[RFC V2 3/3] add decode command (SPD EEPROM data decoder)

[Alexander Smirnov]

decode-dimms perl script is used as prototype
(see https://github.com/groeck/i2c-tools/blob/master/eeprom/decode-dimms).

Here is a sample decode output:

barebox at barebox sandbox:/ decode env/crucial_pc2-6400_ddr2
Decoding EEPROM: env/crucial_pc2-6400_ddr2

---=== SPD EEPROM Information ===---
EEPROM Checksum of bytes 0-62			 OK (0xCA)
Total number of bytes in EEPROM			 256
Fundamental Memory type				 DDR2 SDRAM
SPD Revision					 1.3

---=== Memory Characteristics ===---
Maximum module speed				 800 MHz (PC2-6400)
Size						 1024 MB
Banks x Rows x Columns x Bits			 8 x 14 x 10 x 64
Ranks						 1
SDRAM Device Width				 8 bits
Module Height					 30.0 mm
Module Type					 SO-DIMM (67.6 mm)
DRAM Package					 Planar
Voltage Interface Level				 SSTL 1.8V
Module Configuration Type 			 No Parity
Refresh Rate					 Reduced (7.8 us) - Self Refresh
Supported Burst Lengths				 4, 8
Supported CAS Latencies (tCL)			 6T
tCL-tRCD-tRP-tRAS				 6-6-6-18 as DDR2-800
Minimum Cycle Time				 250 (ns*100) at CAS 6
Maximum Access Time				 4 (ns*10) at CAS 6
Maximum Cycle Time (tCK max)			 8 ns

---=== Timing Parameters ===---
Address/Command Setup Time Before Clock (tIS)	 17 (ns*100)
Address/Command Hold Time After Clock (tIH)	 25 (ns*100)
Data Input Setup Time Before Strobe (tDS)	 5 (ns*100)
Data Input Hold Time After Strobe (tDH)		 12 (ns*100)
Minimum Row Precharge Delay (tRP)		 150 (ns*10)
Minimum Row Active to Row Active Delay (tRRD)	 75 (ns*10)
Minimum RAS# to CAS# Delay (tRCD)		 150 (ns*10)
Minimum RAS# Pulse Width (tRAS)			 450 (ns*10)
Write Recovery Time (tWR)			 150 (ns*10)
Minimum Write to Read CMD Delay (tWTR)		 75 (ns*10)
Minimum Read to Pre-charge CMD Delay (tRTP)	 75 (ns*10)
Minimum Active to Auto-refresh Delay (tRC)	 600 (ns*10)
Minimum Recovery Delay (tRFC)			 1270 (ns*10)
Maximum DQS to DQ Skew (tDQSQ)			 20 (ns*100)
Maximum Read Data Hold Skew (tQHS)		 30 (ns*100)

---=== Manufacturing Information ===---
Manufacturer JEDEC ID				 7f 7f 7f 7f 7f 9b 00 00
Part Number					 CT12864AC800.M8FM8
Manufacturing Date				 2014-W24
Assembly Serial Number				 0x00000000

TODOs:

  * Timing Parameters section output format is slightly
    differ from decode-dimms' format;
  * supports only DDR2 SPD EEPROM.

Signed-off-by: Alexander Smirnov <alllecs at yandex.ru>
---
 commands/Kconfig  |  7 ++++++
 commands/Makefile |  1 +
 commands/decode.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)

diff --git a/commands/Kconfig b/commands/Kconfig
index bb6674e..9230873 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -2102,6 +2102,13 @@ config CMD_STATE
 	depends on STATE
 	prompt "state"
 
+config CMD_DECODE
+	tristate
+	prompt "decode"
+	select DDR_SPD
+	help
+	  decode spd eeprom
+
 # end Miscellaneous commands
 endmenu
 
diff --git a/commands/Makefile b/commands/Makefile
index 3698347..71cd877 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -112,3 +112,4 @@ obj-$(CONFIG_CMD_NV)		+= nv.o
 obj-$(CONFIG_CMD_DEFAULTENV)	+= defaultenv.o
 obj-$(CONFIG_CMD_STATE)		+= state.o
 obj-$(CONFIG_CMD_DHCP)		+= dhcp.o
+obj-$(CONFIG_CMD_DECODE)	+= decode.o
diff --git a/commands/decode.c b/commands/decode.c
new file mode 100644
index 0000000..80da80c
--- /dev/null
+++ b/commands/decode.c
@@ -0,0 +1,65 @@
+#include <fcntl.h>
+#include <common.h>
+#include <getopt.h>
+#include <command.h>
+#include <envfs.h>
+#include <errno.h>
+#include <fs.h>
+#include <libfile.h>
+#include <malloc.h>
+#include <globalvar.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <ddr_spd.h>
+
+void dump(uint8_t *addr, int len)
+{
+	int i;
+
+	printf("\t 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f\n\n");
+
+	for (i = 0; i < len; i++) {
+		if ((i % 0x10) == 0x00) {
+			printf("%07x:", i);
+		}
+		printf(" %02x", addr[i]);
+		if ((i % 0x10) == 0xf) {
+			printf("\n");
+		}
+	}
+
+	printf("\n");
+}
+
+static int do_decode(int argc, char *argv[])
+{
+	int fp;
+	uint8_t record[256];
+
+	if (argc != 2) {
+		return COMMAND_ERROR_USAGE;
+	}
+
+	fp = open(argv[1], O_RDONLY);
+
+	if (fp < 0) {
+		printf("could not open %s: %s\n", argv[args], errno_str());
+	}
+
+	read(fp, &record[0], 256);
+	close(fp);
+
+	printf("Decoding EEPROM: %s\n\n", argv[1]);
+
+	prin(record);
+	printf("\n\n");
+
+	return 0;
+}
+BAREBOX_CMD_HELP_START(decode)
+BAREBOX_CMD_HELP_TEXT("Not enough or more than one argument to continue.")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(decode)
+	.cmd            = do_decode,
+BAREBOX_CMD_END
-- 
2.1.4