writeprotect: Add function to get register values and WP bit masks

Add a new wp_cfg_to_reg_values() function that takes a generic wp_cfg
instance and returns the chip-specific values that need to be written to
the chip's registers to enable the specified protection range/mode.

The function returns three values for each chip register:
- reg_values[reg]  - Value writeprotect will write to reg
- bit_masks[reg]   - Bit mask for WP-related bits in reg
- write_masks[reg] - Bit mask for writable WP-related bits in reg
                     (i.e. the ones writeprotect will try to write)

BUG=b:260019525,b:259013033,260020006
BRANCH=none
TEST=ninja test

Change-Id: Ib2a47153b230c9f82bb4eca357c335f2abbacc20
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/69847
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/writeprotect.c b/writeprotect.c
index d8ffa689..411089de 100644
--- a/writeprotect.c
+++ b/writeprotect.c
@@ -597,3 +597,31 @@ out:
 	free(range_pairs);
 	return ret;
 }
+
+enum flashrom_wp_result wp_cfg_to_reg_values(
+		uint8_t *reg_values, uint8_t *bit_masks, uint8_t *write_masks,
+		struct flashctx *flash, const struct flashrom_wp_cfg *cfg)
+{
+	struct wp_bits bits;
+
+	if (!chip_supported(flash))
+		return FLASHROM_WP_ERR_CHIP_UNSUPPORTED;
+
+	enum flashrom_wp_result ret = read_wp_bits(&bits, flash);
+	if (ret != FLASHROM_WP_OK)
+		return ret;
+
+	/* Set protection range */
+	ret = set_wp_range(&bits, flash, cfg->range);
+	if (ret != FLASHROM_WP_OK)
+		return ret;
+
+	/* Set protection mode */
+	ret = set_wp_mode(&bits, cfg->mode);
+	if (ret != FLASHROM_WP_OK)
+		return ret;
+
+	get_wp_bits_reg_values(reg_values, bit_masks, write_masks, &flash->chip->reg_bits, bits);
+
+	return FLASHROM_WP_OK;
+}