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Subject: [RFC 3/6] pseries/drcinfo: Pseries impl of arch_find_drc_info
From:   Michael Bringmann <mwb@linux.vnet.ibm.com>
To:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
        Thomas Falcon <tlfalcon@linux.vnet.ibm.com>,
        Juliet Kim <minkim@us.ibm.com>
Date:   Fri, 14 Dec 2018 14:51:00 -0600
In-Reply-To: <20181214204914.16435.59083.stgit@powerkvm6.aus.stglabs.ibm.com>
References: <20181214204914.16435.59083.stgit@powerkvm6.aus.stglabs.ibm.com>
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This patch provides a common interface to parse ibm,drc-indexes,
ibm,drc-names, ibm,drc-types, ibm,drc-power-domains, or ibm,drc-info.
The generic interface arch_find_drc_match is provided which accepts
callback functions that may be applied to examine the data for each
entry.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/prom.h             |    3 
 arch/powerpc/platforms/pseries/of_helpers.c |  299 +++++++++++++++++++++++++++
 include/linux/topology.h                    |    2 
 3 files changed, 298 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index b04c5ce..910d1dc 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -91,9 +91,6 @@ struct of_drc_info {
 	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.
diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c
index 0185e50..11c90cd 100644
--- a/arch/powerpc/platforms/pseries/of_helpers.c
+++ b/arch/powerpc/platforms/pseries/of_helpers.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#define pr_fmt(fmt) "drc: " fmt
+
 #include <linux/string.h>
 #include <linux/err.h>
 #include <linux/slab.h>
@@ -11,6 +13,12 @@
 
 #define	MAX_DRC_NAME_LEN 64
 
+static int drc_debug;
+#define dbg(args...) if (drc_debug) { printk(KERN_DEBUG args); }
+#define err(arg...) printk(KERN_ERR args);
+#define info(arg...) printk(KERN_INFO args);
+#define warn(arg...) printk(KERN_WARNING args);
+
 /**
  * pseries_of_derive_parent - basically like dirname(1)
  * @path:  the full_name of a node to be added to the tree
@@ -46,7 +54,8 @@ struct device_node *pseries_of_derive_parent(const char *path)
 
 /* Helper Routines to convert between drc_index to cpu numbers */
 
-int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
+static int of_read_drc_info_cell(struct property **prop,
+			const __be32 **curval,
 			struct of_drc_info *data)
 {
 	const char *p;
@@ -90,4 +99,290 @@ int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
 
 	return 0;
 }
-EXPORT_SYMBOL(of_read_drc_info_cell);
+
+static int walk_drc_info(struct device_node *dn,
+		bool (*usercb)(struct of_drc_info *drc,
+				void *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, ret_code = -EINVAL;
+	bool done = false;
+
+	info = of_find_property(dn, "ibm,drc-info", NULL);
+	if (info == NULL)
+		return -EINVAL;
+
+	value = info->value;
+	entries = of_read_number(value++, 1);
+
+	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, &ret_code);
+	}
+
+	return ret_code;
+}
+
+static int get_children_props(struct device_node *dn, const int **drc_indexes,
+		const int **drc_names, const int **drc_types,
+		const int **drc_power_domains)
+{
+	const int *indexes, *names, *types, *domains;
+
+	indexes = of_get_property(dn, "ibm,drc-indexes", NULL);
+	names = of_get_property(dn, "ibm,drc-names", NULL);
+	types = of_get_property(dn, "ibm,drc-types", NULL);
+	domains = of_get_property(dn, "ibm,drc-power-domains", NULL);
+
+	if (!indexes || !names || !types || !domains) {
+		/* Slot does not have dynamically-removable children */
+		return -EINVAL;
+	}
+	if (drc_indexes)
+		*drc_indexes = indexes;
+	if (drc_names)
+		/* &drc_names[1] contains NULL terminated slot names */
+		*drc_names = names;
+	if (drc_types)
+		/* &drc_types[1] contains NULL terminated slot types */
+		*drc_types = types;
+	if (drc_power_domains)
+		*drc_power_domains = domains;
+
+	return 0;
+}
+
+static int is_php_type(char *drc_type)
+{
+	unsigned long value;
+	char *endptr;
+
+	/* PCI Hotplug nodes have an integer for drc_type */
+	value = simple_strtoul(drc_type, &endptr, 10);
+	if (endptr == drc_type)
+		return 0;
+
+	return 1;
+}
+
+/**
+ * is_php_dn() - return 1 if this is a hotpluggable pci slot, else 0
+ * @dn: target &device_node
+ * @indexes: passed to get_children_props()
+ * @names: passed to get_children_props()
+ * @types: returned from get_children_props()
+ * @power_domains:
+ *
+ * This routine will return true only if the device node is
+ * a hotpluggable slot. This routine will return false
+ * for built-in pci slots (even when the built-in slots are
+ * dlparable.)
+ */
+static int is_php_dn(struct device_node *dn, const int **indexes,
+		const int **names, const int **types,
+		const int **power_domains)
+{
+	const int *drc_types;
+	int rc;
+
+	rc = get_children_props(dn, indexes, names, &drc_types,
+				power_domains);
+	if (rc < 0)
+		return 0;
+
+	if (!is_php_type((char *) &drc_types[1]))
+		return 0;
+
+	*types = drc_types;
+	return 1;
+}
+
+struct find_drc_match_cb_struct {
+	struct device_node *dn;
+	bool (*usercb)(struct device_node *dn,
+			u32 drc_index, char *drc_name,
+			char *drc_type, u32 drc_power_domain,
+			void *data);
+	char *drc_type;
+	char *drc_name;
+	u32 drc_index;
+	bool match_drc_index;
+	bool add_slot;
+	void *data;
+};
+
+static int find_drc_match_v1(struct device_node *dn, void *data)
+{
+	struct find_drc_match_cb_struct *cdata = data;
+	int i, retval = 0;
+	const int *indexes, *names, *types, *domains;
+	char *name, *type;
+	struct device_node *root = dn;
+
+	if (cdata->match_drc_index)
+		root = dn->parent;
+
+	if (cdata->add_slot) {
+		/* If this is not a hotplug slot, return without doing
+		 * anything.
+		 */
+		if (!is_php_dn(root, &indexes, &names, &types, &domains))
+			return 0;
+	} else {
+		if (get_children_props(root, &indexes, &names, &types,
+			&domains) < 0)
+			return 0;
+	}
+
+	dbg("Entry %s: dn=%pOF\n", __func__, dn);
+
+	name = (char *) &names[1];
+	type = (char *) &types[1];
+	for (i = 0; i < be32_to_cpu(indexes[0]); i++) {
+
+		if (cdata->match_drc_index &&
+			((unsigned int) indexes[i + 1] != cdata->drc_index)) {
+			name += strlen(name) + 1;
+			type += strlen(type) + 1;
+			continue;
+		}
+
+		if (((cdata->drc_name == NULL) ||
+		     (cdata->drc_name && !strcmp(cdata->drc_name, name))) &&
+		    ((cdata->drc_type == NULL) ||
+		     (cdata->drc_type && !strcmp(cdata->drc_type, type)))) {
+
+			if (cdata->usercb) {
+				retval = cdata->usercb(dn,
+					be32_to_cpu(indexes[i + 1]),
+					name, type,
+					be32_to_cpu(domains[i + 1]),
+					cdata->data);
+				if (!retval)
+					return retval;
+			} else {
+				return 0;
+			}
+		}
+
+		name += strlen(name) + 1;
+		type += strlen(type) + 1;
+	}
+
+	dbg("%s - Exit: rc[%d]\n", __func__, retval);
+
+	/* XXX FIXME: reports a failure only if last entry in loop failed */
+	return retval;
+}
+
+static bool find_drc_match_v2_cb(struct of_drc_info *drc, void *data,
+				int *ret_code)
+{
+	struct find_drc_match_cb_struct *cdata = data;
+	u32 drc_index;
+	char drc_name[MAX_DRC_NAME_LEN];
+	int i, retval;
+
+	(*ret_code) = -EINVAL;
+
+	/* This set not a PHP type? */
+	if (cdata->add_slot) {
+		if (!is_php_type((char *) drc->drc_type)) {
+			return false;
+		}
+	}
+
+	/* Anything to use from this set? */
+	if (cdata->match_drc_index && (cdata->drc_index > drc->last_drc_index))
+		return false;
+	if ((cdata->drc_type && strcmp(cdata->drc_type, drc->drc_type))
+		return false;
+
+	/* Check the drc-index entries of this set */
+	for (i = 0, drc_index = drc->drc_index_start;
+		i < drc->num_sequential_elems; i++, drc_index++) {
+
+		if (cdata->match_drc_index && (cdata->drc_index != drc_index))
+			continue;
+
+		sprintf(drc_name, "%s%d", drc->drc_name_prefix,
+			drc_index - drc->drc_index_start +
+			drc->drc_name_suffix_start);
+
+		if ((cdata->drc_name == NULL) ||
+		    (cdata->drc_name && !strcmp(cdata->drc_name, drc_name))) {
+
+			if (cdata->usercb) {
+				retval = cdata->usercb(cdata->dn,
+						drc_index, drc_name,
+						drc->drc_type,
+						drc->drc_power_domain,
+						cdata->data);
+				if (!retval) {
+					(*ret_code) = retval;
+					return true;
+				}
+			} else {
+				(*ret_code) = 0;
+				return true;
+			}
+		}
+	}
+
+	(*ret_code) = retval;
+	return false;
+}
+
+static int find_drc_match_v2(struct device_node *dn, void *data)
+{
+	struct find_drc_match_cb_struct *cdata = data;
+	struct device_node *root = cdata->dn;
+
+	if (!cdata->add_slot) {
+		if (!cdata->drc_type ||
+			(cdata->drc_type && strcmp(cdata->drc_type, "SLOT")))
+			root = dn->parent;
+	}
+
+	return walk_drc_info(root, find_drc_match_v2_cb, NULL, data);
+}
+
+int arch_find_drc_match(struct device_node *dn,
+			bool (*usercb)(struct device_node *dn,
+				u32 drc_index, char *drc_name,
+				char *drc_type, u32 drc_power_domain,
+				void *data),
+			char *opt_drc_type, char *opt_drc_name,
+			bool match_drc_index, bool add_slot,
+			void *data)
+{
+	struct find_drc_match_cb_struct cdata = { dn, usercb,
+			opt_drc_type, opt_drc_name, 0,
+			match_drc_index, add_slot, data };
+
+	if (match_drc_index) {
+		const int *my_index =
+			of_get_property(dn, "ibm,my-drc-index", NULL);
+		if (!my_index) {
+			/* Node isn't DLPAR/hotplug capable */
+			return -EINVAL;
+		}
+		cdata.drc_index = *my_index;
+	}
+
+	if (firmware_has_feature(FW_FEATURE_DRC_INFO))
+		return find_drc_match_v2(dn, &cdata);
+	else
+		return find_drc_match_v1(dn, &cdata);
+}
+EXPORT_SYMBOL(arch_find_drc_match);
diff --git a/include/linux/topology.h b/include/linux/topology.h
index df97f5f..c3dfa53 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -50,7 +50,7 @@ int arch_find_drc_match(struct device_node *dn,
 				char *drc_type, u32 drc_power_domain,
 				void *data),
 			char *opt_drc_type, char *opt_drc_name,
-			bool match_drc_index, bool ck_php_type,
+			bool match_drc_index, bool add_slot,
 			void *data);
 
 /* Conform to ACPI 2.0 SLIT distance definitions */