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Commit 5f7dc5d7 authored by Ivan Kokshaysky's avatar Ivan Kokshaysky Committed by Linus Torvalds
Browse files

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: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2f88d151

arch/alpha/include/asm/machvec.h

+4 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ struct pci_dev; 
struct pci_ops;

struct pci_controller;

struct _alpha_agp_info;

struct rtc_time;



struct alpha_machine_vector

{
@@ -94,6 +95,9 @@ struct alpha_machine_vector 


	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;



	/* NUMA information */

arch/alpha/include/asm/rtc.h

+9 −3
Original line number Diff line number Diff line 
#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

+1 −9
Original line number Diff line number Diff line
@@ -658,16 +658,8 @@ __marvel_rtc_io(u8 b, unsigned long addr, int write) 
		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

+4 −1
Original line number Diff line number Diff line
@@ -40,7 +40,10 @@ 
#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

+2 −0
Original line number Diff line number Diff line
@@ -145,6 +145,8 @@ extern void smp_percpu_timer_interrupt(struct pt_regs *); 
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);