Move part of the Nanopb sample documentation to a serialization entry
and add information on how to configure proto files.
Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>
This is the final step in making the `zephyr,memory-attr` property
actually useful.
The problem with the current implementation is that `zephyr,memory-attr`
is an enum type, this is making very difficult to use that to actually
describe the memory capabilities. The solution proposed in this PR is to
use the `zephyr,memory-attr` property as an OR-ed bitmask of memory
attributes.
With the change proposed in this PR it is possible in the DeviceTree to
mark the memory regions with a bitmask of attributes by using the
`zephyr,memory-attr` property. This property and the related memory
region can then be retrieved at run-time by leveraging a provided helper
library or the usual DT helpers.
The set of general attributes that can be specified in the property are
defined and explained in
`include/zephyr/dt-bindings/memory-attr/memory-attr.h` (the list can be
extended when needed).
For example, to mark a memory region in the DeviceTree as volatile,
non-cacheable, out-of-order:
mem: memory@10000000 {
compatible = "mmio-sram";
reg = <0x10000000 0x1000>;
zephyr,memory-attr = <( DT_MEM_VOLATILE |
DT_MEM_NON_CACHEABLE |
DT_MEM_OOO )>;
};
The `zephyr,memory-attr` property can also be used to set
architecture-specific custom attributes that can be interpreted at run
time. This is leveraged, among other things, to create MPU regions out
of DeviceTree defined memory regions on ARM, for example:
mem: memory@10000000 {
compatible = "mmio-sram";
reg = <0x10000000 0x1000>;
zephyr,memory-region = "NOCACHE_REGION";
zephyr,memory-attr = <( DT_ARM_MPU(ATTR_MPU_RAM_NOCACHE) )>;
};
See `include/zephyr/dt-bindings/memory-attr/memory-attr-mpu.h` to see
how an architecture can define its own special memory attributes (in
this case ARM MPU).
The property can also be used to set custom software-specific
attributes. For example we can think of marking a memory region as
available to be used for memory allocation (not yet implemented):
mem: memory@10000000 {
compatible = "mmio-sram";
reg = <0x10000000 0x1000>;
zephyr,memory-attr = <( DT_MEM_NON_CACHEABLE |
DT_MEM_SW_ALLOCATABLE )>;
};
Or maybe we can leverage the property to specify some alignment
requirements for the region:
mem: memory@10000000 {
compatible = "mmio-sram";
reg = <0x10000000 0x1000>;
zephyr,memory-attr = <( DT_MEM_CACHEABLE |
DT_MEM_SW_ALIGN(32) )>;
};
The conventional and recommended way to deal and manage with memory
regions marked with attributes is by using the provided `mem-attr`
helper library by enabling `CONFIG_MEM_ATTR` (or by using the usual DT
helpers).
When this option is enabled the list of memory regions and their
attributes are compiled in a user-accessible array and a set of
functions is made available that can be used to query, probe and act on
regions and attributes, see `include/zephyr/mem_mgmt/mem_attr.h`
Note that the `zephyr,memory-attr` property is only a descriptive
property of the capabilities of the associated memory region, but it
does not result in any actual setting for the memory to be set. The
user, code or subsystem willing to use this information to do some work
(for example creating an MPU region out of the property) must use either
the provided `mem-attr` library or the usual DeviceTree helpers to
perform the required work / setting.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Add a new API to perform an immediate system power off:
`sys_poweroff()`.
Until now, this functionality has been implemented via the system power
management module, but in a clunky fashion. The way system PM works is
by defining some idle states in devicetree, that, given some properties
(e.g. minimal residency, exit latency, etc.) are automatically selected
when system goes to idle based on the expected next wake-up. However,
system off is a power state that one typically wants to control manually
from the application because it implies state loss, and in most cases,
configuring some sort of wake-up source. So in general, it is not
desired to let the system enter this state automatically. This led to
the following stuff in-tree:
from `boards/arm/mimxrt595_evk/mimxrt595_evk_cm33.dts`:
```c
/*
* Deep power-down mode is supported in this SoC through
* 'PM_STATE_SOFT_OFF' state. There is no entry for this in device tree,
* user can call pm_state_force to enter this state.
*/
```
That is, state not being defined in devicetree so that PM subsystem
doesn't pick it automatically, but still implemented in in the PM hooks:
from `soc/arm/nxp_imx/rt5xx/power.c`, `pm_state_set()`:
```c
case PM_STATE_SOFT_OFF:
set_deepsleep_pin_config();
POWER_EnterDeepPowerDown(EXCLUDE_FROM_DEEP_POWERDOWN);
break;
```
And to actually make use of this state, users had to do this kind of
abominations:
```c
pm_state_force(0u, &(struct pm_state_info){ PM_STATE_SOFT_OFF, 0, 0 });
/* Now we need to go sleep. This will let the idle thread runs and
* the pm subsystem will use the forced state. To confirm that the
* forced state is used, lets set the same timeout used previously.
*/
k_sleep(K_SECONDS(SLEEP_S));
printk("ERROR: System off failed\n");
while (true) {
/* spin to avoid fall-off behavior */
}
```
Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>
Mostly moved and reorganised content to the Connectivity chapter,
separated API references. Fill in some gaps in the USB device
documentation.
Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
Adds documentation for the retention subsystem and boot mode
interface. Also marks the retention subsystem as experimental.
Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>
Introduce an API mirroring the CMSIS-DSP's basicmath. If CMSIS_DSP is
enabled, then it will by default be used as a backend. Developers may
opt into a custom backend by setting CONFIG_DSP_BACKEND_CMSIS=n. If
done, the application must provide `zdsp_backend/dsp.h` and optionally
implement the functions in its own .c files.
Signed-off-by: Yuval Peress <peress@google.com>
Add zbus message bus as a Zephyr subsystem. No message bus
or communication abstraction other than the usual (message queues,
mailboxes, etc.) enabled developers to implement event-driven systems in
Zephyr quickly. Zbus would fill that gap by providing the community with
a lightweight and flexible message bus. The implementation tries to be
closest as possible to the existing ones. We use the claim/finish
approach, and the API for publishing and reading channels are similar
in message queues. Zbus is about channels, messages, and observers.
Signed-off-by: Rodrigo Peixoto <rodrigopex@gmail.com>
A DMA friendly Stream API for zephyr. Based on ideas from io_uring
and iio, a queue based API for I/O operations.
Provides a pair of fixed length ringbuffer backed queues for submitting
I/O requests and recieving I/O completions. The requests may be chained
together to ensure the next operation does not start until the current
one is complete.
Requests target an abstract rtio_iodev which is expected to wrap all
the hardware particulars of how to perform the operation. For example
with a SPI bus device, a description of what a read, and write mean
can be decided by the iodev wrapping a particular device
hanging off of a SPI controller.
The queue pair are submitted to an executor which may be a simple
inplace looping executor done in the callers execution context
(thread/stack) but other executors are expected. A threadpool executor
might for example allow for concurrent request chains to execute in
parallel. A DMA executor, in conjunction with DMA aware iodevs
would allow for hardware offloading of operations going so far as to
schedule with priority using hardware arbitration.
Both the iodev and executor are definable by a particular
SoC, meaning they can work in conjuction to perform IO operations
using a particular DMA controller or methodology if desired.
The application decides entirely how large the queues are, where
the buffers to read/write come from (some executors
may have particular demands!), and which executor to submit
requests to.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
Move last remaining items from reference section to the appropriate new
section in the new structure.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Add a new 'OS Services' section to contain all dedicated os services
from other sections of the doc (reference and guides).
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
