Blackfin/ipipe: upgrade to I-pipe mainline

This patch introduces Blackfin-specific bits to support the current
tip of the interrupt pipeline development, mainly:

- 2/3-level interrupt maps (sparse IRQs)
- generic virq handling
- sysinfo v2 format for ipipe_get_sysinfo()

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

4 files changed, 117 insertions, 114 deletions

diff --git a/arch/blackfin/include/asm/ipipe.h b/arch/blackfin/include/asm/ipipe.h
index 40f94a7..9e0cc0e 100644
--- a/arch/blackfin/include/asm/ipipe.h
+++ b/arch/blackfin/include/asm/ipipe.h
@@ -34,11 +34,12 @@
 #include <asm/bitops.h>
 #include <asm/atomic.h>
 #include <asm/traps.h>
+#include <asm/bitsperlong.h>
 
-#define IPIPE_ARCH_STRING     "1.12-00"
+#define IPIPE_ARCH_STRING     "1.16-01"
 #define IPIPE_MAJOR_NUMBER    1
-#define IPIPE_MINOR_NUMBER    12
-#define IPIPE_PATCH_NUMBER    0
+#define IPIPE_MINOR_NUMBER    16
+#define IPIPE_PATCH_NUMBER    1
 
 #ifdef CONFIG_SMP
 #error "I-pipe/blackfin: SMP not implemented"
@@ -55,25 +56,19 @@ do {						\
 #define task_hijacked(p)						\
 	({								\
 		int __x__ = __ipipe_root_domain_p;			\
-		__clear_bit(IPIPE_SYNC_FLAG, &ipipe_root_cpudom_var(status)); \
 		if (__x__)						\
-			hard_local_irq_enable();				\
+			hard_local_irq_enable();			\
 		!__x__;							\
 	})
 
 struct ipipe_domain;
 
 struct ipipe_sysinfo {
-
-	int ncpus;		/* Number of CPUs on board */
-	u64 cpufreq;		/* CPU frequency (in Hz) */
-
-	/* Arch-dependent block */
-
-	struct {
-		unsigned tmirq;	/* Timer tick IRQ */
-		u64 tmfreq;	/* Timer frequency */
-	} archdep;
+	int sys_nr_cpus;	/* Number of CPUs on board */
+	int sys_hrtimer_irq;	/* hrtimer device IRQ */
+	u64 sys_hrtimer_freq;	/* hrtimer device frequency */
+	u64 sys_hrclock_freq;	/* hrclock device frequency */
+	u64 sys_cpu_freq;	/* CPU frequency (Hz) */
 };
 
 #define ipipe_read_tsc(t)					\
@@ -115,9 +110,19 @@ void __ipipe_enable_irqdesc(struct ipipe_domain *ipd,
 void __ipipe_disable_irqdesc(struct ipipe_domain *ipd,
 			     unsigned irq);
 
-#define __ipipe_enable_irq(irq)		(irq_desc[irq].chip->unmask(irq))
+#define __ipipe_enable_irq(irq)						\
+	do {								\
+		struct irq_desc *desc = irq_to_desc(irq);		\
+		struct irq_chip *chip = get_irq_desc_chip(desc);	\
+		chip->irq_unmask(&desc->irq_data);			\
+	} while (0)
 
-#define __ipipe_disable_irq(irq)	(irq_desc[irq].chip->mask(irq))
+#define __ipipe_disable_irq(irq)					\
+	do {								\
+		struct irq_desc *desc = irq_to_desc(irq);		\
+		struct irq_chip *chip = get_irq_desc_chip(desc);	\
+		chip->irq_mask(&desc->irq_data);			\
+	} while (0)
 
 static inline int __ipipe_check_tickdev(const char *devname)
 {
@@ -128,12 +133,11 @@ void __ipipe_enable_pipeline(void);
 
 #define __ipipe_hook_critical_ipi(ipd) do { } while (0)
 
-#define __ipipe_sync_pipeline  ___ipipe_sync_pipeline
-void ___ipipe_sync_pipeline(unsigned long syncmask);
+void ___ipipe_sync_pipeline(void);
 
 void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs);
 
-int __ipipe_get_irq_priority(unsigned irq);
+int __ipipe_get_irq_priority(unsigned int irq);
 
 void __ipipe_serial_debug(const char *fmt, ...);
 
@@ -152,7 +156,10 @@ static inline unsigned long __ipipe_ffnz(unsigned long ul)
 	return ffs(ul) - 1;
 }
 
-#define __ipipe_run_irqtail()  /* Must be a macro */			\
+#define __ipipe_do_root_xirq(ipd, irq)					\
+	((ipd)->irqs[irq].handler(irq, &__raw_get_cpu_var(__ipipe_tick_regs)))
+
+#define __ipipe_run_irqtail(irq)  /* Must be a macro */			\
 	do {								\
 		unsigned long __pending;				\
 		CSYNC();						\
@@ -164,42 +171,8 @@ static inline unsigned long __ipipe_ffnz(unsigned long ul)
 		}							\
 	} while (0)
 
-#define __ipipe_run_isr(ipd, irq)					\
-	do {								\
-		if (!__ipipe_pipeline_head_p(ipd))			\
-			hard_local_irq_enable();				\
-		if (ipd == ipipe_root_domain) {				\
-			if (unlikely(ipipe_virtual_irq_p(irq))) {	\
-				irq_enter();				\
-				ipd->irqs[irq].handler(irq, ipd->irqs[irq].cookie); \
-				irq_exit();				\
-			} else 						\
-				ipd->irqs[irq].handler(irq, &__raw_get_cpu_var(__ipipe_tick_regs)); \
-		} else {						\
-			__clear_bit(IPIPE_SYNC_FLAG, &ipipe_cpudom_var(ipd, status)); \
-			ipd->irqs[irq].handler(irq, ipd->irqs[irq].cookie); \
-			/* Attempt to exit the outer interrupt level before \
-			 * starting the deferred IRQ processing. */	\
-			__ipipe_run_irqtail();				\
-			__set_bit(IPIPE_SYNC_FLAG, &ipipe_cpudom_var(ipd, status)); \
-		}							\
-		hard_local_irq_disable();					\
-	} while (0)
-
 #define __ipipe_syscall_watched_p(p, sc)	\
-	(((p)->flags & PF_EVNOTIFY) || (unsigned long)sc >= NR_syscalls)
-
-void ipipe_init_irq_threads(void);
-
-int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc);
-
-#ifdef CONFIG_TICKSOURCE_CORETMR
-#define IRQ_SYSTMR		IRQ_CORETMR
-#define IRQ_PRIOTMR		IRQ_CORETMR
-#else
-#define IRQ_SYSTMR		IRQ_TIMER0
-#define IRQ_PRIOTMR		CONFIG_IRQ_TIMER0
-#endif
+	(ipipe_notifier_enabled_p(p) || (unsigned long)sc >= NR_syscalls)
 
 #ifdef CONFIG_BF561
 #define bfin_write_TIMER_DISABLE(val)	bfin_write_TMRS8_DISABLE(val)
@@ -219,11 +192,11 @@ int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc);
 
 #define task_hijacked(p)		0
 #define ipipe_trap_notify(t, r)  	0
+#define __ipipe_root_tick_p(regs)	1
 
-#define ipipe_init_irq_threads()		do { } while (0)
-#define ipipe_start_irq_thread(irq, desc)	0
+#endif /* !CONFIG_IPIPE */
 
-#ifndef CONFIG_TICKSOURCE_GPTMR0
+#ifdef CONFIG_TICKSOURCE_CORETMR
 #define IRQ_SYSTMR		IRQ_CORETMR
 #define IRQ_PRIOTMR		IRQ_CORETMR
 #else
@@ -231,10 +204,6 @@ int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc);
 #define IRQ_PRIOTMR		CONFIG_IRQ_TIMER0
 #endif
 
-#define __ipipe_root_tick_p(regs)	1
-
-#endif /* !CONFIG_IPIPE */
-
 #define ipipe_update_tick_evtdev(evtdev)	do { } while (0)
 
 #endif	/* !__ASM_BLACKFIN_IPIPE_H */
diff --git a/arch/blackfin/include/asm/ipipe_base.h b/arch/blackfin/include/asm/ipipe_base.h
index 0040920..84a4ffd 100644
--- a/arch/blackfin/include/asm/ipipe_base.h
+++ b/arch/blackfin/include/asm/ipipe_base.h
@@ -24,8 +24,10 @@
 
 #ifdef CONFIG_IPIPE
 
+#include <asm/bitsperlong.h>
+#include <mach/irq.h>
+
 #define IPIPE_NR_XIRQS		NR_IRQS
-#define IPIPE_IRQ_ISHIFT	5	/* 2^5 for 32bits arch. */
 
 /* Blackfin-specific, per-cpu pipeline status */
 #define IPIPE_SYNCDEFER_FLAG	15
@@ -42,11 +44,14 @@
 #define IPIPE_EVENT_INIT	(IPIPE_FIRST_EVENT + 4)
 #define IPIPE_EVENT_EXIT	(IPIPE_FIRST_EVENT + 5)
 #define IPIPE_EVENT_CLEANUP	(IPIPE_FIRST_EVENT + 6)
-#define IPIPE_LAST_EVENT	IPIPE_EVENT_CLEANUP
+#define IPIPE_EVENT_RETURN	(IPIPE_FIRST_EVENT + 7)
+#define IPIPE_LAST_EVENT	IPIPE_EVENT_RETURN
 #define IPIPE_NR_EVENTS		(IPIPE_LAST_EVENT + 1)
 
 #define IPIPE_TIMER_IRQ		IRQ_CORETMR
 
+#define __IPIPE_FEATURE_SYSINFO_V2	1
+
 #ifndef __ASSEMBLY__
 
 extern unsigned long __ipipe_root_status; /* Alias to ipipe_root_cpudom_var(status) */
@@ -63,6 +68,8 @@ void __ipipe_unlock_root(void);
 
 #endif /* !__ASSEMBLY__ */
 
+#define __IPIPE_FEATURE_SYSINFO_V2	1
+
 #endif /* CONFIG_IPIPE */
 
 #endif /* !__ASM_BLACKFIN_IPIPE_BASE_H */
diff --git a/arch/blackfin/kernel/ipipe.c b/arch/blackfin/kernel/ipipe.c
index 3b1da4a..f37019c 100644
--- a/arch/blackfin/kernel/ipipe.c
+++ b/arch/blackfin/kernel/ipipe.c
@@ -154,7 +154,7 @@ void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs)
 	 * pending for it.
 	 */
 	if (test_bit(IPIPE_AHEAD_FLAG, &this_domain->flags) &&
-	    ipipe_head_cpudom_var(irqpend_himask) == 0)
+	    !__ipipe_ipending_p(ipipe_head_cpudom_ptr()))
 		goto out;
 
 	__ipipe_walk_pipeline(head);
@@ -185,25 +185,21 @@ void __ipipe_disable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
 }
 EXPORT_SYMBOL(__ipipe_disable_irqdesc);
 
-int __ipipe_syscall_root(struct pt_regs *regs)
+asmlinkage int __ipipe_syscall_root(struct pt_regs *regs)
 {
 	struct ipipe_percpu_domain_data *p;
-	unsigned long flags;
+	void (*hook)(void);
 	int ret;
 
+	WARN_ON_ONCE(irqs_disabled_hw());
+
 	/*
-	 * We need to run the IRQ tail hook whenever we don't
-	 * propagate a syscall to higher domains, because we know that
-	 * important operations might be pending there (e.g. Xenomai
-	 * deferred rescheduling).
+	 * We need to run the IRQ tail hook each time we intercept a
+	 * syscall, because we know that important operations might be
+	 * pending there (e.g. Xenomai deferred rescheduling).
 	 */
-
-	if (regs->orig_p0 < NR_syscalls) {
-		void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
-		hook();
-		if ((current->flags & PF_EVNOTIFY) == 0)
-			return 0;
-	}
+	hook = (__typeof__(hook))__ipipe_irq_tail_hook;
+	hook();
 
 	/*
 	 * This routine either returns:
@@ -214,51 +210,47 @@ int __ipipe_syscall_root(struct pt_regs *regs)
 	 * tail work has to be performed (for handling signals etc).
 	 */
 
-	if (!__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL))
+	if (!__ipipe_syscall_watched_p(current, regs->orig_p0) ||
+	    !__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL))
 		return 0;
 
 	ret = __ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs);
 
-	flags = hard_local_irq_save();
+	hard_local_irq_disable();
 
-	if (!__ipipe_root_domain_p) {
-		hard_local_irq_restore(flags);
-		return 1;
+	/*
+	 * This is the end of the syscall path, so we may
+	 * safely assume a valid Linux task stack here.
+	 */
+	if (current->ipipe_flags & PF_EVTRET) {
+		current->ipipe_flags &= ~PF_EVTRET;
+		__ipipe_dispatch_event(IPIPE_EVENT_RETURN, regs);
 	}
 
-	p = ipipe_root_cpudom_ptr();
-	if ((p->irqpend_himask & IPIPE_IRQMASK_VIRT) != 0)
-		__ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT);
+	if (!__ipipe_root_domain_p)
+		ret = -1;
+	else {
+		p = ipipe_root_cpudom_ptr();
+		if (__ipipe_ipending_p(p))
+			__ipipe_sync_pipeline();
+	}
 
-	hard_local_irq_restore(flags);
+	hard_local_irq_enable();
 
 	return -ret;
 }
 
-unsigned long ipipe_critical_enter(void (*syncfn) (void))
-{
-	unsigned long flags;
-
-	flags = hard_local_irq_save();
-
-	return flags;
-}
-
-void ipipe_critical_exit(unsigned long flags)
-{
-	hard_local_irq_restore(flags);
-}
-
 static void __ipipe_no_irqtail(void)
 {
 }
 
 int ipipe_get_sysinfo(struct ipipe_sysinfo *info)
 {
-	info->ncpus = num_online_cpus();
-	info->cpufreq = ipipe_cpu_freq();
-	info->archdep.tmirq = IPIPE_TIMER_IRQ;
-	info->archdep.tmfreq = info->cpufreq;
+	info->sys_nr_cpus = num_online_cpus();
+	info->sys_cpu_freq = ipipe_cpu_freq();
+	info->sys_hrtimer_irq = IPIPE_TIMER_IRQ;
+	info->sys_hrtimer_freq = __ipipe_core_clock;
+	info->sys_hrclock_freq = __ipipe_core_clock;
 
 	return 0;
 }
@@ -289,6 +281,7 @@ int ipipe_trigger_irq(unsigned irq)
 asmlinkage void __ipipe_sync_root(void)
 {
 	void (*irq_tail_hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
+	struct ipipe_percpu_domain_data *p;
 	unsigned long flags;
 
 	BUG_ON(irqs_disabled());
@@ -300,19 +293,20 @@ asmlinkage void __ipipe_sync_root(void)
 
 	clear_thread_flag(TIF_IRQ_SYNC);
 
-	if (ipipe_root_cpudom_var(irqpend_himask) != 0)
-		__ipipe_sync_pipeline(IPIPE_IRQMASK_ANY);
+	p = ipipe_root_cpudom_ptr();
+	if (__ipipe_ipending_p(p))
+		__ipipe_sync_pipeline();
 
 	hard_local_irq_restore(flags);
 }
 
-void ___ipipe_sync_pipeline(unsigned long syncmask)
+void ___ipipe_sync_pipeline(void)
 {
 	if (__ipipe_root_domain_p &&
 	    test_bit(IPIPE_SYNCDEFER_FLAG, &ipipe_root_cpudom_var(status)))
 		return;
 
-	__ipipe_sync_stage(syncmask);
+	__ipipe_sync_stage();
 }
 
 void __ipipe_disable_root_irqs_hw(void)
diff --git a/arch/blackfin/mach-common/ints-priority.c b/arch/blackfin/mach-common/ints-priority.c
index 8e9d3cc..6cd5239 100644
--- a/arch/blackfin/mach-common/ints-priority.c
+++ b/arch/blackfin/mach-common/ints-priority.c
@@ -15,6 +15,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/seq_file.h>
 #include <linux/irq.h>
+#include <linux/sched.h>
 #ifdef CONFIG_IPIPE
 #include <linux/ipipe.h>
 #endif
@@ -556,10 +557,9 @@ static void bfin_demux_mac_status_irq(unsigned int int_err_irq,
 static inline void bfin_set_irq_handler(unsigned irq, irq_flow_handler_t handle)
 {
 #ifdef CONFIG_IPIPE
-	_set_irq_handler(irq, handle_level_irq);
-#else
-	__set_irq_handler_unlocked(irq, handle);
+	handle = handle_level_irq;
 #endif
+	__set_irq_handler_unlocked(irq, handle);
 }
 
 static DECLARE_BITMAP(gpio_enabled, MAX_BLACKFIN_GPIOS);
@@ -1392,7 +1392,7 @@ asmlinkage int __ipipe_grab_irq(int vec, struct pt_regs *regs)
 	struct ipipe_domain *this_domain = __ipipe_current_domain;
 	struct ivgx *ivg_stop = ivg7_13[vec-IVG7].istop;
 	struct ivgx *ivg = ivg7_13[vec-IVG7].ifirst;
-	int irq, s;
+	int irq, s = 0;
 
 	if (likely(vec == EVT_IVTMR_P))
 		irq = IRQ_CORETMR;
@@ -1442,6 +1442,21 @@ asmlinkage int __ipipe_grab_irq(int vec, struct pt_regs *regs)
 			__raw_get_cpu_var(__ipipe_tick_regs).ipend |= 0x10;
 	}
 
+	/*
+	 * We don't want Linux interrupt handlers to run at the
+	 * current core priority level (i.e. < EVT15), since this
+	 * might delay other interrupts handled by a high priority
+	 * domain. Here is what we do instead:
+	 *
+	 * - we raise the SYNCDEFER bit to prevent
+	 * __ipipe_handle_irq() to sync the pipeline for the root
+	 * stage for the incoming interrupt. Upon return, that IRQ is
+	 * pending in the interrupt log.
+	 *
+	 * - we raise the TIF_IRQ_SYNC bit for the current thread, so
+	 * that _schedule_and_signal_from_int will eventually sync the
+	 * pipeline from EVT15.
+	 */
 	if (this_domain == ipipe_root_domain) {
 		s = __test_and_set_bit(IPIPE_SYNCDEFER_FLAG, &p->status);
 		barrier();
@@ -1451,6 +1466,24 @@ asmlinkage int __ipipe_grab_irq(int vec, struct pt_regs *regs)
 	__ipipe_handle_irq(irq, regs);
 	ipipe_trace_irq_exit(irq);
 
+	if (user_mode(regs) &&
+	    !ipipe_test_foreign_stack() &&
+	    (current->ipipe_flags & PF_EVTRET) != 0) {
+		/*
+		 * Testing for user_regs() does NOT fully eliminate
+		 * foreign stack contexts, because of the forged
+		 * interrupt returns we do through
+		 * __ipipe_call_irqtail. In that case, we might have
+		 * preempted a foreign stack context in a high
+		 * priority domain, with a single interrupt level now
+		 * pending after the irqtail unwinding is done. In
+		 * which case user_mode() is now true, and the event
+		 * gets dispatched spuriously.
+		 */
+		current->ipipe_flags &= ~PF_EVTRET;
+		__ipipe_dispatch_event(IPIPE_EVENT_RETURN, regs);
+	}
+
 	if (this_domain == ipipe_root_domain) {
 		set_thread_flag(TIF_IRQ_SYNC);
 		if (!s) {