u-boot/arch/powerpc/cpu/mpc8xx/interrupts.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2000-2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 */

#include <common.h>
#include <mpc8xx.h>
#include <mpc8xx_irq.h>
#include <asm/cpm_8xx.h>
#include <asm/processor.h>
#include <asm/io.h>

/************************************************************************/

/*
 * CPM interrupt vector functions.
 */
struct interrupt_action {
	interrupt_handler_t *handler;
	void *arg;
};

static struct interrupt_action cpm_vecs[CPMVEC_NR];
static struct interrupt_action irq_vecs[NR_IRQS];

static void cpm_interrupt_init(void);
static void cpm_interrupt(void *regs);

/************************************************************************/

void interrupt_init_cpu(unsigned *decrementer_count)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;

	*decrementer_count = get_tbclk() / CONFIG_SYS_HZ;

	/* disable all interrupts */
	out_be32(&immr->im_siu_conf.sc_simask, 0);

	/* Configure CPM interrupts */
	cpm_interrupt_init();
}

/************************************************************************/

/*
 * Handle external interrupts
 */
void external_interrupt(struct pt_regs *regs)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;
	int irq;
	ulong simask;
	ulong vec, v_bit;

	/*
	 * read the SIVEC register and shift the bits down
	 * to get the irq number
	 */
	vec = in_be32(&immr->im_siu_conf.sc_sivec);
	irq = vec >> 26;
	v_bit = 0x80000000UL >> irq;

	/*
	 * Read Interrupt Mask Register and Mask Interrupts
	 */
	simask = in_be32(&immr->im_siu_conf.sc_simask);
	clrbits_be32(&immr->im_siu_conf.sc_simask, 0xFFFF0000 >> irq);

	if (!(irq & 0x1)) {		/* External Interrupt ?     */
		ulong siel;

		/*
		 * Read Interrupt Edge/Level Register
		 */
		siel = in_be32(&immr->im_siu_conf.sc_siel);

		if (siel & v_bit) {	/* edge triggered interrupt ?   */
			/*
			 * Rewrite SIPEND Register to clear interrupt
			 */
			out_be32(&immr->im_siu_conf.sc_sipend, v_bit);
		}
	}

	if (irq_vecs[irq].handler != NULL) {
		irq_vecs[irq].handler(irq_vecs[irq].arg);
	} else {
		printf("\nBogus External Interrupt IRQ %d Vector %ld\n",
		       irq, vec);
		/* turn off the bogus interrupt to avoid it from now */
		simask &= ~v_bit;
	}
	/*
	 * Re-Enable old Interrupt Mask
	 */
	out_be32(&immr->im_siu_conf.sc_simask, simask);
}

/************************************************************************/

/*
 * CPM interrupt handler
 */
static void cpm_interrupt(void *regs)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;
	uint vec;

	/*
	 * Get the vector by setting the ACK bit
	 * and then reading the register.
	 */
	out_be16(&immr->im_cpic.cpic_civr, 1);
	vec = in_be16(&immr->im_cpic.cpic_civr);
	vec >>= 11;

	if (cpm_vecs[vec].handler != NULL) {
		(*cpm_vecs[vec].handler) (cpm_vecs[vec].arg);
	} else {
		clrbits_be32(&immr->im_cpic.cpic_cimr, 1 << vec);
		printf("Masking bogus CPM interrupt vector 0x%x\n", vec);
	}
	/*
	 * After servicing the interrupt,
	 * we have to remove the status indicator.
	 */
	setbits_be32(&immr->im_cpic.cpic_cisr, 1 << vec);
}

/*
 * The CPM can generate the error interrupt when there is a race
 * condition between generating and masking interrupts. All we have
 * to do is ACK it and return. This is a no-op function so we don't
 * need any special tests in the interrupt handler.
 */
static void cpm_error_interrupt(void *dummy)
{
}

/************************************************************************/
/*
 * Install and free an interrupt handler
 */
void irq_install_handler(int vec, interrupt_handler_t *handler, void *arg)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;

	if ((vec & CPMVEC_OFFSET) != 0) {
		/* CPM interrupt */
		vec &= 0xffff;
		if (cpm_vecs[vec].handler != NULL)
			printf("CPM interrupt 0x%x replacing 0x%x\n",
			       (uint)handler, (uint)cpm_vecs[vec].handler);
		cpm_vecs[vec].handler = handler;
		cpm_vecs[vec].arg = arg;
		setbits_be32(&immr->im_cpic.cpic_cimr, 1 << vec);
	} else {
		/* SIU interrupt */
		if (irq_vecs[vec].handler != NULL)
			printf("SIU interrupt %d 0x%x replacing 0x%x\n",
			       vec, (uint)handler, (uint)cpm_vecs[vec].handler);
		irq_vecs[vec].handler = handler;
		irq_vecs[vec].arg = arg;
		setbits_be32(&immr->im_siu_conf.sc_simask, 1 << (31 - vec));
	}
}

void irq_free_handler(int vec)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;

	if ((vec & CPMVEC_OFFSET) != 0) {
		/* CPM interrupt */
		vec &= 0xffff;
		clrbits_be32(&immr->im_cpic.cpic_cimr, 1 << vec);
		cpm_vecs[vec].handler = NULL;
		cpm_vecs[vec].arg = NULL;
	} else {
		/* SIU interrupt */
		clrbits_be32(&immr->im_siu_conf.sc_simask, 1 << (31 - vec));
		irq_vecs[vec].handler = NULL;
		irq_vecs[vec].arg = NULL;
	}
}

/************************************************************************/

static void cpm_interrupt_init(void)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;
	uint cicr;

	/*
	 * Initialize the CPM interrupt controller.
	 */

	cicr = CICR_SCD_SCC4 | CICR_SCC_SCC3 | CICR_SCB_SCC2 | CICR_SCA_SCC1 |
	       ((CPM_INTERRUPT / 2) << 13) | CICR_HP_MASK;

	out_be32(&immr->im_cpic.cpic_cicr, cicr);
	out_be32(&immr->im_cpic.cpic_cimr, 0);

	/*
	 * Install the error handler.
	 */
	irq_install_handler(CPMVEC_ERROR, cpm_error_interrupt, NULL);

	setbits_be32(&immr->im_cpic.cpic_cicr, CICR_IEN);

	/*
	 * Install the cpm interrupt handler
	 */
	irq_install_handler(CPM_INTERRUPT, cpm_interrupt, NULL);
}

/************************************************************************/

/*
 * timer_interrupt - gets called when the decrementer overflows,
 * with interrupts disabled.
 * Trivial implementation - no need to be really accurate.
 */
void timer_interrupt_cpu(struct pt_regs *regs)
{
	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;

	/* Reset Timer Expired and Timers Interrupt Status */
	out_be32(&immr->im_clkrstk.cark_plprcrk, KAPWR_KEY);
	__asm__ ("nop");
	/*
	  Clear TEXPS (and TMIST on older chips). SPLSS (on older
	  chips) is cleared too.

	  Bitwise OR is a read-modify-write operation so ALL bits
	  which are cleared by writing `1' would be cleared by
	  operations like

	  immr->im_clkrst.car_plprcr |= PLPRCR_TEXPS;

	  The same can be achieved by simple writing of the PLPRCR
	  to itself. If a bit value should be preserved, read the
	  register, ZERO the bit and write, not OR, the result back.
	*/
	setbits_be32(&immr->im_clkrst.car_plprcr, 0);
}

/************************************************************************/