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From: Tyrel Datwyler <tyreld@linux.ibm.com>
To: mpe@ellerman.id.au
Cc: nathanl@linux.ibm.com, linuxppc-dev@lists.ozlabs.org,
	Tyrel Datwyler <tyreld@linux.ibm.com>
Subject: [PATCH 2/9] powerpc/pseries: Fix drc-info mappings of logical cpus to drc-index
Date: Tue,  5 Nov 2019 09:24:06 -0600
Message-ID: <1572967453-9586-3-git-send-email-tyreld@linux.ibm.com> (raw)
In-Reply-To: <1572967453-9586-1-git-send-email-tyreld@linux.ibm.com>

There are a couple subtle errors in the mapping between cpu-ids and a
cpus associated drc-index when using the new ibm,drc-info property.

The first is that while drc-info may have been a supported firmware
feature at boot it is possible we have migrated to a CEC with older
firmware that doesn't support the ibm,drc-info property. In that case
the device tree would have been updated after migration to remove the
ibm,drc-info property and replace it with the older style ibm,drc-*
properties for types, indexes, names, and power-domains.

The second is that the first value of the ibm,drc-info property is
the int encoded count of drc-info entries. As such "value" returned
by of_prop_next_u32() is pointing at that count, and not the first
element of the first drc-info entry as is expected by the
of_read_drc_info_cell() helper.

Fix the first by ignoring DRC-INFO firmware feature and instead
testing directly for ibm,drc-info, and then falling back to the
old style ibm,drc-indexes in the case it doesn't exit.

Fix the second by incrementing value to the next element prior to
parsing drc-info entries.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/pseries_energy.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/pseries_energy.c b/arch/powerpc/platforms/pseries/pseries_energy.c
index a96874f..09e98d3 100644
--- a/arch/powerpc/platforms/pseries/pseries_energy.c
+++ b/arch/powerpc/platforms/pseries/pseries_energy.c
@@ -36,6 +36,7 @@ static int sysfs_entries;
 static u32 cpu_to_drc_index(int cpu)
 {
 	struct device_node *dn = NULL;
+	struct property *info;
 	int thread_index;
 	int rc = 1;
 	u32 ret = 0;
@@ -47,20 +48,18 @@ static u32 cpu_to_drc_index(int cpu)
 	/* Convert logical cpu number to core number */
 	thread_index = cpu_core_index_of_thread(cpu);
 
-	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
-		struct property *info = NULL;
+	info = of_find_property(dn, "ibm,drc-info", NULL);
+	if (info) {
 		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;
+		else
+			value++;
 
 		for (j = 0; j < num_set_entries; j++) {
 
@@ -110,6 +109,7 @@ static u32 cpu_to_drc_index(int cpu)
 static int drc_index_to_cpu(u32 drc_index)
 {
 	struct device_node *dn = NULL;
+	struct property *info;
 	const int *indexes;
 	int thread_index = 0, cpu = 0;
 	int rc = 1;
@@ -117,21 +117,18 @@ static int drc_index_to_cpu(u32 drc_index)
 	dn = of_find_node_by_path("/cpus");
 	if (dn == NULL)
 		goto err;
-
-	if (firmware_has_feature(FW_FEATURE_DRC_INFO)) {
-		struct property *info = NULL;
+	info = of_find_property(dn, "ibm,drc-info", NULL);
+	if (info) {
 		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;
+		else
+			value++;
 
 		for (j = 0; j < num_set_entries; j++) {
 
-- 
2.7.4


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-05 15:24 [PATCH 0/9] Fixes and Enablement of ibm,drc-info property Tyrel Datwyler
2019-11-05 15:24 ` [PATCH 1/9] powerpc/pseries: Fix bad drc_index_start value parsing of drc-info entry Tyrel Datwyler
2019-11-05 15:24 ` Tyrel Datwyler [this message]
2019-11-05 15:24 ` [PATCH 3/9] powerpc/pseries: Add cpu DLPAR support for drc-info property Tyrel Datwyler
2019-11-05 16:55   ` Thomas Falcon
2019-11-06 20:15     ` Tyrel Datwyler
2019-11-07 11:35   ` Michael Ellerman
2019-11-05 15:24 ` [PATCH 4/9] PCI: rpaphp: Fix up pointer to first drc-info entry Tyrel Datwyler
2019-11-05 15:24 ` [PATCH 5/9] PCI: rpaphp: Don't rely on firmware feature to imply drc-info support Tyrel Datwyler
2019-11-05 15:24 ` [PATCH 6/9] PCI: rpaphp: Add drc-info support for hotplug slot registration Tyrel Datwyler
2019-11-05 15:24 ` [PATCH 7/9] PCI: rpaphp: annotate and correctly byte swap DRC properties Tyrel Datwyler
2019-11-07 11:40   ` Michael Ellerman
2019-11-05 15:24 ` [PATCH 8/9] PCI: rpaphp: Correctly match ibm, my-drc-index to drc-name when using drc-info Tyrel Datwyler
2019-11-05 15:24 ` [PATCH 9/9] powerpc/pseries: Enable support for ibm, drc-info property Tyrel Datwyler
2019-11-07 11:38   ` Michael Ellerman
2019-11-05 17:03 ` [PATCH 0/9] Fixes and Enablement of ibm,drc-info property Thomas Falcon
2019-11-06 20:12   ` Tyrel Datwyler
2019-11-07 11:26     ` Michael Ellerman

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