[S] Change in flashrom[main]: erasure_layout: Add an option to sacrifice unchanged blocks for speed

[Bill XIE (Code Review)]

Attention is currently required from: Aarya.

Bill XIE has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/84721?usp=email )

Change subject: erasure_layout: Add an option to sacrifice unchanged blocks for speed
......................................................................

erasure_layout: Add an option to sacrifice unchanged blocks for speed

Someone may prefer to sacrifice sub-blocks needless to change within a
larger erase block for programming speed. These people who are okay to
fry their chip sooner can set this option. If the percentage of
sub-blocks needless to change within a larger erase block is lower
than the given value, the whole larger erase block will be erased.

Change-Id: I154e8a713f626c37dbbe118db700055b96d24803
Signed-off-by: persmule 
---
M cli_classic.c
M erasure_layout.c
M include/flash.h
3 files changed, 25 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/21/84721/1

diff --git a/cli_classic.c b/cli_classic.c
index 3343438..dc51259 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -45,6 +45,7 @@
    OPTION_WP_DISABLE,
    OPTION_WP_LIST,
    OPTION_PROGRESS,
+	OPTION_SACRIFICE_RATIO,
 };

struct cli_options {
@@ -73,6 +74,7 @@
    char *logfile;
    char *referencefile;
    const char *chip_to_probe;
+	int sacrifice_ratio;
 };

static void cli_classic_usage(const char *name)
@@ -119,6 +121,10 @@
           "      --flash-contents <ref-file>   assume flash contents to be <ref-file>\n"
           " -L | --list-supported              print supported devices\n"
           "      --progress                    show progress percentage on the standard output\n"
+	       "      --sacrifice-ratio <ratio>     The percentage of overall sub-blocks needless to\n"
+	       "                                    change within a larger erase block to be sacrificed\n"
+	       "                                    for programming speed, default 0, max 100\n"
+	       "                                    DANGEROUS! It wears your chip harder!\n"
           " -p | --programmer <name>[:<param>] specify the programmer device. One of\n");
    list_programmers_linebreak(4, 80, 0);
    printf(".\n\nYou can specify one of -h, -R, -L, "
@@ -810,6 +816,10 @@
    	case OPTION_PROGRESS:
    		options->show_progress = true;
    		break;
+		case OPTION_SACRIFICE_RATIO:
+			/* It is okay to convert invalid input to 0. */
+			options->sacrifice_ratio = atoi(optarg);
+			break;
    	default:
    		cli_classic_abort_usage(NULL);
    		break;
@@ -879,6 +889,7 @@
    	{"version",		0, NULL, 'R'},
    	{"output",		1, NULL, 'o'},
    	{"progress",		0, NULL, OPTION_PROGRESS},
+		{"sacrifice-ratio",	1, NULL, OPTION_SACRIFICE_RATIO},
    	{NULL,			0, NULL, 0},
    };

@@ -1125,6 +1136,14 @@
    	goto out_shutdown;
    }

+	if (options.sacrifice_ratio) {
+		if (options.sacrifice_ratio > 100) {
+			msg_ginfo("Invalid input, use default.\n");
+			options.sacrifice_ratio = 0;
+		}
+		fill_flash->sacrifice_ratio = options.sacrifice_ratio;
+	}
+
    if (options.ifd && (flashrom_layout_read_from_ifd(&options.layout, fill_flash, NULL, 0) ||
    		   process_include_args(options.layout, options.include_args))) {
    	ret = 1;
diff --git a/erasure_layout.c b/erasure_layout.c
index 7f3bb46..56da450 100644
--- a/erasure_layout.c
+++ b/erasure_layout.c
@@ -249,9 +249,10 @@
    	}

const int total_blocks = sub_block_end - sub_block_start + 1;
-		if (count == total_blocks) {
-			/* We are selecting one large block instead, so send opcode once
-			 * instead of sending many smaller ones.
+		if (total_blocks - count <= total_blocks * flashctx->sacrifice_ratio / 100) {
+			/* Number of smaller blocks needless to change is lower than the
+			 * sacrifice ratio, we are selecting one large block instead, so
+			 * send opcode once instead of sending many smaller ones.
    		 */
    		if (ll->start_addr >= rstart && ll->end_addr <= rend) {
    			/* Deselect all smaller blocks covering the same region. */
diff --git a/include/flash.h b/include/flash.h
index d0e55af..90a9201 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -587,6 +587,8 @@
    /* Progress reporting */
    flashrom_progress_callback *progress_callback;
    struct flashrom_progress *progress_state;
+	/* Sacrifice ratio */
+	int sacrifice_ratio;
 };

/* Timing used in probe routines. ZERO is -2 to differentiate between an unset