x86: Re-enable PCAT timer 2 for beeping

While we don't want PCAT timers for timing, we want timer 2 so that we can
still make a beep. Re-purpose the PCAT driver for this, and enable it in
coreboot.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/include/asm/u-boot-x86.h

@@ -41,6 +41,7 @@ typedef void (timer_fnc_t) (void);
 int register_timer_isr (timer_fnc_t *isr_func);
 unsigned long get_tbclk_mhz(void);
 void timer_set_base(uint64_t base);
+int pcat_timer_init(void);
 
 /* Architecture specific - can be in arch/x86/cpu/, arch/x86/lib/, or $(BOARD)/ */
 int dram_init_f(void);

arch/x86/lib/Makefile

@@ -31,7 +31,7 @@ COBJS-y	+= gcc.o
 COBJS-y	+= init_helpers.o
 COBJS-y	+= interrupts.o
 COBJS-$(CONFIG_SYS_PCAT_INTERRUPTS) += pcat_interrupts.o
-COBJS-$(CONFIG_SYS_GENERIC_TIMER) += pcat_timer.o
+COBJS-$(CONFIG_SYS_PCAT_TIMER) += pcat_timer.o
 COBJS-$(CONFIG_PCI) += pci_type1.o
 COBJS-y	+= relocate.o
 COBJS-y += physmem.o

arch/x86/lib/pcat_timer.c

@@ -24,83 +24,20 @@
 #include <common.h>
 #include <asm/io.h>
 #include <asm/i8254.h>
-#include <asm/ibmpc.h>
-#include <asm/interrupt.h>
 
-#define TIMER0_VALUE 0x04aa /* 1kHz 1.9318MHz / 1000 */
 #define TIMER2_VALUE 0x0a8e /* 440Hz */
 
-static int timer_init_done;
-
-int timer_init(void)
+int pcat_timer_init(void)
 {
-	/* initialize timer 0 and 2
-	 *
-	 * Timer 0 is used to increment system_tick 1000 times/sec
-	 * Timer 1 was used for DRAM refresh in early PC's
-	 * Timer 2 is used to drive the speaker
+	/*
+	 * initialize 2, used to drive the speaker
 	 * (to start a beep: write 3 to port 0x61,
 	 * to stop it again: write 0)
 	 */
-	outb(PIT_CMD_CTR0 | PIT_CMD_BOTH | PIT_CMD_MODE2,
-			PIT_BASE + PIT_COMMAND);
-	outb(TIMER0_VALUE & 0xff, PIT_BASE + PIT_T0);
-	outb(TIMER0_VALUE >> 8, PIT_BASE + PIT_T0);
-
 	outb(PIT_CMD_CTR2 | PIT_CMD_BOTH | PIT_CMD_MODE3,
 			PIT_BASE + PIT_COMMAND);
 	outb(TIMER2_VALUE & 0xff, PIT_BASE + PIT_T2);
 	outb(TIMER2_VALUE >> 8, PIT_BASE + PIT_T2);
 
-	irq_install_handler(0, timer_isr, NULL);
-	unmask_irq(0);
-
-	timer_init_done = 1;
-
 	return 0;
 }
-
-static u16 read_pit(void)
-{
-	u8 low;
-
-	outb(PIT_CMD_LATCH, PIT_BASE + PIT_COMMAND);
-	low = inb(PIT_BASE + PIT_T0);
-
-	return (inb(PIT_BASE + PIT_T0) << 8) | low;
-}
-
-/* this is not very exact */
-void __udelay(unsigned long usec)
-{
-	int counter;
-	int wraps;
-
-	if (timer_init_done) {
-		counter = read_pit();
-		wraps = usec / 1000;
-		usec = usec % 1000;
-
-		usec *= 1194;
-		usec /= 1000;
-		usec += counter;
-
-		while (usec > 1194) {
-			usec -= 1194;
-			wraps++;
-		}
-
-		while (1) {
-			int new_count = read_pit();
-
-			if (((new_count < usec) && !wraps) || wraps < 0)
-				break;
-
-			if (new_count > counter)
-				wraps--;
-
-			counter = new_count;
-		}
-	}
-
-}

arch/x86/lib/tsc_timer.c

@@ -98,6 +98,10 @@ void __udelay(unsigned long usec)
 
 int timer_init(void)
 {
-	/* Nothing to do here - the timer needs no init */
+#ifdef CONFIG_SYS_PCAT_TIMER
+	/* Set up the PCAT timer if required */
+	pcat_timer_init();
+#endif
+
 	return 0;
 }

include/configs/coreboot.h

@@ -235,6 +235,7 @@
 
 #define CONFIG_SYS_X86_TSC_TIMER
 #define CONFIG_SYS_PCAT_INTERRUPTS
+#define CONFIG_SYS_PCAT_TIMER
 #define CONFIG_SYS_NUM_IRQS			16
 
 /*-----------------------------------------------------------------------