powerpc: Remove __USE_RTC()

Now that PowerPC 601 is gone, __USE_RTC() is never true.

Remove it.

That also leads to removing get_rtc() and get_rtcl()
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4757e1ed21fe1968c761ae081d1f3d790a9673f8.1601362098.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/time.h

@@ -38,9 +38,6 @@ struct div_result {
 	u64 result_low;
 };
 
-/* Accessor functions for the timebase (RTC on 601) registers. */
-#define __USE_RTC()	(0)
-
 #ifdef CONFIG_PPC64
 
 /* For compatibility, get_tbl() is defined as get_tb() on ppc64 */
@@ -59,25 +56,6 @@ static inline unsigned int get_tbu(void)
 }
 #endif /* !CONFIG_PPC64 */
 
-static inline unsigned int get_rtcl(void)
-{
-	unsigned int rtcl;
-
-	asm volatile("mfrtcl %0" : "=r" (rtcl));
-	return rtcl;
-}
-
-static inline u64 get_rtc(void)
-{
-	unsigned int hi, lo, hi2;
-
-	do {
-		asm volatile("mfrtcu %0; mfrtcl %1; mfrtcu %2"
-			     : "=r" (hi), "=r" (lo), "=r" (hi2));
-	} while (hi2 != hi);
-	return (u64)hi * 1000000000 + lo;
-}
-
 static inline u64 get_vtb(void)
 {
 #ifdef CONFIG_PPC_BOOK3S_64
@@ -109,7 +87,7 @@ static inline u64 get_tb(void)
 
 static inline u64 get_tb_or_rtc(void)
 {
-	return __USE_RTC() ? get_rtc() : get_tb();
+	return get_tb();
 }
 
 static inline void set_tb(unsigned int upper, unsigned int lower)
@@ -153,10 +131,6 @@ static inline void set_dec(u64 val)
 
 static inline unsigned long tb_ticks_since(unsigned long tstamp)
 {
-	if (__USE_RTC()) {
-		int delta = get_rtcl() - (unsigned int) tstamp;
-		return delta < 0 ? delta + 1000000000 : delta;
-	}
 	return get_tbl() - tstamp;
 }
 

arch/powerpc/kernel/time.c

@@ -75,15 +75,6 @@
 #include <linux/clockchips.h>
 #include <linux/timekeeper_internal.h>
 
-static u64 rtc_read(struct clocksource *);
-static struct clocksource clocksource_rtc = {
-	.name         = "rtc",
-	.rating       = 400,
-	.flags        = CLOCK_SOURCE_IS_CONTINUOUS,
-	.mask         = CLOCKSOURCE_MASK(64),
-	.read         = rtc_read,
-};
-
 static u64 timebase_read(struct clocksource *);
 static struct clocksource clocksource_timebase = {
 	.name         = "timebase",
@@ -447,19 +438,9 @@ void vtime_flush(struct task_struct *tsk)
 void __delay(unsigned long loops)
 {
 	unsigned long start;
-	int diff;
 
 	spin_begin();
-	if (__USE_RTC()) {
-		start = get_rtcl();
-		do {
-			/* the RTCL register wraps at 1000000000 */
-			diff = get_rtcl() - start;
-			if (diff < 0)
-				diff += 1000000000;
-			spin_cpu_relax();
-		} while (diff < loops);
-	} else if (tb_invalid) {
+	if (tb_invalid) {
 		/*
 		 * TB is in error state and isn't ticking anymore.
 		 * HMI handler was unable to recover from TB error.
@@ -696,8 +677,6 @@ EXPORT_SYMBOL_GPL(tb_to_ns);
  */
 notrace unsigned long long sched_clock(void)
 {
-	if (__USE_RTC())
-		return get_rtc();
 	return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
 }
 
@@ -847,11 +826,6 @@ void read_persistent_clock64(struct timespec64 *ts)
 }
 
 /* clocksource code */
-static notrace u64 rtc_read(struct clocksource *cs)
-{
-	return (u64)get_rtc();
-}
-
 static notrace u64 timebase_read(struct clocksource *cs)
 {
 	return (u64)get_tb();
@@ -948,12 +922,7 @@ void update_vsyscall_tz(void)
 
 static void __init clocksource_init(void)
 {
-	struct clocksource *clock;
-
-	if (__USE_RTC())
-		clock = &clocksource_rtc;
-	else
-		clock = &clocksource_timebase;
+	struct clocksource *clock = &clocksource_timebase;
 
 	if (clocksource_register_hz(clock, tb_ticks_per_sec)) {
 		printk(KERN_ERR "clocksource: %s is already registered\n",
@@ -1071,17 +1040,12 @@ void __init time_init(void)
 	u64 scale;
 	unsigned shift;
 
-	if (__USE_RTC()) {
-		/* 601 processor: dec counts down by 128 every 128ns */
-		ppc_tb_freq = 1000000000;
-	} else {
-		/* Normal PowerPC with timebase register */
-		ppc_md.calibrate_decr();
-		printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
-		       ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
-		printk(KERN_DEBUG "time_init: processor frequency   = %lu.%.6lu MHz\n",
-		       ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
-	}
+	/* Normal PowerPC with timebase register */
+	ppc_md.calibrate_decr();
+	printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
+	       ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
+	printk(KERN_DEBUG "time_init: processor frequency   = %lu.%.6lu MHz\n",
+	       ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
 
 	tb_ticks_per_jiffy = ppc_tb_freq / HZ;
 	tb_ticks_per_sec = ppc_tb_freq;