[PATCH v16 00/15] mtd: spi-nor: add xSPI Octal DTR support

Pratyush Yadav
2020-10-05T15:37:44Z

Hi,

This series adds support for Octal DTR flashes in the SPI NOR framework,
and then adds hooks for the Cypress Semper and Micron Xcella flashes to
allow running them in Octal DTR mode. This series assumes that the flash
is handed to the kernel in Legacy SPI mode.

Tested on Micron MT35X and S28HS flashes for Octal DTR. Tested on Micron
MT25Q, and Cypress S25FL for regressions. All flashes were tested by
running a read/write stress test on top of UBIFS. On the Cypress S28HS
flash 1-bit ECC had to be used to allow UBIFS to work since partial page
writes don't work with 2-bit ECC.

Changes in v16:
- Do not wait for Micron flash to switch to 8D mode. The switch is
instant according to the datasheet.

- Read flash ID in both Micron and Cypress Octal enable hooks as a
confirmation that the switch to 8D mode was successful. This way we
can catch any errors early rather than later commands failing.

- Add Tudor's Reviewed-by on patch 10/15.

Changes in v15:
- Give precedence to addr_width found via SFDP over forcing it to 4 for
8D. The standard knows better.

- Sleep for a range of 1000 to 1500 us instead of 400 to 600. The 400 to
600 range was too close to the actual time it took to change to 8D
mode (discovered by polling SR right after and observing that it
freezed the controller sometimes). Bump it to 1000 - 1500 to be safe.

- Do not initialize dummy to 0 in Profile 1.0 parsing.

- Drop the variable io_mode_en_volatile in spi_nor_parse_sccr(). Use the
FIELD_GET expression in the if statement directly.

- Drop the debug message when setting dummy cycle configuration failed
for S28HS flash.

- Move the patches that introduce SNOR_F_IO_MODE_EN_VOLATILE to before
the one that introduces spi_nor_octal_dtr_enable(). This way we can
reject flashes with non-volatile configuration from day 0.

Changes in v14:
- Rename spi_nor_{read,write}_reg() to
spi_nor_controller_ops_{read,write}_reg().

- When spi_nor_spimem_setup_op() will be called after a spi_mem_op is
initialized, set buswidth of all phases to 0. This will make the
reader question where the buswidth is actually set and avoid any
confusions.

- Only use address and dummy bytes from Profile 1.0 table for 8D-8D-8D
Read SR/FSR instead of all DTR ones.

- Do not make spi_nor_default_setup_op() public. It is not used anymore
in latest iterations so this is not needed.

- Only enable Octal DTR mode when the configuration to enable it is
volatile.

- Do not prevent modes other than 8D-8D-8D from enabling 4-byte
addressing. All other modes don't automatically imply 4-byte
addressing.

- Add some blank lines in spi_nor_soft_reset().

- Drop the local variable 'dev' in spi_nor_suspend().

- Do not force 4-byte addressing on all DTR modes. Only force it for
Octal DTR because only in that case 3-byte addresses are not allowed.

- Drop variable addr_width from spi_nor_micron_octal_dtr_enable() and
spi_nor_cypress_octal_dtr_enable().

- Remove print from spi_nor_micron_octal_dtr_enable() and
spi_nor_cypress_octal_dtr_enable() when enabling/disabling Octal DTR
fails.

- Wait some time after enabling Octal DTR mode in
spi_nor_micron_octal_dtr_enable() and
spi_nor_cypress_octal_dtr_enable(). This makes sure the mode is
enabled and flash is usuable.

- Fix alignment of .fixups in micron_parts and spansion_parts.

- s/BFPT_DWORD16_SOFT_RST/BFPT_DWORD16_SWRST_EN_RST

- Fix copy-paste leftover in spi_nor_parse_profile1() documentation.

- Do not assume a default dummy cycle value if none is found in Profile
1.0 parsing. Leave it to 0 and let flashes fix it up via fixup hooks.

- Parse the SCCR table to discover if the Octal DTR enable bit is
volatile or not.

- Drop variable addr_width in s28hs512t_post_bfpt_fixup() and move op
initialization to the declaration to avoid a cast and use
nor->bouncebuf directly instead of declaring a local variable.

Changes in v13:
- Do not use multiple assignments in spi_nor_spimem_setup_op().

- Use EOPNOTSUPP instead of ENOTSUPP.

- Fix unbalanced braces around else statements.

- Fix whitespace alignment for spi_nor_set_read_settings() prototype.

Changes in v12:
- Rebase on latest master.

- Set dummy and data nbytes to 1 in spi_nor_spimem_check_readop() before
calling spi_nor_spimem_check_op() to make sure the buswidth for them
is properly set up. Similarly, set data nbytes to 1 for
spi_nor_spimem_check_pp(). This makes sure we don't send the wrong
dummy and data buswidth to the controller's supports_op().

- Enable DQS for Micron MT35XU512ABA. No reason not to.

- Update doc comment for spi_nor_parse_profile1() and
spi_nor_cypress_octal_dtr_enable() to add missing fields.

Changes in v11:
- Add helpers spi_nor_{read,write}_reg() to make it easier to reject DTR
ops for them.

- Add helper for spi_nor_controller_ops_erase() to make it easier to
reject DTR ops.

- s/spi-mem/SPIMEM/ and s/spi-nor/SPI NOR/

- Avoid enabling 4-byte addressing mode for all DTR ops instead of just
Octal DTR ops. This is based on the assumption that DTR ops can only
use 4-byte addressing.

- Use round_up() instead of defining ROUND_UP_TO().

- Rename 'table' to 'dwords' in xSPI Profile 1.0 parsing.

- Re-order Profile 1.0 related defines by DWORD order.

- Move rdsr parameter parsing to where opcode is parsed because it is
from the same DWORD.

- Drop local variables addr_width and dummy in spi_nor_read_sr()
spi_nor_read_fsr().

- Allow soft reset for all protocols, not just 8D-8D-8D.

- Do not set address value to 0 is spi_nor_read_sr() and
spi_nor_read_fsr(). It is 0 by default when we create the op.

- Do not make having command opcode extension as a reserved field fatal.

- Introduce the flag SPI_NOR_OCTAL_DTR_PP to indicate 8D page program
support since it can't be detected from SFDP.

- Move the call to spi_nor_spimem_setup_op() in spi_nor_read_sr() to the
commit which introduces it.

- Convert a comment in Profile 1.0 parsing from multi-line to one line.

Changes in v10:
- Rebase on latest linux-next/master. Drop a couple patches that made it
in the previous release.

- Move the code that sets 20 dummy cycles for MT35XU512ABA to its octal
enable function. This way, if the controller doesn't support 8D mode
20 dummy cycles won't be used.

Changes in v9:
- Do not use '& 0xff' to get the opcode LSB in spi-mxic and
spi-zynq-qspi. The cast to u8 will do that anyway.

- Do not use if (opcode) as a check for whether the command phase exists
in spi-zynq-qspi because the opcode 0 can be valid. Use the new
cmd.nbytes instead.

Changes in v8:
- Move controller changes in spi-mxic to the commit which introduces
2-byte opcodes to avoid problems when bisecting.

- Replace usage of sizeof(op->cmd.opcode) with op->cmd.nbytes.

- Extract opcode in spi-zynq-qspi instead of using &op->cmd.opcode.

Changes in v7:
- Reject ops with more than 1 command byte in
spi_mem_default_supports_op().

- Reject ops with more than 1 command byte in atmel and mtk controllers.

- Reject ops with 0 command bytes in spi_mem_check_op().

- Set cmd.nbytes to 1 when using SPI_MEM_OP_CMD().

- Avoid endianness problems in spi-mxic.

Changes in v6:
- Instead of hard-coding 8D-8D-8D Fast Read dummy cycles to 20, find
them out from the Profile 1.0 table.

Changes in v5:
- Do not enable stateful X-X-X modes if the reset line is broken.

- Instead of setting SNOR_READ_HWCAPS_8_8_8_DTR from Profile 1.0 table
parsing, do it in spi_nor_info_init_params() instead based on the
SPI_NOR_OCTAL_DTR_READ flag instead.

- Set SNOR_HWCAPS_PP_8_8_8_DTR in s28hs post_sfdp hook since this
capability is no longer set in Profile 1.0 parsing.

- Instead of just checking for spi_nor_get_protocol_width() in
spi_nor_octal_dtr_enable(), make sure the protocol is
SNOR_PROTO_8_8_8_DTR since get_protocol_width() only cares about data
width.

- Drop flag SPI_NOR_SOFT_RESET. Instead, discover soft reset capability
via BFPT.

- Do not make an invalid Quad Enable BFPT field a fatal error. Silently
ignore it by assuming no quad enable bit is present.

- Set dummy cycles for Cypress Semper flash to 24 instead of 20. This
allows for 200MHz operation in 8D mode compared to the 166MHz with 20.

- Rename spi_nor_cypress_octal_enable() to
spi_nor_cypress_octal_dtr_enable().

- Update spi-mtk-nor.c to reject DTR ops since it doesn't call
spi_mem_default_supports_op().

Changes in v4:
- Refactor the series to use the new spi-nor framework with the
manufacturer-specific bits separated from the core.

- Add support for Micron MT35XU512ABA.

- Use cmd.nbytes as the criteria of whether the data phase exists or not
instead of cmd.buf.in || cmd.buf.out in spi_nor_spimem_setup_op().

- Update Read FSR to use the same dummy cycles and address width as Read
SR.

- Fix BFPT parsing stopping too early for JESD216 rev B flashes.

- Use 2 byte reads for Read SR and FSR commands in DTR mode.

Changes in v3:
- Drop the DT properties "spi-rx-dtr" and "spi-tx-dtr". Instead, if
later a need is felt to disable DTR in case someone has a board with
Octal DTR capable flash but does not support DTR transactions for some
reason, a property like "spi-no-dtr" can be added.

- Remove mode bits SPI_RX_DTR and SPI_TX_DTR.

- Remove the Cadence Quadspi controller patch to un-block this series. I
will submit it as a separate patch.

- Rebase on latest 'master' and fix merge conflicts.

- Update read and write dirmap templates to use DTR.

- Rename 'is_dtr' to 'dtr'.

- Make 'dtr' a bitfield.

- Reject DTR ops in spi_mem_default_supports_op().

- Update atmel-quadspi to reject DTR ops. All other controller drivers
call spi_mem_default_supports_op() so they will automatically reject
DTR ops.

- Add support for both enabling and disabling DTR modes.

- Perform a Software Reset on flashes that support it when shutting
down.

- Disable Octal DTR mode on suspend, and re-enable it on resume.

- Drop enum 'spi_mem_cmd_ext' and make command opcode u16 instead.
Update spi-nor to use the 2-byte command instead of the command
extension. Since we still need a "extension type", mode that enum to
spi-nor and name it 'spi_nor_cmd_ext'.

- Default variable address width to 3 to fix SMPT parsing.

- Drop non-volatile change to uniform sector mode and rely on parsing
SMPT.

Changes in v2:
- Add DT properties "spi-rx-dtr" and "spi-tx-dtr" to allow expressing
DTR capabilities.

- Set the mode bits SPI_RX_DTR and SPI_TX_DTR when we discover the DT
properties "spi-rx-dtr" and spi-tx-dtr".

- spi_nor_cypress_octal_enable() was updating nor->params.read[] with
the intention of setting the correct number of dummy cycles. But this
function is called _after_ selecting the read so setting
nor->params.read[] will have no effect. So, update nor->read_dummy
directly.

- Fix spi_nor_spimem_check_readop() and spi_nor_spimem_check_pp()
passing nor->read_proto and nor->write_proto to
spi_nor_spimem_setup_op() instead of read->proto and pp->proto
respectively.

- Move the call to cqspi_setup_opcode_ext() inside cqspi_enable_dtr().
This avoids repeating the 'if (f_pdata->is_dtr)
cqspi_setup_opcode_ext()...` snippet multiple times.

- Call the default 'supports_op()' from cqspi_supports_mem_op(). This
makes sure the buswidth requirements are also enforced along with the
DTR requirements.

- Drop the 'is_dtr' argument from spi_check_dtr_req(). We only call it
when a phase is DTR so it is redundant.

Pratyush Yadav (13):
mtd: spi-nor: core: use EOPNOTSUPP instead of ENOTSUPP
mtd: spi-nor: add spi_nor_controller_ops_{read_reg,write_reg,erase}()
mtd: spi-nor: add support for DTR protocol
mtd: spi-nor: sfdp: get command opcode extension type from BFPT
mtd: spi-nor: sfdp: parse xSPI Profile 1.0 table
mtd: spi-nor: core: use dummy cycle and address width info from SFDP
mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode
mtd: spi-nor: core: enable octal DTR mode when possible
mtd: spi-nor: sfdp: detect Soft Reset sequence support from BFPT
mtd: spi-nor: core: perform a Soft Reset on shutdown
mtd: spi-nor: core: disable Octal DTR mode on suspend.
mtd: spi-nor: spansion: add support for Cypress Semper flash
mtd: spi-nor: micron-st: allow using MT35XU512ABA in Octal DTR mode

Tudor Ambarus (2):
mtd: spi-nor: Introduce SNOR_F_IO_MODE_EN_VOLATILE
mtd: spi-nor: Parse SFDP SCCR Map

drivers/mtd/spi-nor/core.c | 544 ++++++++++++++++++++++++--------
drivers/mtd/spi-nor/core.h | 26 ++
drivers/mtd/spi-nor/micron-st.c | 115 ++++++-
drivers/mtd/spi-nor/sfdp.c | 170 +++++++++-
drivers/mtd/spi-nor/sfdp.h | 8 +
drivers/mtd/spi-nor/spansion.c | 174 ++++++++++
include/linux/mtd/spi-nor.h | 53 +++-
7 files changed, 951 insertions(+), 139 deletions(-)

--
2.28.0