[M] Change in flashrom[master]: ichspi: Fix number of bytes for read, write, flash id, erase operation

[Subrata Banik (Code Review)]

Subrata Banik has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/69750 )

Change subject: ichspi: Fix number of bytes for read, write, flash id, erase operation
......................................................................

ichspi: Fix number of bytes for read, write, flash id, erase operation

This patch fixes a potential issue where the SPI controller register
HSFC.FDBC (bits 24-29) value gets wrongly calculated while passing
the `len` as `0` instead `1`.

As per Intel EDS, `0b` in the FDBC represents 1 byte while `0x3f`
represents 64-bytes to be transferred. The number of bytes
transferred is the value of this field plus 1.

If we would like to transfer 1 byte then we need to set `0b` in
FDBC for operations like read, write, flash id to account the `set
byte count` hence, the `len` argument should be `1`.

Additionally, as per EDS, the FDBC field is ignored for any block
erase command.

Note: `FDBC` field still holds the wrong value (3) before any HW seq
operation which will be fixed with incremental patch in this train.

BUG=b:258280679
TEST=Able to build flashrom and perform below operations on Google,
Rex and Google, Kano/Taeko.

Without this patch:

HSFC register value inside ich_start_hwseq_xfer() before initiating
the HW seq operations: 0x3f00
HSFC register value inside ich_start_hwseq_xfer() during the HW seq
operations (--wp-disable): 0x3f11

With this patch:

HSFC register value inside ich_start_hwseq_xfer() before initiating
the HW seq operations: 0x300
HSFC register value inside ich_start_hwseq_xfer() during the HW seq
operations (--wp-disable): 0x311

Signed-off-by: Subrata Banik 
Change-Id: Ie5de7c5bd9809d146a317df56996f7f8a85ca9a5
---
M ichspi.c
1 file changed, 49 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/50/69750/1

diff --git a/ichspi.c b/ichspi.c
index 4e982f0..d2600ff 100644
--- a/ichspi.c
+++ b/ichspi.c
@@ -1401,7 +1401,7 @@
    }
    msg_pdbg("Reading Status register\n");

-	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_RD_STATUS, 0, len, ich_generation,
+	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_RD_STATUS, 1, len, ich_generation,
    	hwseq_data->addr_mask)) {
    	msg_perr("Reading Status register failed\n!!");
    	return -1;
@@ -1424,7 +1424,7 @@

ich_fill_data(&value, len, ICH9_REG_FDATA0);

-	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_WR_STATUS, 0, len, ich_generation,
+	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_WR_STATUS, 1, len, ich_generation,
    	hwseq_data->addr_mask)) {
    	msg_perr("Writing Status register failed\n!!");
    	return -1;
@@ -1520,7 +1520,7 @@

msg_pdbg("Erasing %d bytes starting at 0x%06x.\n", len, addr);

-	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_BLOCK_ERASE, addr, 0, ich_generation,
+	if (ich_exec_sync_hwseq_xfer(flash, HSFC_CYCLE_BLOCK_ERASE, addr, 1, ich_generation,
    	hwseq_data->addr_mask))
    	return -1;
    return 0;