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

[Sascha Hauer]

On Wed, Jun 24, 2015 at 03:57:29PM +0300, Alexander Smirnov wrote:
> 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);

read_file_2 is your friend here. It reads a file into an allocated
buffer.

Sascha


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