core/pldm: Find lid attribute from bios tables

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.

Reviewed-by: Abhishek Singh Tomar <abhishek@linux.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.ibm.com>
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>

2 files changed, 151 insertions, 0 deletions

diff --git a/core/pldm/pldm-bios-requests.c b/core/pldm/pldm-bios-requests.c
index 0fa198a..d3aeb18 100644
--- a/core/pldm/pldm-bios-requests.c
+++ b/core/pldm/pldm-bios-requests.c
@@ -85,6 +85,154 @@ static void bios_init_complete(bool success)
 }
 
 /*
+ * 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)
+{
+	const char *pp = "=";
+	char *attr, *attr_end;
+	char *p;
+
+	for (p = strtok(str, ","); p != NULL; p = strtok(NULL, ",")) {
+		/* parse now the following string <ATTR>=<lid_id> */
+		attr = p;
+		while ((*pp != *p) && (*p != '\0'))
+			p++;
+
+		attr_end = p;
+		*attr_end = '\0';
+
+		if (!strncmp(attr, name, strlen(name)) &&
+		    (strlen(attr) == strlen(name))) {
+			*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_HARDWARE;
+
+	/* 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
  */
 static int get_bios_table_req(enum pldm_bios_table_types table_type,
diff --git a/core/pldm/pldm.h b/core/pldm/pldm.h
index 3f46590..0601349 100644
--- a/core/pldm/pldm.h
+++ b/core/pldm/pldm.h
@@ -7,6 +7,7 @@
 
 #include <ast.h>
 #include <base.h>
+#include <utils.h>
 #include <pldm.h>
 
 #define PLDM_MSG_SIZE(x) (sizeof(struct pldm_msg_hdr) + sizeof(x))
@@ -51,6 +52,8 @@ int pldm_responder_handle_request(struct pldm_rx_data *rx);
 int pldm_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);
 
 uint8_t pldm_base_get_bmc_tid(void);