,67 @@ static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
 	return found;
 }
 
-static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
+static bool check_cpu_drc_index(struct device_node *parent,
+				int (*checkRun)(struct of_drc_info *drc,
+						void *data,
+						void *not_used,
+						int *ret_code),
+				void *cdata)
 {
-	bool found = false;
-	int rc, index;
+	int found = 0;
+
+	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
+		found = drc_info_parser(parent, checkRun, "CPU", cdata);
+	} else {
+		int rc, index = 0;
 
-	index = 0;
-	while (!found) {
-		u32 drc;
+		while (!found) {
+			u32 drc;
 
-		rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
+			rc = of_property_read_u32_index(parent,
+						"ibm,drc-indexes",
 						index++, &drc);
-		if (rc)
-			break;
+			if (rc)
+				break;
+			found = checkRun(NULL, cdata, &drc, NULL);
+		}
+	}
 
-		if (drc == drc_index)
-			found = true;
+	return (bool)found;
+}
+
+struct valid_cpu_drc_index_struct {
+	u32 targ_drc_index;
+};
+
+static int valid_cpu_drc_index_checkRun(struct of_drc_info *drc,
+					void *idata,
+					void *drc_index,
+					int *ret_code)
+{
+	struct valid_cpu_drc_index_struct *cdata = idata;
+
+	if (drc) {
+		if ((drc->drc_index_start <= cdata->targ_drc_index) &&
+			(cdata->targ_drc_index <= drc->last_drc_index)) {
+			(*ret_code) = 1;
+			return 1;
+		}
+	} else {
+		if (*((u32*)drc_index) == cdata->targ_drc_index) {
+			(*ret_code) = 1;
+			return 1;
+		}
 	}
+	return 0;
+}
 
-	return found;
+static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
+{
+	struct valid_cpu_drc_index_struct cdata = { drc_index };
+
+	return check_cpu_drc_index(parent, valid_cpu_drc_index_checkRun,
+				&cdata);
 }
 
 static ssize_t dlpar_cpu_add(u32 drc_index)
@@ -721,11 +763,45 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
 	return rc;
 }
 
+struct find_dlpar_cpus_to_add_struct {
+	struct device_node *parent;
+	u32 *cpu_drcs;
+	u32 cpus_to_add;
+	u32 cpus_found;
+};
+
+static int find_dlpar_cpus_to_add_checkRun(struct of_drc_info *drc,
+					void *idata,
+					void *drc_index,
+					int *ret_code)
+{
+	struct find_dlpar_cpus_to_add_struct *cdata = idata;
+
+	if (drc) {
+		int k;
+
+		for (k = 0; (k < drc->num_sequential_elems) &&
+			(cdata->cpus_found < cdata->cpus_to_add); k++) {
+			u32 idrc = drc->drc_index_start +
+				(k * drc->sequential_inc);
+
+			if (dlpar_cpu_exists(cdata->parent, idrc))
+				continue;
+			cdata->cpu_drcs[cdata->cpus_found++] = idrc;
+		}
+	} else {
+		if (!dlpar_cpu_exists(cdata->parent, *((u32*)drc_index)))
+			cdata->cpu_drcs[cdata->cpus_found++] =
+				*((u32*)drc_index);
+	}
+	return 0;
+}
+
 static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
 {
 	struct device_node *parent;
-	int cpus_found = 0;
-	int index, rc;
+	struct find_dlpar_cpus_to_add_struct cdata = {
+		NULL, cpu_drcs, cpus_to_add, 0 };
 
 	parent = of_find_node_by_path("/cpus");
 	if (!parent) {
@@ -734,28 +810,15 @@ static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
 		return -1;
 	}
 
-	/* Search the ibm,drc-indexes array for possible CPU drcs to
-	 * add. Note that the format of the ibm,drc-indexes array is
-	 * the number of entries in the array followed by the array
-	 * of drc values so we start looking at index = 1.
+	/* Search the appropriate property for possible CPU drcs to
+	 * add.
 	 */
-	index = 1;
-	while (cpus_found < cpus_to_add) {
-		u32 drc;
-
-		rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
-						index++, &drc);
-		if (rc)
-			break;
-
-		if (dlpar_cpu_exists(parent, drc))
-			continue;
-
-		cpu_drcs[cpus_found++] = drc;
-	}
+	cdata.parent = parent;
+	check_cpu_drc_index(parent, find_dlpar_cpus_to_add_checkRun,
+				&cdata);
 
 	of_node_put(parent);
-	return cpus_found;
+	return cdata.cpus_found;
 }
 
 static int dlpar_cpu_add_by_count(u32 cpus_to_add)
diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
index c7d84aa..332f3ce 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -36,6 +36,26 @@
 
 /* Helper Routines to convert between drc_index to cpu numbers */
 
+struct cpu_to_drc_index_struct {
+	u32	thread_index;
+	u32	ret;
+};
+
+static int cpu_to_drc_index_checkRun(struct of_drc_info *drc,
+				void *idata, void *not_used, int *ret_code)
+{
+        struct cpu_to_drc_index_struct *cdata = idata;
+
+	if (cdata->thread_index < drc->last_drc_index) {
+		cdata->ret = drc->drc_index_start +
+			(cdata->thread_index * drc->sequential_inc);
+		(*ret_code) = 1;
+		return 1;
+	}
+	(*ret_code) = 0;
+        return 0;
+}
+
 static u32 cpu_to_drc_index(int cpu)
 {
 	struct device_node *dn = NULL;
@@ -51,32 +71,16 @@ static u32 cpu_to_drc_index(int cpu)
 	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;
+		struct cpu_to_drc_index_struct cdata = {
+			thread_index, 0 };
 
-		value = of_prop_next_u32(info, NULL, &num_set_entries);
-		if (!value)
-			goto err_of_node_put;
-		value++;
-
-		for (j = 0; j < num_set_entries; j++) {
+		rc = drc_info_parser(dn, &cpu_to_drc_index_checkRun,
+				"CPU", &cdata);
 
-			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;
-		}
+		if (rc < 0)
+			goto err_of_node_put;
 
-		ret = drc.drc_index_start + (thread_index * drc.sequential_inc);
+		ret = cdata.ret;
 	} else {
 		const __be32 *indexes;
 
@@ -102,11 +106,36 @@ static u32 cpu_to_drc_index(int cpu)
 	return ret;
 }
 
+struct drc_index_to_cpu_struct {
+	u32	drc_index;
+	u32	thread_index;
+	u32	cpu;
+};
+
+static int drc_index_to_cpu_checkRun(struct of_drc_info *drc,
+				void *idata, void *not_used, int *ret_code)
+{
+        struct drc_index_to_cpu_struct *cdata = idata;
+
+	if (cdata->drc_index > drc->last_drc_index) {
+		cdata->cpu += drc->num_sequential_elems;
+		(*ret_code) = 0;
+		return 0;
+	} else {
+		cdata->cpu += ((cdata->drc_index - drc->drc_index_start) /
+				drc->sequential_inc);
+
+		cdata->thread_index = cpu_first_thread_of_core(cdata->cpu);
+		(*ret_code) = 0;
+		return 0;
+	}
+}
+
 static int drc_index_to_cpu(u32 drc_index)
 {
 	struct device_node *dn = NULL;
 	const int *indexes;
-	int thread_index = 0, cpu = 0;
+	int thread_index = 0;
 	int rc = 1;
 
 	dn = of_find_node_by_path("/cpus");
@@ -114,38 +143,13 @@ static int drc_index_to_cpu(u32 drc_index)
 		goto err;
 
 	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 = of_prop_next_u32(info, NULL, &num_set_entries);
-		if (!value)
-			goto err_of_node_put;
-		value++;
-
-		for (j = 0; j < num_set_entries; j++) {
+		struct drc_index_to_cpu_struct cdata = {
+			drc_index, 0, 0 };
 
-			of_read_drc_info_cell(&info, &value, &drc);
-			if (strncmp(drc.drc_type, "CPU", 3))
-				goto err;
+		rc = drc_info_parser(dn, &drc_index_to_cpu_checkRun,
+					"CPU", &cdata);
+		thread_index = cdata.thread_index;
 
-			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;
 

[RFC v3 4/4] powerpc/hotplug/drcinfo: Improve code for ibm,drc-info device processing

[Michael Bringmann]

This patch extends the use of a common parse function for the
ibm,drc-info property that can be modified by a callback function
to the hotplug device processing.  Candidate code is replaced by
a call to the parser including a pointer to a local context-specific
functions, and local data.

In addition, the original set missed several opportunities to compress
and reuse common code which this patch attempts to provide.

Finally, a bug with the registration of slots was observed on some
systems, and the code was rewritten to prevent its reoccurrence.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
Fixes: 3f38000eda48 ("powerpc/firmware: Add definitions for new drc-info firmwar
e feature" -- end of patch series applied to powerpc next)
---
Changes in V3:
  -- Update code to account for latest kernel checkins.
  -- Fix bug searching for virtual device slots.
  -- Rebased to 4.17-rc5 kernel
---
 drivers/pci/hotplug/rpaphp_core.c |  188 ++++++++++++++++++++++++++-----------
 1 file changed, 130 insertions(+), 58 deletions(-)

diff --git a/drivers/pci/hotplug/rpaphp_core.c b/drivers/pci/hotplug/rpaphp_core.c
index dccdf62..974147a 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -222,49 +222,52 @@ static int rpaphp_check_drc_props_v1(struct device_node *dn, char *drc_name,
 	return -EINVAL;
 }
 
-static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
-				char *drc_type, unsigned int my_index)
+struct check_drc_props_v2_struct {
+	char *drc_name;
+	char *drc_type;
+        unsigned int my_index;
+};
+
+static int check_drc_props_v2_checkRun(struct of_drc_info *drc,
+                                        void *idata, void *not_used,
+					int *ret_code)
 {
-	struct property *info;
-	unsigned int entries;
-	struct of_drc_info drc;
-	const __be32 *value;
+	struct check_drc_props_v2_struct *cdata = idata;
 	char cell_drc_name[MAX_DRC_NAME_LEN];
-	int j, fndit;
-
-	info = of_find_property(dn->parent, "ibm,drc-info", NULL);
-	if (info == NULL)
-		return -EINVAL;
-
-	value = of_prop_next_u32(info, NULL, &entries);
-	if (!value)
-		return -EINVAL;
-	value++;
-
-	for (j = 0; j < entries; j++) {
-		of_read_drc_info_cell(&info, &value, &drc);
 
-		/* Should now know end of current entry */
+	(*ret_code) = -EINVAL;
 
-		if (my_index > drc.last_drc_index)
-			continue;
+	if (cdata->my_index > drc->last_drc_index)
+		return 0;
 
-		fndit = 1;
-		break;
+	/* Found drc_index.  Now match the rest. */
+	sprintf(cell_drc_name, "%s%d", drc->drc_name_prefix, 
+		cdata->my_index - drc->drc_index_start +
+		drc->drc_name_suffix_start);
+
+	if (((cdata->drc_name == NULL) ||
+	     (cdata->drc_name && !strcmp(cdata->drc_name, cell_drc_name))) &&
+	    ((cdata->drc_type == NULL) ||
+	     (cdata->drc_type && !strcmp(cdata->drc_type, drc->drc_type)))) {
+		(*ret_code) = 0;
+		return 1;
 	}
-	/* Found it */
 
-	if (fndit)
-		sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, 
-			my_index);
+        return 0;
+}
 
-	if (((drc_name == NULL) ||
-	     (drc_name && !strcmp(drc_name, cell_drc_name))) &&
-	    ((drc_type == NULL) ||
-	     (drc_type && !strcmp(drc_type, drc.drc_type))))
-		return 0;
+static int rpaphp_check_drc_props_v2(struct device_node *dn, char *drc_name,
+				char *drc_type, unsigned int my_index)
+{
+	struct device_node *root = dn;
+	struct check_drc_props_v2_struct cdata = {
+		drc_name, drc_type, be32_to_cpu(my_index) };
 
-	return -EINVAL;
+	if (!drc_type || (drc_type && strcmp(drc_type, "SLOT")))
+		root = dn->parent;
+
+	return drc_info_parser(root, check_drc_props_v2_checkRun,
+				drc_type, &cdata);
 }
 
 int rpaphp_check_drc_props(struct device_node *dn, char *drc_name,
@@ -287,7 +290,6 @@ int rpaphp_check_drc_props(struct device_node *dn, char *drc_name,
 }
 EXPORT_SYMBOL_GPL(rpaphp_check_drc_props);
 
-
 static int is_php_type(char *drc_type)
 {
 	unsigned long value;
@@ -347,17 +349,40 @@ static int is_php_dn(struct device_node *dn, const int **indexes,
  *
  * To remove a slot, it suffices to call rpaphp_deregister_slot().
  */
-int rpaphp_add_slot(struct device_node *dn)
+
+static int rpaphp_add_slot_common(struct device_node *dn,
+			u32 drc_index, char *drc_name, char *drc_type,
+			u32 drc_power_domain)
 {
 	struct slot *slot;
 	int retval = 0;
-	int i;
+
+	slot = alloc_slot_struct(dn, drc_index, drc_name,
+				 drc_power_domain);
+	if (!slot)
+		return -ENOMEM;
+
+	slot->type = simple_strtoul(drc_type, NULL, 10);
+
+	dbg("Found drc-index:0x%x drc-name:%s drc-type:%s\n",
+		drc_index, drc_name, drc_type);
+
+	retval = rpaphp_enable_slot(slot);
+	if (!retval)
+		retval = rpaphp_register_slot(slot);
+
+	if (retval)
+		dealloc_slot_struct(slot);
+
+	return retval;
+}
+
+static int rpaphp_add_slot_v1(struct device_node *dn)
+{
+	int i, retval = 0;
 	const int *indexes, *names, *types, *power_domains;
 	char *name, *type;
 
-	if (!dn->name || strcmp(dn->name, "pci"))
-		return 0;
-
 	/* If this is not a hotplug slot, return without doing anything. */
 	if (!is_php_dn(dn, &indexes, &names, &types, &power_domains))
 		return 0;
@@ -368,25 +393,13 @@ int rpaphp_add_slot(struct device_node *dn)
 	name = (char *) &names[1];
 	type = (char *) &types[1];
 	for (i = 0; i < be32_to_cpu(indexes[0]); i++) {
-		int index;
-
-		index = be32_to_cpu(indexes[i + 1]);
-		slot = alloc_slot_struct(dn, index, name,
-					 be32_to_cpu(power_domains[i + 1]));
-		if (!slot)
-			return -ENOMEM;
-
-		slot->type = simple_strtoul(type, NULL, 10);
-
-		dbg("Found drc-index:0x%x drc-name:%s drc-type:%s\n",
-				index, name, type);
-
-		retval = rpaphp_enable_slot(slot);
+	
+		retval = rpaphp_add_slot_common(dn,
+				be32_to_cpu(indexes[i + 1]),
+				name, type,
+				be32_to_cpu(power_domains[i + 1]));
 		if (!retval)
-			retval = rpaphp_register_slot(slot);
-
-		if (retval)
-			dealloc_slot_struct(slot);
+			return retval;
 
 		name += strlen(name) + 1;
 		type += strlen(type) + 1;
@@ -396,6 +409,65 @@ int rpaphp_add_slot(struct device_node *dn)
 	/* XXX FIXME: reports a failure only if last entry in loop failed */
 	return retval;
 }
+
+struct rpaphp_add_slot_v2_struct {
+	struct device_node *dn;
+};
+
+static int rpaphp_add_slot_v2_checkRun(struct of_drc_info *drc,
+                                        void *idata, void *not_used,
+					int *ret_code)
+{
+	struct rpaphp_add_slot_v2_struct *cdata = idata;
+	u32 drc_index;
+	char drc_name[MAX_DRC_NAME_LEN];
+	int i, retval;
+
+	(*ret_code) = -EINVAL;
+
+	if (!is_php_type((char *) drc->drc_type)) {
+		(*ret_code) = 0;
+		return 1;
+	}
+
+	for (i = 0, drc_index = drc->drc_index_start;
+		i < drc->num_sequential_elems; i++, drc_index++) {
+
+        	sprintf(drc_name, "%s%d", drc->drc_name_prefix,
+			drc_index - drc->drc_index_start +
+			drc->drc_name_suffix_start);
+
+		retval = rpaphp_add_slot_common(cdata->dn,
+				drc_index, drc_name, drc->drc_type,
+				drc->drc_power_domain);
+		if (!retval) {
+			(*ret_code) = retval;
+			return 1;
+		}
+	}
+
+	(*ret_code) = retval;
+	return 0;
+}
+
+static int rpaphp_add_slot_v2(struct device_node *dn)
+{
+	struct rpaphp_add_slot_v2_struct cdata = { dn };
+
+	return drc_info_parser(dn, rpaphp_add_slot_v2_checkRun,
+				NULL, &cdata);
+}
+
+int rpaphp_add_slot(struct device_node *dn)
+{
+	if (!dn->name || strcmp(dn->name, "pci"))
+		return 0;
+
+	if (firmware_has_feature(FW_FEATURE_DRC_INFO))
+		return rpaphp_add_slot_v2(dn);
+	else
+		return rpaphp_add_slot_v1(dn);
+}
 EXPORT_SYMBOL_GPL(rpaphp_add_slot);
 
 static void __exit cleanup_slots(void)