From 523f6f4bb2735b2a48f137a95344df9476e65a16 Mon Sep 17 00:00:00 2001
From: Felix Kopp <sandtler@sandtler.club>
Date: Sun, 29 Nov 2020 20:38:16 +0100
Subject: [PATCH] serial: forgot to commit some shit

---
 include/arch/at91sam3x8e/serial.h | 38 +++++++++++++++++++++++++++++++
 include/arch/serial.h             |  8 +++++++
 include/ardix/serial.h            |  2 +-
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/include/arch/at91sam3x8e/serial.h b/include/arch/at91sam3x8e/serial.h
index 325be71..e253258 100644
--- a/include/arch/at91sam3x8e/serial.h
+++ b/include/arch/at91sam3x8e/serial.h
@@ -4,6 +4,44 @@
 #pragma once
 
 #include <ardix/serial.h>
+#include <ardix/types.h>
+#include <ardix/util.h>
+
+#include <stdbool.h>
+
+#ifndef CONFIG_ARCH_SERIAL_BUFSZ
+#define CONFIG_ARCH_SERIAL_BUFSZ 32
+#endif /* CONFIG_ARCH_SERIAL_BUFSZ */
+
+/** Architecture-specific extension of `struct serial_interface` */
+struct arch_serial_interface {
+	struct serial_interface interface;
+
+	/*
+	 * two hardware buffers; one is for being written to while the other one can be read from
+	 * by the hardware w/out interfering with each other.  `arch_serial_hwbuf_rotate()` is
+	 * responsible for writing this to the respective hardware register and swapping them out.
+	 * The platform's buffer length registers only allow 16-byte numbers, so we can save some
+	 * memory by not using `size_t`
+	 */
+	uint16_t current_len; /* buffer length registers are only 16 bytes */
+	uint8_t tx1[CONFIG_ARCH_SERIAL_BUFSZ];
+	uint8_t tx2[CONFIG_ARCH_SERIAL_BUFSZ];
+	/** hardware has finished sending the current buffer and ready for a swap */
+	bool hw_txrdy;
+	/** which hardware buffer is currently being written to (use `ARCH_SERIAL_BUF*`) */
+	bool current_txbuf;
+};
+#define ARCH_SERIAL_BUF1 false
+#define ARCH_SERIAL_BUF2 true
+
+/**
+ * Cast a `struct serial_interface` out to a `struct arch_serial_interface`.
+ *
+ * @param ptr: The `struct serial_interface *` to cast out from.
+ * @returns The containing `struct arch_serial_interface *`.
+ */
+#define to_arch_serial_interface(ptr) container_of(ptr, struct arch_serial_interface, interface)
 
 /*
  * Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
diff --git a/include/arch/serial.h b/include/arch/serial.h
index 91b1ccd..1ac0d4a 100644
--- a/include/arch/serial.h
+++ b/include/arch/serial.h
@@ -17,6 +17,14 @@ void arch_serial_exit(struct serial_interface *interface);
  */
 void arch_serial_notify(struct serial_interface *interface);
 
+/**
+ * Copy the current TX ring buffer content to a new hardware buffer.
+ *
+ * @param interface: The serial interface to rotate the hardware buffer of.
+ * @returns 0 on success, or a negative number on failure.
+ */
+int arch_serial_txbuf_rotate(struct serial_interface *interface);
+
 #ifdef ARCH_AT91SAM3X8E
 #include <arch/at91sam3x8e/serial.h>
 #else
diff --git a/include/ardix/serial.h b/include/ardix/serial.h
index 896e0be..1ad184e 100644
--- a/include/ardix/serial.h
+++ b/include/ardix/serial.h
@@ -9,7 +9,7 @@
 
 #ifndef SERIAL_BUFSZ
 /** size of a serial I/O buffer in bytes */
-#define SERIAL_BUFSZ 64
+#define SERIAL_BUFSZ 256
 #endif
 
 struct serial_interface {