microblaze: Add xmb_manager_register function

Triple Modular Redundancy (TMR) Microblaze solution provides soft error
injection, detection, correction and recovery for Microblaze cores in the
system. The Xilinx/AMD Triple Modular Redundancy (TMR) solution in Vivado
provides all the necessary building blocks to implement a redundant
triplicated MicroBlaze subsystem. This processing subsystem is
fault-tolerant and continues to operate nominally after encountering an
error. Together with the capability to detect and recover from errors,
the implementation ensures the reliability of the entire subsystem.

When the break vector gets asserted because of error injection,
the break signal must be blocked before exiting from the break handler,
This commit adds support for xmb_manager_register api which updates the
TMR manager address and control register and error count and reset callback
function arguments, which will be used by the break handler to block the
break and call the error count callback function and reset callback
function.

Signed-off-by: Appana Durga Kedareswara rao <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michal Simek <[e-mail]>

arch/microblaze/Kconfig

···
 	hex "Size of user task space" if TASK_SIZE_BOOL
 	default "0x80000000"
 
+config MB_MANAGER
+	bool "Support for Microblaze Manager"
+	depends on ADVANCED_OPTIONS
+	help
+	  This option enables API for configuring the MicroBlaze manager
+	  control register, which is consumed by the break handler to
+	  block the break.
+
+	  Say N here unless you know what you are doing.
+
 endmenu
 
 menu "Bus Options"

arch/microblaze/include/asm/xilinx_mb_manager.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 Xilinx, Inc.
+ */
+#ifndef _XILINX_MB_MANAGER_H
+#define _XILINX_MB_MANAGER_H
+
+#include <linux/of_address.h>
+
+/*
+ * When the break vector gets asserted because of error injection, the break
+ * signal must be blocked before exiting from the break handler, Below api
+ * updates the manager address and control register and error counter callback
+ * arguments, which will be used by the break handler to block the break and
+ * call the callback function.
+ */
+void xmb_manager_register(uintptr_t phys_baseaddr, u32 cr_val,
+			  void (*callback)(void *data),
+			  void *priv, void (*reset_callback)(void *data));
+
+#endif /* _XILINX_MB_MANAGER_H */

arch/microblaze/kernel/entry.S

···
 	rtsd	r15, 8
 	nop
 
+#ifdef CONFIG_MB_MANAGER
+.section .data
+.global xmb_manager_dev
+.global xmb_manager_baseaddr
+.global xmb_manager_crval
+.global xmb_manager_callback
+.global xmb_manager_reset_callback
+.align 4
+xmb_manager_dev:
+	.long 0
+xmb_manager_baseaddr:
+	.long 0
+xmb_manager_crval:
+	.long 0
+xmb_manager_callback:
+	.long 0
+xmb_manager_reset_callback:
+	.long 0
+
+/*
+ * When the break vector gets asserted because of error injection,
+ * the break signal must be blocked before exiting from the
+ * break handler, Below api updates the manager address and
+ * control register and error count callback arguments,
+ * which will be used by the break handler to block the
+ * break and call the callback function.
+ */
+.global xmb_manager_register
+.section .text
+.align 2
+.ent xmb_manager_register
+.type xmb_manager_register, @function
+xmb_manager_register:
+	swi	r5, r0, xmb_manager_baseaddr
+	swi	r6, r0, xmb_manager_crval
+	swi	r7, r0, xmb_manager_callback
+	swi	r8, r0, xmb_manager_dev
+	swi	r9, r0, xmb_manager_reset_callback
+
+	rtsd	r15, 8;
+	nop;
+.end xmb_manager_register
+#endif
+
 ENTRY(_reset)
 	VM_OFF
 	brai	0; /* Jump to reset vector */