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[POWERPC] Cell interrupt rework
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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>
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Benjamin Herrenschmidt authored and Paul Mackerras committed Oct 4, 2006
1 parent f3c87a8 commit 2e19458
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Showing 4 changed files with 238 additions and 122 deletions.
235 changes: 163 additions & 72 deletions arch/powerpc/platforms/cell/interrupt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -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)
Expand All @@ -86,34 +93,78 @@ 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

/* 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)
Expand All @@ -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)
Expand All @@ -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);

Expand All @@ -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)
Expand All @@ -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;
}

Expand All @@ -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 = {
Expand All @@ -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
Expand All @@ -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;
Expand All @@ -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)
Expand All @@ -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");
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