This is a note to let you know that I've just added the patch titled
spi: cadence: Ensure data lines set to low during dummy-cycle period
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-cadence-ensure-data-lines-set-to-low-during-dumm.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d9ad8f83a690be487a82ad47141bf6311954317c
Author: Witold Sadowski <wsadowski@xxxxxxxxxxx>
Date: Wed May 29 00:40:32 2024 -0700
spi: cadence: Ensure data lines set to low during dummy-cycle period
[ Upstream commit 4a69c1264ff41bc5bf7c03101ada0454fbf08868 ]
During dummy-cycles xSPI will switch GPIO into Hi-Z mode. In that dummy
period voltage on data lines will slowly drop, what can cause
unintentional modebyte transmission. Value send to SPI memory chip will
depend on last address, and clock frequency.
To prevent unforeseen consequences of that behaviour, force send
single modebyte(0x00).
Modebyte will be send only if number of dummy-cycles is not equal
to 0. Code must also reduce dummycycle byte count by one - as one byte
is send as modebyte.
Signed-off-by: Witold Sadowski <wsadowski@xxxxxxxxxxx>
Link: https://msgid.link/r/20240529074037.1345882-2-wsadowski@xxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
index 8648b8eb080dc..cdce2e280f663 100644
--- a/drivers/spi/spi-cadence-xspi.c
+++ b/drivers/spi/spi-cadence-xspi.c
@@ -145,6 +145,9 @@
#define CDNS_XSPI_STIG_DONE_FLAG BIT(0)
#define CDNS_XSPI_TRD_STATUS 0x0104
+#define MODE_NO_OF_BYTES GENMASK(25, 24)
+#define MODEBYTES_COUNT 1
+
/* Helper macros for filling command registers */
#define CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_1(op, data_phase) ( \
FIELD_PREP(CDNS_XSPI_CMD_INSTR_TYPE, (data_phase) ? \
@@ -157,9 +160,10 @@
FIELD_PREP(CDNS_XSPI_CMD_P1_R2_ADDR3, ((op)->addr.val >> 24) & 0xFF) | \
FIELD_PREP(CDNS_XSPI_CMD_P1_R2_ADDR4, ((op)->addr.val >> 32) & 0xFF))
-#define CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_3(op) ( \
+#define CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_3(op, modebytes) ( \
FIELD_PREP(CDNS_XSPI_CMD_P1_R3_ADDR5, ((op)->addr.val >> 40) & 0xFF) | \
FIELD_PREP(CDNS_XSPI_CMD_P1_R3_CMD, (op)->cmd.opcode) | \
+ FIELD_PREP(MODE_NO_OF_BYTES, modebytes) | \
FIELD_PREP(CDNS_XSPI_CMD_P1_R3_NUM_ADDR_BYTES, (op)->addr.nbytes))
#define CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_4(op, chipsel) ( \
@@ -173,12 +177,12 @@
#define CDNS_XSPI_CMD_FLD_DSEQ_CMD_2(op) \
FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R2_DCNT_L, (op)->data.nbytes & 0xFFFF)
-#define CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op) ( \
+#define CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op, dummybytes) ( \
FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_DCNT_H, \
((op)->data.nbytes >> 16) & 0xffff) | \
FIELD_PREP(CDNS_XSPI_CMD_DSEQ_R3_NUM_OF_DUMMY, \
(op)->dummy.buswidth != 0 ? \
- (((op)->dummy.nbytes * 8) / (op)->dummy.buswidth) : \
+ (((dummybytes) * 8) / (op)->dummy.buswidth) : \
0))
#define CDNS_XSPI_CMD_FLD_DSEQ_CMD_4(op, chipsel) ( \
@@ -351,6 +355,7 @@ static int cdns_xspi_send_stig_command(struct cdns_xspi_dev *cdns_xspi,
u32 cmd_regs[6];
u32 cmd_status;
int ret;
+ int dummybytes = op->dummy.nbytes;
ret = cdns_xspi_wait_for_controller_idle(cdns_xspi);
if (ret < 0)
@@ -365,7 +370,12 @@ static int cdns_xspi_send_stig_command(struct cdns_xspi_dev *cdns_xspi,
memset(cmd_regs, 0, sizeof(cmd_regs));
cmd_regs[1] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_1(op, data_phase);
cmd_regs[2] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_2(op);
- cmd_regs[3] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_3(op);
+ if (dummybytes != 0) {
+ cmd_regs[3] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_3(op, 1);
+ dummybytes--;
+ } else {
+ cmd_regs[3] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_3(op, 0);
+ }
cmd_regs[4] = CDNS_XSPI_CMD_FLD_P1_INSTR_CMD_4(op,
cdns_xspi->cur_cs);
@@ -375,7 +385,7 @@ static int cdns_xspi_send_stig_command(struct cdns_xspi_dev *cdns_xspi,
cmd_regs[0] = CDNS_XSPI_STIG_DONE_FLAG;
cmd_regs[1] = CDNS_XSPI_CMD_FLD_DSEQ_CMD_1(op);
cmd_regs[2] = CDNS_XSPI_CMD_FLD_DSEQ_CMD_2(op);
- cmd_regs[3] = CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op);
+ cmd_regs[3] = CDNS_XSPI_CMD_FLD_DSEQ_CMD_3(op, dummybytes);
cmd_regs[4] = CDNS_XSPI_CMD_FLD_DSEQ_CMD_4(op,
cdns_xspi->cur_cs);
