[coreboot-gerrit] Patch set updated for coreboot: chromeos: Implement locating and decoding wifi sar data from VPD

[Robbie Zhang (robbie.zhang@intel.com)]

Robbie Zhang (robbie.zhang at intel.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/17958

-gerrit

commit 7280b732a14404aa96ffc77bcfa10f70bbcd6501
Author: Robbie Zhang <robbie.zhang at intel.com>
Date:   Fri Dec 23 11:43:07 2016 -0800

    chromeos: Implement locating and decoding wifi sar data from VPD
    
    A VPD entry "wifi_sar" needs to be created which contains a heximal
    encoded string in length of 40 bytes. wifi_sar_limits() function
    retrieves and decodes the data from the VPD entry, which would later
    be consumed by platform code.
    
    BUG=chrome-os-partner:60821
    TEST=Build and boot lars and reef
    
    Change-Id: I923b58a63dc1f8a7fdd685cf1c618b2fdf4e7061
    Signed-off-by: Robbie Zhang <robbie.zhang at intel.com>
---
 src/include/sar.h                           | 28 ++++++++++
 src/vendorcode/google/chromeos/Makefile.inc |  1 +
 src/vendorcode/google/chromeos/cros_vpd.h   |  1 +
 src/vendorcode/google/chromeos/sar.c        | 82 +++++++++++++++++++++++++++++
 4 files changed, 112 insertions(+)

diff --git a/src/include/sar.h b/src/include/sar.h
new file mode 100644
index 0000000..32e83ec
--- /dev/null
+++ b/src/include/sar.h
@@ -0,0 +1,28 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corp.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+#ifndef _SAR_H_
+#define _SAR_H_
+
+#include <stdint.h>
+
+/* Wifi SAR limit table structure */
+struct wifi_sar_limit_t{
+	uint8_t sar_limit[40]; /* Total 4 SAR limit sets, each has 10 bytes */
+};
+
+/* Retrieve the SAR limits data from VPD and decode it */
+void wifi_sar_limits(struct wifi_sar_limit_t *sar_limits);
+
+#endif /* _SAR_H_ */
diff --git a/src/vendorcode/google/chromeos/Makefile.inc b/src/vendorcode/google/chromeos/Makefile.inc
index e84eb3d..878b068 100644
--- a/src/vendorcode/google/chromeos/Makefile.inc
+++ b/src/vendorcode/google/chromeos/Makefile.inc
@@ -25,6 +25,7 @@ ramstage-$(CONFIG_CHROMEOS_RAMOOPS) += ramoops.c
 romstage-y += vpd_decode.c
 ramstage-y += vpd_decode.c cros_vpd.c vpd_mac.c vpd_serialno.c vpd_calibration.c
 ramstage-$(CONFIG_HAVE_REGULATORY_DOMAIN) += wrdd.c
+ramstage-$(CONFIG_USE_SAR) += sar.c
 ifeq ($(CONFIG_ARCH_MIPS),)
 bootblock-y += watchdog.c
 ramstage-y += watchdog.c
diff --git a/src/vendorcode/google/chromeos/cros_vpd.h b/src/vendorcode/google/chromeos/cros_vpd.h
index 96ca8af..1fa56a4 100644
--- a/src/vendorcode/google/chromeos/cros_vpd.h
+++ b/src/vendorcode/google/chromeos/cros_vpd.h
@@ -8,6 +8,7 @@
 #define __CROS_VPD_H__
 
 #define CROS_VPD_REGION_NAME "region"
+#define CROS_VPD_WIFI_SAR_NAME "wifi_sar"
 
 /*
  * Reads VPD string value by key.
diff --git a/src/vendorcode/google/chromeos/sar.c b/src/vendorcode/google/chromeos/sar.c
new file mode 100644
index 0000000..c5adbf1
--- /dev/null
+++ b/src/vendorcode/google/chromeos/sar.c
@@ -0,0 +1,82 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corp.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ */
+#include <console/console.h>
+#include <types.h>
+#include <string.h>
+#include <sar.h>
+#include "cros_vpd.h"
+
+/*
+ * Decode string representation of the SAR limits (a string of hex symbols)
+ * into binary. 'key_name' is the name of the VPD field, it's used if
+ * it is necessary to report an input data format problem.
+ */
+static void decode_sar_limit(struct wifi_sar_limit_t *sar_limits,
+		       const char *sar_limit_str,
+		       const char *key_name)
+{
+	int i;
+	size_t size = sizeof(struct wifi_sar_limit_t) / sizeof(uint8_t);
+
+	for (i = 0; i < size; i++) {
+		int j;
+		int n = 0;
+
+		for (j = 0; j < 2; j++) {
+			char c = sar_limit_str[i * 2 + j];
+			if (isxdigit(c)) {
+				if (isdigit(c))
+					c = c - '0';
+				else
+					c =  tolower(c) - 'a' + 10;
+			} else {
+				printk(BIOS_ERR, "%s: non hexadecimal symbol "
+					"%#2.2x in the VPD field %s:%s\n",
+					__func__, (uint8_t)c, key_name,
+					sar_limit_str);
+			}
+			n <<= 4;
+			n |= c;
+		}
+		sar_limits->sar_limit[i] = n;
+	}
+}
+
+/* Retrieve the wifi SAR limits from VPD and decode it */
+void wifi_sar_limits(struct wifi_sar_limit_t *sar_limits)
+{
+	const char *wifi_sar_limit_key = CROS_VPD_WIFI_SAR_NAME;
+	/*
+	 * cros_vpd_gets() reads in one less than size characters from the VPD
+	 * with a terminating null byte ('\0') stored as the last character into
+	 * the buffer, thus the increasing by 1 for buffer_size.
+	 */
+	const size_t buffer_size = (sizeof(struct wifi_sar_limit_t) /
+				    sizeof(uint8_t)) * 2 + 1;
+	char wifi_sar_limit_str[buffer_size];
+
+	/* Try to read the SAR limit entry from VPD */
+	if (!cros_vpd_gets(wifi_sar_limit_key, wifi_sar_limit_str,
+		ARRAY_SIZE(wifi_sar_limit_str))) {
+		printk(BIOS_DEBUG,
+			"Error: Could not locate '%s' in VPD\n",
+			wifi_sar_limit_key);
+		return;
+	}
+	printk(BIOS_ERR, "VPD wifi_sar = %s\n", wifi_sar_limit_str);
+
+	/* Decode the heximal encoded string to binary values */
+	decode_sar_limit(sar_limits, wifi_sar_limit_str, wifi_sar_limit_key);
+}