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>

1 files changed, 37 insertions, 4 deletions

diff --git a/arch/blackfin/mach-common/ints-priority.c b/arch/blackfin/mach-common/ints-priority.c
index 8e9d3cc30885..6cd52395a999 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) {