intr/x86: add ioapic_drv_t to reduce number of casts in IO-APIC implementation

void * is handy when you truly do not care about the type.  Yet there is
so much casting back and forth in the IO-APIC code as to be hazardous.
Achieve better static checking by the compiler using a typedef.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1457

3 files changed, 26 insertions, 44 deletions

diff --git a/sys/x86/include/apicvar.h b/sys/x86/include/apicvar.h
index 61c726f150df..fc9bb0123539 100644
--- a/sys/x86/include/apicvar.h
+++ b/sys/x86/include/apicvar.h
@@ -196,19 +196,21 @@ extern int *apic_cpuids;
 /* Allow to replace the lapic_ipi_vectored implementation. */
 extern void (*ipi_vectored)(u_int, int);
 
+typedef struct ioapic *ioapic_drv_t;
+
 void	apic_register_enumerator(struct apic_enumerator *enumerator);
-void	*ioapic_create(vm_paddr_t addr, int32_t apic_id, int intbase);
-int	ioapic_disable_pin(void *cookie, u_int pin);
-int	ioapic_get_vector(void *cookie, u_int pin);
-void	ioapic_register(void *cookie);
-int	ioapic_remap_vector(void *cookie, u_int pin, int vector);
-int	ioapic_set_bus(void *cookie, u_int pin, int bus_type);
-int	ioapic_set_extint(void *cookie, u_int pin);
-int	ioapic_set_nmi(void *cookie, u_int pin);
-int	ioapic_set_polarity(void *cookie, u_int pin, enum intr_polarity pol);
-int	ioapic_set_triggermode(void *cookie, u_int pin,
+ioapic_drv_t	ioapic_create(vm_paddr_t addr, int32_t apic_id, int intbase);
+int	ioapic_disable_pin(ioapic_drv_t cookie, u_int pin);
+int	ioapic_get_vector(ioapic_drv_t cookie, u_int pin);
+void	ioapic_register(ioapic_drv_t cookie);
+int	ioapic_remap_vector(ioapic_drv_t cookie, u_int pin, int vector);
+int	ioapic_set_bus(ioapic_drv_t cookie, u_int pin, int bus_type);
+int	ioapic_set_extint(ioapic_drv_t cookie, u_int pin);
+int	ioapic_set_nmi(ioapic_drv_t cookie, u_int pin);
+int	ioapic_set_polarity(ioapic_drv_t cookie, u_int pin, enum intr_polarity pol);
+int	ioapic_set_triggermode(ioapic_drv_t cookie, u_int pin,
 	    enum intr_trigger trigger);
-int	ioapic_set_smi(void *cookie, u_int pin);
+int	ioapic_set_smi(ioapic_drv_t cookie, u_int pin);
 
 void	lapic_create(u_int apic_id, int boot_cpu);
 void	lapic_init(vm_paddr_t addr);
diff --git a/sys/x86/x86/io_apic.c b/sys/x86/x86/io_apic.c
index 36c7cba77a35..d0f47f82011a 100644
--- a/sys/x86/x86/io_apic.c
+++ b/sys/x86/x86/io_apic.c
@@ -606,7 +606,7 @@ ioapic_resume(struct pic *pic, bool suspend_cancelled)
 /*
  * Create a plain I/O APIC object.
  */
-void *
+ioapic_drv_t
 ioapic_create(vm_paddr_t addr, int32_t apic_id, int intbase)
 {
 	struct ioapic *io;
@@ -727,22 +727,18 @@ ioapic_create(vm_paddr_t addr, int32_t apic_id, int intbase)
 }
 
 int
-ioapic_get_vector(void *cookie, u_int pin)
+ioapic_get_vector(ioapic_drv_t io, u_int pin)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (-1);
 	return (io->io_pins[pin].io_irq);
 }
 
 int
-ioapic_disable_pin(void *cookie, u_int pin)
+ioapic_disable_pin(ioapic_drv_t io, u_int pin)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq == IRQ_DISABLED)
@@ -754,11 +750,9 @@ ioapic_disable_pin(void *cookie, u_int pin)
 }
 
 int
-ioapic_remap_vector(void *cookie, u_int pin, int vector)
+ioapic_remap_vector(ioapic_drv_t io, u_int pin, int vector)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr || vector < 0)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq < 0)
@@ -771,13 +765,11 @@ ioapic_remap_vector(void *cookie, u_int pin, int vector)
 }
 
 int
-ioapic_set_bus(void *cookie, u_int pin, int bus_type)
+ioapic_set_bus(ioapic_drv_t io, u_int pin, int bus_type)
 {
-	struct ioapic *io;
 
 	if (bus_type < 0 || bus_type > APIC_BUS_MAX)
 		return (EINVAL);
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq < 0)
@@ -792,11 +784,9 @@ ioapic_set_bus(void *cookie, u_int pin, int bus_type)
 }
 
 int
-ioapic_set_nmi(void *cookie, u_int pin)
+ioapic_set_nmi(ioapic_drv_t io, u_int pin)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq == IRQ_NMI)
@@ -815,11 +805,9 @@ ioapic_set_nmi(void *cookie, u_int pin)
 }
 
 int
-ioapic_set_smi(void *cookie, u_int pin)
+ioapic_set_smi(ioapic_drv_t io, u_int pin)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq == IRQ_SMI)
@@ -838,11 +826,9 @@ ioapic_set_smi(void *cookie, u_int pin)
 }
 
 int
-ioapic_set_extint(void *cookie, u_int pin)
+ioapic_set_extint(ioapic_drv_t io, u_int pin)
 {
-	struct ioapic *io;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq == IRQ_EXTINT)
@@ -864,12 +850,10 @@ ioapic_set_extint(void *cookie, u_int pin)
 }
 
 int
-ioapic_set_polarity(void *cookie, u_int pin, enum intr_polarity pol)
+ioapic_set_polarity(ioapic_drv_t io, u_int pin, enum intr_polarity pol)
 {
-	struct ioapic *io;
 	int activehi;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr || pol == INTR_POLARITY_CONFORM)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq < 0)
@@ -885,12 +869,10 @@ ioapic_set_polarity(void *cookie, u_int pin, enum intr_polarity pol)
 }
 
 int
-ioapic_set_triggermode(void *cookie, u_int pin, enum intr_trigger trigger)
+ioapic_set_triggermode(ioapic_drv_t io, u_int pin, enum intr_trigger trigger)
 {
-	struct ioapic *io;
 	int edgetrigger;
 
-	io = (struct ioapic *)cookie;
 	if (pin >= io->io_numintr || trigger == INTR_TRIGGER_CONFORM)
 		return (EINVAL);
 	if (io->io_pins[pin].io_irq < 0)
@@ -909,15 +891,13 @@ ioapic_set_triggermode(void *cookie, u_int pin, enum intr_trigger trigger)
  * Register a complete I/O APIC object with the interrupt subsystem.
  */
 void
-ioapic_register(void *cookie)
+ioapic_register(ioapic_drv_t io)
 {
 	struct ioapic_intsrc *pin;
-	struct ioapic *io;
 	volatile ioapic_t *apic;
 	uint32_t flags;
 	int i;
 
-	io = (struct ioapic *)cookie;
 	apic = io->io_addr;
 	mtx_lock_spin(&icu_lock);
 	flags = ioapic_read(apic, IOAPIC_VER) & IOART_VER_VERSION;
diff --git a/sys/x86/x86/mptable.c b/sys/x86/x86/mptable.c
index 03b4d4362baa..4f078fd05ec6 100644
--- a/sys/x86/x86/mptable.c
+++ b/sys/x86/x86/mptable.c
@@ -157,7 +157,7 @@ struct pci_route_interrupt_args {
 static mpfps_t mpfps;
 static mpcth_t mpct;
 static ext_entry_ptr mpet;
-static void *ioapics[IOAPIC_MAX_ID + 1];
+static ioapic_drv_t ioapics[IOAPIC_MAX_ID + 1];
 static bus_datum *busses;
 static int mptable_nioapics, mptable_nbusses, mptable_maxbusid;
 static int pci0 = -1;
@@ -760,7 +760,7 @@ intentry_trigger(int_entry_ptr intr)
 static void
 mptable_parse_io_int(int_entry_ptr intr)
 {
-	void *ioapic;
+	ioapic_drv_t ioapic;
 	u_int pin, apic_id;
 
 	apic_id = intr->dst_apic_id;