xtensa: drop platform_restart

Instead of using xtensa-specific platform_restart callback use
do_kernel_restart in the machine_restart implementation and reimplement
existing platform_restart users with register_restart_handler.
Drop platform_restart declaration and default implementation.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/platform.h

@@ -27,11 +27,6 @@ extern void platform_init(bp_tag_t*);
  */
 extern void platform_setup (char **);
 
-/*
- * platform_restart is called to restart the system.
- */
-extern void platform_restart (void);
-
 /*
  * platform_halt is called to stop the system and halt.
  */

arch/xtensa/kernel/platform.c

@@ -28,7 +28,6 @@
 
 _F(void, init, (bp_tag_t *first), { });
 _F(void, setup, (char** cmd), { });
-_F(void, restart, (void), { while(1); });
 _F(void, halt, (void), { while(1); });
 _F(void, power_off, (void), { while(1); });
 _F(void, idle, (void), { __asm__ __volatile__ ("waiti 0" ::: "memory"); });

arch/xtensa/kernel/setup.c

@@ -22,6 +22,7 @@
 #include <linux/screen_info.h>
 #include <linux/kernel.h>
 #include <linux/percpu.h>
+#include <linux/reboot.h>
 #include <linux/cpu.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
@@ -522,7 +523,12 @@ void cpu_reset(void)
 
 void machine_restart(char * cmd)
 {
-	platform_restart();
+	local_irq_disable();
+	smp_send_stop();
+	do_kernel_restart(cmd);
+	pr_err("Reboot failed -- System halted\n");
+	while (1)
+		cpu_relax();
 }
 
 void machine_halt(void)

arch/xtensa/platforms/iss/setup.c

@@ -16,6 +16,7 @@
 #include <linux/notifier.h>
 #include <linux/panic_notifier.h>
 #include <linux/printk.h>
+#include <linux/reboot.h>
 #include <linux/string.h>
 
 #include <asm/platform.h>
@@ -36,14 +37,20 @@ void platform_power_off(void)
 	simc_exit(0);
 }
 
-void platform_restart(void)
+static int iss_restart(struct notifier_block *this,
+		       unsigned long event, void *ptr)
 {
 	/* Flush and reset the mmu, simulate a processor reset, and
 	 * jump to the reset vector. */
 	cpu_reset();
-	/* control never gets here */
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block iss_restart_block = {
+	.notifier_call = iss_restart,
+};
+
 static int
 iss_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
@@ -82,4 +89,5 @@ void __init platform_setup(char **p_cmdline)
 	}
 
 	atomic_notifier_chain_register(&panic_notifier_list, &iss_panic_block);
+	register_restart_handler(&iss_restart_block);
 }

arch/xtensa/platforms/xt2000/setup.c

@@ -56,14 +56,20 @@ void platform_power_off(void)
 	while (1);
 }
 
-void platform_restart(void)
+static int xt2000_restart(struct notifier_block *this,
+			  unsigned long event, void *ptr)
 {
 	/* Flush and reset the mmu, simulate a processor reset, and
 	 * jump to the reset vector. */
 	cpu_reset();
-	/* control never gets here */
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block xt2000_restart_block = {
+	.notifier_call = xt2000_restart,
+};
+
 void __init platform_setup(char** cmdline)
 {
 	led_print (0, "LINUX   ");
@@ -140,6 +146,7 @@ static int __init xt2000_setup_devinit(void)
 	platform_device_register(&xt2000_serial8250_device);
 	platform_device_register(&xt2000_sonic_device);
 	mod_timer(&heartbeat_timer, jiffies + HZ / 2);
+	register_restart_handler(&xt2000_restart_block);
 	return 0;
 }
 

arch/xtensa/platforms/xtfpga/setup.c

@@ -49,7 +49,8 @@ void platform_power_off(void)
 		cpu_relax();
 }
 
-void platform_restart(void)
+static int xtfpga_restart(struct notifier_block *this,
+			  unsigned long event, void *ptr)
 {
 	/* Try software reset first. */
 	WRITE_ONCE(*(u32 *)XTFPGA_SWRST_VADDR, 0xdead);
@@ -58,9 +59,14 @@ void platform_restart(void)
 	 * simulate a processor reset, and jump to the reset vector.
 	 */
 	cpu_reset();
-	/* control never gets here */
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block xtfpga_restart_block = {
+	.notifier_call = xtfpga_restart,
+};
+
 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
 
 void __init platform_calibrate_ccount(void)
@@ -70,6 +76,11 @@ void __init platform_calibrate_ccount(void)
 
 #endif
 
+static void __init xtfpga_register_handlers(void)
+{
+	register_restart_handler(&xtfpga_restart_block);
+}
+
 #ifdef CONFIG_USE_OF
 
 static void __init xtfpga_clk_setup(struct device_node *np)
@@ -134,6 +145,9 @@ static int __init machine_setup(void)
 	if ((eth = of_find_compatible_node(eth, NULL, "opencores,ethoc")))
 		update_local_mac(eth);
 	of_node_put(eth);
+
+	xtfpga_register_handlers();
+
 	return 0;
 }
 arch_initcall(machine_setup);
@@ -281,6 +295,8 @@ static int __init xtavnet_init(void)
 	pr_info("XTFPGA: Ethernet MAC %pM\n", ethoc_pdata.hwaddr);
 	ethoc_pdata.eth_clkfreq = *(long *)XTFPGA_CLKFRQ_VADDR;
 
+	xtfpga_register_handlers();
+
 	return 0;
 }