spi_mem_default_supports_op() rejects DTR ops by default to ensure that
the controller drivers that haven't been updated with DTR support
continue to reject them. It also makes sure that controllers that don't
support DTR mode at all (which is most of them at the moment) also
reject them.
This means that controller drivers that want to support DTR mode can't
use spi_mem_default_supports_op(). Driver authors have to roll their own
supports_op() function and mimic the buswidth checks. See
spi-cadence-quadspi.c for example. Or even worse, driver authors might
skip it completely or get it wrong.
Add spi_mem_dtr_supports_op(). It provides a basic sanity check for DTR
ops and performs the buswidth requirement check. Move the logic for
checking buswidth in spi_mem_default_supports_op() to a separate
function so the logic is not repeated twice.
Signed-off-by: Pratyush Yadav <[email protected]>
---
drivers/spi/spi-mem.c | 22 +++++++++++++++++++---
include/linux/spi/spi-mem.h | 9 +++++++++
2 files changed, 28 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index c64371ce6c38..dc713b0c3c4d 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -137,8 +137,8 @@ static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
return -ENOTSUPP;
}
-bool spi_mem_default_supports_op(struct spi_mem *mem,
- const struct spi_mem_op *op)
+static bool spi_mem_check_buswidth(struct spi_mem *mem,
+ const struct spi_mem_op *op)
{
if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
return false;
@@ -156,13 +156,29 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
op->data.dir == SPI_MEM_DATA_OUT))
return false;
+ return true;
+}
+
+bool spi_mem_dtr_supports_op(struct spi_mem *mem,
+ const struct spi_mem_op *op)
+{
+ if (op->cmd.nbytes != 2)
+ return false;
+
+ return spi_mem_check_buswidth(mem, op);
+}
+EXPORT_SYMBOL_GPL(spi_mem_dtr_supports_op);
+
+bool spi_mem_default_supports_op(struct spi_mem *mem,
+ const struct spi_mem_op *op)
+{
if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
return false;
if (op->cmd.nbytes != 1)
return false;
- return true;
+ return spi_mem_check_buswidth(mem, op);
}
EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index 159463cc659c..2b65c9edc34e 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -311,6 +311,9 @@ void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
bool spi_mem_default_supports_op(struct spi_mem *mem,
const struct spi_mem_op *op);
+bool spi_mem_dtr_supports_op(struct spi_mem *mem,
+ const struct spi_mem_op *op);
+
#else
static inline int
spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
@@ -334,6 +337,12 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
return false;
}
+static inline
+bool spi_mem_dtr_supports_op(struct spi_mem *mem,
+ const struct spi_mem_op *op)
+{
+ return false;
+}
#endif /* CONFIG_SPI_MEM */
int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
--
2.30.0
Use the newly introduced spi_mem_dtr_supports_op() to check DTR op
support. This means the buswidth check does not need to be replicated.
It also happens to fix a bug where STR ops with a 2-byte opcode would be
reported as supported.
Signed-off-by: Pratyush Yadav <[email protected]>
---
Tested on TI's J721E with MT35XU512ABA and J7200 with S28HS512T.
drivers/spi/spi-cadence-quadspi.c | 63 ++-----------------------------
1 file changed, 4 insertions(+), 59 deletions(-)
diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index b7ecbc8c1caa..442cc7c53a47 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1219,65 +1219,11 @@ static int cqspi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
return ret;
}
-static int cqspi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
-{
- u32 mode = mem->spi->mode;
-
- switch (buswidth) {
- case 1:
- return 0;
-
- case 2:
- if ((tx &&
- (mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) ||
- (!tx &&
- (mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))))
- return 0;
-
- break;
-
- case 4:
- if ((tx && (mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) ||
- (!tx && (mode & (SPI_RX_QUAD | SPI_RX_OCTAL))))
- return 0;
-
- break;
-
- case 8:
- if ((tx && (mode & SPI_TX_OCTAL)) ||
- (!tx && (mode & SPI_RX_OCTAL)))
- return 0;
-
- break;
-
- default:
- break;
- }
-
- return -EOPNOTSUPP;
-}
-
static bool cqspi_supports_mem_op(struct spi_mem *mem,
const struct spi_mem_op *op)
{
bool all_true, all_false;
- if (cqspi_check_buswidth_req(mem, op->cmd.buswidth, true))
- return false;
-
- if (op->addr.nbytes &&
- cqspi_check_buswidth_req(mem, op->addr.buswidth, true))
- return false;
-
- if (op->dummy.nbytes &&
- cqspi_check_buswidth_req(mem, op->dummy.buswidth, true))
- return false;
-
- if (op->data.nbytes &&
- cqspi_check_buswidth_req(mem, op->data.buswidth,
- op->data.dir == SPI_MEM_DATA_OUT))
- return false;
-
all_true = op->cmd.dtr && op->addr.dtr && op->dummy.dtr &&
op->data.dtr;
all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
@@ -1287,11 +1233,10 @@ static bool cqspi_supports_mem_op(struct spi_mem *mem,
if (!(all_true || all_false))
return false;
- /* DTR mode opcodes should be 2 bytes. */
- if (all_true && op->cmd.nbytes != 2)
- return false;
-
- return true;
+ if (all_true)
+ return spi_mem_dtr_supports_op(mem, op);
+ else
+ return spi_mem_default_supports_op(mem, op);
}
static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
--
2.30.0
Hi Pratyush,
Pratyush Yadav <[email protected]> wrote on Thu, 4 Feb 2021 19:42:17 +0530:
> spi_mem_default_supports_op() rejects DTR ops by default to ensure that
> the controller drivers that haven't been updated with DTR support
> continue to reject them. It also makes sure that controllers that don't
> support DTR mode at all (which is most of them at the moment) also
> reject them.
>
> This means that controller drivers that want to support DTR mode can't
> use spi_mem_default_supports_op(). Driver authors have to roll their own
> supports_op() function and mimic the buswidth checks. See
> spi-cadence-quadspi.c for example. Or even worse, driver authors might
> skip it completely or get it wrong.
>
> Add spi_mem_dtr_supports_op(). It provides a basic sanity check for DTR
> ops and performs the buswidth requirement check. Move the logic for
> checking buswidth in spi_mem_default_supports_op() to a separate
> function so the logic is not repeated twice.
>
> Signed-off-by: Pratyush Yadav <[email protected]>
I am not a SPI-NOR expert but for what I know this approach looks good
to me. Let's see what other maintainers think.
Reviewed-by: Miquel Raynal <[email protected]>
Thanks,
Miquèl
On Thu, 4 Feb 2021 19:42:17 +0530, Pratyush Yadav wrote:
> spi_mem_default_supports_op() rejects DTR ops by default to ensure that
> the controller drivers that haven't been updated with DTR support
> continue to reject them. It also makes sure that controllers that don't
> support DTR mode at all (which is most of them at the moment) also
> reject them.
>
> This means that controller drivers that want to support DTR mode can't
> use spi_mem_default_supports_op(). Driver authors have to roll their own
> supports_op() function and mimic the buswidth checks. See
> spi-cadence-quadspi.c for example. Or even worse, driver authors might
> skip it completely or get it wrong.
>
> [...]
Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next
Thanks!
[1/2] spi: spi-mem: add spi_mem_dtr_supports_op()
commit: 539cf68cd51bfcd2987ce1c44e628e9da69de7c8
[2/2] spi: cadence-quadspi: Use spi_mem_dtr_supports_op()
commit: d2275139649bc34b8b5c3e33d26d991ab8a1364c
All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying
to this mail.
Thanks,
Mark