isa-bus: Remove bogus IRQ sharing check

Nothing prevented IRQ sharing on the ISA bus in principle. Not all
boards supported this, neither each and every card nor driver and OS.
Still, there existed valid IRQ sharing scenarios, (at least) two of them
can also be found in QEMU: >2 PC UARTs and the PREP IDE buses.

So remove this artificial restriction from our ISA model.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit ee951a37d8873bff7aa58e23222dfd984111b6cb)

9 files changed, 12 insertions, 23 deletions

diff --git a/hw/hpet.c b/hw/hpet.c
index 8fb6811a2c..c12064dae6 100644
--- a/hw/hpet.c
+++ b/hw/hpet.c
@@ -715,7 +715,6 @@ static int hpet_init(SysBusDevice *dev)
     s->capability |= (s->num_timers - 1) << HPET_ID_NUM_TIM_SHIFT;
     s->capability |= ((HPET_CLK_PERIOD) << 32);
 
-    isa_reserve_irq(RTC_ISA_IRQ);
     qdev_init_gpio_in(&dev->qdev, hpet_handle_rtc_irq, 1);
 
     /* HPET Area */
diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index d4289af9c4..c3496448c3 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -122,7 +122,7 @@ static void pci_piix_init_ports(PCIIDEState *d) {
     for (i = 0; i < 2; i++) {
         ide_bus_new(&d->bus[i], &d->dev.qdev, i);
         ide_init_ioport(&d->bus[i], port_info[i].iobase, port_info[i].iobase2);
-        ide_init2(&d->bus[i], isa_reserve_irq(port_info[i].isairq));
+        ide_init2(&d->bus[i], isa_get_irq(port_info[i].isairq));
 
         bmdma_init(&d->bus[i], &d->bmdma[i]);
         d->bmdma[i].bus = &d->bus[i];
diff --git a/hw/ide/via.c b/hw/ide/via.c
index 0e906797cd..04f3290960 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -145,7 +145,7 @@ static void vt82c686b_init_ports(PCIIDEState *d) {
     for (i = 0; i < 2; i++) {
         ide_bus_new(&d->bus[i], &d->dev.qdev, i);
         ide_init_ioport(&d->bus[i], port_info[i].iobase, port_info[i].iobase2);
-        ide_init2(&d->bus[i], isa_reserve_irq(port_info[i].isairq));
+        ide_init2(&d->bus[i], isa_get_irq(port_info[i].isairq));
 
         bmdma_init(&d->bus[i], &d->bmdma[i]);
         d->bmdma[i].bus = &d->bus[i];
diff --git a/hw/isa-bus.c b/hw/isa-bus.c
index 0cb1afbf2e..9e33e71b9f 100644
--- a/hw/isa-bus.c
+++ b/hw/isa-bus.c
@@ -25,7 +25,6 @@
 struct ISABus {
     BusState qbus;
     qemu_irq *irqs;
-    uint32_t assigned;
 };
 static ISABus *isabus;
 target_phys_addr_t isa_mem_base = 0;
@@ -61,33 +60,24 @@ void isa_bus_irqs(qemu_irq *irqs)
 }
 
 /*
- * isa_reserve_irq() reserves the ISA irq and returns the corresponding
- * qemu_irq entry for the i8259.
+ * isa_get_irq() returns the corresponding qemu_irq entry for the i8259.
  *
  * This function is only for special cases such as the 'ferr', and
  * temporary use for normal devices until they are converted to qdev.
  */
-qemu_irq isa_reserve_irq(int isairq)
+qemu_irq isa_get_irq(int isairq)
 {
     if (isairq < 0 || isairq > 15) {
         hw_error("isa irq %d invalid", isairq);
     }
-    if (isabus->assigned & (1 << isairq)) {
-        hw_error("isa irq %d already assigned", isairq);
-    }
-    isabus->assigned |= (1 << isairq);
     return isabus->irqs[isairq];
 }
 
 void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq)
 {
     assert(dev->nirqs < ARRAY_SIZE(dev->isairq));
-    if (isabus->assigned & (1 << isairq)) {
-        hw_error("isa irq %d already assigned", isairq);
-    }
-    isabus->assigned |= (1 << isairq);
     dev->isairq[dev->nirqs] = isairq;
-    *p = isabus->irqs[isairq];
+    *p = isa_get_irq(isairq);
     dev->nirqs++;
 }
 
diff --git a/hw/isa.h b/hw/isa.h
index 19aa94c9fd..f1335ff2d6 100644
--- a/hw/isa.h
+++ b/hw/isa.h
@@ -26,7 +26,7 @@ struct ISADeviceInfo {
 
 ISABus *isa_bus_new(DeviceState *dev);
 void isa_bus_irqs(qemu_irq *irqs);
-qemu_irq isa_reserve_irq(int isairq);
+qemu_irq isa_get_irq(int isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq);
 void isa_init_ioport(ISADevice *dev, uint16_t ioport);
 void isa_init_ioport_range(ISADevice *dev, uint16_t start, uint16_t length);
diff --git a/hw/mips_fulong2e.c b/hw/mips_fulong2e.c
index 2783ed5837..3b0abdba8a 100644
--- a/hw/mips_fulong2e.c
+++ b/hw/mips_fulong2e.c
@@ -369,7 +369,7 @@ static void mips_fulong2e_init(ram_addr_t ram_size, const char *boot_device,
     qdev_init_nofail(eeprom);
 
     /* init other devices */
-    pit = pit_init(0x40, isa_reserve_irq(0));
+    pit = pit_init(0x40, isa_get_irq(0));
     cpu_exit_irq = qemu_allocate_irqs(cpu_request_exit, NULL, 1);
     DMA_init(0, cpu_exit_irq);
 
diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index 2d3f242cc8..7211d98a19 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -919,7 +919,7 @@ void mips_malta_init (ram_addr_t ram_size,
     isa_bus_irqs(i8259);
     pci_piix4_ide_init(pci_bus, hd, piix4_devfn + 1);
     usb_uhci_piix4_init(pci_bus, piix4_devfn + 2);
-    smbus = piix4_pm_init(pci_bus, piix4_devfn + 3, 0x1100, isa_reserve_irq(9),
+    smbus = piix4_pm_init(pci_bus, piix4_devfn + 3, 0x1100, isa_get_irq(9),
                           NULL, NULL, 0);
     eeprom_buf = qemu_mallocz(8 * 256); /* XXX: make this persistent */
     for (i = 0; i < 8; i++) {
@@ -930,7 +930,7 @@ void mips_malta_init (ram_addr_t ram_size,
         qdev_prop_set_ptr(eeprom, "data", eeprom_buf + (i * 256));
         qdev_init_nofail(eeprom);
     }
-    pit = pit_init(0x40, isa_reserve_irq(0));
+    pit = pit_init(0x40, isa_get_irq(0));
     cpu_exit_irq = qemu_allocate_irqs(cpu_request_exit, NULL, 1);
     DMA_init(0, cpu_exit_irq);
 
diff --git a/hw/pc.c b/hw/pc.c
index 4dfdc0be53..9f1b7765f7 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1110,7 +1110,7 @@ void pc_basic_device_init(qemu_irq *isa_irq,
 
     qemu_register_boot_set(pc_boot_set, *rtc_state);
 
-    pit = pit_init(0x40, isa_reserve_irq(0));
+    pit = pit_init(0x40, isa_get_irq(0));
     pcspk_init(pit);
 
     for(i = 0; i < MAX_SERIAL_PORTS; i++) {
diff --git a/hw/pc_piix.c b/hw/pc_piix.c
index 7b744730f7..3fa1e9d821 100644
--- a/hw/pc_piix.c
+++ b/hw/pc_piix.c
@@ -110,7 +110,7 @@ static void pc_init1(ram_addr_t ram_size,
     }
     isa_bus_irqs(isa_irq);
 
-    pc_register_ferr_irq(isa_reserve_irq(13));
+    pc_register_ferr_irq(isa_get_irq(13));
 
     pc_vga_init(pci_enabled? pci_bus: NULL);
 
@@ -166,7 +166,7 @@ static void pc_init1(ram_addr_t ram_size,
         smi_irq = qemu_allocate_irqs(pc_acpi_smi_interrupt, first_cpu, 1);
         /* TODO: Populate SPD eeprom data.  */
         smbus = piix4_pm_init(pci_bus, piix3_devfn + 3, 0xb100,
-                              isa_reserve_irq(9), *cmos_s3, *smi_irq,
+                              isa_get_irq(9), *cmos_s3, *smi_irq,
                               kvm_enabled());
         for (i = 0; i < 8; i++) {
             DeviceState *eeprom;