rust: Add ioremap_np support to io_mem & friends

Apple SoCs require non-posted mappings for MMIO, and this is
automatically handled by devm_ioremap_resource() and friends via a
resource flag. Implement the same logic in kernel::io_mem, so it can
work the same way.

Signed-off-by: Asahi Lina <lina@asahilina.net>

Author: hoshinolina

rust/helpers/iomem.c

@@ -7,6 +7,11 @@ void __iomem *rust_helper_ioremap(resource_size_t offset, unsigned long size)
 	return ioremap(offset, size);
 }
 
+void __iomem *rust_helper_ioremap_np(resource_size_t offset, unsigned long size)
+{
+	return ioremap_np(offset, size);
+}
+
 void rust_helper_memcpy_fromio(void *to, const volatile void __iomem *from, long count)
 {
 	memcpy_fromio(to, from, count);

rust/kernel/io_mem.rs

@@ -19,19 +19,22 @@ pub enum IoResource {
 pub struct Resource {
     offset: bindings::resource_size_t,
     size: bindings::resource_size_t,
+    flags: core::ffi::c_ulong,
 }
 
 impl Resource {
     pub(crate) fn new(
         start: bindings::resource_size_t,
         end: bindings::resource_size_t,
+        flags: core::ffi::c_ulong,
     ) -> Option<Self> {
         if start == 0 {
             return None;
         }
         Some(Self {
             offset: start,
             size: end.checked_sub(start)?.checked_add(1)?,
+            flags,
         })
     }
 }
@@ -160,8 +163,14 @@ impl<const SIZE: usize> IoMem<SIZE> {
         }
 
         // Try to map the resource.
-        // SAFETY: Just mapping the memory range.
-        let addr = unsafe { bindings::ioremap(res.offset, res.size as _) };
+        let addr = if res.flags & (bindings::IORESOURCE_MEM_NONPOSTED as core::ffi::c_ulong) != 0 {
+            // SAFETY: Just mapping the memory range.
+            unsafe { bindings::ioremap_np(res.offset, res.size as _) }
+        } else {
+            // SAFETY: Just mapping the memory range.
+            unsafe { bindings::ioremap(res.offset, res.size as _) }
+        };
+
         if addr.is_null() {
             Err(ENOMEM)
         } else {

rust/kernel/platform.rs

@@ -247,7 +247,7 @@ impl Device {
 
         // SAFETY: The pointer `res` is returned from `bindings::platform_get_resource`
         // above and checked if it is not a NULL.
-        unsafe { Resource::new((*res).start, (*res).end) }.ok_or(EINVAL)
+        unsafe { Resource::new((*res).start, (*res).end, (*res).flags) }.ok_or(EINVAL)
     }
 
     /// Ioremaps resources of a platform device.