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Commit a7de7c74 authored by Michael Ellerman's avatar Michael Ellerman Committed by Paul Mackerras
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[POWERPC] MPIC MSI allocator 



To support MSI on MPIC we need a way to reserve and allocate hardware irq
numbers, this patch implements an allocator for that purpose.

New firmware platforms must define a "msi-available-ranges" property on their
MPIC node for MSI to work. For U3/U4 we do a best-guess setup.

Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 812fd1fd

arch/powerpc/sysdev/Makefile

+3 −1
Original line number Diff line number Diff line
@@ -2,7 +2,9 @@ ifeq ($(CONFIG_PPC64),y) 
EXTRA_CFLAGS			+= -mno-minimal-toc

endif



obj-$(CONFIG_MPIC)		+= mpic.o

mpic-msi-obj-$(CONFIG_PCI_MSI)	+= mpic_msi.o

obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y)



obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o

obj-$(CONFIG_PPC_MPC106)	+= grackle.o

obj-$(CONFIG_PPC_DCR)		+= dcr.o

arch/powerpc/sysdev/mpic.c

+4 −0
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
#include <asm/mpic.h>

#include <asm/smp.h>



#include "mpic.h"



#ifdef DEBUG

#define DBG(fmt...) printk(fmt)

#else
@@ -891,6 +893,8 @@ static int mpic_host_map(struct irq_host *h, unsigned int virq, 
	if (hw >= mpic->irq_count)

		return -EINVAL;



	mpic_msi_reserve_hwirq(mpic, hw);



	/* Default chip */

	chip = &mpic->hc_irq;

arch/powerpc/sysdev/mpic.h

0 → 100644
+27 −0
Original line number Diff line number Diff line 
#ifndef _POWERPC_SYSDEV_MPIC_H

#define _POWERPC_SYSDEV_MPIC_H



/*

 * Copyright 2006-2007, Michael Ellerman, IBM Corporation.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; version 2 of the

 * License.

 *

 */



#ifdef CONFIG_PCI_MSI

extern void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq);

extern int mpic_msi_init_allocator(struct mpic *mpic);

extern irq_hw_number_t mpic_msi_alloc_hwirqs(struct mpic *mpic, int num);

extern void mpic_msi_free_hwirqs(struct mpic *mpic, int offset, int num);

#else

static inline void mpic_msi_reserve_hwirq(struct mpic *mpic,

					  irq_hw_number_t hwirq)

{

	return;

}

#endif



#endif /* _POWERPC_SYSDEV_MPIC_H */

arch/powerpc/sysdev/mpic_msi.c

0 → 100644
+183 −0
Original line number Diff line number Diff line 
/*

 * Copyright 2006-2007, Michael Ellerman, IBM Corporation.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; version 2 of the

 * License.

 *

 */



#include <linux/irq.h>

#include <linux/bootmem.h>

#include <linux/bitmap.h>

#include <linux/msi.h>

#include <asm/mpic.h>

#include <asm/prom.h>

#include <asm/hw_irq.h>

#include <asm/ppc-pci.h>





static void __mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)

{

	pr_debug("mpic: reserving hwirq 0x%lx\n", hwirq);

	bitmap_allocate_region(mpic->hwirq_bitmap, hwirq, 0);

}



void mpic_msi_reserve_hwirq(struct mpic *mpic, irq_hw_number_t hwirq)

{

	unsigned long flags;



	/* The mpic calls this even when there is no allocator setup */

	if (!mpic->hwirq_bitmap)

		return;



	spin_lock_irqsave(&mpic->bitmap_lock, flags);

	__mpic_msi_reserve_hwirq(mpic, hwirq);

	spin_unlock_irqrestore(&mpic->bitmap_lock, flags);

}



irq_hw_number_t mpic_msi_alloc_hwirqs(struct mpic *mpic, int num)

{

	unsigned long flags;

	int offset, order = get_count_order(num);



	spin_lock_irqsave(&mpic->bitmap_lock, flags);

	/*

	 * This is fast, but stricter than we need. We might want to add

	 * a fallback routine which does a linear search with no alignment.

	 */

	offset = bitmap_find_free_region(mpic->hwirq_bitmap, mpic->irq_count,

					 order);

	spin_unlock_irqrestore(&mpic->bitmap_lock, flags);



	pr_debug("mpic: allocated 0x%x (2^%d) at offset 0x%x\n",

		 num, order, offset);



	return offset;

}



void mpic_msi_free_hwirqs(struct mpic *mpic, int offset, int num)

{

	unsigned long flags;

	int order = get_count_order(num);



	pr_debug("mpic: freeing 0x%x (2^%d) at offset 0x%x\n",

		 num, order, offset);



	spin_lock_irqsave(&mpic->bitmap_lock, flags);

	bitmap_release_region(mpic->hwirq_bitmap, offset, order);

	spin_unlock_irqrestore(&mpic->bitmap_lock, flags);

}



#ifdef CONFIG_MPIC_U3_HT_IRQS

static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)

{

	irq_hw_number_t hwirq;

	struct irq_host_ops *ops = mpic->irqhost->ops;

	struct device_node *np;

	int flags, index, i;

	struct of_irq oirq;



	pr_debug("mpic: found U3, guessing msi allocator setup\n");



	/* Reserve source numbers we know are reserved in the HW */

	for (i = 0;   i < 8;   i++)

		__mpic_msi_reserve_hwirq(mpic, i);



	for (i = 42;  i < 46;  i++)

		__mpic_msi_reserve_hwirq(mpic, i);



	for (i = 100; i < 105; i++)

		__mpic_msi_reserve_hwirq(mpic, i);



	np = NULL;

	while ((np = of_find_all_nodes(np))) {

		pr_debug("mpic: mapping hwirqs for %s\n", np->full_name);



		index = 0;

		while (of_irq_map_one(np, index++, &oirq) == 0) {

			ops->xlate(mpic->irqhost, NULL, oirq.specifier,

						oirq.size, &hwirq, &flags);

			__mpic_msi_reserve_hwirq(mpic, hwirq);

		}

	}



	return 0;

}

#else

static int mpic_msi_reserve_u3_hwirqs(struct mpic *mpic)

{

	return -1;

}

#endif



static int mpic_msi_reserve_dt_hwirqs(struct mpic *mpic)

{

	int i, len;

	const u32 *p;



	p = of_get_property(mpic->of_node, "msi-available-ranges", &len);

	if (!p) {

		pr_debug("mpic: no msi-available-ranges property found on %s\n",

			  mpic->of_node->full_name);

		return -ENODEV;

	}



	if (len % 8 != 0) {

		printk(KERN_WARNING "mpic: Malformed msi-available-ranges "

		       "property on %s\n", mpic->of_node->full_name);

		return -EINVAL;

	}



	bitmap_allocate_region(mpic->hwirq_bitmap, 0,

			       get_count_order(mpic->irq_count));



	/* Format is: (<u32 start> <u32 count>)+ */

	len /= sizeof(u32);

	for (i = 0; i < len / 2; i++, p += 2)

		mpic_msi_free_hwirqs(mpic, *p, *(p + 1));



	return 0;

}



int mpic_msi_init_allocator(struct mpic *mpic)

{

	int rc, size;



	BUG_ON(mpic->hwirq_bitmap);

	spin_lock_init(&mpic->bitmap_lock);



	size = BITS_TO_LONGS(mpic->irq_count) * sizeof(long);

	pr_debug("mpic: allocator bitmap size is 0x%x bytes\n", size);



	if (mem_init_done)

		mpic->hwirq_bitmap = kmalloc(size, GFP_KERNEL);

	else

		mpic->hwirq_bitmap = alloc_bootmem(size);



	if (!mpic->hwirq_bitmap) {

		pr_debug("mpic: ENOMEM allocating allocator bitmap!\n");

		return -ENOMEM;

	}



	memset(mpic->hwirq_bitmap, 0, size);



	rc = mpic_msi_reserve_dt_hwirqs(mpic);

	if (rc) {

		if (mpic->flags & MPIC_U3_HT_IRQS)

			rc = mpic_msi_reserve_u3_hwirqs(mpic);



		if (rc)

			goto out_free;

	}



	return 0;



 out_free:

	if (mem_init_done)

		kfree(mpic->hwirq_bitmap);



	mpic->hwirq_bitmap = NULL;

	return rc;

}

include/asm-powerpc/mpic.h

+5 −0
Original line number Diff line number Diff line
@@ -301,6 +301,11 @@ struct mpic 
	u32			*hw_set;

#endif



#ifdef CONFIG_PCI_MSI

	spinlock_t		bitmap_lock;

	unsigned long		*hwirq_bitmap;

#endif



	/* link */

	struct mpic		*next;