flashrom.c: Make 'chip_to_probe' a param to probe_flash()

Apart from the very bespoke case of 'probe_w29ee011()'
the override 'chip_to_probe' name is a nature parameter
to 'probe_flash()'. However we can deal with w29ee011
by providing a probe specific validation function to
check if the chip can indeed be overriden.

TEST=`./flashrom -p internal --flash-name`.

Change-Id: Ifcdace07ea2135d83dea92cfa5c6bec8d7ddf05d
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67091
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>

6 files changed, 27 insertions, 18 deletions

diff --git a/cli_classic.c b/cli_classic.c
index b66094cc..574afff1 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -646,6 +646,7 @@ int main(int argc, char *argv[])
 	char *pparam = NULL;
 	struct layout_include_args *include_args = NULL;
 	char *wp_region = NULL;
+	const char *chip_to_probe = NULL;
 
 	/*
 	 * Safety-guard against a user who has (mistakenly) closed
@@ -977,7 +978,7 @@ int main(int argc, char *argv[])
 	for (j = 0; j < registered_master_count; j++) {
 		startchip = 0;
 		while (chipcount < (int)ARRAY_SIZE(flashes)) {
-			startchip = probe_flash(&registered_masters[j], startchip, &flashes[chipcount], 0);
+			startchip = probe_flash(&registered_masters[j], startchip, &flashes[chipcount], 0, chip_to_probe);
 			if (startchip == -1)
 				break;
 			chipcount++;
@@ -1020,7 +1021,7 @@ int main(int argc, char *argv[])
 					  "chip, using the first one.\n");
 			for (j = 0; j < registered_master_count; j++) {
 				mst = &registered_masters[j];
-				startchip = probe_flash(mst, 0, &flashes[0], 1);
+				startchip = probe_flash(mst, 0, &flashes[0], 1, chip_to_probe);
 				if (startchip != -1)
 					break;
 			}
diff --git a/flashrom.c b/flashrom.c
index 694e2c5e..db4dd7d0 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -35,7 +35,6 @@
 #include "chipdrivers.h"
 
 const char flashrom_version[] = FLASHROM_VERSION;
-const char *chip_to_probe = NULL;
 
 static const struct programmer_entry *programmer = NULL;
 
@@ -824,7 +823,7 @@ static probe_func_t *lookup_probe_func_ptr(const struct flashchip *chip)
 	return NULL;
 }
 
-int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force)
+int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force, const char *const chip_to_probe)
 {
 	const struct flashchip *chip;
 	enum chipbustype buses_common;
@@ -864,6 +863,10 @@ int probe_flash(struct registered_master *mst, int startchip, struct flashctx *f
 		if (force)
 			break;
 
+		if (probe_func == &probe_w29ee011)
+			if (!w29ee011_can_override(flash->chip->name, chip_to_probe))
+				goto notfound;
+
 		if (probe_func(flash) != 1)
 			goto notfound;
 
diff --git a/include/chipdrivers.h b/include/chipdrivers.h
index 61d43c9f..470d1fe2 100644
--- a/include/chipdrivers.h
+++ b/include/chipdrivers.h
@@ -195,6 +195,7 @@ int printlock_at49f(struct flashctx *flash);
 
 /* w29ee011.c */
 int probe_w29ee011(struct flashctx *flash);
+bool w29ee011_can_override(const char *const chip_name, const char *const override_chip);
 
 /* stm50.c */
 int erase_sector_stm50(struct flashctx *flash, unsigned int block, unsigned int blocksize);
diff --git a/include/flash.h b/include/flash.h
index 2ba235db..da200ea9 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -475,13 +475,12 @@ size_t strnlen(const char *str, size_t n);
 
 /* flashrom.c */
 extern const char flashrom_version[];
-extern const char *chip_to_probe;
 char *flashbuses_to_text(enum chipbustype bustype);
 int map_flash(struct flashctx *flash);
 void unmap_flash(struct flashctx *flash);
 int read_memmapped(struct flashctx *flash, uint8_t *buf, unsigned int start, unsigned int len);
 int erase_flash(struct flashctx *flash);
-int probe_flash(struct registered_master *mst, int startchip, struct flashctx *fill_flash, int force);
+int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force, const char *const chip_to_probe);
 int verify_range(struct flashctx *flash, const uint8_t *cmpbuf, unsigned int start, unsigned int len);
 void emergency_help_message(void);
 void print_version(void);
diff --git a/libflashrom.c b/libflashrom.c
index cbc62430..c83c1bd8 100644
--- a/libflashrom.c
+++ b/libflashrom.c
@@ -221,8 +221,6 @@ int flashrom_flash_probe(struct flashrom_flashctx **const flashctx,
 	int i, ret = 2;
 	struct flashrom_flashctx second_flashctx = { 0, };
 
-	chip_to_probe = chip_name; /* chip_to_probe is global in flashrom.c */
-
 	*flashctx = malloc(sizeof(**flashctx));
 	if (!*flashctx)
 		return 1;
@@ -230,10 +228,10 @@ int flashrom_flash_probe(struct flashrom_flashctx **const flashctx,
 
 	for (i = 0; i < registered_master_count; ++i) {
 		int flash_idx = -1;
-		if (!ret || (flash_idx = probe_flash(&registered_masters[i], 0, *flashctx, 0)) != -1) {
+		if (!ret || (flash_idx = probe_flash(&registered_masters[i], 0, *flashctx, 0, chip_name)) != -1) {
 			ret = 0;
 			/* We found one chip, now check that there is no second match. */
-			if (probe_flash(&registered_masters[i], flash_idx + 1, &second_flashctx, 0) != -1) {
+			if (probe_flash(&registered_masters[i], flash_idx + 1, &second_flashctx, 0, chip_name) != -1) {
 				flashrom_layout_release(second_flashctx.default_layout);
 				free(second_flashctx.chip);
 				ret = 3;
diff --git a/w29ee011.c b/w29ee011.c
index 62d7a0f7..234b865c 100644
--- a/w29ee011.c
+++ b/w29ee011.c
@@ -15,9 +15,24 @@
  */
 
 #include <string.h>
+#include <stdbool.h>
+
 #include "flash.h"
 #include "chipdrivers.h"
 
+bool w29ee011_can_override(const char *const chip_name, const char *const override_chip)
+{
+	if (!override_chip || strcmp(override_chip, chip_name)) {
+		msg_cdbg("Old Winbond W29* probe method disabled because "
+			 "the probing sequence puts the AMIC A49LF040A in "
+			 "a funky state. Use 'flashrom -c %s' if you "
+			 "have a board with such a chip.\n", chip_name);
+		return false;
+	}
+
+	return true;
+}
+
 /* According to the Winbond W29EE011, W29EE012, W29C010M, W29C011A
  * datasheets this is the only valid probe function for those chips.
  */
@@ -26,14 +41,6 @@ int probe_w29ee011(struct flashctx *flash)
 	chipaddr bios = flash->virtual_memory;
 	uint8_t id1, id2;
 
-	if (!chip_to_probe || strcmp(chip_to_probe, flash->chip->name)) {
-		msg_cdbg("Old Winbond W29* probe method disabled because "
-			 "the probing sequence puts the AMIC A49LF040A in "
-			 "a funky state. Use 'flashrom -c %s' if you "
-			 "have a board with such a chip.\n", flash->chip->name);
-		return 0;
-	}
-
 	/* Issue JEDEC Product ID Entry command */
 	chip_writeb(flash, 0xAA, bios + 0x5555);
 	programmer_delay(flash, 10);