flashrom.c: implement chip restore callback registration

Allows drivers to register a callback function to reset the
chip state once programming has finished. This is used by
the s25f driver added in a later patch, which needs to change
the chip's sector layout to be able to write to the entire flash.

Adapted from cros flashrom at
`9c4c9a56b6a0370b383df9c75d71b3bd469e672d`.

BUG=b:153800073
BRANCH=none
TEST=builds

Change-Id: I2a522dc1fd3952793fbcad70afc6dd43850fbbc5
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/47276
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

2 files changed, 41 insertions, 0 deletions

diff --git a/flash.h b/flash.h
index a1e766920..883b6f4b4 100644
--- a/flash.h
+++ b/flash.h
@@ -103,6 +103,8 @@ enum write_granularity {
  */
 #define NUM_ERASEFUNCTIONS 8
 
+#define MAX_CHIP_RESTORE_FUNCTIONS 4
+
 /* Feature bits used for non-SPI only */
 #define FEATURE_REGISTERMAP	(1 << 0)
 #define FEATURE_LONG_RESET	(0 << 4)
@@ -248,6 +250,8 @@ struct flashchip {
 	struct wp *wp;
 };
 
+typedef int (*chip_restore_fn_cb_t)(struct flashctx *flash, uint8_t status);
+
 struct flashrom_flashctx {
 	struct flashchip *chip;
 	/* FIXME: The memory mappings should be saved in a more structured way. */
@@ -275,6 +279,12 @@ struct flashrom_flashctx {
 	 */
 	int address_high_byte;
 	bool in_4ba_mode;
+
+	int chip_restore_fn_count;
+	struct chip_restore_func_data {
+		chip_restore_fn_cb_t func;
+		uint8_t status;
+	} chip_restore_fn[MAX_CHIP_RESTORE_FUNCTIONS];
 };
 
 /* Timing used in probe routines. ZERO is -2 to differentiate between an unset
@@ -350,6 +360,7 @@ int do_read(struct flashctx *, const char *filename);
 int do_erase(struct flashctx *);
 int do_write(struct flashctx *, const char *const filename, const char *const referencefile);
 int do_verify(struct flashctx *, const char *const filename);
+int register_chip_restore(chip_restore_fn_cb_t func, struct flashctx *flash, uint8_t status);
 
 /* Something happened that shouldn't happen, but we can go on. */
 #define ERROR_NONFATAL 0x100
diff --git a/flashrom.c b/flashrom.c
index 7f5f2a84f..c89abad60 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -580,6 +580,34 @@ int register_shutdown(int (*function) (void *data), void *data)
 	return 0;
 }
 
+int register_chip_restore(chip_restore_fn_cb_t func,
+			  struct flashctx *flash, uint8_t status)
+{
+	if (flash->chip_restore_fn_count >= MAX_CHIP_RESTORE_FUNCTIONS) {
+		msg_perr("Tried to register more than %i chip restore"
+		         " functions.\n", MAX_CHIP_RESTORE_FUNCTIONS);
+		return 1;
+	}
+	flash->chip_restore_fn[flash->chip_restore_fn_count].func = func;
+	flash->chip_restore_fn[flash->chip_restore_fn_count].status = status;
+	flash->chip_restore_fn_count++;
+
+	return 0;
+}
+
+static int deregister_chip_restore(struct flashctx *flash)
+{
+	int rc = 0;
+
+	while (flash->chip_restore_fn_count > 0) {
+		int i = --flash->chip_restore_fn_count;
+		rc |= flash->chip_restore_fn[i].func(
+			flash, flash->chip_restore_fn[i].status);
+	}
+
+	return rc;
+}
+
 int programmer_init(enum programmer prog, const char *param)
 {
 	int ret;
@@ -2256,6 +2284,7 @@ int prepare_flash_access(struct flashctx *const flash,
 
 	flash->address_high_byte = -1;
 	flash->in_4ba_mode = false;
+	flash->chip_restore_fn_count = 0;
 
 	/* Be careful about 4BA chips and broken masters */
 	if (flash->chip->total_size > 16 * 1024 && spi_master_no_4ba_modes(flash)) {
@@ -2285,6 +2314,7 @@ int prepare_flash_access(struct flashctx *const flash,
 
 void finalize_flash_access(struct flashctx *const flash)
 {
+	deregister_chip_restore(flash);
 	unmap_flash(flash);
 }