SPI command black-/ignorelisting for the flash chip emulator in the dummy programmer

Usage:
flashrom -p dummy:spi_blacklist=commandlist
flashrom -p dummy:spi_ignorelist=commandlist

If commandlist is 0302, flashrom will refuse (blacklist) or ignore
(ignorelist) command 0x03 (READ) and command 0x02 (WRITE). The
commandlist can be up to 512 bytes (256 commands) long.
Specifying flash chip emulation is a good idea to get useful results.

Very useful for testing corner cases if you don't own a locked down
Intel chipset and want to simulate such a thing.

Example usage:
dd if=/dev/zeros bs=1024k count=4 of=dummy_simulator.rom
dd if=/dev/urandom bs=1024k count=4 of=randomimage.rom
flashrom -p dummy:emulate=SST25VF032B,image=dummy_simulator.rom,\
spi_blacklist=20,spi_ignorelist=52 -w randomimage.rom -V

Corresponding to flashrom svn r1490.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: David Hendricks <dhendrix@google.com>

dummyflasher.c

@@ -19,6 +19,8 @@
 
 #include <string.h>
 #include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
 #include "flash.h"
 #include "chipdrivers.h"
 #include "programmer.h"
@@ -55,6 +57,10 @@ static unsigned int emu_jedec_be_52_size = 0;
 static unsigned int emu_jedec_be_d8_size = 0;
 static unsigned int emu_jedec_ce_60_size = 0;
 static unsigned int emu_jedec_ce_c7_size = 0;
+unsigned char spi_blacklist[256];
+unsigned char spi_ignorelist[256];
+int spi_blacklist_size = 0;
+int spi_ignorelist_size = 0;
 #endif
 #endif
 
@@ -126,6 +132,7 @@ int dummy_init(void)
 {
 	char *bustext = NULL;
 	char *tmp = NULL;
+	int i;
 #if EMULATE_CHIP
 	struct stat image_stat;
 #endif
@@ -170,6 +177,68 @@ int dummy_init(void)
 		}
 	}
 
+	tmp = extract_programmer_param("spi_blacklist");
+	if (tmp) {
+		i = strlen(tmp);
+		if (!strncmp(tmp, "0x", 2)) {
+			i -= 2;
+			memmove(tmp, tmp + 2, i + 1);
+		}
+		if ((i > 512) || (i % 2)) {
+			msg_perr("Invalid SPI command blacklist length\n");
+			free(tmp);
+			return 1;
+		}
+		spi_blacklist_size = i / 2;
+		for (i = 0; i < spi_blacklist_size * 2; i++) {
+			if (!isxdigit((unsigned char)tmp[i])) {
+				msg_perr("Invalid char \"%c\" in SPI command "
+					 "blacklist\n", tmp[i]);
+				free(tmp);
+				return 1;
+			}
+		}
+		for (i = 0; i < spi_blacklist_size; i++) {
+			sscanf(tmp + i * 2, "%2hhx", &spi_blacklist[i]);
+		}
+		msg_pdbg("SPI blacklist is ");
+		for (i = 0; i < spi_blacklist_size; i++)
+			msg_pdbg("%02x ", spi_blacklist[i]);
+		msg_pdbg(", size %i\n", spi_blacklist_size);
+	}
+	free(tmp);
+
+	tmp = extract_programmer_param("spi_ignorelist");
+	if (tmp) {
+		i = strlen(tmp);
+		if (!strncmp(tmp, "0x", 2)) {
+			i -= 2;
+			memmove(tmp, tmp + 2, i + 1);
+		}
+		if ((i > 512) || (i % 2)) {
+			msg_perr("Invalid SPI command ignorelist length\n");
+			free(tmp);
+			return 1;
+		}
+		spi_ignorelist_size = i / 2;
+		for (i = 0; i < spi_ignorelist_size * 2; i++) {
+			if (!isxdigit((unsigned char)tmp[i])) {
+				msg_perr("Invalid char \"%c\" in SPI command "
+					 "ignorelist\n", tmp[i]);
+				free(tmp);
+				return 1;
+			}
+		}
+		for (i = 0; i < spi_ignorelist_size; i++) {
+			sscanf(tmp + i * 2, "%2hhx", &spi_ignorelist[i]);
+		}
+		msg_pdbg("SPI ignorelist is ");
+		for (i = 0; i < spi_ignorelist_size; i++)
+			msg_pdbg("%02x ", spi_ignorelist[i]);
+		msg_pdbg(", size %i\n", spi_ignorelist_size);
+	}
+	free(tmp);
+
 #if EMULATE_CHIP
 	tmp = extract_programmer_param("emulate");
 	if (!tmp) {
@@ -348,7 +417,7 @@ static int emulate_spi_chip_response(unsigned int writecnt,
 				     const unsigned char *writearr,
 				     unsigned char *readarr)
 {
-	unsigned int offs;
+	unsigned int offs, i;
 	static int unsigned aai_offs;
 	static int aai_active = 0;
 
@@ -356,7 +425,24 @@ static int emulate_spi_chip_response(unsigned int writecnt,
 		msg_perr("No command sent to the chip!\n");
 		return 1;
 	}
-	/* TODO: Implement command blacklists here. */
+	/* spi_blacklist has precedence before spi_ignorelist. */
+	for (i = 0; i < spi_blacklist_size; i++) {
+		if (writearr[0] == spi_blacklist[i]) {
+			msg_pdbg("Refusing blacklisted SPI command 0x%02x\n",
+				 spi_blacklist[i]);
+			return SPI_INVALID_OPCODE;
+		}
+	}
+	for (i = 0; i < spi_ignorelist_size; i++) {
+		if (writearr[0] == spi_ignorelist[i]) {
+			msg_cdbg("Ignoring ignorelisted SPI command 0x%02x\n",
+				 spi_ignorelist[i]);
+			/* Return success because the command does not fail,
+			 * it is simply ignored.
+			 */
+			return 0;
+		}
+	}
 	switch (writearr[0]) {
 	case JEDEC_RES:
 		if (emu_chip != EMULATE_ST_M25P10_RES)
@@ -563,7 +649,7 @@ static int dummy_spi_send_command(struct flashctx *flash, unsigned int writecnt,
 	case EMULATE_SST_SST25VF032B:
 		if (emulate_spi_chip_response(writecnt, readcnt, writearr,
 					      readarr)) {
-			msg_perr("Invalid command sent to flash chip!\n");
+			msg_pdbg("Invalid command sent to flash chip!\n");
 			return 1;
 		}
 		break;

flashrom.8

@@ -421,6 +421,28 @@ is the number of bytes (min. 1, max. 256).
 Example:
 .sp
 .B "  flashrom -p dummy:emulate=M25P10.RES,spi_write_256_chunksize=5"
+.sp
+To simulate a programmer which refuses to send certain SPI commands to the
+flash chip, you can specify a blacklist of SPI commands with the
+.sp
+.B "  flashrom -p dummy:spi_blacklist=commandlist"
+.sp
+syntax where commandlist is a list of two-digit hexadecimal representations of
+SPI commands. If commandlist is e.g. 0302, flashrom will behave as if the SPI
+controller refuses to run command 0x03 (READ) and command 0x02 (WRITE).
+commandlist may be up to 512 characters (256 commands) long.
+Implementation note: flashrom will detect an error during command execution.
+.sp
+To simulate a flash chip which ignores (doesn't support) certain SPI commands,
+you can specify an ignorelist of SPI commands with the
+.sp
+.B "  flashrom -p dummy:spi_ignorelist=commandlist"
+.sp
+syntax where commandlist is a list of two-digit hexadecimal representations of
+SPI commands. If commandlist is e.g. 0302, the emulated flash chip will ignore
+command 0x03 (READ) and command 0x02 (WRITE).  commandlist may be up to 512
+characters (256 commands) long.
+Implementation note: flashrom won't detect an error during command execution.
 .TP
 .BR "nic3com" , " nicrealtek" , " nicsmc1211" , " nicnatsemi" , " nicintel\
 " , " nicintel_spi" , " gfxnvidia" , " ogp_spi" , " drkaiser" , " satasii\