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powerpc/mpic: Add "last-interrupt-source" property to override hardware 

The FreeScale PowerQUICC-III-compatible (mpc85xx/mpc86xx) MPICs do not
correctly report the number of hardware interrupt sources, so software
needs to override the detected value with "256".

To avoid needing to write custom board-specific code to detect that
scenario, allow it to be easily overridden in the device-tree.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Kyle Moffett 2011-12-22 10:19:13 +00:00 committed by Benjamin Herrenschmidt
parent 5019609fce
commit c1b8d45db4
3 changed files with 34 additions and 20 deletions
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7
Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
View File

@ -70,6 +70,13 @@ PROPERTIES
If present the MPIC will be assumed to only be able to route
non-IPI interrupts to a single CPU at a time (EG: Freescale MPIC).
- last-interrupt-source
Usage: optional
Value type: <u32>
Some MPICs do not correctly report the number of hardware sources
in the global feature registers. If specified, this field will
override the value read from MPIC_GREG_FEATURE_LAST_SRC.
INTERRUPT SPECIFIER DEFINITION
Interrupt specifiers consists of 4 cells encoded as

1
arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi
View File

@ -41,6 +41,7 @@ mpic: pic@40000 {
device_type = "open-pic";
big-endian;
single-cpu-affinity;
last-interrupt-source = <255>;
};
timer@41100 {

46
arch/powerpc/sysdev/mpic.c
View File

@ -1149,6 +1149,7 @@ struct mpic * __init mpic_alloc(struct device_node *node,
u32 greg_feature;
const char *vers;
const u32 *psrc;
u32 last_irq;
/* Default MPIC search parameters */
static const struct of_device_id __initconst mpic_device_id[] = {
@ -1220,7 +1221,6 @@ struct mpic * __init mpic_alloc(struct device_node *node,
mpic->hc_tm = mpic_tm_chip;
mpic->hc_tm.name = name;
mpic->isu_size = isu_size;
mpic->num_sources = 0; /* so far */
if (mpic->flags & MPIC_LARGE_VECTORS)
@ -1307,20 +1307,6 @@ struct mpic * __init mpic_alloc(struct device_node *node,
mpic_read(mpic->gregs, MPIC_INFO(GREG_GLOBAL_CONF_0))
| MPIC_GREG_GCONF_MCK);
/*
* Read feature register. For non-ISU MPICs, num sources as well. On
* ISU MPICs, sources are counted as ISUs are added
*/
greg_feature = mpic_read(mpic->gregs, MPIC_INFO(GREG_FEATURE_0));
if (isu_size == 0) {
if (irq_count)
mpic->num_sources = irq_count;
else
mpic->num_sources =
((greg_feature & MPIC_GREG_FEATURE_LAST_SRC_MASK)
>> MPIC_GREG_FEATURE_LAST_SRC_SHIFT) + 1;
}
/*
* The MPIC driver will crash if there are more cores than we
* can initialize, so we may as well catch that problem here.
@ -1336,18 +1322,38 @@ struct mpic * __init mpic_alloc(struct device_node *node,
0x1000);
}
/*
* Read feature register. For non-ISU MPICs, num sources as well. On
* ISU MPICs, sources are counted as ISUs are added
*/
greg_feature = mpic_read(mpic->gregs, MPIC_INFO(GREG_FEATURE_0));
/*
* By default, the last source number comes from the MPIC, but the
* device-tree and board support code can override it on buggy hw.
*/
last_irq = (greg_feature & MPIC_GREG_FEATURE_LAST_SRC_MASK)
>> MPIC_GREG_FEATURE_LAST_SRC_SHIFT;
of_property_read_u32(mpic->node, "last-interrupt-source", &last_irq);
if (irq_count)
last_irq = irq_count - 1;
/* Initialize main ISU if none provided */
if (mpic->isu_size == 0) {
mpic->isu_size = mpic->num_sources;
if (!isu_size) {
isu_size = last_irq + 1;
mpic->num_sources = isu_size;
mpic_map(mpic, mpic->paddr, &mpic->isus[0],
MPIC_INFO(IRQ_BASE), MPIC_INFO(IRQ_STRIDE) * mpic->isu_size);
MPIC_INFO(IRQ_BASE),
MPIC_INFO(IRQ_STRIDE) * isu_size);
}
mpic->isu_size = isu_size;
mpic->isu_shift = 1 + __ilog2(mpic->isu_size - 1);
mpic->isu_mask = (1 << mpic->isu_shift) - 1;
mpic->irqhost = irq_alloc_host(mpic->node, IRQ_HOST_MAP_LINEAR,
isu_size ? isu_size : mpic->num_sources,
&mpic_host_ops, intvec_top + 1);
mpic->isu_size, &mpic_host_ops,
intvec_top + 1);
/*
* FIXME: The code leaks the MPIC object and mappings here; this