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>

diff --git a/Documentation/devicetree/bindings/powerpc/fsl/mpic.txt b/Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
index b393ccf1e9f302cd8f8e965b74ad2bad8ab005d5..dc5744636a5792610f48e34812569acd25b3eda9 100644 (file)
--- a/Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
+++ b/Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
@@ -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

diff --git a/arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi b/arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi
index 658bd81982cbb05b5722648925f316532b1825d5..fdedf7b1fe0f2e25d47729470e1665be9615a3d8 100644 (file)
--- a/arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi
+++ b/arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi
@@ -41,6 +41,7 @@ mpic: pic@40000 {
        device_type = "open-pic";
        big-endian;
        single-cpu-affinity;
+       last-interrupt-source = <255>;
 };
 
 timer@41100 {

diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index cbffeb742d669ecf0a888ecfceddc317b6e7f24e..90171d447c3d482b30bd8eaeaa40fdb696a632cb 100644 (file)
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -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