Anastasia Klimchuk submitted this change.

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9 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.

Approvals: build bot (Jenkins): Verified Nikolai Artemiev: Looks good to me, but someone else must approve Anastasia Klimchuk: Looks good to me, approved
writeprotect_ranges.c: add more range functions

Not all chips follow the same pattern. There are differences in how CMP
bit is treated or in block size used.

Change-Id: Ied7b27be2ee2426af8f473432e2b01a290de2365
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/66212
Reviewed-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
M include/chipdrivers.h
M include/flash.h
M writeprotect.c
M writeprotect_ranges.c
4 files changed, 90 insertions(+), 12 deletions(-)

diff --git a/include/chipdrivers.h b/include/chipdrivers.h
index 3b07afe..34e3af8 100644
--- a/include/chipdrivers.h
+++ b/include/chipdrivers.h
@@ -216,5 +216,8 @@

/* writeprotect_ranges.c */
void decode_range_spi25(size_t *start, size_t *len, const struct wp_bits *, size_t chip_len);
+void decode_range_spi25_64k_block(size_t *start, size_t *len, const struct wp_bits *, size_t chip_len);
+void decode_range_spi25_bit_cmp(size_t *start, size_t *len, const struct wp_bits *, size_t chip_len);
+void decode_range_spi25_2x_block(size_t *start, size_t *len, const struct wp_bits *, size_t chip_len);

#endif /* !__CHIPDRIVERS_H__ */
diff --git a/include/flash.h b/include/flash.h
index 23222c7..b4b56fe 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -224,8 +224,11 @@
struct wp_bits;

enum decode_range_func {
- NO_DECODE_RANGE_FUNC = 0, /* 0 indicates no range decode funciton is set. */
+ NO_DECODE_RANGE_FUNC = 0, /* 0 indicates no range decode function is set. */
DECODE_RANGE_SPI25 = 1,
+ DECODE_RANGE_SPI25_64K_BLOCK = 2,
+ DECODE_RANGE_SPI25_BIT_CMP = 3,
+ DECODE_RANGE_SPI25_2X_BLOCK = 4,
};
typedef void (decode_range_func_t)(size_t *start, size_t *len, const struct wp_bits *, size_t chip_len);

diff --git a/writeprotect.c b/writeprotect.c
index 1ac0c1a..38ac997 100644
--- a/writeprotect.c
+++ b/writeprotect.c
@@ -211,6 +211,9 @@
{
switch (chip->decode_range) {
case DECODE_RANGE_SPI25: return &decode_range_spi25;
+ case DECODE_RANGE_SPI25_64K_BLOCK: return &decode_range_spi25_64k_block;
+ case DECODE_RANGE_SPI25_BIT_CMP: return &decode_range_spi25_bit_cmp;
+ case DECODE_RANGE_SPI25_2X_BLOCK: return &decode_range_spi25_2x_block;
/* default: total function, 0 indicates no decode range function set. */
case NO_DECODE_RANGE_FUNC: return NULL;
};
diff --git a/writeprotect_ranges.c b/writeprotect_ranges.c
index dacce32..45678f2 100644
--- a/writeprotect_ranges.c
+++ b/writeprotect_ranges.c
@@ -17,11 +17,11 @@
#include "writeprotect.h"
#include "chipdrivers.h"

-/*
- * Protection range calculation that works with many common SPI flash chips.
- */
-void decode_range_spi25(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len)
+static void decode_range_generic(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len,
+ bool fixed_block_len, bool apply_cmp_to_bp, int coeff_offset)
{
+ const bool cmp = bits->cmp_bit_present && bits->cmp == 1;
+
/* Interpret BP bits as an integer */
size_t bp = 0;
size_t bp_max = 0;
@@ -31,6 +31,15 @@
bp_max |= 1 << i;
}

+ /*
+ * Most chips: the CMP bit only negates the range.
+ *
+ * Some MX chips: the CMP bit negates the BP bits and the range.
+ * (CMP bit is often the MSB BP bit in such chips.)
+ */
+ if (cmp && apply_cmp_to_bp)
+ bp ^= bp_max;
+
if (bp == 0) {
/* Special case: all BP bits are 0 => no write protection */
*len = 0;
@@ -40,14 +49,14 @@
} else {
/*
* Usual case: the BP bits encode a coefficient in the form
- * `coeff = 2 ** (bp - 1)`.
+ * `coeff = 2 ** (bp - offset)` where `offset == 1`.
*
* The range's length is given by multiplying the coefficient
* by a base unit, usually a 4K sector or a 64K block.
*/

- size_t coeff = 1 << (bp - 1);
- size_t max_coeff = 1 << (bp_max - 2);
+ size_t coeff = 1 << (bp - coeff_offset);
+ size_t max_coeff = 1 << (bp_max - coeff_offset - 1);

size_t sector_len = 4 * KiB;
size_t default_block_len = 64 * KiB;
@@ -62,14 +71,19 @@
} else {
/*
* SEC=0 or is not present, protect blocks.
- *
+ */
+ size_t block_len = default_block_len;
+
+ /*
* With very large chips, the 'block' size can be
* larger than 64K. This occurs when a larger block
* size is needed so that half the chip can be
* protected by the maximum possible coefficient.
*/
- size_t min_block_len = chip_len / 2 / max_coeff;
- size_t block_len = max(min_block_len, default_block_len);
+ if (!fixed_block_len) {
+ size_t min_block_len = chip_len / 2 / max_coeff;
+ block_len = max(min_block_len, default_block_len);
+ }

*len = min(block_len * coeff, chip_len);
}
@@ -79,7 +93,7 @@
bool protect_top = bits->tb_bit_present ? (bits->tb == 0) : 1;

/* Apply CMP bit */
- if (bits->cmp_bit_present && bits->cmp == 1) {
+ if (cmp) {
*len = chip_len - *len;
protect_top = !protect_top;
}
@@ -90,3 +104,41 @@
else
*start = 0;
}
+
+/*
+ * Protection range calculation that works with many common SPI flash chips.
+ */
+void decode_range_spi25(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len)
+{
+ decode_range_generic(start, len, bits, chip_len,
+ /*fixed_block_len=*/false, /*apply_cmp_to_bp=*/false, /*coeff_offset=*/1);
+}
+
+/*
+ * Do not adjust block size to be able to fill half of the chip.
+ */
+void decode_range_spi25_64k_block(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len)
+{
+ decode_range_generic(start, len, bits, chip_len,
+ /*fixed_block_len=*/true, /*apply_cmp_to_bp=*/false, /*coeff_offset=*/1);
+}
+
+/*
+ * Inverts BP bits when CMP is set and treats all ones in BP bits as a request to protect whole chip regardless
+ * of the CMP bit.
+ */
+void decode_range_spi25_bit_cmp(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len)
+{
+ decode_range_generic(start, len, bits, chip_len,
+ /*fixed_block_len=*/false, /*apply_cmp_to_bp=*/true, /*coeff_offset=*/1);
+}
+
+/*
+ * This multiplies coefficient by 2. To be used with chips which have more BP bits than needed, such that the
+ * most significant BP bit effectively acts as "protect whole chip" flag.
+ */
+void decode_range_spi25_2x_block(size_t *start, size_t *len, const struct wp_bits *bits, size_t chip_len)
+{
+ decode_range_generic(start, len, bits, chip_len,
+ /*fixed_block_len=*/false, /*apply_cmp_to_bp=*/false, /*coeff_offset=*/0);
+}

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Gerrit-Project: flashrom
Gerrit-Branch: master
Gerrit-Change-Id: Ied7b27be2ee2426af8f473432e2b01a290de2365
Gerrit-Change-Number: 66212
Gerrit-PatchSet: 11
Gerrit-Owner: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Gerrit-Reviewer: Anastasia Klimchuk <aklm@chromium.org>
Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com>
Gerrit-Reviewer: Nico Huber <nico.h@gmx.de>
Gerrit-Reviewer: Nikolai Artemiev <nartemiev@google.com>
Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org>
Gerrit-CC: Maciej Pijanowski <maciej.pijanowski@3mdeb.com>
Gerrit-MessageType: merged