From d1ba4d4e2b4307afc1c49b1c8f9979b655fb2bc4 Mon Sep 17 00:00:00 2001
From: yellows8 <yellows8@users.noreply.github.com>
Date: Tue, 10 Oct 2017 00:44:00 -0400
Subject: [PATCH] Added osDCacheFlush() for use by usbds.

---
 nx/include/switch.h      |  1 +
 nx/include/switch/os.h   |  1 +
 nx/source/kernel/cache.s | 34 ++++++++++++++++++++++++++++++++++
 nx/source/services/usb.c |  2 +-
 4 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 nx/include/switch/os.h
 create mode 100644 nx/source/kernel/cache.s

diff --git a/nx/include/switch.h b/nx/include/switch.h
index 63d6662b..5773eacd 100644
--- a/nx/include/switch.h
+++ b/nx/include/switch.h
@@ -12,6 +12,7 @@ extern "C" {
 #include <switch/result.h>
 #include <switch/svc.h>
 #include <switch/ipc.h>
+#include <switch/os.h>
 
 #include <switch/kernel/tmem.h>
 #include <switch/kernel/mutex.h>
diff --git a/nx/include/switch/os.h b/nx/include/switch/os.h
new file mode 100644
index 00000000..2f6a8cc8
--- /dev/null
+++ b/nx/include/switch/os.h
@@ -0,0 +1 @@
+void osDCacheFlush(void* addr, size_t size);
diff --git a/nx/source/kernel/cache.s b/nx/source/kernel/cache.s
new file mode 100644
index 00000000..816b921e
--- /dev/null
+++ b/nx/source/kernel/cache.s
@@ -0,0 +1,34 @@
+.macro CODE_BEGIN name
+	.section .text.\name, "ax", %progbits
+	.global \name
+	.type \name, %function
+	.align 2
+	.cfi_startproc
+\name:
+.endm
+
+.macro CODE_END
+	.cfi_endproc
+.endm
+
+CODE_BEGIN osDCacheFlush
+	add x1, x1, x0
+	mrs x8, CTR_EL0
+	lsr x8, x8, #16
+	and x8, x8, #0xf
+	mov x9, #4
+	lsl x9, x9, x8
+	sub x10, x9, #1
+	bic x8, x0, x10
+	mov x10, x1
+
+osDCacheFlush_L0:
+	dc civac, x8
+	add x8, x8, x9
+	cmp x8, x10
+	bcc osDCacheFlush_L0
+
+	dsb sy
+	ret
+CODE_END
+
diff --git a/nx/source/services/usb.c b/nx/source/services/usb.c
index 5008b45a..6847424c 100644
--- a/nx/source/services/usb.c
+++ b/nx/source/services/usb.c
@@ -382,7 +382,7 @@ static Result _usbDsCmdNoParams(Handle sessionhandle, u64 cmd_id) {
 static Result _usbDsPostBuffer(Handle sessionhandle, u64 cmd_id, void* buffer, size_t size, u32 *out) {
     if(sessionhandle==0)return MAKERESULT(MODULE_LIBNX, LIBNX_NOTINITIALIZED);
 
-    //TODO: Add dache-flush code here, breaks otherwise.
+    osDCacheFlush(buffer, size);
 
     IpcCommand c;
     ipcInitialize(&c);