[RFC PATCH v1 15/31] ARC: Process/scheduling/clock/Timers/Delay Management

From: Vineet Gupta
Date: Wed Nov 07 2012 - 04:51:59 EST

Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
---
arch/arc/include/asm/arcregs.h | 31 +++++
arch/arc/include/asm/delay.h | 68 +++++++++++
arch/arc/include/asm/processor.h | 3 +
arch/arc/include/asm/switch_to.h | 41 +++++++
arch/arc/include/asm/timex.h | 18 +++
arch/arc/kernel/ctx_sw.c | 91 +++++++++++++++
arch/arc/kernel/ctx_sw_asm.S | 58 +++++++++
arch/arc/kernel/fpu.c | 55 +++++++++
arch/arc/kernel/process.c | 201 ++++++++++++++++++++++++++++++++
arch/arc/kernel/time.c | 237 ++++++++++++++++++++++++++++++++++++++
10 files changed, 803 insertions(+), 0 deletions(-)
create mode 100644 arch/arc/include/asm/delay.h
create mode 100644 arch/arc/include/asm/switch_to.h
create mode 100644 arch/arc/include/asm/timex.h
create mode 100644 arch/arc/kernel/ctx_sw.c
create mode 100644 arch/arc/kernel/ctx_sw_asm.S
create mode 100644 arch/arc/kernel/fpu.c
create mode 100644 arch/arc/kernel/time.c

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 3fccb04..5131bb3 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -47,6 +47,28 @@
#define AUX_ITRIGGER 0x40d
#define AUX_IPULSE 0x415

+/* Timer related Aux registers */
+#define ARC_REG_TIMER0_LIMIT 0x23 /* timer 0 limit */
+#define ARC_REG_TIMER0_CTRL 0x22 /* timer 0 control */
+#define ARC_REG_TIMER0_CNT 0x21 /* timer 0 count */
+#define ARC_REG_TIMER1_LIMIT 0x102 /* timer 1 limit */
+#define ARC_REG_TIMER1_CTRL 0x101 /* timer 1 control */
+#define ARC_REG_TIMER1_CNT 0x100 /* timer 1 count */
+
+#define TIMER_CTRL_IE (1 << 0) /* Interupt when Count reachs limit */
+#define TIMER_CTRL_NH (1 << 1) /* Count only when CPU NOT halted */
+
+/*
+ * Floating Pt Registers
+ * Status regs are read-only (build-time) so need not be saved/restored
+ */
+#define ARC_AUX_FP_STAT 0x300
+#define ARC_AUX_DPFP_1L 0x301
+#define ARC_AUX_DPFP_1H 0x302
+#define ARC_AUX_DPFP_2L 0x303
+#define ARC_AUX_DPFP_2H 0x304
+#define ARC_AUX_DPFP_STAT 0x305
+
#ifndef __ASSEMBLY__

/*
@@ -110,6 +132,15 @@

#endif

+#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
+/* These DPFP regs need to be saved/restored across ctx-sw */
+struct arc_fpu {
+ struct {
+ unsigned int l, h;
+ } aux_dpfp[2];
+};
+#endif
+
#endif /* __ASEMBLY__ */

#endif /* __KERNEL__ */
diff --git a/arch/arc/include/asm/delay.h b/arch/arc/include/asm/delay.h
new file mode 100644
index 0000000..442ce5d
--- /dev/null
+++ b/arch/arc/include/asm/delay.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Delay routines using pre computed loops_per_jiffy value.
+ *
+ * vineetg: Feb 2012
+ * -Rewrote in "C" to avoid dealing with availability of H/w MPY
+ * -Also reduced the num of MPY operations from 3 to 2
+ *
+ * Amit Bhor: Codito Technologies 2004
+ */
+
+#ifndef __ASM_ARC_UDELAY_H
+#define __ASM_ARC_UDELAY_H
+
+#include <asm/param.h> /* HZ */
+
+static inline void __delay(unsigned long loops)
+{
+ __asm__ __volatile__(
+ "1: sub.f %0, %0, 1 \n"
+ " jpnz 1b \n"
+ : "+r"(loops)
+ :
+ : "cc");
+}
+
+extern void __bad_udelay(void);
+
+/*
+ * Normal Math for computing loops in "N" usecs
+ * -we have precomputed @loops_per_jiffy
+ * -1 sec has HZ jiffies
+ * loops per "N" usecs = ((loops_per_jiffy * HZ / 1000000) * N)
+ *
+ * Approximate Division by multiplication:
+ * -Mathematically if we multiply and divide a number by same value the
+ * result remains unchanged: In this case, we use 2^32
+ * -> (loops_per_N_usec * 2^32 ) / 2^32
+ * -> (((loops_per_jiffy * HZ / 1000000) * N) * 2^32) / 2^32
+ * -> (loops_per_jiffy * HZ * N * 4295) / 2^32
+ *
+ * -Divide by 2^32 is very simply right shift by 32
+ * -We simply need to ensure that the multiply per above eqn happens in
+ * 64-bit precision (if CPU doesn't support it - gcc can emaulate it)
+ */
+
+static inline void __udelay(unsigned long usecs)
+{
+ unsigned long loops;
+
+ /* (long long) cast ensures 64 bit MPY - real or emulated
+ * HZ * 4295 is pre-evaluated by gcc - hence only 2 mpy ops
+ */
+ loops = ((long long)(usecs * 4295 * HZ) *
+ (long long)(loops_per_jiffy)) >> 32;
+
+ __delay(loops);
+}
+
+#define udelay(n) (__builtin_constant_p(n) ? ((n) > 20000 ? __bad_udelay() \
+ : __udelay(n)) : __udelay(n))
+
+#endif /* __ASM_ARC_UDELAY_H */
diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h
index e2445bc..38ea5fb 100644
--- a/arch/arc/include/asm/processor.h
+++ b/arch/arc/include/asm/processor.h
@@ -29,6 +29,9 @@ struct thread_struct {
unsigned long callee_reg; /* pointer to callee regs */
unsigned long fault_address; /* dbls as brkpt holder as well */
unsigned long cause_code; /* Exception Cause Code (ECR) */
+#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
+ struct arc_fpu fpu;
+#endif
};

#define INIT_THREAD { \
diff --git a/arch/arc/include/asm/switch_to.h b/arch/arc/include/asm/switch_to.h
new file mode 100644
index 0000000..1b171ab
--- /dev/null
+++ b/arch/arc/include/asm/switch_to.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARC_SWITCH_TO_H
+#define _ASM_ARC_SWITCH_TO_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/sched.h>
+
+#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
+
+extern void fpu_save_restore(struct task_struct *p, struct task_struct *n);
+#define ARC_FPU_PREV(p, n) fpu_save_restore(p, n)
+#define ARC_FPU_NEXT(t)
+
+#else
+
+#define ARC_FPU_PREV(p, n)
+#define ARC_FPU_NEXT(n)
+
+#endif /* !CONFIG_ARC_FPU_SAVE_RESTORE */
+
+struct task_struct *__switch_to(struct task_struct *p, struct task_struct *n);
+
+#define switch_to(prev, next, last) \
+do { \
+ ARC_FPU_PREV(prev, next); \
+ last = __switch_to(prev, next);\
+ ARC_FPU_NEXT(next); \
+ mb(); \
+} while (0)
+
+#endif
+
+#endif
diff --git a/arch/arc/include/asm/timex.h b/arch/arc/include/asm/timex.h
new file mode 100644
index 0000000..2c9bfb2
--- /dev/null
+++ b/arch/arc/include/asm/timex.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARC_TIMEX_H
+#define _ASM_ARC_TIMEX_H
+
+#define CLOCK_TICK_RATE CONFIG_ARC_PLAT_CLK /* Underlying HZ */
+
+#include <asm-generic/timex.h>
+
+/* XXX: get_cycles() to be implemented with RTSC insn */
+
+#endif /* _ASM_ARC_TIMEX_H */
diff --git a/arch/arc/kernel/ctx_sw.c b/arch/arc/kernel/ctx_sw.c
new file mode 100644
index 0000000..647e37a
--- /dev/null
+++ b/arch/arc/kernel/ctx_sw.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Vineetg: Aug 2009
+ * -"C" version of lowest level context switch asm macro called by schedular
+ * gcc doesn't generate the dward CFI info for hand written asm, hence can't
+ * backtrace out of it (e.g. tasks sleeping in kernel).
+ * So we cheat a bit by writing almost similar code in inline-asm.
+ * -This is a hacky way of doing things, but there is no other simple way.
+ * I don't want/intend to extend unwinding code to understand raw asm
+ */
+
+#include <asm/asm-offsets.h>
+#include <linux/sched.h>
+
+struct task_struct *__sched
+__switch_to(struct task_struct *prev_task, struct task_struct *next_task)
+{
+ unsigned int tmp;
+ unsigned int prev = (unsigned int)prev_task;
+ unsigned int next = (unsigned int)next_task;
+ int num_words_to_skip = 1;
+
+ __asm__ __volatile__(
+ /* FP/BLINK save generated by gcc (standard function prologue */
+ "st.a r13, [sp, -4] \n\t"
+ "st.a r14, [sp, -4] \n\t"
+ "st.a r15, [sp, -4] \n\t"
+ "st.a r16, [sp, -4] \n\t"
+ "st.a r17, [sp, -4] \n\t"
+ "st.a r18, [sp, -4] \n\t"
+ "st.a r19, [sp, -4] \n\t"
+ "st.a r20, [sp, -4] \n\t"
+ "st.a r21, [sp, -4] \n\t"
+ "st.a r22, [sp, -4] \n\t"
+ "st.a r23, [sp, -4] \n\t"
+ "st.a r24, [sp, -4] \n\t"
+ "st.a r25, [sp, -4] \n\t"
+ "sub sp, sp, %4 \n\t" /* create gutter at top */
+
+ /* set ksp of outgoing task in tsk->thread.ksp */
+ "st.as sp, [%3, %1] \n\t"
+
+ "sync \n\t"
+
+ /*
+ * setup _current_task with incoming tsk.
+ * optionally, set r25 to that as well
+ * For SMP extra work to get to &_current_task[cpu]
+ * (open coded SET_CURR_TASK_ON_CPU)
+ */
+ "st %2, [@_current_task] \n\t"
+
+ /* get ksp of incoming task from tsk->thread.ksp */
+ "ld.as sp, [%2, %1] \n\t"
+
+ /* start loading it's CALLEE reg file */
+
+ "add sp, sp, %4 \n\t" /* skip gutter at top */
+
+ "ld.ab r25, [sp, 4] \n\t"
+ "ld.ab r24, [sp, 4] \n\t"
+ "ld.ab r23, [sp, 4] \n\t"
+ "ld.ab r22, [sp, 4] \n\t"
+ "ld.ab r21, [sp, 4] \n\t"
+ "ld.ab r20, [sp, 4] \n\t"
+ "ld.ab r19, [sp, 4] \n\t"
+ "ld.ab r18, [sp, 4] \n\t"
+ "ld.ab r17, [sp, 4] \n\t"
+ "ld.ab r16, [sp, 4] \n\t"
+ "ld.ab r15, [sp, 4] \n\t"
+ "ld.ab r14, [sp, 4] \n\t"
+ "ld.ab r13, [sp, 4] \n\t"
+
+ /* last (ret value) = prev : although for ARC it mov r0, r0 */
+ "mov %0, %3 \n\t"
+
+ /* FP/BLINK restore generated by gcc (standard func epilogue */
+
+ : "=r"(tmp)
+ : "n"((TASK_THREAD + THREAD_KSP) / 4), "r"(next), "r"(prev),
+ "n"(num_words_to_skip * 4)
+ : "blink"
+ );
+
+ return (struct task_struct *)tmp;
+}
diff --git a/arch/arc/kernel/ctx_sw_asm.S b/arch/arc/kernel/ctx_sw_asm.S
new file mode 100644
index 0000000..d897234
--- /dev/null
+++ b/arch/arc/kernel/ctx_sw_asm.S
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Vineetg: Aug 2009
+ * -Moved core context switch macro out of entry.S into this file.
+ * -This is the more "natural" hand written assembler
+ */
+
+#include <asm/entry.h> /* For the SAVE_* macros */
+#include <asm/asm-offsets.h>
+#include <asm/linkage.h>
+
+;################### Low Level Context Switch ##########################
+
+ .section .sched.text,"ax",@progbits
+ .align 4
+ .global __switch_to
+ .type __switch_to, @function
+__switch_to:
+
+ /* Save regs on kernel mode stack of task */
+ st.a blink, [sp, -4]
+ st.a fp, [sp, -4]
+ SAVE_CALLEE_SAVED_KERNEL
+
+ /* Save the now KSP in task->thread.ksp */
+ st.as sp, [r0, (TASK_THREAD + THREAD_KSP)/4]
+
+ /*
+ * Return last task in r0 (return reg)
+ * On ARC, Return reg = First Arg reg = r0.
+ * Since we already have last task in r0,
+ * don't need to do anything special to return it
+ */
+
+ /* hardware memory barrier */
+ sync
+
+ /*
+ * switch to new task, contained in r1
+ * Temp reg r3 is required to get the ptr to store val
+ */
+ SET_CURR_TASK_ON_CPU r1, r3
+
+ /* reload SP with kernel mode stack pointer in task->thread.ksp */
+ ld.as sp, [r1, (TASK_THREAD + THREAD_KSP)/4]
+
+ /* restore the registers */
+ RESTORE_CALLEE_SAVED_KERNEL
+ ld.ab fp, [sp, 4]
+ ld.ab blink, [sp, 4]
+ j [blink]
+
+ARC_EXIT __switch_to
diff --git a/arch/arc/kernel/fpu.c b/arch/arc/kernel/fpu.c
new file mode 100644
index 0000000..f352e51
--- /dev/null
+++ b/arch/arc/kernel/fpu.c
@@ -0,0 +1,55 @@
+/*
+ * fpu.c - save/restore of Floating Point Unit Registers on task switch
+ *
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/sched.h>
+#include <asm/switch_to.h>
+
+/*
+ * To save/restore FPU regs, simplest scheme would use LR/SR insns.
+ * However since SR serializes the pipeline, an alternate "hack" can be used
+ * which uses the FPU Exchange insn (DEXCL) to r/w FPU regs.
+ *
+ * Store to 64bit dpfp1 reg from a pair of core regs:
+ * dexcl1 0, r1, r0 ; where r1:r0 is the 64 bit val
+ *
+ * Read from dpfp1 into pair of core regs (w/o clobbering dpfp1)
+ * mov_s r3, 0
+ * daddh11 r1, r3, r3 ; get "hi" into r1 (dpfp1 unchanged)
+ * dexcl1 r0, r1, r3 ; get "low" into r0 (dpfp1 low clobbered)
+ * dexcl1 0, r1, r0 ; restore dpfp1 to orig value
+ *
+ * However we can tweak the read, so that read-out of outgoing task's FPU regs
+ * and write of incoming task's regs happen in one shot. So all the work is
+ * done before context switch
+ */
+
+void fpu_save_restore(struct task_struct *prev, struct task_struct *next)
+{
+ unsigned int *saveto = &prev->thread.fpu.aux_dpfp[0].l;
+ unsigned int *readfrom = &next->thread.fpu.aux_dpfp[0].l;
+
+ const unsigned int zero = 0;
+
+ __asm__ __volatile__(
+ "daddh11 %0, %2, %2\n"
+ "dexcl1 %1, %3, %4\n"
+ : "=&r" (*(saveto + 1)), /* early clobber must here */
+ "=&r" (*(saveto))
+ : "r" (zero), "r" (*(readfrom + 1)), "r" (*(readfrom))
+ );
+
+ __asm__ __volatile__(
+ "daddh22 %0, %2, %2\n"
+ "dexcl2 %1, %3, %4\n"
+ : "=&r"(*(saveto + 3)), /* early clobber must here */
+ "=&r"(*(saveto + 2))
+ : "r" (zero), "r" (*(readfrom + 3)), "r" (*(readfrom + 2))
+ );
+}
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index 21d1889..c116fa5 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -117,3 +117,204 @@ SYSCALL_DEFINE0(arc_gettls)
{
return task_thread_info(current)->thr_ptr;
}
+
+static inline void arch_idle(void)
+{
+ __asm__("sleep");
+}
+
+void cpu_idle(void)
+{
+ /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
+
+ /* endless idle loop with no priority at all */
+ while (1) {
+ tick_nohz_idle_enter();
+
+ while (!need_resched())
+ arch_idle();
+
+ tick_nohz_idle_exit();
+
+ preempt_enable_no_resched();
+ schedule();
+ preempt_disable();
+ }
+}
+
+void kernel_thread_helper(void)
+{
+ __asm__ __volatile__(
+ "mov r0, r2 \n\t"
+ "mov r1, r3 \n\t"
+ "j [r1] \n\t");
+}
+
+int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
+{
+ struct pt_regs regs;
+
+ memset(&regs, 0, sizeof(regs));
+
+ regs.r2 = (unsigned long)arg;
+ regs.r3 = (unsigned long)fn;
+ regs.blink = (unsigned long)do_exit;
+ regs.ret = (unsigned long)kernel_thread_helper;
+ regs.status32 = read_aux_reg(0xa);
+
+ /* Ok, create the new process.. */
+ return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
+ NULL);
+
+}
+EXPORT_SYMBOL(kernel_thread);
+
+asmlinkage void ret_from_fork(void);
+
+/* Layout of Child kernel mode stack as setup at the end of this function is
+ *
+ * | ... |
+ * | ... |
+ * | unused |
+ * | |
+ * ------------------ <==== top of Stack (thread.ksp)
+ * | UNUSED 1 word|
+ * ------------------
+ * | r25 |
+ * ~ ~
+ * | --to-- | (CALLEE Regs of user mode)
+ * | r13 |
+ * ------------------
+ * | fp |
+ * | blink | @ret_from_fork
+ * ------------------
+ * | |
+ * ~ ~
+ * ~ ~
+ * | |
+ * ------------------
+ * | r12 |
+ * ~ ~
+ * | --to-- | (scratch Regs of user mode)
+ * | r0 |
+ * ------------------
+ * | UNUSED 1 word|
+ * ------------------ <===== END of PAGE
+ */
+int copy_thread(unsigned long clone_flags,
+ unsigned long usp, unsigned long topstk,
+ struct task_struct *p, struct pt_regs *regs)
+{
+ struct pt_regs *c_regs; /* child's pt_regs */
+ unsigned long *childksp; /* to unwind out of __switch_to() */
+ struct callee_regs *c_callee; /* child's callee regs */
+ struct callee_regs *parent_callee; /* paren't callee */
+
+ /* Mark the specific anchors to begin with (see pic above) */
+ c_regs = task_pt_regs(p);
+ childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */
+ c_callee = ((struct callee_regs *)childksp) - 1;
+
+ /*
+ * At the end of this function, kernel SP is all set for
+ * switch_to to start unwinding.
+ * For kernel threads we don't have callee regs, but the stack
+ * layout nevertheless needs to remain the same
+ */
+ p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */
+
+ /* Copy parents pt regs on child's kernel mode stack */
+ *c_regs = *regs;
+
+ /* __switch_to expects FP(0), BLINK(return addr) at top of stack */
+ childksp[0] = 0; /* for POP fp */
+ childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */
+
+ if (!(user_mode(regs))) {
+ c_regs->sp =
+ (unsigned long)task_thread_info(p) + (THREAD_SIZE - 4);
+ return 0;
+ }
+
+ /*--------- User Task Only --------------*/
+
+ c_regs->sp = usp;
+ c_regs->r0 = 0; /* fork returns 0 in child */
+
+ parent_callee = ((struct callee_regs *)regs) - 1;
+ *c_callee = *parent_callee;
+
+ if (unlikely(clone_flags & CLONE_SETTLS)) {
+ /*
+ * set task's userland tls data ptr from 4th arg
+ * clone C-lib call is difft from clone sys-call
+ */
+ task_thread_info(p)->thr_ptr = regs->r3;
+ } else {
+ /* Normal fork case: set parent's TLS ptr in child */
+ task_thread_info(p)->thr_ptr =
+ task_thread_info(current)->thr_ptr;
+ }
+
+ return 0;
+}
+
+/*
+ * Some archs flush debug and FPU info here
+ */
+void flush_thread(void)
+{
+}
+
+/*
+ * Free any architecture-specific thread data structures, etc.
+ */
+void exit_thread(void)
+{
+}
+
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
+{
+ return 0;
+}
+
+/*
+ * API: expected by schedular Code: If thread is sleeping where is that.
+ * What is this good for? it will be always the scheduler or ret_from_fork.
+ * So we hard code that anyways.
+ */
+unsigned long thread_saved_pc(struct task_struct *t)
+{
+ struct pt_regs *regs = task_pt_regs(t);
+ unsigned long blink = 0;
+
+ /*
+ * If the thread being queried for in not itself calling this, then it
+ * implies it is not executing, which in turn implies it is sleeping,
+ * which in turn implies it got switched OUT by the schedular.
+ * In that case, it's kernel mode blink can reliably retrieved as per
+ * the picture above (right above pt_regs).
+ */
+ if (t != current && t->state != TASK_RUNNING)
+ blink = *((unsigned int *)regs - 1);
+
+ return blink;
+}
+
+int elf_check_arch(const struct elf32_hdr *x)
+{
+ unsigned int eflags;
+
+ if (x->e_machine != EM_ARCOMPACT)
+ return 0;
+
+ eflags = x->e_flags;
+ if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_V2) {
+ pr_err("ABI mismatch - you need newer toolchain\n");
+ force_sigsegv(SIGSEGV, current);
+ return 0;
+ }
+
+ return 1;
+}
+EXPORT_SYMBOL(elf_check_arch);
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
new file mode 100644
index 0000000..a0aa884
--- /dev/null
+++ b/arch/arc/kernel/time.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * vineetg: Jan 1011
+ * -sched_clock( ) no longer jiffies based. Uses the same clocksource
+ * as gtod
+ *
+ * Rajeshwarr/Vineetg: Mar 2008
+ * -Implemented CONFIG_GENERIC_TIME (rather deleted arch specific code)
+ * for arch independent gettimeofday()
+ * -Implemented CONFIG_GENERIC_CLOCKEVENTS as base for hrtimers
+ *
+ * Vineetg: Mar 2008: Forked off from time.c which now is time-jiff.c
+ */
+
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/timex.h>
+#include <linux/profile.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <asm/irq.h>
+#include <asm/arcregs.h>
+
+/* ARC700 has two 32bit independent prog Timers: TIMER0 and TIMER1
+ * Each can programmed to go from @count to @limit and optionally
+ * interrupt when that happens
+ *
+ * We've designated TIMER0 for events (clockevents)
+ * while TIMER1 for free running (clocksource)
+ */
+#define ARC_TIMER_MAX 0xFFFFFFFF
+
+/******************************************************************
+ * Hardware Interface routines to program the ARC TIMERs
+ ******************************************************************/
+
+/*
+ * Arm the timer to interrupt after @limit cycles
+ */
+static void arc_periodic_timer_setup(unsigned int limit)
+{
+ /* setup start and end markers */
+ write_aux_reg(ARC_REG_TIMER0_LIMIT, limit);
+ write_aux_reg(ARC_REG_TIMER0_CNT, 0); /* start from 0 */
+
+ /* IE: Interrupt on count = limit,
+ * NH: Count cycles only when CPU running (NOT Halted)
+ */
+ write_aux_reg(ARC_REG_TIMER0_CTRL, TIMER_CTRL_IE | TIMER_CTRL_NH);
+}
+
+/*
+ * Acknowledge the interrupt & enable/disable the interrupt
+ */
+static void arc_periodic_timer_ack(unsigned int irq_reenable)
+{
+ /* 1. Ack the interrupt by writing to CTRL reg.
+ * Any write will cause intr to be ack, however it has to be one of
+ * writable bits (NH: Count when not halted)
+ * 2. If required by caller, re-arm timer to Interrupt at the end of
+ * next cycle.
+ *
+ * Small optimisation:
+ * Normal code would have been
+ * if (irq_reenable) CTRL_REG = (IE | NH); else CTRL_REG = NH;
+ * However since IE is BIT0 we can fold the branch
+ */
+ write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH);
+}
+
+/*
+ * Arm the timer to keep counting monotonically
+ */
+void __cpuinit arc_clock_counter_setup(void)
+{
+ unsigned int limit = ARC_TIMER_MAX;
+
+ /* although for free flowing case, limit would alway be max 32 bits
+ * still we've kept the interface open, just in case ...
+ */
+ write_aux_reg(ARC_REG_TIMER1_LIMIT, limit);
+ write_aux_reg(ARC_REG_TIMER1_CNT, 0);
+ write_aux_reg(ARC_REG_TIMER1_CTRL, TIMER_CTRL_NH);
+}
+
+/********** Clock Source Device *********/
+
+static cycle_t cycle_read_t1(struct clocksource *cs)
+{
+ return (cycle_t) read_aux_reg(ARC_REG_TIMER1_CNT);
+}
+
+static struct clocksource clocksource_t1 = {
+ .name = "ARC Timer1",
+ .rating = 300,
+ .read = cycle_read_t1,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+void __cpuinit arc_clocksource_init(void)
+{
+ arc_clock_counter_setup();
+
+ /*
+ * CLK upto 4.29 GHz can be safely represented in 32 bits because
+ * Max 32 bit number is 4,294,967,295
+ */
+ clocksource_register_hz(&clocksource_t1, CONFIG_ARC_PLAT_CLK);
+}
+
+/********** Clock Event Device *********/
+
+static int arc_clkevent_set_next_event(unsigned long delta,
+ struct clock_event_device *dev)
+{
+ arc_periodic_timer_setup(delta);
+ return 0;
+}
+
+static void arc_clkevent_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev)
+{
+ pr_info("Device [%s] clockevent mode now [%d]\n", dev->name, mode);
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ arc_periodic_timer_setup(CONFIG_ARC_PLAT_CLK / HZ);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ break;
+ default:
+ break;
+ }
+
+ return;
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = {
+ .name = "ARC Timer0",
+ .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
+ .mode = CLOCK_EVT_MODE_UNUSED,
+ .rating = 300,
+ .irq = TIMER0_IRQ, /* hardwired, no need for resources */
+ .set_next_event = arc_clkevent_set_next_event,
+ .set_mode = arc_clkevent_set_mode,
+};
+
+irqreturn_t timer_irq_handler(int irq, void *dev_id)
+{
+ unsigned int cpu = smp_processor_id();
+ struct clock_event_device *evt = &per_cpu(arc_clockevent_device, cpu);
+
+ arc_periodic_timer_ack(evt->mode == CLOCK_EVT_MODE_PERIODIC);
+ evt->event_handler(evt);
+ return IRQ_HANDLED;
+}
+
+void __cpuinit arc_clockevent_init(void)
+{
+ int rc;
+ unsigned int cpu = smp_processor_id();
+ struct clock_event_device *evt = &per_cpu(arc_clockevent_device, cpu);
+
+ clockevents_calc_mult_shift(evt, CONFIG_ARC_PLAT_CLK, 5);
+
+ evt->max_delta_ns = clockevent_delta2ns(ARC_TIMER_MAX, evt);
+ evt->cpumask = cpumask_of(cpu);
+
+ clockevents_register_device(evt);
+
+ /*
+ * Done only on Boot CPU as it would fail on others.
+ * (Treated a re-registration for a !IRQF_SHARED irq)
+ */
+ if (cpu == 0) {
+ rc = request_percpu_irq(TIMER0_IRQ, timer_irq_handler,
+ "Timer0 (clock-evt-dev)", evt);
+
+ if (rc)
+ panic("TIMER0 IRQ reg failed on BOOT cpu\n");
+ }
+
+ /* This is done on each CPU */
+ enable_percpu_irq(TIMER0_IRQ, 0);
+
+}
+
+void __init time_init(void)
+{
+ arc_clocksource_init();
+ arc_clockevent_init();
+}
+
+static int arc_finished_booting;
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ * It's return value must NOT wrap around.
+ *
+ * Although the return value is nanosec units based, what's more important
+ * is whats the "source" of this value. The orig jiffies based computation
+ * was only as granular as jiffies itself (10ms on ARC).
+ * We need something that is more granular, so use the same mechanism as
+ * gettimeofday(), which uses ARC Timer T1 wrapped as a clocksource.
+ * Unfortunately the first call to sched_clock( ) is way before that subsys
+ * is initialiased, thus use the jiffies based value in the interim.
+ */
+unsigned long long sched_clock(void)
+{
+ if (!arc_finished_booting) {
+ return (unsigned long long)(jiffies - INITIAL_JIFFIES)
+ * (NSEC_PER_SEC / HZ);
+ } else {
+ struct timespec ts;
+ getrawmonotonic(&ts);
+ return (unsigned long long)timespec_to_ns(&ts);
+ }
+}
+
+static int __init arc_clocksource_done_booting(void)
+{
+ arc_finished_booting = 1;
+ return 0;
+}
+
+fs_initcall(arc_clocksource_done_booting);
--
1.7.4.1

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