Edward O'Callaghan submitted this change.

View Change

dummyflasher.c: Only write back emulated image if modified

When the image is not modified, there is no point in writing it back.
In fact we may not have file permissions to do so.

Signed-off-by: Namyoon Woo <namyoon@google.com>
Change-Id: I3bf2d7edb28a9a1e5406b67a88a0ee6e07db83e3
Reviewed-on: https://review.coreboot.org/c/flashrom/+/44907
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
M dummyflasher.c
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/dummyflasher.c b/dummyflasher.c
index b2b3b54..145fe11 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -50,6 +50,7 @@
 static enum emu_chip emu_chip = EMULATE_NONE;
 static char *emu_persistent_image = NULL;
 static unsigned int emu_chip_size = 0;
+static int emu_modified = 0;	/* is the image modified since reading it? */
 #if EMULATE_SPI_CHIP
 static unsigned int emu_max_byteprogram_size = 0;
 static unsigned int emu_max_aai_size = 0;
@@ -137,7 +138,7 @@
 	msg_pspew("%s\n", __func__);
 #if EMULATE_CHIP
 	if (emu_chip != EMULATE_NONE) {
-		if (emu_persistent_image) {
+		if (emu_persistent_image && emu_modified) {
 			msg_pdbg("Writing %s\n", emu_persistent_image);
 			write_buf_to_file(flashchip_contents, emu_chip_size, emu_persistent_image);
 			free(emu_persistent_image);
@@ -698,6 +699,7 @@
 			return 1;
 		}
 		memcpy(flashchip_contents + offs, writearr + 4, writecnt - 4);
+		emu_modified = 1;
 		break;
 	case JEDEC_AAI_WORD_PROGRAM:
 		if (!emu_max_aai_size)
@@ -734,6 +736,7 @@
 			memcpy(flashchip_contents + aai_offs, writearr + 1, 2);
 			aai_offs += 2;
 		}
+		emu_modified = 1;
 		break;
 	case JEDEC_WRDI:
 		if (emu_max_aai_size)
@@ -755,6 +758,7 @@
 			msg_pdbg("Unaligned SECTOR ERASE 0x20: 0x%x\n", offs);
 		offs &= ~(emu_jedec_se_size - 1);
 		memset(flashchip_contents + offs, 0xff, emu_jedec_se_size);
+		emu_modified = 1;
 		break;
 	case JEDEC_BE_52:
 		if (!emu_jedec_be_52_size)
@@ -772,6 +776,7 @@
 			msg_pdbg("Unaligned BLOCK ERASE 0x52: 0x%x\n", offs);
 		offs &= ~(emu_jedec_be_52_size - 1);
 		memset(flashchip_contents + offs, 0xff, emu_jedec_be_52_size);
+		emu_modified = 1;
 		break;
 	case JEDEC_BE_D8:
 		if (!emu_jedec_be_d8_size)
@@ -789,6 +794,7 @@
 			msg_pdbg("Unaligned BLOCK ERASE 0xd8: 0x%x\n", offs);
 		offs &= ~(emu_jedec_be_d8_size - 1);
 		memset(flashchip_contents + offs, 0xff, emu_jedec_be_d8_size);
+		emu_modified = 1;
 		break;
 	case JEDEC_CE_60:
 		if (!emu_jedec_ce_60_size)
@@ -804,6 +810,7 @@
 		/* JEDEC_CE_60_OUTSIZE is 1 (no address) -> no offset. */
 		/* emu_jedec_ce_60_size is emu_chip_size. */
 		memset(flashchip_contents, 0xff, emu_jedec_ce_60_size);
+		emu_modified = 1;
 		break;
 	case JEDEC_CE_C7:
 		if (!emu_jedec_ce_c7_size)
@@ -819,6 +826,7 @@
 		/* JEDEC_CE_C7_OUTSIZE is 1 (no address) -> no offset. */
 		/* emu_jedec_ce_c7_size is emu_chip_size. */
 		memset(flashchip_contents, 0xff, emu_jedec_ce_c7_size);
+		emu_modified = 1;
 		break;
 	case JEDEC_SFDP:
 		if (emu_chip != EMULATE_MACRONIX_MX25L6436)

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