[POWERPC] Cell interrupt rework

This patch reworks the cell iic interrupt handling so that:

 - Node ID is back in the interrupt number (only one IRQ host is created
for all nodes). This allows interrupts from sources on another node to
be routed non-locally. This will allow possibly one day to fix maxcpus=1
or 2 and still get interrupts from devices on BE 1. (A bit more fixing
is needed for that) and it will allow us to implement actual affinity
control of external interrupts.

 - Added handling of the IO exceptions interrupts (badly named, but I
re-used the name initially used by STI). Those are the interrupts
exposed by IIC_ISR and IIC_IRR, such as the IOC translation exception,
performance monitor, etc... Those get their special numbers in the IRQ
number space and are internally implemented as a cascade on unit 0xe,
class 1 of each node.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/cell/interrupt.h

@@ -2,48 +2,76 @@
 #define ASM_CELL_PIC_H
 #ifdef __KERNEL__
 /*
- * Mapping of IIC pending bits into per-node
- * interrupt numbers.
+ * Mapping of IIC pending bits into per-node interrupt numbers.
  *
- * IRQ     FF CC SS PP   FF CC SS PP	Description
+ * Interrupt numbers are in the range 0...0x1ff where the top bit
+ * (0x100) represent the source node. Only 2 nodes are supported with
+ * the current code though it's trivial to extend that if necessary using
+ * higher level bits
  *
- * 00-3f   80 02 +0 00 - 80 02 +0 3f	South Bridge
- * 00-3f   80 02 +b 00 - 80 02 +b 3f	South Bridge
- * 41-4a   80 00 +1 ** - 80 00 +a **	SPU Class 0
- * 51-5a   80 01 +1 ** - 80 01 +a **	SPU Class 1
- * 61-6a   80 02 +1 ** - 80 02 +a **	SPU Class 2
- * 70-7f   C0 ** ** 00 - C0 ** ** 0f	IPI
+ * The bottom 8 bits are split into 2 type bits and 6 data bits that
+ * depend on the type:
  *
- *    F flags
- *    C class
- *    S source
- *    P Priority
- *    + node number
- *    * don't care
+ * 00 (0x00 | data) : normal interrupt. data is (class << 4) | source
+ * 01 (0x40 | data) : IO exception. data is the exception number as
+ *                    defined by bit numbers in IIC_SR
+ * 10 (0x80 | data) : IPI. data is the IPI number (obtained from the priority)
+ *                    and node is always 0 (IPIs are per-cpu, their source is
+ *                    not relevant)
+ * 11 (0xc0 | data) : reserved
  *
- * A node consists of a Cell Broadband Engine and an optional
- * south bridge device providing a maximum of 64 IRQs.
- * The south bridge may be connected to either IOIF0
- * or IOIF1.
- * Each SPE is represented as three IRQ lines, one per
- * interrupt class.
- * 16 IRQ numbers are reserved for inter processor
- * interruptions, although these are only used in the
- * range of the first node.
+ * In addition, interrupt number 0x80000000 is defined as always invalid
+ * (that is the node field is expected to never extend to move than 23 bits)
  *
- * This scheme needs 128 IRQ numbers per BIF node ID,
- * which means that with the total of 512 lines
- * available, we can have a maximum of four nodes.
  */
 
 enum {
-	IIC_IRQ_INVALID		= 0xff,
-	IIC_IRQ_MAX		= 0x3f,
-	IIC_IRQ_EXT_IOIF0	= 0x20,
-	IIC_IRQ_EXT_IOIF1	= 0x2b,
-	IIC_IRQ_IPI0		= 0x40,
-	IIC_NUM_IPIS    	= 0x10, /* IRQs reserved for IPI */
-	IIC_SOURCE_COUNT	= 0x50,
+	IIC_IRQ_INVALID		= 0x80000000u,
+	IIC_IRQ_NODE_MASK	= 0x100,
+	IIC_IRQ_NODE_SHIFT	= 8,
+	IIC_IRQ_MAX		= 0x1ff,
+	IIC_IRQ_TYPE_MASK	= 0xc0,
+	IIC_IRQ_TYPE_NORMAL	= 0x00,
+	IIC_IRQ_TYPE_IOEXC	= 0x40,
+	IIC_IRQ_TYPE_IPI	= 0x80,
+	IIC_IRQ_CLASS_SHIFT	= 4,
+	IIC_IRQ_CLASS_0		= 0x00,
+	IIC_IRQ_CLASS_1		= 0x10,
+	IIC_IRQ_CLASS_2		= 0x20,
+	IIC_SOURCE_COUNT	= 0x200,
+
+	/* Here are defined the various source/dest units. Avoid using those
+	 * definitions if you can, they are mostly here for reference
+	 */
+	IIC_UNIT_SPU_0		= 0x4,
+	IIC_UNIT_SPU_1		= 0x7,
+	IIC_UNIT_SPU_2		= 0x3,
+	IIC_UNIT_SPU_3		= 0x8,
+	IIC_UNIT_SPU_4		= 0x2,
+	IIC_UNIT_SPU_5		= 0x9,
+	IIC_UNIT_SPU_6		= 0x1,
+	IIC_UNIT_SPU_7		= 0xa,
+	IIC_UNIT_IOC_0		= 0x0,
+	IIC_UNIT_IOC_1		= 0xb,
+	IIC_UNIT_THREAD_0	= 0xe, /* target only */
+	IIC_UNIT_THREAD_1	= 0xf, /* target only */
+	IIC_UNIT_IIC		= 0xe, /* source only (IO exceptions) */
+
+	/* Base numbers for the external interrupts */
+	IIC_IRQ_EXT_IOIF0	=
+		IIC_IRQ_TYPE_NORMAL | IIC_IRQ_CLASS_2 | IIC_UNIT_IOC_0,
+	IIC_IRQ_EXT_IOIF1	=
+		IIC_IRQ_TYPE_NORMAL | IIC_IRQ_CLASS_2 | IIC_UNIT_IOC_1,
+
+	/* Base numbers for the IIC_ISR interrupts */
+	IIC_IRQ_IOEX_TMI	= IIC_IRQ_TYPE_IOEXC | IIC_IRQ_CLASS_1 | 63,
+	IIC_IRQ_IOEX_PMI	= IIC_IRQ_TYPE_IOEXC | IIC_IRQ_CLASS_1 | 62,
+	IIC_IRQ_IOEX_ATI	= IIC_IRQ_TYPE_IOEXC | IIC_IRQ_CLASS_1 | 61,
+	IIC_IRQ_IOEX_MATBFI	= IIC_IRQ_TYPE_IOEXC | IIC_IRQ_CLASS_1 | 60,
+	IIC_IRQ_IOEX_ELDI	= IIC_IRQ_TYPE_IOEXC | IIC_IRQ_CLASS_1 | 59,
+
+	/* Which bits in IIC_ISR are edge sensitive */
+	IIC_ISR_EDGE_MASK	= 0x4ul,
 };
 
 extern void iic_init_IRQ(void);
@@ -52,7 +80,6 @@ extern void iic_request_IPIs(void);
 extern void iic_setup_cpu(void);
 
 extern u8 iic_get_target_id(int cpu);
-extern struct irq_host *iic_get_irq_host(int node);
 
 extern void spider_init_IRQ(void);
 

arch/powerpc/platforms/cell/spider-pic.c

@@ -243,7 +243,6 @@ static unsigned int __init spider_find_cascade_and_node(struct spider_pic *pic)
 	const u32 *imap, *tmp;
 	int imaplen, intsize, unit;
 	struct device_node *iic;
-	struct irq_host *iic_host;
 
 #if 0 /* Enable that when we have a way to retreive the node as well */
 	/* First, we check wether we have a real "interrupts" in the device
@@ -289,11 +288,11 @@ static unsigned int __init spider_find_cascade_and_node(struct spider_pic *pic)
 	 * the iic host from the iic OF node, but that way I'm still compatible
 	 * with really really old old firmwares for which we don't have a node
 	 */
-	iic_host = iic_get_irq_host(pic->node_id);
-	if (iic_host == NULL)
-		return NO_IRQ;
 	/* Manufacture an IIC interrupt number of class 2 */
-	virq = irq_create_mapping(iic_host, 0x20 | unit);
+	virq = irq_create_mapping(NULL,
+				  (pic->node_id << IIC_IRQ_NODE_SHIFT) |
+				  (2 << IIC_IRQ_CLASS_SHIFT) |
+				  unit);
 	if (virq == NO_IRQ)
 		printk(KERN_ERR "spider_pic: failed to map cascade !");
 	return virq;

arch/powerpc/platforms/cell/spu_base.c

@@ -568,24 +568,23 @@ static void spu_unmap(struct spu *spu)
 /* This function shall be abstracted for HV platforms */
 static int __init spu_map_interrupts(struct spu *spu, struct device_node *np)
 {
-	struct irq_host *host;
 	unsigned int isrc;
 	const u32 *tmp;
 
-	host = iic_get_irq_host(spu->node);
-	if (host == NULL)
-		return -ENODEV;
-
-	/* Get the interrupt source from the device-tree */
+	/* Get the interrupt source unit from the device-tree */
 	tmp = get_property(np, "isrc", NULL);
 	if (!tmp)
 		return -ENODEV;
-	spu->isrc = isrc = tmp[0];
+	isrc = tmp[0];
+
+	/* Add the node number */
+	isrc |= spu->node << IIC_IRQ_NODE_SHIFT;
+	spu->isrc = isrc;
 
 	/* Now map interrupts of all 3 classes */
-	spu->irqs[0] = irq_create_mapping(host, 0x00 | isrc);
-	spu->irqs[1] = irq_create_mapping(host, 0x10 | isrc);
-	spu->irqs[2] = irq_create_mapping(host, 0x20 | isrc);
+	spu->irqs[0] = irq_create_mapping(NULL, IIC_IRQ_CLASS_0 | isrc);
+	spu->irqs[1] = irq_create_mapping(NULL, IIC_IRQ_CLASS_1 | isrc);
+	spu->irqs[2] = irq_create_mapping(NULL, IIC_IRQ_CLASS_2 | isrc);
 
 	/* Right now, we only fail if class 2 failed */
 	return spu->irqs[2] == NO_IRQ ? -EINVAL : 0;