[Skiboot] [PATCH V2 15/21] core/pldm: Find lid attribute from bios tables

[Christophe Lombard]

This specification defines the data structures and messages for
communicating BIOS settings, BIOS attributes, boot configurations, and
boot order settings.

Use the GetBIOSTable command to get STRING, Attribute and Attribute values
tables from the BIOS.

The contents of these tables are needed to read/write the desired lid
files located on the BMC.

Signed-off-by: Christophe Lombard <clombard at linux.vnet.ibm.com>
---
 core/pldm/pldm-bios-requests.c | 138 +++++++++++++++++++++++++++++++++
 core/pldm/pldm.h               |   2 +
 2 files changed, 140 insertions(+)

diff --git a/core/pldm/pldm-bios-requests.c b/core/pldm/pldm-bios-requests.c
index 0e2f9a25..80ceb471 100644
--- a/core/pldm/pldm-bios-requests.c
+++ b/core/pldm/pldm-bios-requests.c
@@ -84,6 +84,144 @@ static void bios_init_complete(bool success)
 	bios_ready = true;
 }
 
+/*
+ * parse a string, format:
+ * <ATTR_a>=<lid_id_1>,<ATTR_b>=<lid_id_2>
+ */
+static int find_lid_by_attr_name(char *str, const char *name,
+				 char **lid)
+{
+	char *p;
+
+	for (p = strtok(str, ","); p != NULL; p = strtok(NULL, ",")) {
+		if (!strncmp(p, name, strlen(name))) {
+			p += strlen(name) + 1;
+			*lid = strdup(p);
+			return OPAL_SUCCESS;
+		}
+	}
+	prlog(PR_ERR, "%s - lid not found, attr name: %s\n",
+		      __func__, name);
+
+	return OPAL_PARAMETER;
+}
+
+/*
+ * Retrieve attribut value from string.
+ *
+ * Ex:   string value = "hb_lid_ids"
+ *  From STRING table (with string value = "hb_lid_ids") -> string_handle = 60
+ *  From ATTR table (with attr name handle = 60)         -> attr handle = 8
+ *  From ATTR VAL table (with attr handle = 8)
+ *    -> CurrentString = ATTR_PERM=81e00663,ATTR_TMP=81e00664, ...
+ *                       NVRAM=81e0066b,...,pnor.toc=NA"
+ */
+static int find_bios_table_attr_values_by_string(const char *str,
+						 char **current_string)
+{
+	const struct pldm_bios_string_table_entry *string_entry;
+	const struct pldm_bios_attr_table_entry *attr_entry;
+	const struct pldm_bios_attr_val_table_entry *val_entry;
+	uint16_t string_handle, attr_handle;
+	struct variable_field currentString;
+
+	if ((!bios_string_table) || (!bios_attr_table))
+		return OPAL_PARAMETER;
+
+	/* decode string table */
+	string_entry = pldm_bios_table_string_find_by_string(
+			bios_string_table, bios_string_length, str);
+	if (!string_entry) {
+		prlog(PR_ERR, "String table entry not found, str: %s\n",
+			      str);
+		return OPAL_PARAMETER;
+	}
+
+	/* get the string handle for the entry */
+	string_handle = pldm_bios_table_string_entry_decode_handle(string_entry);
+	prlog(PR_TRACE, "%s - string_handle: %d\n", __func__, string_handle);
+
+	/* decode attribute table */
+	attr_entry = pldm_bios_table_attr_find_by_string_handle(
+		      bios_attr_table, bios_attr_length, string_handle);
+	if (!attr_entry) {
+		prlog(PR_ERR, "Attribute table entry not found, string_handle: %d\n",
+			      string_handle);
+		return OPAL_PARAMETER;
+	}
+
+	/* get the attribute handle from the attribute table entry */
+	attr_handle = pldm_bios_table_attr_entry_decode_attribute_handle(attr_entry);
+	prlog(PR_TRACE, "%s - attr_handle: %d\n", __func__, attr_handle);
+
+	/* decode attribute value table */
+	val_entry = pldm_bios_table_attr_value_find_by_handle(
+			bios_val_table, bios_val_length, attr_handle);
+
+	if (!val_entry) {
+		prlog(PR_ERR, "Attribute val table entry not found, attr_handle: %d\n",
+			      attr_handle);
+		return OPAL_PARAMETER;
+	}
+
+	/* get Current String Itself */
+	pldm_bios_table_attr_value_entry_string_decode_string(
+			val_entry,
+			&currentString);
+	*current_string = strdup(currentString.ptr);
+
+	return OPAL_SUCCESS;
+}
+
+#define HB_LID_IDS "hb_lid_ids"
+
+/*
+ * Find lid attribute from bios tables
+ */
+int pldm_bios_find_lid_by_attr_name(const char *name, char **lid)
+{
+	char *hb_lid_ids_string = NULL;
+	int rc = OPAL_SUCCESS;
+
+	if (!bios_ready)
+		return OPAL_HARDWARE;
+
+	/* find current attribut string */
+	rc = find_bios_table_attr_values_by_string(HB_LID_IDS, &hb_lid_ids_string);
+	if (rc)
+		goto err;
+
+	/* find lid attribut from current string */
+	rc = find_lid_by_attr_name(hb_lid_ids_string, name, lid);
+	if (rc)
+		goto err;
+
+	free(hb_lid_ids_string);
+
+	prlog(PR_DEBUG, "%s - lid: %s, attr name: %s\n",
+			__func__, *lid, name);
+
+	return OPAL_SUCCESS;
+
+err:
+	if (hb_lid_ids_string)
+		free(hb_lid_ids_string);
+
+	return rc;
+}
+
+/*
+ * Get lid ids string from bios tables
+ */
+int pldm_bios_get_lids_id(char **lid_ids_string)
+{
+	if (!bios_ready)
+		return OPAL_HARDWARE;
+
+	/* find current attribut string */
+	return find_bios_table_attr_values_by_string(HB_LID_IDS, lid_ids_string);
+}
+
 /*
  * Send/receive a PLDM GetBIOSTable request message
  */
diff --git a/core/pldm/pldm.h b/core/pldm/pldm.h
index d90ff84c..4f3d262a 100644
--- a/core/pldm/pldm.h
+++ b/core/pldm/pldm.h
@@ -51,6 +51,8 @@ int pldm_rx_handle_request(struct pldm_rx_data *rx);
 int pldm_mctp_responder_init(void);
 
 /* Requester support */
+int pldm_bios_find_lid_by_attr_name(const char *name, char **lid);
+int pldm_bios_get_lids_id(char **lid_ids_string);
 int pldm_bios_init(void);
 
 void pldm_platform_exit(void);
-- 
2.35.1