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

[Michael Bringmann <mwb@linux.vnet.ibm.com>]

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)
---
 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 7db7958..e75963e 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);