alpha: fix RTC on marvel

Unlike other alphas, marvel doesn't have real PC-style CMOS clock hardware
- RTC accesses are emulated via PAL calls. Unfortunately, for unknown
reason these calls work only on CPU #0. So current implementation for
arbitrary CPU makes CMOS_READ/WRITE to be executed on CPU #0 via IPI.
However, for obvious reason this doesn't work with standard
get/set_rtc_time() functions, where a bunch of CMOS accesses is done with
disabled interrupts.

Solved by making the IPI calls for entire get/set_rtc_time() functions,
not for individual CMOS accesses. Which is also a lot more effective
performance-wise.

The patch is largely based on the code from Jay Estabrook.
My changes:
- tweak asm-generic/rtc.h by adding a couple of #defines to
avoid a massive code duplication in arch/alpha/include/asm/rtc.h;
- sys_marvel.c: fix get/set_rtc_time() return values (Jay's FIXMEs).

NOTE: this fixes *only* LIB_RTC drivers. Legacy (CONFIG_RTC) driver
wont't work on marvel. Actually I think that we should just disable
CONFIG_RTC on alpha (maybe in 2.6.30?), like most other arches - AFAIK,
all modern distributions use LIB_RTC anyway.

Signed-off-by: Ivan Kokshaysky <[e-mail]>
Cc: Richard Henderson <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/alpha/include/asm/machvec.h

···
 struct pci_ops;
 struct pci_controller;
 struct _alpha_agp_info;
+struct rtc_time;
 
 struct alpha_machine_vector
 {
···
 	struct pci_ops *pci_ops;
 
 	struct _alpha_agp_info *(*agp_info)(void);
+
+	unsigned int (*rtc_get_time)(struct rtc_time *);
+	int (*rtc_set_time)(struct rtc_time *);
 
 	const char *vector_name;
 

arch/alpha/include/asm/rtc.h

···
 #ifndef _ALPHA_RTC_H
 #define _ALPHA_RTC_H
 
-/*
- * Alpha uses the default access methods for the RTC.
- */
+#if defined(CONFIG_ALPHA_GENERIC)
+# define get_rtc_time		alpha_mv.rtc_get_time
+# define set_rtc_time		alpha_mv.rtc_set_time
+#else
+# if defined(CONFIG_ALPHA_MARVEL) && defined(CONFIG_SMP)
+#  define get_rtc_time		marvel_get_rtc_time
+#  define set_rtc_time		marvel_set_rtc_time
+# endif
+#endif
 
 #include <asm-generic/rtc.h>
 

arch/alpha/kernel/core_marvel.c

···
 		rtc_access.data = bcd2bin(b);
 		rtc_access.function = 0x48 + !write;	/* GET/PUT_TOY */
 
-#ifdef CONFIG_SMP
-		if (smp_processor_id() != boot_cpuid)
-			smp_call_function_single(boot_cpuid,
-						 __marvel_access_rtc,
-						 &rtc_access, 1);
-		else
-			__marvel_access_rtc(&rtc_access);
-#else
 		__marvel_access_rtc(&rtc_access);
-#endif
+
 		ret = bin2bcd(rtc_access.data);
 		break;
 

arch/alpha/kernel/machvec_impl.h

···
 #define CAT1(x,y)  x##y
 #define CAT(x,y)   CAT1(x,y)
 
-#define DO_DEFAULT_RTC .rtc_port = 0x70
+#define DO_DEFAULT_RTC \
+	.rtc_port = 0x70, \
+	.rtc_get_time = common_get_rtc_time, \
+	.rtc_set_time = common_set_rtc_time
 
 #define DO_EV4_MMU							\
 	.max_asn =			EV4_MAX_ASN,			\

arch/alpha/kernel/proto.h

···
 extern irqreturn_t timer_interrupt(int irq, void *dev);
 extern void common_init_rtc(void);
 extern unsigned long est_cycle_freq;
+extern unsigned int common_get_rtc_time(struct rtc_time *time);
+extern int common_set_rtc_time(struct rtc_time *time);
 
 /* smc37c93x.c */
 extern void SMC93x_Init(void);

arch/alpha/kernel/sys_jensen.c

···
 	.machine_check		= jensen_machine_check,
 	.max_isa_dma_address	= ALPHA_MAX_ISA_DMA_ADDRESS,
 	.rtc_port		= 0x170,
+	.rtc_get_time		= common_get_rtc_time,
+	.rtc_set_time		= common_set_rtc_time,
 
 	.nr_irqs		= 16,
 	.device_interrupt	= jensen_device_interrupt,

arch/alpha/kernel/sys_marvel.c

···
 #include <asm/hwrpb.h>
 #include <asm/tlbflush.h>
 #include <asm/vga.h>
+#include <asm/rtc.h>
 
 #include "proto.h"
 #include "err_impl.h"
···
 	init_rtc_irq();
 }
 
+struct marvel_rtc_time {
+	struct rtc_time *time;
+	int retval;
+};
+
+#ifdef CONFIG_SMP
+static void
+smp_get_rtc_time(void *data)
+{
+	struct marvel_rtc_time *mrt = data;
+	mrt->retval = __get_rtc_time(mrt->time);
+}
+
+static void
+smp_set_rtc_time(void *data)
+{
+	struct marvel_rtc_time *mrt = data;
+	mrt->retval = __set_rtc_time(mrt->time);
+}
+#endif
+
+static unsigned int
+marvel_get_rtc_time(struct rtc_time *time)
+{
+#ifdef CONFIG_SMP
+	struct marvel_rtc_time mrt;
+
+	if (smp_processor_id() != boot_cpuid) {
+		mrt.time = time;
+		smp_call_function_single(boot_cpuid, smp_get_rtc_time, &mrt, 1);
+		return mrt.retval;
+	}
+#endif
+	return __get_rtc_time(time);
+}
+
+static int
+marvel_set_rtc_time(struct rtc_time *time)
+{
+#ifdef CONFIG_SMP
+	struct marvel_rtc_time mrt;
+
+	if (smp_processor_id() != boot_cpuid) {
+		mrt.time = time;
+		smp_call_function_single(boot_cpuid, smp_set_rtc_time, &mrt, 1);
+		return mrt.retval;
+	}
+#endif
+	return __set_rtc_time(time);
+}
+
 static void
 marvel_smp_callin(void)
 {
···
 struct alpha_machine_vector marvel_ev7_mv __initmv = {
 	.vector_name		= "MARVEL/EV7",
 	DO_EV7_MMU,
-	DO_DEFAULT_RTC,
+	.rtc_port		= 0x70,
+	.rtc_get_time		= marvel_get_rtc_time,
+	.rtc_set_time		= marvel_set_rtc_time,
 	DO_MARVEL_IO,
 	.machine_check		= marvel_machine_check,
 	.max_isa_dma_address	= ALPHA_MAX_ISA_DMA_ADDRESS,

arch/alpha/kernel/time.c

···
 #include <asm/io.h>
 #include <asm/hwrpb.h>
 #include <asm/8253pit.h>
+#include <asm/rtc.h>
 
 #include <linux/mc146818rtc.h>
 #include <linux/time.h>
···
 	init_rtc_irq();
 }
 
+unsigned int common_get_rtc_time(struct rtc_time *time)
+{
+	return __get_rtc_time(time);
+}
+
+int common_set_rtc_time(struct rtc_time *time)
+{
+	return __set_rtc_time(time);
+}
 
 /* Validate a computed cycle counter result against the known bounds for
    the given processor core.  There's too much brokenness in the way of

include/asm-generic/rtc.h

···
 	return uip;
 }
 
-static inline unsigned int get_rtc_time(struct rtc_time *time)
+static inline unsigned int __get_rtc_time(struct rtc_time *time)
 {
 	unsigned char ctrl;
 	unsigned long flags;
···
 	return RTC_24H;
 }
 
+#ifndef get_rtc_time
+#define get_rtc_time	__get_rtc_time
+#endif
+
 /* Set the current date and time in the real time clock. */
-static inline int set_rtc_time(struct rtc_time *time)
+static inline int __set_rtc_time(struct rtc_time *time)
 {
 	unsigned long flags;
 	unsigned char mon, day, hrs, min, sec;
···
 	return 0;
 }
 
+#ifndef set_rtc_time
+#define set_rtc_time	__set_rtc_time
+#endif
+
 static inline unsigned int get_rtc_ss(void)
 {
 	struct rtc_time h;
 
-	get_rtc_time(&h);
+	__get_rtc_time(&h);
 	return h.tm_sec;
 }