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Commit c1b8d45d authored by Kyle Moffett's avatar Kyle Moffett Committed by Benjamin Herrenschmidt
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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: default avatarKyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 5019609f

Documentation/devicetree/bindings/powerpc/fsl/mpic.txt

+7 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/boot/dts/fsl/pq3-mpic.dtsi

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ mpic: pic@40000 { 
	device_type = "open-pic";

	big-endian;

	single-cpu-affinity;

	last-interrupt-source = <255>;

};



timer@41100 {

arch/powerpc/sysdev/mpic.c

+26 −20
Original line number Diff line number Diff line
@@ -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