[Patch Part1 V2 18/29] x86, irq: introduce mechanisms to support dynamically allocate IRQ for IOAPIC
From: Jiang Liu
Date: Mon May 19 2014 - 12:24:32 EST
Currently x86 support identity mapping between GSI(IOAPIC pin) and IRQ
number, so continous IRQs at low end are statically allocated to IOAPICs
at boot time. This design causes trouble to support IOAPIC hotplug.
This patch implements basic mechanism to dynamically allocate IRQ on
demand for IOAPIC pins by using irqdomain framework.
It first adds several fields into struct ioapic to support irqdomain.
Then it implements an algorithm to dynamically allocate IRQ number
on demand.
1) Legacy(ISA) IRQs is not managed by irqdomain because there may be
multiple pins sharing the same IRQ number and current irqdomain
only supports 1:1 mapping between pins and IRQ.
2) Build identity mapping for GSIs between NR_IRQS_LEGACY and
arch_dynirq_lower_bound(0). This is typically used to support legacy
IRQs and simple platforms.
3) Dynamically allocate IRQs for GSIs above arch_dynirq_lower_bound(0).
This may be used to support big system and IOAPIC hotplug.
4) Dynamically allocate IRQs for non-ISA IRQs below NR_IRQS_LEGACY. This
is to support some really weired platforms.
Function arch_dynirq_lower_bound(0) will be enhanced in coming patch
to enable dynamic IRQ allocation for IOAPIC. To ease our life,
arch_dynirq_lower_bound(0) must be greater than or equal to
NR_IRQS_LEGACY, otherwise it may break backward compatibilities.
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/io_apic.h | 12 ++++-
arch/x86/kernel/acpi/boot.c | 10 ++--
arch/x86/kernel/apic/io_apic.c | 111 ++++++++++++++++++++++++++++------------
3 files changed, 94 insertions(+), 39 deletions(-)
diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index f4fd0be26cec..2e593832ec6f 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -98,6 +98,8 @@ struct IR_IO_APIC_route_entry {
#define IOAPIC_AUTO -1
#define IOAPIC_EDGE 0
#define IOAPIC_LEVEL 1
+#define IOAPIC_MAP_ALLOC 0x1
+#define IOAPIC_MAP_CHECK 0x2
#ifdef CONFIG_X86_IO_APIC
@@ -169,9 +171,11 @@ struct mp_ioapic_gsi{
};
extern u32 gsi_top;
+typedef struct irq_domain *(*ioapic_create_domain_fn)(int idx, void *arg);
+
extern int mp_find_ioapic(u32 gsi);
extern int mp_find_ioapic_pin(int ioapic, u32 gsi);
-extern int mp_map_pin_to_irq(int ioapic, int pin);
+extern int mp_map_pin_to_irq(int ioapic, int pin, int idx, unsigned int flags);
extern void __init mp_register_ioapic(int id, u32 address, u32 gsi_base);
extern void __init pre_init_apic_IRQ0(void);
@@ -213,7 +217,11 @@ extern void io_apic_eoi(unsigned int apic, unsigned int vector);
static inline void ioapic_insert_resources(void) { }
#define gsi_top (NR_IRQS_LEGACY)
static inline int mp_find_ioapic(u32 gsi) { return 0; }
-static inline int mp_map_pin_to_irq(int ioapic, int pin) { return -1; }
+static inline int mp_map_pin_to_irq(int ioapic, int pin, int idx,
+ unsigned int flags)
+{
+ return -1;
+}
struct io_apic_irq_attr;
static inline int io_apic_set_pci_routing(struct device *dev, int irq,
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 6eae9a7231c4..9aa02b30a8bc 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -99,7 +99,7 @@ static u32 isa_irq_to_gsi[NR_IRQS_LEGACY] __read_mostly = {
#define ACPI_INVALID_GSI INT_MIN
-static int map_gsi_to_irq(unsigned int gsi)
+static int map_gsi_to_irq(unsigned int gsi, unsigned int flags)
{
int i, ioapic, pin;
@@ -110,7 +110,7 @@ static int map_gsi_to_irq(unsigned int gsi)
ioapic = mp_find_ioapic(gsi);
if (ioapic >= 0) {
pin = mp_find_ioapic_pin(ioapic, gsi);
- return mp_map_pin_to_irq(ioapic, pin);
+ return mp_map_pin_to_irq(ioapic, pin, -1, flags);
}
pr_err("Failed to map GSI%d to IRQ number.\n", gsi);
@@ -490,7 +490,7 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger)
int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)
{
- int irq = map_gsi_to_irq(gsi);
+ int irq = map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
if (irq >= 0) {
#ifdef CONFIG_X86_IO_APIC
@@ -559,7 +559,7 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
plat_gsi = (*__acpi_register_gsi)(dev, gsi, trigger, polarity);
if (plat_gsi != ACPI_INVALID_GSI)
- return map_gsi_to_irq(plat_gsi);
+ return map_gsi_to_irq(plat_gsi, 0);
return -1;
}
@@ -1041,7 +1041,7 @@ static int mp_register_gsi(struct device *dev, u32 gsi, int trigger,
if (acpi_gbl_FADT.sci_interrupt == gsi)
return gsi;
- irq = map_gsi_to_irq(gsi);
+ irq = map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC);
if (irq < 0)
return ACPI_INVALID_GSI;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 2d776f69f4e8..d0dd904007aa 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -31,6 +31,7 @@
#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/syscore_ops.h>
+#include <linux/irqdomain.h>
#include <linux/msi.h>
#include <linux/htirq.h>
#include <linux/freezer.h>
@@ -83,6 +84,7 @@ int sis_apic_bug = -1;
static DEFINE_RAW_SPINLOCK(ioapic_lock);
static DEFINE_RAW_SPINLOCK(vector_lock);
+static DEFINE_MUTEX(ioapic_mutex);
static struct ioapic {
/*
@@ -97,6 +99,9 @@ static struct ioapic {
struct mpc_ioapic mp_config;
/* IO APIC gsi routing info */
struct mp_ioapic_gsi gsi_config;
+ struct irq_domain *irqdomain;
+ ioapic_create_domain_fn irqdomain_cb;
+ void *irqdomain_arg;
DECLARE_BITMAP(pin_programmed, MP_MAX_IOAPIC_PIN + 1);
} ioapics[MAX_IO_APICS];
@@ -135,6 +140,11 @@ static inline int mp_init_irq_at_boot(int ioapic, int irq)
return ioapic == 0 || (irq >= 0 && irq < NR_IRQS_LEGACY);
}
+static inline struct irq_domain *mp_ioapic_irqdomain(int ioapic)
+{
+ return ioapics[ioapic].irqdomain;
+}
+
int nr_ioapics;
/* The one past the highest gsi number used */
@@ -963,19 +973,47 @@ static int irq_trigger(int idx)
return trigger;
}
-int mp_map_pin_to_irq(int apic, int pin)
+int mp_map_pin_to_irq(int ioapic, int pin, int idx, unsigned int flags)
{
- struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(apic);
- u32 gsi = gsi_cfg->gsi_base + pin;
+ int irq = -1;
+ u32 gsi = mp_pin_2_gsi(ioapic, pin);
+ struct irq_domain *domain = mp_ioapic_irqdomain(ioapic);
- /*
- * Provide an identity mapping of gsi == irq except on truly weird
- * platforms that have non isa irqs in the first 16 gsis.
- */
- return gsi >= NR_IRQS_LEGACY ? gsi : gsi_top + gsi;
+ if (!domain) {
+ /*
+ * Provide an identity mapping of gsi == irq except on truly
+ * weird platforms that have non isa irqs in the first 16 gsis.
+ */
+ return gsi >= NR_IRQS_LEGACY ? gsi : gsi_top + gsi;
+ }
+
+ mutex_lock(&ioapic_mutex);
+ irq = irq_find_mapping(domain, pin);
+ if (irq <= 0 && (flags & IOAPIC_MAP_ALLOC)) {
+ if ((flags & IOAPIC_MAP_CHECK) && idx < 0) {
+ idx = find_irq_entry(ioapic, pin, mp_INT);
+ if (idx < 0)
+ goto out;
+ }
+
+ /*
+ * Dynamically allocate IRQ for GSI above
+ * arch_dynirq_lower_bound(0), and build identity mapping for
+ * statically assigned IRQ, and specially handle non-ISA IRQs
+ * below NR_IRQS_LEGACY.
+ */
+ if (gsi >= arch_dynirq_lower_bound(0) || gsi < NR_IRQS_LEGACY)
+ irq = irq_create_mapping(domain, pin);
+ else if (irq_create_strict_mappings(domain, gsi, pin, 1) == 0)
+ irq = gsi;
+ }
+out:
+ mutex_unlock(&ioapic_mutex);
+
+ return irq > 0 ? irq : -1;
}
-static int pin_2_irq(int idx, int apic, int pin)
+static int pin_2_irq(int idx, int ioapic, int pin, unsigned int flags)
{
int irq;
int bus = mp_irqs[idx].srcbus;
@@ -1009,7 +1047,7 @@ static int pin_2_irq(int idx, int apic, int pin)
if (test_bit(bus, mp_bus_not_pci))
irq = mp_irqs[idx].srcbusirq;
else
- irq = mp_map_pin_to_irq(apic, pin);
+ irq = mp_map_pin_to_irq(ioapic, pin, idx, flags);
return irq;
}
@@ -1021,7 +1059,7 @@ static int pin_2_irq(int idx, int apic, int pin)
int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin,
struct io_apic_irq_attr *irq_attr)
{
- int irq, i, best_guess = -1;
+ int irq, i, best_ioapic = -1, best_idx = -1;
apic_printk(APIC_DEBUG,
"querying PCI -> IRQ mapping bus:%d, slot:%d, pin:%d.\n",
@@ -1035,6 +1073,7 @@ int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin,
for (i = 0; i < mp_irq_entries; i++) {
int lbus = mp_irqs[i].srcbus;
int ioapic_idx, found = 0;
+ int gsi;
if (test_bit(lbus, mp_bus_not_pci) || (bus != lbus) ||
mp_irqs[i].irqtype != mp_INT ||
@@ -1051,30 +1090,37 @@ int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin,
continue;
/* Skip ISA IRQs */
- irq = pin_2_irq(i, ioapic_idx, mp_irqs[i].dstirq);
- if (ioapic_idx == 0 && !IO_APIC_IRQ(irq))
+ gsi = mp_pin_2_gsi(ioapic_idx, mp_irqs[i].dstirq);
+ if (gsi < arch_dynirq_lower_bound(0) && !IO_APIC_IRQ(gsi))
continue;
if (pin == (mp_irqs[i].srcbusirq & 3)) {
- set_io_apic_irq_attr(irq_attr, ioapic_idx,
- mp_irqs[i].dstirq,
- irq_trigger(i),
- irq_polarity(i));
- return irq;
+ best_idx = i;
+ best_ioapic = ioapic_idx;
+ goto out;
}
+
/*
* Use the first all-but-pin matching entry as a
* best-guess fuzzy result for broken mptables.
*/
- if (best_guess < 0) {
- set_io_apic_irq_attr(irq_attr, ioapic_idx,
- mp_irqs[i].dstirq,
- irq_trigger(i),
- irq_polarity(i));
- best_guess = irq;
+ if (best_idx < 0) {
+ best_idx = i;
+ best_ioapic = ioapic_idx;
}
}
- return best_guess;
+ if (best_idx < 0)
+ return -1;
+
+out:
+ irq = pin_2_irq(best_idx, best_ioapic, mp_irqs[best_idx].dstirq,
+ IOAPIC_MAP_ALLOC);
+ if (irq > 0)
+ set_io_apic_irq_attr(irq_attr, best_ioapic,
+ mp_irqs[best_idx].dstirq,
+ irq_trigger(best_idx),
+ irq_polarity(best_idx));
+ return irq;
}
EXPORT_SYMBOL(IO_APIC_get_PCI_irq_vector);
@@ -1265,7 +1311,7 @@ static inline int IO_APIC_irq_trigger(int irq)
for_each_ioapic_pin(apic, pin) {
idx = find_irq_entry(apic, pin, mp_INT);
- if ((idx != -1) && (irq == pin_2_irq(idx, apic, pin)))
+ if ((idx != -1) && (irq == pin_2_irq(idx, apic, pin, 0)))
return irq_trigger(idx);
}
/*
@@ -1391,8 +1437,9 @@ static void __init __io_apic_setup_irqs(unsigned int ioapic_idx)
if (io_apic_pin_not_connected(idx, ioapic_idx, pin))
continue;
- irq = pin_2_irq(idx, ioapic_idx, pin);
- if (!mp_init_irq_at_boot(ioapic_idx, irq))
+ irq = pin_2_irq(idx, ioapic_idx, pin,
+ ioapic_idx ? 0 : IOAPIC_MAP_ALLOC);
+ if (irq < 0 || !mp_init_irq_at_boot(ioapic_idx, irq))
continue;
/*
@@ -1442,8 +1489,8 @@ void setup_IO_APIC_irq_extra(u32 gsi)
if (idx == -1)
return;
- irq = pin_2_irq(idx, ioapic_idx, pin);
- if (mp_init_irq_at_boot(ioapic_idx, irq))
+ irq = pin_2_irq(idx, ioapic_idx, pin, IOAPIC_MAP_ALLOC);
+ if (irq < 0 || mp_init_irq_at_boot(ioapic_idx, irq))
return;
set_io_apic_irq_attr(&attr, ioapic_idx, pin, irq_trigger(idx),
@@ -3558,8 +3605,8 @@ void __init setup_ioapic_dest(void)
if (irq_entry == -1)
continue;
- irq = pin_2_irq(irq_entry, ioapic, pin);
- if (!mp_init_irq_at_boot(ioapic, irq))
+ irq = pin_2_irq(irq_entry, ioapic, pin, 0);
+ if (irq < 0 || !mp_init_irq_at_boot(ioapic, irq))
continue;
idata = irq_get_irq_data(irq);
--
1.7.10.4
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