7 files changed, 75 insertions, 18 deletions

diff --git a/arch/mips/dec/int-handler.S b/arch/mips/dec/int-handler.S
index 22afed16ccde..41a2fa1fa12e 100644
--- a/arch/mips/dec/int-handler.S
+++ b/arch/mips/dec/int-handler.S
@@ -118,7 +118,7 @@
  *	       7	FPU/R4k timer
  *
  * We handle the IRQ according to _our_ priority (see setup.c),
- * then we just return.	 If multiple IRQs are pending then we will
+ * then we just return.  If multiple IRQs are pending then we will
  * just take another exception, big deal.
  */
 		.align	5
@@ -146,7 +146,7 @@
 		/*
 		 * Find irq with highest priority
 		 */
-		 PTR_LA t1,cpu_mask_nr_tbl
+		 PTR_LA	t1,cpu_mask_nr_tbl
 1:		lw	t2,(t1)
 		nop
 		and	t2,t0
@@ -195,7 +195,7 @@
 		/*
 		 * Find irq with highest priority
 		 */
-		 PTR_LA t1,asic_mask_nr_tbl
+		 PTR_LA	t1,asic_mask_nr_tbl
 2:		lw	t2,(t1)
 		nop
 		and	t2,t0
@@ -221,7 +221,7 @@
 		FEXPORT(cpu_all_int)		# HALT, timers, software junk
 		li	a0,DEC_CPU_IRQ_BASE
 		srl	t0,CAUSEB_IP
-		li	t1,CAUSEF_IP>>CAUSEB_IP # mask
+		li	t1,CAUSEF_IP>>CAUSEB_IP	# mask
 		b	1f
 		 li	t2,4			# nr of bits / 2
 
diff --git a/arch/mips/dec/ioasic-irq.c b/arch/mips/dec/ioasic-irq.c
index 824e08c73798..e04d973ce5aa 100644
--- a/arch/mips/dec/ioasic-irq.c
+++ b/arch/mips/dec/ioasic-irq.c
@@ -1,7 +1,7 @@
 /*
  *	DEC I/O ASIC interrupts.
  *
- *	Copyright (c) 2002, 2003  Maciej W. Rozycki
+ *	Copyright (c) 2002, 2003, 2013  Maciej W. Rozycki
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
@@ -51,14 +51,51 @@ static struct irq_chip ioasic_irq_type = {
 	.irq_unmask = unmask_ioasic_irq,
 };
 
+static void clear_ioasic_dma_irq(struct irq_data *d)
+{
+	u32 sir;
+
+	sir = ~(1 << (d->irq - ioasic_irq_base));
+	ioasic_write(IO_REG_SIR, sir);
+	fast_iob();
+}
+
 static struct irq_chip ioasic_dma_irq_type = {
 	.name = "IO-ASIC-DMA",
-	.irq_ack = ack_ioasic_irq,
+	.irq_ack = clear_ioasic_dma_irq,
 	.irq_mask = mask_ioasic_irq,
-	.irq_mask_ack = ack_ioasic_irq,
 	.irq_unmask = unmask_ioasic_irq,
+	.irq_eoi = clear_ioasic_dma_irq,
 };
 
+/*
+ * I/O ASIC implements two kinds of DMA interrupts, informational and
+ * error interrupts.
+ *
+ * The formers do not stop DMA and should be cleared as soon as possible
+ * so that if they retrigger before the handler has completed, usually as
+ * a side effect of actions taken by the handler, then they are reissued.
+ * These use the `handle_edge_irq' handler that clears the request right
+ * away.
+ *
+ * The latters stop DMA and do not resume it until the interrupt has been
+ * cleared.  This cannot be done until after a corrective action has been
+ * taken and this also means they will not retrigger.  Therefore they use
+ * the `handle_fasteoi_irq' handler that only clears the request on the
+ * way out.  Because MIPS processor interrupt inputs, one of which the I/O
+ * ASIC is cascaded to, are level-triggered it is recommended that error
+ * DMA interrupt action handlers are registered with the IRQF_ONESHOT flag
+ * set so that they are run with the interrupt line masked.
+ *
+ * This mask has `1' bits in the positions of informational interrupts.
+ */
+#define IO_IRQ_DMA_INFO							\
+	(IO_IRQ_MASK(IO_INR_SCC0A_RXDMA) |				\
+	 IO_IRQ_MASK(IO_INR_SCC1A_RXDMA) |				\
+	 IO_IRQ_MASK(IO_INR_ISDN_TXDMA) |				\
+	 IO_IRQ_MASK(IO_INR_ISDN_RXDMA) |				\
+	 IO_IRQ_MASK(IO_INR_ASC_DMA))
+
 void __init init_ioasic_irqs(int base)
 {
 	int i;
@@ -71,7 +108,9 @@ void __init init_ioasic_irqs(int base)
 		irq_set_chip_and_handler(i, &ioasic_irq_type,
 					 handle_level_irq);
 	for (; i < base + IO_IRQ_LINES; i++)
-		irq_set_chip(i, &ioasic_dma_irq_type);
+		irq_set_chip_and_handler(i, &ioasic_dma_irq_type,
+					 1 << (i - base) & IO_IRQ_DMA_INFO ?
+					 handle_edge_irq : handle_fasteoi_irq);
 
 	ioasic_irq_base = base;
 }
diff --git a/arch/mips/dec/prom/call_o32.S b/arch/mips/dec/prom/call_o32.S
index c0d1522d448f..8c8498159e43 100644
--- a/arch/mips/dec/prom/call_o32.S
+++ b/arch/mips/dec/prom/call_o32.S
@@ -14,7 +14,7 @@
 
 /* Maximum number of arguments supported.  Must be even!  */
 #define O32_ARGC	32
-/* Number of static registers we save.	*/
+/* Number of static registers we save.  */
 #define O32_STATC	11
 /* Frame size for both of the above.  */
 #define O32_FRAMESZ	(4 * O32_ARGC + SZREG * O32_STATC)
diff --git a/arch/mips/dec/prom/init.c b/arch/mips/dec/prom/init.c
index ab169046e442..4e1761e0a09a 100644
--- a/arch/mips/dec/prom/init.c
+++ b/arch/mips/dec/prom/init.c
@@ -13,6 +13,7 @@
 
 #include <asm/bootinfo.h>
 #include <asm/cpu.h>
+#include <asm/cpu-type.h>
 #include <asm/processor.h>
 
 #include <asm/dec/prom.h>
@@ -103,7 +104,7 @@ void __init prom_init(void)
 	if (prom_is_rex(magic))
 		rex_clear_cache();
 
-	/* Register the early console.	*/
+	/* Register the early console.  */
 	register_prom_console();
 
 	/* Were we compiled with the right CPU option? */
diff --git a/arch/mips/dec/prom/memory.c b/arch/mips/dec/prom/memory.c
index 0aadac742900..8c62316f22f4 100644
--- a/arch/mips/dec/prom/memory.c
+++ b/arch/mips/dec/prom/memory.c
@@ -22,7 +22,7 @@ volatile unsigned long mem_err;		/* So we know an error occurred */
 
 /*
  * Probe memory in 4MB chunks, waiting for an error to tell us we've fallen
- * off the end of real memory.	Only suitable for the 2100/3100's (PMAX).
+ * off the end of real memory.  Only suitable for the 2100/3100's (PMAX).
  */
 
 #define CHUNK_SIZE 0x400000
diff --git a/arch/mips/dec/setup.c b/arch/mips/dec/setup.c
index 741cb4235bde..56e6e2c23683 100644
--- a/arch/mips/dec/setup.c
+++ b/arch/mips/dec/setup.c
@@ -65,7 +65,7 @@ EXPORT_SYMBOL(ioasic_base);
 /*
  * IRQ routing and priority tables.  Priorites are set as follows:
  *
- *		KN01	KN230	KN02	KN02-BA KN02-CA KN03
+ *		KN01	KN230	KN02	KN02-BA	KN02-CA	KN03
  *
  * MEMORY	CPU	CPU	CPU	ASIC	CPU	CPU
  * RTC		CPU	CPU	CPU	ASIC	CPU	CPU
@@ -413,7 +413,7 @@ static void __init dec_init_kn02(void)
 
 /*
  * Machine-specific initialisation for KN02-BA, aka DS5000/1xx
- * (xx = 20, 25, 33), aka 3min.	 Also applies to KN04(-BA), aka
+ * (xx = 20, 25, 33), aka 3min.  Also applies to KN04(-BA), aka
  * DS5000/150, aka 4min.
  */
 static int kn02ba_interrupt[DEC_NR_INTS] __initdata = {
diff --git a/arch/mips/dec/time.c b/arch/mips/dec/time.c
index ea57f39e6736..1914e56f0d96 100644
--- a/arch/mips/dec/time.c
+++ b/arch/mips/dec/time.c
@@ -125,13 +125,18 @@ int rtc_mips_set_mmss(unsigned long nowtime)
 
 void __init plat_time_init(void)
 {
+	int ioasic_clock = 0;
 	u32 start, end;
-	int i = HZ / 10;
+	int i = HZ / 8;
 
 	/* Set up the rate of periodic DS1287 interrupts. */
 	ds1287_set_base_clock(HZ);
 
+	/* On some I/O ASIC systems we have the I/O ASIC's counter.  */
+	if (IOASIC)
+		ioasic_clock = dec_ioasic_clocksource_init() == 0;
 	if (cpu_has_counter) {
+		ds1287_timer_state();
 		while (!ds1287_timer_state())
 			;
 
@@ -143,12 +148,24 @@ void __init plat_time_init(void)
 
 		end = read_c0_count();
 
-		mips_hpt_frequency = (end - start) * 10;
+		mips_hpt_frequency = (end - start) * 8;
 		printk(KERN_INFO "MIPS counter frequency %dHz\n",
 			mips_hpt_frequency);
-	} else if (IOASIC)
-		/* For pre-R4k systems we use the I/O ASIC's counter.  */
-		dec_ioasic_clocksource_init();
+
+		/*
+		 * All R4k DECstations suffer from the CP0 Count erratum,
+		 * so we can't use the timer as a clock source, and a clock
+		 * event both at a time.  An accurate wall clock is more
+		 * important than a high-precision interval timer so only
+		 * use the timer as a clock source, and not a clock event
+		 * if there's no I/O ASIC counter available to serve as a
+		 * clock source.
+		 */
+		if (!ioasic_clock) {
+			init_r4k_clocksource();
+			mips_hpt_frequency = 0;
+		}
+	}
 
 	ds1287_clockevent_init(dec_interrupt[DEC_IRQ_RTC]);
 }