Add SPI flash emulation capability to the dummy programmer

You have to choose between
- no emulation
- ST M25P10.RES SPI flash chip (RES, page write)
- SST SST25VF040.REMS SPI flash chip (REMS, byte write)
- SST SST25VF032B SPI flash chip (RDID, AAI write)
Example usage: flashrom -p dummy:emulate=SST25VF032B

Flash image persistence is available as well.
Example usage: flashrom -p dummy:image=dummy_simulator.rom

Allow setting the max chunksize for page write with the dummy
programmer.
Example usage: flashrom -p dummy:spi_write_256_chunksize=5

Flash emulation is compiled in by default. 

This code helped me find and fix various bugs in the SPI write code
as well as in the testsuite.

Corresponding to flashrom svn r1220.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: David Hendricks <dhendrix@google.com>
diff --git a/dummyflasher.c b/dummyflasher.c
index 9b8bb53..21ee9b4 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -1,12 +1,11 @@
 /*
  * This file is part of the flashrom project.
  *
- * Copyright (C) 2009 Carl-Daniel Hailfinger
+ * Copyright (C) 2009,2010 Carl-Daniel Hailfinger
  *
  * 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; either version 2 of the License, or
- * (at your option) any later version.
+ * 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
@@ -25,6 +24,43 @@
 #include "chipdrivers.h"
 #include "programmer.h"
 
+/* Remove the #define below if you don't want SPI flash chip emulation. */
+#define EMULATE_SPI_CHIP 1
+
+#if EMULATE_SPI_CHIP
+#define EMULATE_CHIP 1
+#include "spi.h"
+#endif
+
+#if EMULATE_CHIP
+#include <sys/types.h>
+#include <sys/stat.h>
+#endif
+
+#if EMULATE_CHIP
+static uint8_t *flashchip_contents = NULL;
+enum emu_chip {
+	EMULATE_NONE,
+	EMULATE_ST_M25P10_RES,
+	EMULATE_SST_SST25VF040_REMS,
+	EMULATE_SST_SST25VF032B,
+};
+static enum emu_chip emu_chip = EMULATE_NONE;
+static char *emu_persistent_image = NULL;
+static int emu_chip_size = 0;
+#if EMULATE_SPI_CHIP
+static int emu_max_byteprogram_size = 0;
+static int emu_max_aai_size = 0;
+static int emu_jedec_se_size = 0;
+static int emu_jedec_be_52_size = 0;
+static int emu_jedec_be_d8_size = 0;
+static int emu_jedec_ce_60_size = 0;
+static int emu_jedec_ce_c7_size = 0;
+#endif
+#endif
+
+static int spi_write_256_chunksize = 256;
+
 static void tolower_string(char *str)
 {
 	for (; *str != '\0'; str++)
@@ -34,6 +70,10 @@
 int dummy_init(void)
 {
 	char *bustext = NULL;
+	char *tmp = NULL;
+#if EMULATE_CHIP
+	struct stat image_stat;
+#endif
 
 	msg_pspew("%s\n", __func__);
 
@@ -65,12 +105,113 @@
 	if (buses_supported == CHIP_BUSTYPE_NONE)
 		msg_pdbg("Support for all flash bus types disabled.\n");
 	free(bustext);
+
+	tmp = extract_programmer_param("spi_write_256_chunksize");
+	if (tmp) {
+		spi_write_256_chunksize = atoi(tmp);
+		free(tmp);
+		if (spi_write_256_chunksize < 1) {
+			msg_perr("invalid spi_write_256_chunksize\n");
+			return 1;
+		}
+	}
+
+#if EMULATE_CHIP
+	tmp = extract_programmer_param("emulate");
+	if (!tmp) {
+		msg_pdbg("Not emulating any flash chip.\n");
+		/* Nothing else to do. */
+		return 0;
+	}
+#if EMULATE_SPI_CHIP
+	if (!strcmp(tmp, "M25P10.RES")) {
+		emu_chip = EMULATE_ST_M25P10_RES;
+		emu_chip_size = 128 * 1024;
+		emu_max_byteprogram_size = 128;
+		emu_max_aai_size = 0;
+		emu_jedec_se_size = 0;
+		emu_jedec_be_52_size = 0;
+		emu_jedec_be_d8_size = 32 * 1024;
+		emu_jedec_ce_60_size = 0;
+		emu_jedec_ce_c7_size = emu_chip_size;
+		msg_pdbg("Emulating ST M25P10.RES SPI flash chip (RES, page "
+			 "write)\n");
+	}
+	if (!strcmp(tmp, "SST25VF040.REMS")) {
+		emu_chip = EMULATE_SST_SST25VF040_REMS;
+		emu_chip_size = 512 * 1024;
+		emu_max_byteprogram_size = 1;
+		emu_max_aai_size = 0;
+		emu_jedec_se_size = 4 * 1024;
+		emu_jedec_be_52_size = 32 * 1024;
+		emu_jedec_be_d8_size = 0;
+		emu_jedec_ce_60_size = emu_chip_size;
+		emu_jedec_ce_c7_size = 0;
+		msg_pdbg("Emulating SST SST25VF040.REMS SPI flash chip (REMS, "
+			 "byte write)\n");
+	}
+	if (!strcmp(tmp, "SST25VF032B")) {
+		emu_chip = EMULATE_SST_SST25VF032B;
+		emu_chip_size = 4 * 1024 * 1024;
+		emu_max_byteprogram_size = 1;
+		emu_max_aai_size = 2;
+		emu_jedec_se_size = 4 * 1024;
+		emu_jedec_be_52_size = 32 * 1024;
+		emu_jedec_be_d8_size = 64 * 1024;
+		emu_jedec_ce_60_size = emu_chip_size;
+		emu_jedec_ce_c7_size = emu_chip_size;
+		msg_pdbg("Emulating SST SST25VF032B SPI flash chip (RDID, AAI "
+			 "write)\n");
+	}
+#endif
+	if (emu_chip == EMULATE_NONE) {
+		msg_perr("Invalid chip specified for emulation: %s\n", tmp);
+		free(tmp);
+		return 1;
+	}
+	free(tmp);
+	flashchip_contents = malloc(emu_chip_size);
+	if (!flashchip_contents) {
+		msg_perr("Out of memory!\n");
+		return 1;
+	}
+	msg_pdbg("Filling fake flash chip with 0xff, size %i\n", emu_chip_size);
+	memset(flashchip_contents, 0xff, emu_chip_size);
+
+	emu_persistent_image = extract_programmer_param("image");
+	if (!emu_persistent_image) {
+		/* Nothing else to do. */
+		return 0;
+	}
+	if (!stat(emu_persistent_image, &image_stat)) {
+		msg_pdbg("Found persistent image %s, size %li ",
+			 emu_persistent_image, (long)image_stat.st_size);
+		if (image_stat.st_size == emu_chip_size) {
+			msg_pdbg("matches.\n");
+			msg_pdbg("Reading %s\n", emu_persistent_image);
+			read_buf_from_file(flashchip_contents, emu_chip_size,
+					   emu_persistent_image);
+		} else {
+			msg_pdbg("doesn't match.\n");
+		}
+	}
+#endif
 	return 0;
 }
 
 int dummy_shutdown(void)
 {
 	msg_pspew("%s\n", __func__);
+#if EMULATE_CHIP
+	if (emu_chip != EMULATE_NONE) {
+		if (emu_persistent_image) {
+			msg_pdbg("Writing %s\n", emu_persistent_image);
+			write_buf_to_file(flashchip_contents, emu_chip_size,
+					  emu_persistent_image);
+		}
+		free(flashchip_contents);
+	}
+#endif
 	return 0;
 }
 
@@ -140,6 +281,209 @@
 	return;
 }
 
+#if EMULATE_SPI_CHIP
+static int emulate_spi_chip_response(unsigned int writecnt, unsigned int readcnt,
+		      const unsigned char *writearr, unsigned char *readarr)
+{
+	int offs;
+	static int aai_offs;
+	static int aai_active = 0;
+
+	if (writecnt == 0) {
+		msg_perr("No command sent to the chip!\n");
+		return 1;
+	}
+	/* TODO: Implement command blacklists here. */
+	switch (writearr[0]) {
+	case JEDEC_RES:
+		if (emu_chip != EMULATE_ST_M25P10_RES)
+			break;
+		/* Respond with ST_M25P10_RES. */
+		if (readcnt > 0)
+			readarr[0] = 0x10;
+		break;
+	case JEDEC_REMS:
+		if (emu_chip != EMULATE_SST_SST25VF040_REMS)
+			break;
+		/* Respond with SST_SST25VF040_REMS. */
+		if (readcnt > 0)
+			readarr[0] = 0xbf;
+		if (readcnt > 1)
+			readarr[1] = 0x44;
+		break;
+	case JEDEC_RDID:
+		if (emu_chip != EMULATE_SST_SST25VF032B)
+			break;
+		/* Respond with SST_SST25VF032B. */
+		if (readcnt > 0)
+			readarr[0] = 0xbf;
+		if (readcnt > 1)
+			readarr[1] = 0x25;
+		if (readcnt > 2)
+			readarr[2] = 0x4a;
+		break;
+	case JEDEC_RDSR:
+		memset(readarr, 0, readcnt);
+		if (aai_active)
+			memset(readarr, 1 << 6, readcnt);
+		break;
+	case JEDEC_READ:
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		/* Truncate to emu_chip_size. */
+		offs %= emu_chip_size;
+		if (readcnt > 0)
+			memcpy(readarr, flashchip_contents + offs, readcnt);
+		break;
+	case JEDEC_BYTE_PROGRAM:
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		/* Truncate to emu_chip_size. */
+		offs %= emu_chip_size;
+		if (writecnt < 5) {
+			msg_perr("BYTE PROGRAM size too short!\n");
+			return 1;
+		}
+		if (writecnt - 4 > emu_max_byteprogram_size) {
+			msg_perr("Max BYTE PROGRAM size exceeded!\n");
+			return 1;
+		}
+		memcpy(flashchip_contents + offs, writearr + 4, writecnt - 4);
+		break;
+	case JEDEC_AAI_WORD_PROGRAM:
+		if (!emu_max_aai_size)
+			break;
+		if (!aai_active) {
+			if (writecnt < JEDEC_AAI_WORD_PROGRAM_OUTSIZE) {
+				msg_perr("Initial AAI WORD PROGRAM size too "
+					 "short!\n");
+				return 1;
+			}
+			if (writecnt > JEDEC_AAI_WORD_PROGRAM_OUTSIZE) {
+				msg_perr("Initial AAI WORD PROGRAM size too "
+					 "long!\n");
+				return 1;
+			}
+			aai_active = 1;
+			aai_offs = writearr[1] << 16 | writearr[2] << 8 |
+				   writearr[3];
+			/* Truncate to emu_chip_size. */
+			aai_offs %= emu_chip_size;
+			memcpy(flashchip_contents + aai_offs, writearr + 4, 2);
+			aai_offs += 2;
+		} else {
+			if (writecnt < JEDEC_AAI_WORD_PROGRAM_CONT_OUTSIZE) {
+				msg_perr("Continuation AAI WORD PROGRAM size "
+					 "too short!\n");
+				return 1;
+			}
+			if (writecnt > JEDEC_AAI_WORD_PROGRAM_CONT_OUTSIZE) {
+				msg_perr("Continuation AAI WORD PROGRAM size "
+					 "too long!\n");
+				return 1;
+			}
+			memcpy(flashchip_contents + aai_offs, writearr + 1, 2);
+			aai_offs += 2;
+		}
+		break;
+	case JEDEC_WRDI:
+		if (!emu_max_aai_size)
+			break;
+		aai_active = 0;
+		break;
+	case JEDEC_SE:
+		if (!emu_jedec_se_size)
+			break;
+		if (writecnt != JEDEC_SE_OUTSIZE) {
+			msg_perr("SECTOR ERASE 0x20 outsize invalid!\n");
+			return 1;
+		}
+		if (readcnt != JEDEC_SE_INSIZE) {
+			msg_perr("SECTOR ERASE 0x20 insize invalid!\n");
+			return 1;
+		}
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		if (offs & (emu_jedec_se_size - 1))
+			msg_pdbg("Unaligned SECTOR ERASE 0x20\n");
+		offs &= ~(emu_jedec_se_size - 1);
+		memset(flashchip_contents + offs, 0xff, emu_jedec_se_size);
+		break;
+	case JEDEC_BE_52:
+		if (!emu_jedec_be_52_size)
+			break;
+		if (writecnt != JEDEC_BE_52_OUTSIZE) {
+			msg_perr("BLOCK ERASE 0x52 outsize invalid!\n");
+			return 1;
+		}
+		if (readcnt != JEDEC_BE_52_INSIZE) {
+			msg_perr("BLOCK ERASE 0x52 insize invalid!\n");
+			return 1;
+		}
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		if (offs & (emu_jedec_be_52_size - 1))
+			msg_pdbg("Unaligned BLOCK ERASE 0x52\n");
+		offs &= ~(emu_jedec_be_52_size - 1);
+		memset(flashchip_contents + offs, 0xff, emu_jedec_be_52_size);
+		break;
+	case JEDEC_BE_D8:
+		if (!emu_jedec_be_d8_size)
+			break;
+		if (writecnt != JEDEC_BE_D8_OUTSIZE) {
+			msg_perr("BLOCK ERASE 0xd8 outsize invalid!\n");
+			return 1;
+		}
+		if (readcnt != JEDEC_BE_D8_INSIZE) {
+			msg_perr("BLOCK ERASE 0xd8 insize invalid!\n");
+			return 1;
+		}
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		if (offs & (emu_jedec_be_d8_size - 1))
+			msg_pdbg("Unaligned BLOCK ERASE 0xd8\n");
+		offs &= ~(emu_jedec_be_d8_size - 1);
+		memset(flashchip_contents + offs, 0xff, emu_jedec_be_d8_size);
+		break;
+	case JEDEC_CE_60:
+		if (!emu_jedec_ce_60_size)
+			break;
+		if (writecnt != JEDEC_CE_60_OUTSIZE) {
+			msg_perr("CHIP ERASE 0x60 outsize invalid!\n");
+			return 1;
+		}
+		if (readcnt != JEDEC_CE_60_INSIZE) {
+			msg_perr("CHIP ERASE 0x60 insize invalid!\n");
+			return 1;
+		}
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		if (offs & (emu_jedec_ce_60_size - 1))
+			msg_pdbg("Unaligned CHIP ERASE 0x60\n");
+		offs &= ~(emu_jedec_ce_60_size - 1);
+		/* emu_jedec_ce_60_size is emu_chip_size. */
+		memset(flashchip_contents + offs, 0xff, emu_jedec_ce_60_size);
+		break;
+	case JEDEC_CE_C7:
+		if (!emu_jedec_ce_c7_size)
+			break;
+		if (writecnt != JEDEC_CE_C7_OUTSIZE) {
+			msg_perr("CHIP ERASE 0xc7 outsize invalid!\n");
+			return 1;
+		}
+		if (readcnt != JEDEC_CE_C7_INSIZE) {
+			msg_perr("CHIP ERASE 0xc7 insize invalid!\n");
+			return 1;
+		}
+		offs = writearr[1] << 16 | writearr[2] << 8 | writearr[3];
+		if (offs & (emu_jedec_ce_c7_size - 1))
+			msg_pdbg("Unaligned CHIP ERASE 0xc7\n");
+		offs &= ~(emu_jedec_ce_c7_size - 1);
+		/* emu_jedec_ce_c7_size is emu_chip_size. */
+		memset(flashchip_contents, 0xff, emu_jedec_ce_c7_size);
+		break;
+	default:
+		/* No special response. */
+		break;
+	}
+	return 0;
+}
+#endif
+
 int dummy_spi_send_command(unsigned int writecnt, unsigned int readcnt,
 		      const unsigned char *writearr, unsigned char *readarr)
 {
@@ -151,12 +495,27 @@
 	for (i = 0; i < writecnt; i++)
 		msg_pspew(" 0x%02x", writearr[i]);
 
+	/* Response for unknown commands and missing chip is 0xff. */
+	memset(readarr, 0xff, readcnt);
+#if EMULATE_SPI_CHIP
+	switch (emu_chip) {
+	case EMULATE_ST_M25P10_RES:
+	case EMULATE_SST_SST25VF040_REMS:
+	case EMULATE_SST_SST25VF032B:
+		if (emulate_spi_chip_response(writecnt, readcnt, writearr,
+					      readarr)) {
+			msg_perr("Invalid command sent to flash chip!\n");
+			return 1;
+		}
+		break;
+	default:
+		break;
+	}
+#endif
 	msg_pspew(" reading %u bytes:", readcnt);
 	for (i = 0; i < readcnt; i++) {
-		msg_pspew(" 0xff");
-		readarr[i] = 0xff;
+		msg_pspew(" 0x%02x", readarr[i]);
 	}
-
 	msg_pspew("\n");
 	return 0;
 }
@@ -167,11 +526,8 @@
 	return spi_read_chunked(flash, buf, start, len, 64 * 1024);
 }
 
-/* Is is impossible to trigger this code path because dummyflasher probing will
- * never be successful, and the current frontend refuses to write in that case.
- * Other frontends may allow writing even for non-detected chips, though.
- */
 int dummy_spi_write_256(struct flashchip *flash, uint8_t *buf, int start, int len)
 {
-	return spi_write_chunked(flash, buf, start, len, 256);
+	return spi_write_chunked(flash, buf, start, len,
+				 spi_write_256_chunksize);
 }