From 6fffe57a6349cbd6f2eb71b78a9f5719d163589f Mon Sep 17 00:00:00 2001
From: Felipe Balbi <felipe@balbi.sh>
Date: Wed, 5 Apr 2023 14:42:47 +0300
Subject: [PATCH] uefi: debug: add DebugPort protocol

DebugPort might be useful for some uefi applications.
---
 uefi-test-runner/src/proto/debug.rs | 66 ++++++++++++++++++++++++++-
 uefi/src/proto/debug/mod.rs         | 69 +++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+), 1 deletion(-)

diff --git a/uefi-test-runner/src/proto/debug.rs b/uefi-test-runner/src/proto/debug.rs
index 40b0cc50d..d3ce523f9 100644
--- a/uefi-test-runner/src/proto/debug.rs
+++ b/uefi-test-runner/src/proto/debug.rs
@@ -1,8 +1,72 @@
+use alloc::vec::Vec;
 use core::ffi::c_void;
-use uefi::proto::debug::{DebugSupport, ExceptionType, ProcessorArch, SystemContext};
+use uefi::proto::debug::{DebugPort, DebugSupport, ExceptionType, ProcessorArch, SystemContext};
 use uefi::table::boot::BootServices;
 
 pub fn test(bt: &BootServices) {
+    test_debug_support(bt);
+    test_debug_port(bt);
+}
+
+fn test_debug_port(bt: &BootServices) {
+    info!("Running UEFI debug port protocol test");
+    if let Ok(handles) = bt.find_handles::<DebugPort>() {
+        for handle in handles {
+            if let Ok(debug_port) = bt.open_protocol_exclusive::<DebugPort>(handle) {
+                let timeout = 1000;
+
+                debug_port
+                    .reset()
+                    .expect("Error while resetting debug port");
+                let data: Vec<_> = r##"
+                                ..    .=-     .                                 
+                          .    :##+  .*##=  -*#+    ..                          
+                         =#*=:.*####+#####**####-.-*##                          
+                   .=-.  *############################:  :-:                    
+                   -###**##############################*###*                    
+               :.  -#######################################*  .::               
+              =##################################################               
+              .#################################################=               
+          -====#################################################+====.          
+          =##########################################################.          
+           +########################################################.           
+       -==+#########################################################*+=-.       
+       +######################=:=@@%#########+:-%@%####################*:       
+        =####################+   +@@@%######%.  -@@@##################*.        
+      :+#####################@-.:%@@@@#####%@*::#@@@%###################+:      
+     +#######################@@@@@@@@@######@@@@@@@@%#####################-     
+    -#########################@@@@@@@########@@@@@@%#######################     
+    -#######%%%##################%##############################%%%%######*     
+     +########%%%%############################################*%%%%#######:     
+      =######+=%%%#####***##%%#####################%#**++####=:%%%#######:      
+       :*#####:.*%#-####+==*########+-::::::=*#######*=+###*- *%*:-####*.       
+         -####*  .+. -*###############=   .*#############*-  .*:  *###+         
+           =###:        *##############+ .##############+        .###=          
+            .+#*        -######*=+++**** =###***++######-        :#*.           
+              .-         -######-               .*#####-         .-             
+                           =*####*.            =####+-                          
+                              .:--:           ::::.                             
+"##
+                .bytes()
+                .collect();
+
+                debug_port
+                    .write(timeout, &data)
+                    .expect("Error while writing to debug port");
+
+                debug_port.poll().expect("Error while polling debug port");
+
+                let mut data = Vec::with_capacity(4096);
+
+                debug_port
+                    .read(timeout, &mut data)
+                    .expect("Error while reading from debug port");
+            }
+        }
+    }
+}
+
+fn test_debug_support(bt: &BootServices) {
     info!("Running UEFI debug connection protocol test");
     let handles = bt
         .find_handles::<DebugSupport>()
diff --git a/uefi/src/proto/debug/mod.rs b/uefi/src/proto/debug/mod.rs
index 776b43497..22ad4983b 100644
--- a/uefi/src/proto/debug/mod.rs
+++ b/uefi/src/proto/debug/mod.rs
@@ -170,3 +170,72 @@ pub enum ProcessorArch: u32 => {
     /// RISC-V 128-bit
     RISCV_128   = 0x5128,
 }}
+
+/// The debug port protocol abstracts the underlying debug port
+/// hardware, whether it is a regular Serial port or something else.
+#[repr(C)]
+#[unsafe_protocol("eba4e8d2-3858-41ec-a281-2647ba9660d0")]
+pub struct DebugPort {
+    reset: extern "efiapi" fn(this: &DebugPort) -> Status,
+    write: extern "efiapi" fn(
+        this: &DebugPort,
+        timeout: u32,
+        buffer_size: &mut usize,
+        buffer: *const c_void,
+    ) -> Status,
+    read: extern "efiapi" fn(
+        this: &DebugPort,
+        timeout: u32,
+        buffer_size: &mut usize,
+        buffer: *mut c_void,
+    ) -> Status,
+    poll: extern "efiapi" fn(this: &DebugPort) -> Status,
+}
+
+impl DebugPort {
+    /// Resets the debugport device.
+    pub fn reset(&self) -> Result {
+        (self.reset)(self).into()
+    }
+
+    /// Write data to the debugport device.
+    ///
+    /// Note: `timeout` is given in microseconds
+    pub fn write(&self, timeout: u32, data: &[u8]) -> Result<(), usize> {
+        let mut buffer_size = data.len();
+
+        (self.write)(
+            self,
+            timeout,
+            &mut buffer_size,
+            data.as_ptr().cast::<c_void>(),
+        )
+        .into_with(
+            || debug_assert_eq!(buffer_size, data.len()),
+            |_| buffer_size,
+        )
+    }
+
+    /// Read data from the debugport device.
+    ///
+    /// Note: `timeout` is given in microseconds
+    pub fn read(&self, timeout: u32, data: &mut [u8]) -> Result<(), usize> {
+        let mut buffer_size = data.len();
+
+        (self.read)(
+            self,
+            timeout,
+            &mut buffer_size,
+            data.as_mut_ptr().cast::<c_void>(),
+        )
+        .into_with(
+            || debug_assert_eq!(buffer_size, data.len()),
+            |_| buffer_size,
+        )
+    }
+
+    /// Check to see if any data is available to be read from the debugport device.
+    pub fn poll(&self) -> Result {
+        (self.poll)(self).into()
+    }
+}