MIPS: Loongson64: Switch to SYNC_R4K

Nowadays SYNC_R4K is performing better than Loongson64's
custom sync mechanism.

Switch to SYNC_R4K to improve performance and reduce code
duplication.

Signed-off-by: Jiaxun Yang <[e-mail]>
Reviewed-by: Huacai Chen <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/Kconfig

···
 	select BOARD_SCACHE
 	select CSRC_R4K
 	select CEVT_R4K
+	select SYNC_R4K
 	select FORCE_PCI
 	select ISA
 	select I8259

arch/mips/include/asm/smp.h

···
 #define SMP_CALL_FUNCTION	0x2
 /* Octeon - Tell another core to flush its icache */
 #define SMP_ICACHE_FLUSH	0x4
-#define SMP_ASK_C0COUNT		0x8
 
 /* Mask of CPUs which are currently definitely operating coherently */
 extern cpumask_t cpu_coherent_mask;

arch/mips/loongson64/smp.c

···
 static void __iomem *ipi_status0_regs[16];
 static void __iomem *ipi_en0_regs[16];
 static void __iomem *ipi_mailbox_buf[16];
-static uint32_t core0_c0count[NR_CPUS];
 
 static u32 (*ipi_read_clear)(int cpu);
 static void (*ipi_write_action)(int cpu, u32 action);
···
 		ipi_write_action(cpu_logical_map(i), (u32)action);
 }
 
-
 static irqreturn_t loongson3_ipi_interrupt(int irq, void *dev_id)
 {
-	int i, cpu = smp_processor_id();
-	unsigned int action, c0count;
+	int cpu = smp_processor_id();
+	unsigned int action;
 
 	action = ipi_read_clear(cpu);
 
···
 		irq_exit();
 	}
 
-	if (action & SMP_ASK_C0COUNT) {
-		BUG_ON(cpu != 0);
-		c0count = read_c0_count();
-		c0count = c0count ? c0count : 1;
-		for (i = 1; i < nr_cpu_ids; i++)
-			core0_c0count[i] = c0count;
-		nudge_writes(); /* Let others see the result ASAP */
-	}
-
 	return IRQ_HANDLED;
 }
 
-#define MAX_LOOPS 800
 /*
  * SMP init and finish on secondary CPUs
  */
 static void loongson3_init_secondary(void)
 {
-	int i;
-	uint32_t initcount;
 	unsigned int cpu = smp_processor_id();
 	unsigned int imask = STATUSF_IP7 | STATUSF_IP6 |
 			     STATUSF_IP3 | STATUSF_IP2;
···
 		     cpu_logical_map(cpu) % loongson_sysconf.cores_per_package);
 	cpu_data[cpu].package =
 		cpu_logical_map(cpu) / loongson_sysconf.cores_per_package;
-
-	i = 0;
-	core0_c0count[cpu] = 0;
-	loongson3_send_ipi_single(0, SMP_ASK_C0COUNT);
-	while (!core0_c0count[cpu]) {
-		i++;
-		cpu_relax();
-	}
-
-	if (i > MAX_LOOPS)
-		i = MAX_LOOPS;
-	if (cpu_data[cpu].package)
-		initcount = core0_c0count[cpu] + i;
-	else /* Local access is faster for loops */
-		initcount = core0_c0count[cpu] + i/2;
-
-	write_c0_count(initcount);
 }
 
 static void loongson3_smp_finish(void)