[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.c

@@ -21,6 +21,12 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * TODO:
+ * - Fix various assumptions related to HW CPU numbers vs. linux CPU numbers
+ *   vs node numbers in the setup code
+ * - Implement proper handling of maxcpus=1/2 (that is, routing of irqs from
+ *   a non-active node to the active node)
  */
 
 #include <linux/interrupt.h>
@@ -44,24 +50,25 @@ struct iic {
 	u8 target_id;
 	u8 eoi_stack[16];
 	int eoi_ptr;
-	struct irq_host *host;
+	struct device_node *node;
 };
 
 static DEFINE_PER_CPU(struct iic, iic);
 #define IIC_NODE_COUNT	2
-static struct irq_host *iic_hosts[IIC_NODE_COUNT];
+static struct irq_host *iic_host;
 
 /* Convert between "pending" bits and hw irq number */
 static irq_hw_number_t iic_pending_to_hwnum(struct cbe_iic_pending_bits bits)
 {
 	unsigned char unit = bits.source & 0xf;
+	unsigned char node = bits.source >> 4;
+	unsigned char class = bits.class & 3;
 
+	/* Decode IPIs */
 	if (bits.flags & CBE_IIC_IRQ_IPI)
-		return IIC_IRQ_IPI0 | (bits.prio >> 4);
-	else if (bits.class <= 3)
-		return (bits.class << 4) | unit;
+		return IIC_IRQ_TYPE_IPI | (bits.prio >> 4);
 	else
-		return IIC_IRQ_INVALID;
+		return (node << IIC_IRQ_NODE_SHIFT) | (class << 4) | unit;
 }
 
 static void iic_mask(unsigned int irq)
@@ -86,21 +93,70 @@ static struct irq_chip iic_chip = {
 	.eoi = iic_eoi,
 };
 
+
+static void iic_ioexc_eoi(unsigned int irq)
+{
+}
+
+static void iic_ioexc_cascade(unsigned int irq, struct irq_desc *desc,
+			    struct pt_regs *regs)
+{
+	struct cbe_iic_regs *node_iic = desc->handler_data;
+	unsigned int base = (irq & 0xffffff00) | IIC_IRQ_TYPE_IOEXC;
+	unsigned long bits, ack;
+	int cascade;
+
+	for (;;) {
+		bits = in_be64(&node_iic->iic_is);
+		if (bits == 0)
+			break;
+		/* pre-ack edge interrupts */
+		ack = bits & IIC_ISR_EDGE_MASK;
+		if (ack)
+			out_be64(&node_iic->iic_is, ack);
+		/* handle them */
+		for (cascade = 63; cascade >= 0; cascade--)
+			if (bits & (0x8000000000000000UL >> cascade)) {
+				unsigned int cirq =
+					irq_linear_revmap(iic_host,
+							  base | cascade);
+				if (cirq != NO_IRQ)
+					generic_handle_irq(cirq, regs);
+			}
+		/* post-ack level interrupts */
+		ack = bits & ~IIC_ISR_EDGE_MASK;
+		if (ack)
+			out_be64(&node_iic->iic_is, ack);
+	}
+	desc->chip->eoi(irq);
+}
+
+
+static struct irq_chip iic_ioexc_chip = {
+	.typename = " CELL-IOEX",
+	.mask = iic_mask,
+	.unmask = iic_unmask,
+	.eoi = iic_ioexc_eoi,
+};
+
 /* Get an IRQ number from the pending state register of the IIC */
 static unsigned int iic_get_irq(struct pt_regs *regs)
 {
 	struct cbe_iic_pending_bits pending;
 	struct iic *iic;
+	unsigned int virq;
 
 	iic = &__get_cpu_var(iic);
 	*(unsigned long *) &pending =
 		in_be64((unsigned long __iomem *) &iic->regs->pending_destr);
+	if (!(pending.flags & CBE_IIC_IRQ_VALID))
+		return NO_IRQ;
+	virq = irq_linear_revmap(iic_host, iic_pending_to_hwnum(pending));
+	if (virq == NO_IRQ)
+		return NO_IRQ;
 	iic->eoi_stack[++iic->eoi_ptr] = pending.prio;
 	BUG_ON(iic->eoi_ptr > 15);
-	if (pending.flags & CBE_IIC_IRQ_VALID)
-		return irq_linear_revmap(iic->host,
-					 iic_pending_to_hwnum(pending));
-	return NO_IRQ;
+	return virq;
 }
 
 #ifdef CONFIG_SMP
@@ -108,12 +164,7 @@ static unsigned int iic_get_irq(struct pt_regs *regs)
 /* Use the highest interrupt priorities for IPI */
 static inline int iic_ipi_to_irq(int ipi)
 {
-	return IIC_IRQ_IPI0 + IIC_NUM_IPIS - 1 - ipi;
-}
-
-static inline int iic_irq_to_ipi(int irq)
-{
-	return IIC_NUM_IPIS - 1 - (irq - IIC_IRQ_IPI0);
+	return IIC_IRQ_TYPE_IPI + 0xf - ipi;
 }
 
 void iic_setup_cpu(void)
@@ -123,7 +174,7 @@ void iic_setup_cpu(void)
 
 void iic_cause_IPI(int cpu, int mesg)
 {
-	out_be64(&per_cpu(iic, cpu).regs->generate, (IIC_NUM_IPIS - 1 - mesg) << 4);
+	out_be64(&per_cpu(iic, cpu).regs->generate, (0xf - mesg) << 4);
 }
 
 u8 iic_get_target_id(int cpu)
@@ -134,9 +185,7 @@ EXPORT_SYMBOL_GPL(iic_get_target_id);
 
 struct irq_host *iic_get_irq_host(int node)
 {
-	if (node < 0 || node >= IIC_NODE_COUNT)
-		return NULL;
-	return iic_hosts[node];
+	return iic_host;
 }
 EXPORT_SYMBOL_GPL(iic_get_irq_host);
 
@@ -149,34 +198,20 @@ static irqreturn_t iic_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
 
 	return IRQ_HANDLED;
 }
-
 static void iic_request_ipi(int ipi, const char *name)
 {
-	int node, virq;
+	int virq;
 
-	for (node = 0; node < IIC_NODE_COUNT; node++) {
-		char *rname;
-		if (iic_hosts[node] == NULL)
-			continue;
-		virq = irq_create_mapping(iic_hosts[node],
-					  iic_ipi_to_irq(ipi));
-		if (virq == NO_IRQ) {
-			printk(KERN_ERR
-			       "iic: failed to map IPI %s on node %d\n",
-			       name, node);
-			continue;
-		}
-		rname = kzalloc(strlen(name) + 16, GFP_KERNEL);
-		if (rname)
-			sprintf(rname, "%s node %d", name, node);
-		else
-			rname = (char *)name;
-		if (request_irq(virq, iic_ipi_action, IRQF_DISABLED,
-				rname, (void *)(long)ipi))
-			printk(KERN_ERR
-			       "iic: failed to request IPI %s on node %d\n",
-			       name, node);
+	virq = irq_create_mapping(iic_host, iic_ipi_to_irq(ipi));
+	if (virq == NO_IRQ) {
+		printk(KERN_ERR
+		       "iic: failed to map IPI %s\n", name);
+		return;
 	}
+	if (request_irq(virq, iic_ipi_action, IRQF_DISABLED, name,
+			(void *)(long)ipi))
+		printk(KERN_ERR
+		       "iic: failed to request IPI %s\n", name);
 }
 
 void iic_request_IPIs(void)
@@ -193,16 +228,24 @@ void iic_request_IPIs(void)
 
 static int iic_host_match(struct irq_host *h, struct device_node *node)
 {
-	return h->host_data != NULL && node == h->host_data;
+	return device_is_compatible(node,
+				    "IBM,CBEA-Internal-Interrupt-Controller");
 }
 
 static int iic_host_map(struct irq_host *h, unsigned int virq,
 			irq_hw_number_t hw)
 {
-	if (hw < IIC_IRQ_IPI0)
-		set_irq_chip_and_handler(virq, &iic_chip, handle_fasteoi_irq);
-	else
+	switch (hw & IIC_IRQ_TYPE_MASK) {
+	case IIC_IRQ_TYPE_IPI:
 		set_irq_chip_and_handler(virq, &iic_chip, handle_percpu_irq);
+		break;
+	case IIC_IRQ_TYPE_IOEXC:
+		set_irq_chip_and_handler(virq, &iic_ioexc_chip,
+					 handle_fasteoi_irq);
+		break;
+	default:
+		set_irq_chip_and_handler(virq, &iic_chip, handle_fasteoi_irq);
+	}
 	return 0;
 }
 
@@ -211,11 +254,39 @@ static int iic_host_xlate(struct irq_host *h, struct device_node *ct,
 			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 
 {
-	/* Currently, we don't translate anything. That needs to be fixed as
-	 * we get better defined device-trees. iic interrupts have to be
-	 * explicitely mapped by whoever needs them
-	 */
-	return -ENODEV;
+	unsigned int node, ext, unit, class;
+	const u32 *val;
+
+	if (!device_is_compatible(ct,
+				     "IBM,CBEA-Internal-Interrupt-Controller"))
+		return -ENODEV;
+	if (intsize != 1)
+		return -ENODEV;
+	val = get_property(ct, "#interrupt-cells", NULL);
+	if (val == NULL || *val != 1)
+		return -ENODEV;
+
+	node = intspec[0] >> 24;
+	ext = (intspec[0] >> 16) & 0xff;
+	class = (intspec[0] >> 8) & 0xff;
+	unit = intspec[0] & 0xff;
+
+	/* Check if node is in supported range */
+	if (node > 1)
+		return -EINVAL;
+
+	/* Build up interrupt number, special case for IO exceptions */
+	*out_hwirq = (node << IIC_IRQ_NODE_SHIFT);
+	if (unit == IIC_UNIT_IIC && class == 1)
+		*out_hwirq |= IIC_IRQ_TYPE_IOEXC | ext;
+	else
+		*out_hwirq |= IIC_IRQ_TYPE_NORMAL |
+			(class << IIC_IRQ_CLASS_SHIFT) | unit;
+
+	/* Dummy flags, ignored by iic code */
+	*out_flags = IRQ_TYPE_EDGE_RISING;
+
+	return 0;
 }
 
 static struct irq_host_ops iic_host_ops = {
@@ -225,7 +296,7 @@ static struct irq_host_ops iic_host_ops = {
 };
 
 static void __init init_one_iic(unsigned int hw_cpu, unsigned long addr,
-				struct irq_host *host)
+				struct device_node *node)
 {
 	/* XXX FIXME: should locate the linux CPU number from the HW cpu
 	 * number properly. We are lucky for now
@@ -237,19 +308,19 @@ static void __init init_one_iic(unsigned int hw_cpu, unsigned long addr,
 
 	iic->target_id = ((hw_cpu & 2) << 3) | ((hw_cpu & 1) ? 0xf : 0xe);
 	iic->eoi_stack[0] = 0xff;
-	iic->host = host;
+	iic->node = of_node_get(node);
 	out_be64(&iic->regs->prio, 0);
 
-	printk(KERN_INFO "IIC for CPU %d at %lx mapped to %p, target id 0x%x\n",
-	       hw_cpu, addr, iic->regs, iic->target_id);
+	printk(KERN_INFO "IIC for CPU %d target id 0x%x : %s\n",
+	       hw_cpu, iic->target_id, node->full_name);
 }
 
 static int __init setup_iic(void)
 {
 	struct device_node *dn;
 	struct resource r0, r1;
-	struct irq_host *host;
-	int found = 0;
+	unsigned int node, cascade, found = 0;
+	struct cbe_iic_regs *node_iic;
 	const u32 *np;
 
 	for (dn = NULL;
@@ -269,19 +340,33 @@ static int __init setup_iic(void)
 			of_node_put(dn);
 			return -ENODEV;
 		}
-		host = NULL;
-		if (found < IIC_NODE_COUNT) {
-			host = irq_alloc_host(IRQ_HOST_MAP_LINEAR,
-					      IIC_SOURCE_COUNT,
-					      &iic_host_ops,
-					      IIC_IRQ_INVALID);
-			iic_hosts[found] = host;
-			BUG_ON(iic_hosts[found] == NULL);
-			iic_hosts[found]->host_data = of_node_get(dn);
-			found++;
-		}
-		init_one_iic(np[0], r0.start, host);
-		init_one_iic(np[1], r1.start, host);
+		found++;
+		init_one_iic(np[0], r0.start, dn);
+		init_one_iic(np[1], r1.start, dn);
+
+		/* Setup cascade for IO exceptions. XXX cleanup tricks to get
+		 * node vs CPU etc...
+		 * Note that we configure the IIC_IRR here with a hard coded
+		 * priority of 1. We might want to improve that later.
+		 */
+		node = np[0] >> 1;
+		node_iic = cbe_get_cpu_iic_regs(np[0]);
+		cascade = node << IIC_IRQ_NODE_SHIFT;
+		cascade |= 1 << IIC_IRQ_CLASS_SHIFT;
+		cascade |= IIC_UNIT_IIC;
+		cascade = irq_create_mapping(iic_host, cascade);
+		if (cascade == NO_IRQ)
+			continue;
+		set_irq_data(cascade, node_iic);
+		set_irq_chained_handler(cascade , iic_ioexc_cascade);
+		out_be64(&node_iic->iic_ir,
+			 (1 << 12)		/* priority */ |
+			 (node << 4)		/* dest node */ |
+			 IIC_UNIT_THREAD_0	/* route them to thread 0 */);
+		/* Flush pending (make sure it triggers if there is
+		 * anything pending
+		 */
+		out_be64(&node_iic->iic_is, 0xfffffffffffffffful);
 	}
 
 	if (found)
@@ -292,6 +377,12 @@ static int __init setup_iic(void)
 
 void __init iic_init_IRQ(void)
 {
+	/* Setup an irq host data structure */
+	iic_host = irq_alloc_host(IRQ_HOST_MAP_LINEAR, IIC_SOURCE_COUNT,
+				  &iic_host_ops, IIC_IRQ_INVALID);
+	BUG_ON(iic_host == NULL);
+	irq_set_default_host(iic_host);
+
 	/* Discover and initialize iics */
 	if (setup_iic() < 0)
 		panic("IIC: Failed to initialize !\n");

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;