zephyr: device: Add a possible static element with each device (WIP)

Allow the dt-rust.yaml file to specify a `static_type` value for device
nodes.  The generated code for the nodes will reserve a static value of
that type, and pass it into the constructor.  There is a NoStatic which
is the default.  As it is zero size, it will not cause any code to be
generated for the types that do not need static.

Fix the flash device to accept this argument, but the fix for gpio will
come in a subsequent patch.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

dt-rust.yaml

@@ -15,6 +15,7 @@
       raw:
         type: myself
       device: crate::device::gpio::Gpio
+      static_type: crate::device::gpio::GpioStatic
 
 # The gpio-leds node will have #children nodes describing each led.  We'll match on the parent
 # having this compatible property.  The nodes themselves are built out of the properties associated

zephyr-build/src/devicetree/augment.rs

@@ -130,6 +130,8 @@ pub enum Action {
         /// The name of the full path (within the zephyr-sys crate) for the wrapper node for this
         /// device.
         device: String,
+        /// Full path to a type if this node needs a static associated with each instance.
+        static_type: Option<String>,
     },
     /// Generate all of the labels as its own node.
     Labels,
@@ -138,7 +140,7 @@ pub enum Action {
 impl Action {
     fn generate(&self, _name: &Ident, node: &Node, tree: &DeviceTree) -> TokenStream {
         match self {
-            Action::Instance { raw, device } => raw.generate(node, device),
+            Action::Instance { raw, device, static_type } => raw.generate(node, device, static_type.as_deref()),
             Action::Labels => {
                 let nodes = tree.labels.iter().map(|(k, v)| {
                     let name = dt_to_lower_id(k);
@@ -181,8 +183,9 @@ pub enum RawInfo {
 }
 
 impl RawInfo {
-    fn generate(&self, node: &Node, device: &str) -> TokenStream {
+    fn generate(&self, node: &Node, device: &str, static_type: Option<&str>) -> TokenStream {
         let device_id = str_to_path(device);
+        let static_type = str_to_path(static_type.unwrap_or("crate::device::NoStatic"));
         match self {
             Self::Myself => {
                 let ord = node.ord;
@@ -192,12 +195,17 @@ impl RawInfo {
                     pub unsafe fn get_instance_raw() -> *const crate::raw::device {
                         &crate::raw::#rawdev
                     }
+                    #[allow(dead_code)]
+                    pub(crate) unsafe fn get_static_raw() -> &'static #static_type {
+                        &STATIC
+                    }
 
                     static UNIQUE: crate::device::Unique = crate::device::Unique::new();
+                    static STATIC: #static_type = #static_type::new();
                     pub fn get_instance() -> Option<#device_id> {
                         unsafe {
                             let device = get_instance_raw();
-                            #device_id::new(&UNIQUE, device)
+                            #device_id::new(&UNIQUE, &STATIC, device)
                         }
                     }
                 }
@@ -220,10 +228,12 @@ impl RawInfo {
 
                 quote! {
                     static UNIQUE: crate::device::Unique = crate::device::Unique::new();
+                    static STATIC: #static_type = #static_type::new();
                     pub fn get_instance() -> Option<#device_id> {
                         unsafe {
                             let device = #target_route :: get_instance_raw();
-                            #device_id::new(&UNIQUE, device, #(#args),*)
+                            let device_static = #target_route :: get_static_raw();
+                            #device_id::new(&UNIQUE, &STATIC, device, device_static, #(#args),*)
                         }
                     }
                 }
@@ -239,10 +249,11 @@ impl RawInfo {
 
                 quote! {
                     static UNIQUE: crate::device::Unique = crate::device::Unique::new();
+                    static STATIC: #static_type = #static_type::new();
                     pub fn get_instance() -> Option<#device_id> {
                         unsafe {
                             let device = #path :: get_instance_raw();
-                            #device_id::new(&UNIQUE, device, #(#get_args),*)
+                            #device_id::new(&UNIQUE, &STATIC, device, #(#get_args),*)
                         }
                     }
                 }

zephyr/src/device.rs

@@ -41,3 +41,13 @@ impl Unique {
         !self.0.fetch_or(true, Ordering::AcqRel)
     }
 }
+
+/// For devices that don't need any associated static data, This NoStatic type will take no space
+/// and generate no code, and has the const constructor needed for the type.
+pub(crate) struct NoStatic;
+
+impl NoStatic {
+    pub(crate) const fn new() -> Self {
+        Self
+    }
+}

zephyr/src/device/flash.rs

@@ -3,7 +3,7 @@
 // Note that currently, the flash partition shares the controller, so the underlying operations
 // are not actually safe.  Need to rethink how to manage this.
 
-use super::Unique;
+use super::{NoStatic, Unique};
 use crate::raw;
 
 /// A flash controller
@@ -22,6 +22,7 @@ impl FlashController {
     #[allow(dead_code)]
     pub(crate) unsafe fn new(
         unique: &Unique,
+        _static: &NoStatic,
         device: *const raw::device,
     ) -> Option<FlashController> {
         if !unique.once() {
@@ -50,6 +51,7 @@ impl FlashPartition {
     #[allow(dead_code)]
     pub(crate) unsafe fn new(
         unique: &Unique,
+        _static: &NoStatic,
         device: *const raw::device,
         offset: u32,
         size: u32,