x86: Avoid magic number with ELCR register accesses

Define PIC_ELCR1 and PIC_ELCR2 macros for accesses to the ELCR registers
implemented by many chipsets in their embedded 8259A PIC cores, avoiding
magic numbers that are difficult to handle, and complementing the macros
we already have for registers originally defined with discrete 8259A PIC
implementations. No functional change.

Signed-off-by: Maciej W. Rozycki <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/include/asm/i8259.h

···
 #define PIC_MASTER_OCW3		PIC_MASTER_ISR
 #define PIC_SLAVE_CMD		0xa0
 #define PIC_SLAVE_IMR		0xa1
+#define PIC_ELCR1		0x4d0
+#define PIC_ELCR2		0x4d1
 
 /* i8259A PIC related value */
 #define PIC_CASCADE_IR		2

arch/x86/kernel/acpi/boot.c

···
 	unsigned int old, new;
 
 	/* Real old ELCR mask */
-	old = inb(0x4d0) | (inb(0x4d1) << 8);
+	old = inb(PIC_ELCR1) | (inb(PIC_ELCR2) << 8);
 
 	/*
 	 * If we use ACPI to set PCI IRQs, then we should clear ELCR
···
 		return;
 
 	pr_warn("setting ELCR to %04x (from %04x)\n", new, old);
-	outb(new, 0x4d0);
-	outb(new >> 8, 0x4d1);
+	outb(new, PIC_ELCR1);
+	outb(new >> 8, PIC_ELCR2);
 }
 
 int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)

arch/x86/kernel/apic/io_apic.c

···
 static bool EISA_ELCR(unsigned int irq)
 {
 	if (irq < nr_legacy_irqs()) {
-		unsigned int port = 0x4d0 + (irq >> 3);
+		unsigned int port = PIC_ELCR1 + (irq >> 3);
 		return (inb(port) >> (irq & 7)) & 1;
 	}
 	apic_printk(APIC_VERBOSE, KERN_INFO

arch/x86/kernel/apic/vector.c

···
 
 	pr_debug("... PIC  ISR: %04x\n", v);
 
-	v = inb(0x4d1) << 8 | inb(0x4d0);
+	v = inb(PIC_ELCR2) << 8 | inb(PIC_ELCR1);
 	pr_debug("... PIC ELCR: %04x\n", v);
 }
 

arch/x86/kernel/i8259.c

···
  */
 static void restore_ELCR(char *trigger)
 {
-	outb(trigger[0], 0x4d0);
-	outb(trigger[1], 0x4d1);
+	outb(trigger[0], PIC_ELCR1);
+	outb(trigger[1], PIC_ELCR2);
 }
 
 static void save_ELCR(char *trigger)
 {
 	/* IRQ 0,1,2,8,13 are marked as reserved */
-	trigger[0] = inb(0x4d0) & 0xF8;
-	trigger[1] = inb(0x4d1) & 0xDE;
+	trigger[0] = inb(PIC_ELCR1) & 0xF8;
+	trigger[1] = inb(PIC_ELCR2) & 0xDE;
 }
 
 static void i8259A_resume(void)

arch/x86/kernel/mpparse.c

···
 #include <linux/smp.h>
 #include <linux/pci.h>
 
+#include <asm/i8259.h>
 #include <asm/io_apic.h>
 #include <asm/acpi.h>
 #include <asm/irqdomain.h>
···
 {
 	unsigned int port;
 
-	port = 0x4d0 + (irq >> 3);
+	port = PIC_ELCR1 + (irq >> 3);
 	return (inb(port) >> (irq & 7)) & 1;
 }
 

arch/x86/pci/irq.c

···
 #include <linux/irq.h>
 #include <linux/acpi.h>
 
+#include <asm/i8259.h>
 #include <asm/pc-conf-reg.h>
 #include <asm/pci_x86.h>
 
···
 void elcr_set_level_irq(unsigned int irq)
 {
 	unsigned char mask = 1 << (irq & 7);
-	unsigned int port = 0x4d0 + (irq >> 3);
+	unsigned int port = PIC_ELCR1 + (irq >> 3);
 	unsigned char val;
 	static u16 elcr_irq_mask;