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hw/block: m25p80: Fix dummy byte handling for Spansion flash

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Spansion flashes expose the number of dummy clock cycles through CR2V
register [1]. The value is a cycle count, not a byte count, so the
m25p80 model has to convert it to the number of whole SSI transfer
bytes consumed while collecting read command data.

Add a helper that multiplies the CR2V dummy cycle count by the phase
width and rounds up non-byte-aligned counts, matching the byte-oriented
SSI model. The default eight-cycle configuration keeps the same byte
counts as before.

[1] https://www.infineon.com/assets/row/public/documents/10/49/infineon-s25fs128s-s25fs256s-1-datasheet-en.pdf

Fixes: cf6f1efe0b ("m25p80: Fast read commands family changes")
Signed-off-by: Bin Meng <bin.meng@processmission.com>
Tested-by: Cédric Le Goater <clg@redhat.com>
Message-ID: <20260707083431.219671-5-bin.meng@processmission.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
This commit is contained in:
Bin Meng
2026-07-07 16:34:23 +08:00
committed by Philippe Mathieu-Daudé
parent 08557a089e
commit 4957f668c4
1 changed files with 20 additions and 12 deletions
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32
hw/block/m25p80.c
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@@ -1057,6 +1057,23 @@ static uint8_t macronix_extract_cfg_dummy_bytes(Flash *s, uint8_t bus_width)
return dummy_bits / 8;
}
static uint8_t spansion_extract_cfg_dummy_bytes(Flash *s, uint8_t bus_width)
{
uint8_t dummy_bits;
dummy_bits = extract32(s->spansion_cr2v, SPANSION_DUMMY_CLK_POS,
SPANSION_DUMMY_CLK_LEN);
dummy_bits *= bus_width;
/*
* Assert that the dummy bit count is byte-aligned
* as SSI core can only consume whole dummy bytes.
*/
assert(dummy_bits % 8 == 0);
return dummy_bits / 8;
}
static void decode_fast_read_cmd(Flash *s)
{
s->needed_bytes = get_addr_length(s);
@@ -1075,10 +1092,7 @@ static void decode_fast_read_cmd(Flash *s)
s->needed_bytes += macronix_extract_cfg_dummy_bytes(s, 1);
break;
case MAN_SPANSION:
s->needed_bytes += extract32(s->spansion_cr2v,
SPANSION_DUMMY_CLK_POS,
SPANSION_DUMMY_CLK_LEN
);
s->needed_bytes += spansion_extract_cfg_dummy_bytes(s, 1);
break;
case MAN_ISSI:
/*
@@ -1111,10 +1125,7 @@ static void decode_dio_read_cmd(Flash *s)
break;
case MAN_SPANSION:
s->needed_bytes += SPANSION_CONTINUOUS_READ_MODE_CMD_LEN;
s->needed_bytes += extract32(s->spansion_cr2v,
SPANSION_DUMMY_CLK_POS,
SPANSION_DUMMY_CLK_LEN
);
s->needed_bytes += spansion_extract_cfg_dummy_bytes(s, 2);
break;
case MAN_NUMONYX:
s->needed_bytes += numonyx_extract_cfg_dummy_bytes(s);
@@ -1151,10 +1162,7 @@ static void decode_qio_read_cmd(Flash *s)
break;
case MAN_SPANSION:
s->needed_bytes += SPANSION_CONTINUOUS_READ_MODE_CMD_LEN;
s->needed_bytes += extract32(s->spansion_cr2v,
SPANSION_DUMMY_CLK_POS,
SPANSION_DUMMY_CLK_LEN
);
s->needed_bytes += spansion_extract_cfg_dummy_bytes(s, 4);
break;
case MAN_NUMONYX:
s->needed_bytes += numonyx_extract_cfg_dummy_bytes(s);