Polled and IRQ-driven SPI I/O share code for cleanup and completion,
which can now be factored into its own routine.
This keeps a single point of truth for common paths, which will allow
a subsequent bug fix to happen in one place, and help avoid future
regressions.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
In polled mode, the STM32 SPI driver is signaling completion when
there are no waiters:
- the only spi_context_wait_for_completion() caller in this driver is
in the IRQ-driven portion of transceive() itself, which isn't
compiled in polled mode.
- the "asynchronous completion + polled I/O" combination is not
supported by the driver, so there are no other threads polling on
this I/O we need to signal completion to.
What should be happening instead of signaling completion is releasing
the chip select pin, which polled I/O currently doesn't do.
Fix these issues.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
The LL_SPI_NSS_* macros used in spi_stm32_configure() when
hardware-based NSS management is requested are incorrect; fix them.
In master mode, this seems like a copy/paste error. The slave mode
case is likely due to following incorrect documentation in the ST LL
headers.
Note that in my testing on STM32F4, NSS appears to be open drain when
managed by hardware, making that configuration harder to test (and
probably less useful).
Details for the curious:
The ST LL headers (for example stm32f4xx_ll_spi.h) claim
LL_SPI_NSS_HARD_INPUT is to be used only in master mode, and
LL_SPI_NSS_HARD_OUTPUT is to be used in slave mode.
The opposite is true: when NSS is not handled by software, the SPI
peripheral is responsible for driving NSS as an output, and the
slave peripheral is responsible for reading it as an input.
This is an error in the LL header files; the reference manuals and
the other LL code make this clear.
- The ST reference manuals specify that LL_SPI_HARD_OUTPUT (which
corresponds to SSM unset, SSOE set) is a master-only
configuration. For example, STM32 RM0368 says:
"NSS output enabled (SSM = 0, SSOE = 1)
This configuration is used only when the device operates in
master mode."
- LL_SPI_HARD_INPUT (SSM unset, SSOE unset) is either a master or
a slave configuration; in the slave case (which is what we're
interested in here), it corresponds to the "usual" NSS
input. RM0368, again:
"NSS output disabled (SSM = 0, SSOE = 0)
This configuration allows multimaster capability for devices
operating in master mode. For devices set as slave, the NSS
pin acts as a classical NSS input: the slave is selected when
NSS is low and deselected when NSS high."
The LL_SPI_StructInit() implementations similarly combine
LL_SPI_MODE_SLAVE with LL_SPI_NSS_HARD_INPUT.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
Now that struct spi_context supports passing errors from
interrupt-driven I/O handlers to waiting threads, we can enable error
interrupts and propagate errors to spi_transceive() callers.
To make it easier for users to debug SPI-related issues, log any error
bits set in SR when failures occur.
A subsequent patch will add error checking to polled mode as well, but
other cleanups and fixes will go in first to make this easier.
Note that this breaks the spi_loopback test on some targets, but it's
not a regression, as it wasn't working properly anyway. Subsequent
patches the bugs that this error checking has exposed.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
It is incorrect to call spi_context_release() on an STM32
spi_stm32_data object's ctx field before data->ctx->config is first
set in spi_stm32_configure(). This is because spi_context_release()
reads ctx->config->operation. In particular, during spi_stm32_init(),
calling spi_context_release() reads the uninitialized memory in
data->ctx->config->operation.
Call spi_context_unlock_unconditionally() instead to properly increase
the semaphore count.
Without this patch, the first call to spi_transceive() can block
forever depending on the value of the uninitialized memory holding
data->ctx->config->operation.
Signed-off-by: Marti Bolivar <marti.bolivar@linaro.org>
Add a SPI master and slave driver for the L4, F4 and F3 STM32
SoCs families.
Change-Id: I1faf5c97f992c91eba852fd126e7d3b83158993d
Origin: Original
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Tested-by: Lee Jones <lee.jones@linaro.org>
