xics.c

linux-2.6.15.6

/*
 * arch/powerpc/platforms/pseries/xics.c
 *
 * Copyright 2000 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; either version
 *  2 of the License, or (at your option) any later version.
 */
#include <linux/config.h>
#include <linux/types.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/signal.h>
#include <linux/init.h>
#include <linux/gfp.h>
#include <linux/radix-tree.h>
#include <linux/cpu.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/smp.h>
#include <asm/rtas.h>
#include <asm/hvcall.h>
#include <asm/machdep.h>
#include <asm/i8259.h>

#include "xics.h"

static unsigned int xics_startup(unsigned int irq);
static void xics_enable_irq(unsigned int irq);
static void xics_disable_irq(unsigned int irq);
static void xics_mask_and_ack_irq(unsigned int irq);
static void xics_end_irq(unsigned int irq);
static void xics_set_affinity(unsigned int irq_nr, cpumask_t cpumask);

static struct hw_interrupt_type xics_pic = {
	.typename = " XICS     ",
	.startup = xics_startup,
	.enable = xics_enable_irq,
	.disable = xics_disable_irq,
	.ack = xics_mask_and_ack_irq,
	.end = xics_end_irq,
	.set_affinity = xics_set_affinity
};

/* This is used to map real irq numbers to virtual */
static struct radix_tree_root irq_map = RADIX_TREE_INIT(GFP_ATOMIC);

#define XICS_IPI		2
#define XICS_IRQ_SPURIOUS	0

/* Want a priority other than 0.  Various HW issues require this. */
#define	DEFAULT_PRIORITY	5

/*
 * Mark IPIs as higher priority so we can take them inside interrupts that
 * arent marked SA_INTERRUPT
 */
#define IPI_PRIORITY		4

struct xics_ipl {
	union {
		u32 word;
		u8 bytes[4];
	} xirr_poll;
	union {
		u32 word;
		u8 bytes[4];
	} xirr;
	u32 dummy;
	union {
		u32 word;
		u8 bytes[4];
	} qirr;
};

static struct xics_ipl __iomem *xics_per_cpu[NR_CPUS];

static int xics_irq_8259_cascade = 0;
static int xics_irq_8259_cascade_real = 0;
static unsigned int default_server = 0xFF;
static unsigned int default_distrib_server = 0;
static unsigned int interrupt_server_size = 8;

/*
 * XICS only has a single IPI, so encode the messages per CPU
 */
struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;

/* RTAS service tokens */
static int ibm_get_xive;
static int ibm_set_xive;
static int ibm_int_on;
static int ibm_int_off;

typedef struct {
	int (*xirr_info_get)(int cpu);
	void (*xirr_info_set)(int cpu, int val);
	void (*cppr_info)(int cpu, u8 val);
	void (*qirr_info)(int cpu, u8 val);
} xics_ops;


/* SMP */

static int pSeries_xirr_info_get(int n_cpu)
{
	return in_be32(&xics_per_cpu[n_cpu]->xirr.word);
}

static void pSeries_xirr_info_set(int n_cpu, int value)
{
	out_be32(&xics_per_cpu[n_cpu]->xirr.word, value);
}

static void pSeries_cppr_info(int n_cpu, u8 value)
{
	out_8(&xics_per_cpu[n_cpu]->xirr.bytes[0], value);
}

static void pSeries_qirr_info(int n_cpu, u8 value)
{
	out_8(&xics_per_cpu[n_cpu]->qirr.bytes[0], value);
}

static xics_ops pSeries_ops = {
	pSeries_xirr_info_get,
	pSeries_xirr_info_set,
	pSeries_cppr_info,
	pSeries_qirr_info
};

static xics_ops *ops = &pSeries_ops;


/* LPAR */

static inline long plpar_eoi(unsigned long xirr)
{
	return plpar_hcall_norets(H_EOI, xirr);
}

static inline long plpar_cppr(unsigned long cppr)
{
	return plpar_hcall_norets(H_CPPR, cppr);
}

static inline long plpar_ipi(unsigned long servernum, unsigned long mfrr)
{
	return plpar_hcall_norets(H_IPI, servernum, mfrr);
}

static inline long plpar_xirr(unsigned long *xirr_ret)
{
	unsigned long dummy;
	return plpar_hcall(H_XIRR, 0, 0, 0, 0, xirr_ret, &dummy, &dummy);
}

static int pSeriesLP_xirr_info_get(int n_cpu)
{
	unsigned long lpar_rc;
	unsigned long return_value;

	lpar_rc = plpar_xirr(&return_value);
	if (lpar_rc != H_Success)
		panic(" bad return code xirr - rc = %lx \n", lpar_rc);
	return (int)return_value;
}

static void pSeriesLP_xirr_info_set(int n_cpu, int value)
{
	unsigned long lpar_rc;
	unsigned long val64 = value & 0xffffffff;

	lpar_rc = plpar_eoi(val64);
	if (lpar_rc != H_Success)
		panic("bad return code EOI - rc = %ld, value=%lx\n", lpar_rc,
		      val64);
}

void pSeriesLP_cppr_info(int n_cpu, u8 value)
{
	unsigned long lpar_rc;

	lpar_rc = plpar_cppr(value);
	if (lpar_rc != H_Success)
		panic("bad return code cppr - rc = %lx\n", lpar_rc);
}

static void pSeriesLP_qirr_info(int n_cpu , u8 value)
{
	unsigned long lpar_rc;

	lpar_rc = plpar_ipi(get_hard_smp_processor_id(n_cpu), value);
	if (lpar_rc != H_Success)
		panic("bad return code qirr - rc = %lx\n", lpar_rc);
}

xics_ops pSeriesLP_ops = {
	pSeriesLP_xirr_info_get,
	pSeriesLP_xirr_info_set,
	pSeriesLP_cppr_info,
	pSeriesLP_qirr_info
};

static unsigned int xics_startup(unsigned int virq)
{
	unsigned int irq;

	irq = irq_offset_down(virq);
	if (radix_tree_insert(&irq_map, virt_irq_to_real(irq),
			      &virt_irq_to_real_map[irq]) == -ENOMEM)
		printk(KERN_CRIT "Out of memory creating real -> virtual"
		       " IRQ mapping for irq %u (real 0x%x)\n",
		       virq, virt_irq_to_real(irq));
	xics_enable_irq(virq);
	return 0;	/* return value is ignored */
}

static unsigned int real_irq_to_virt(unsigned int real_irq)
{
	unsigned int *ptr;

	ptr = radix_tree_lookup(&irq_map, real_irq);
	if (ptr == NULL)
		return NO_IRQ;
	return ptr - virt_irq_to_real_map;
}

#ifdef CONFIG_SMP
static int get_irq_server(unsigned int irq)
{
	unsigned int server;
	/* For the moment only implement delivery to all cpus or one cpu */
	cpumask_t cpumask = irq_affinity[irq];
	cpumask_t tmp = CPU_MASK_NONE;

	if (!distribute_irqs)
		return default_server;

	if (cpus_equal(cpumask, CPU_MASK_ALL)) {
		server = default_distrib_server;
	} else {
		cpus_and(tmp, cpu_online_map, cpumask);

		if (cpus_empty(tmp))
			server = default_distrib_server;
		else
			server = get_hard_smp_processor_id(first_cpu(tmp));
	}

	return server;

}
#else
static int get_irq_server(unsigned int irq)
{
	return default_server;
}
#endif

static void xics_enable_irq(unsigned int virq)
{
	unsigned int irq;
	int call_status;
	unsigned int server;

	irq = virt_irq_to_real(irq_offset_down(virq));
	if (irq == XICS_IPI)
		return;

	server = get_irq_server(virq);
	call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server,
				DEFAULT_PRIORITY);
	if (call_status != 0) {
		printk(KERN_ERR "xics_enable_irq: irq=%u: ibm_set_xive "
		       "returned %d\n", irq, call_status);
		printk("set_xive %x, server %x\n", ibm_set_xive, server);
		return;
	}

	/* Now unmask the interrupt (often a no-op) */
	call_status = rtas_call(ibm_int_on, 1, 1, NULL, irq);
	if (call_status != 0) {
		printk(KERN_ERR "xics_enable_irq: irq=%u: ibm_int_on "
		       "returned %d\n", irq, call_status);
		return;
	}
}

static void xics_disable_real_irq(unsigned int irq)
{
	int call_status;
	unsigned int server;

	if (irq == XICS_IPI)
		return;

	call_status = rtas_call(ibm_int_off, 1, 1, NULL, irq);
	if (call_status != 0) {
		printk(KERN_ERR "xics_disable_real_irq: irq=%u: "
		       "ibm_int_off returned %d\n", irq, call_status);
		return;
	}

	server = get_irq_server(irq);
	/* Have to set XIVE to 0xff to be able to remove a slot */
	call_status = rtas_call(ibm_set_xive, 3, 1, NULL, irq, server, 0xff);
	if (call_status != 0) {
		printk(KERN_ERR "xics_disable_irq: irq=%u: ibm_set_xive(0xff)"
		       " returned %d\n", irq, call_status);
		return;
	}
}

static void xics_disable_irq(unsigned int virq)
{
	unsigned int irq;

	irq = virt_irq_to_real(irq_offset_down(virq));
	xics_disable_real_irq(irq);
}

static void xics_end_irq(unsigned int irq)
{
	int cpu = smp_processor_id();

	iosync();
	ops->xirr_info_set(cpu, ((0xff << 24) |
				 (virt_irq_to_real(irq_offset_down(irq)))));

}

static void xics_mask_and_ack_irq(unsigned int irq)
{
	int cpu = smp_processor_id();

	if (irq < irq_offset_value()) {
		i8259_pic.ack(irq);
		iosync();
		ops->xirr_info_set(cpu, ((0xff<<24) |
					 xics_irq_8259_cascade_real));
		iosync();
	}
}

int xics_get_irq(struct pt_regs *regs)
{
	unsigned int cpu = smp_processor_id();
	unsigned int vec;
	int irq;

	vec = ops->xirr_info_get(cpu);
	/*  (vec >> 24) == old priority */
	vec &= 0x00ffffff;

	/* for sanity, this had better be < NR_IRQS - 16 */
	if (vec == xics_irq_8259_cascade_real) {
		irq = i8259_irq(regs);
		xics_end_irq(irq_offset_up(xics_irq_8259_cascade));
	} else if (vec == XICS_IRQ_SPURIOUS) {
		irq = -1;