// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/sys_rawhide.c
 *
 *      Copyright (C) 1995 David A Rusling
 *      Copyright (C) 1996 Jay A Estabrook
 *      Copyright (C) 1998, 1999 Richard Henderson
 *
 * Code supporting the RAWHIDE.
 */

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/pci.h>
#include <linux/init.h>

#include <asm/ptrace.h>
#include <asm/dma.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/core_mcpcia.h>
#include <asm/tlbflush.h>

#include "proto.h"
#include "irq_impl.h"
#include "pci_impl.h"
#include "machvec_impl.h"


/*
 * HACK ALERT! only the boot cpu is used for interrupts.
 */


/* Note mask bit is true for ENABLED irqs.  */

static unsigned int hose_irq_masks[4] = {
        0xff0000, 0xfe0000, 0xff0000, 0xff0000
};
static unsigned int cached_irq_masks[4];
DEFINE_SPINLOCK(rawhide_irq_lock);

static inline void
rawhide_update_irq_hw(int hose, int mask)
{
        *(vuip)MCPCIA_INT_MASK0(MCPCIA_HOSE2MID(hose)) = mask;
        mb();
        *(vuip)MCPCIA_INT_MASK0(MCPCIA_HOSE2MID(hose));
}

#define hose_exists(h) \
  (((h) < MCPCIA_MAX_HOSES) && (cached_irq_masks[(h)] != 0))

static inline void 
rawhide_enable_irq(struct irq_data *d)
{
        unsigned int mask, hose;
        unsigned int irq = d->irq;

        irq -= 16;
        hose = irq / 24;
        if (!hose_exists(hose)) /* if hose non-existent, exit */
                return;

        irq -= hose * 24;
        mask = 1 << irq;

        spin_lock(&rawhide_irq_lock);
        mask |= cached_irq_masks[hose];
        cached_irq_masks[hose] = mask;
        rawhide_update_irq_hw(hose, mask);
        spin_unlock(&rawhide_irq_lock);
}

static void 
rawhide_disable_irq(struct irq_data *d)
{
        unsigned int mask, hose;
        unsigned int irq = d->irq;

        irq -= 16;
        hose = irq / 24;
        if (!hose_exists(hose)) /* if hose non-existent, exit */
                return;

        irq -= hose * 24;
        mask = ~(1 << irq) | hose_irq_masks[hose];

        spin_lock(&rawhide_irq_lock);
        mask &= cached_irq_masks[hose];
        cached_irq_masks[hose] = mask;
        rawhide_update_irq_hw(hose, mask);
        spin_unlock(&rawhide_irq_lock);
}

static void
rawhide_mask_and_ack_irq(struct irq_data *d)
{
        unsigned int mask, mask1, hose;
        unsigned int irq = d->irq;

        irq -= 16;
        hose = irq / 24;
        if (!hose_exists(hose)) /* if hose non-existent, exit */
                return;

        irq -= hose * 24;
        mask1 = 1 << irq;
        mask = ~mask1 | hose_irq_masks[hose];

        spin_lock(&rawhide_irq_lock);

        mask &= cached_irq_masks[hose];
        cached_irq_masks[hose] = mask;
        rawhide_update_irq_hw(hose, mask);

        /* Clear the interrupt.  */
        *(vuip)MCPCIA_INT_REQ(MCPCIA_HOSE2MID(hose)) = mask1;

        spin_unlock(&rawhide_irq_lock);
}

static struct irq_chip rawhide_irq_type = {
        .name           = "RAWHIDE",
        .irq_unmask     = rawhide_enable_irq,
        .irq_mask       = rawhide_disable_irq,
        .irq_mask_ack   = rawhide_mask_and_ack_irq,
};

static void 
rawhide_srm_device_interrupt(unsigned long vector)
{
        int irq;

        irq = (vector - 0x800) >> 4;

        /*
         * The RAWHIDE SRM console reports PCI interrupts with a vector
         * 0x80 *higher* than one might expect, as PCI IRQ 0 (ie bit 0)
         * shows up as IRQ 24, etc, etc. We adjust it down by 8 to have
         * it line up with the actual bit numbers from the REQ registers,
         * which is how we manage the interrupts/mask. Sigh...
         *
         * Also, PCI #1 interrupts are offset some more... :-(
         */

        if (irq == 52) {
                /* SCSI on PCI1 is special.  */
                irq = 72;
        }

        /* Adjust by which hose it is from.  */
        irq -= ((irq + 16) >> 2) & 0x38;

        handle_irq(irq);
}

static void __init
rawhide_init_irq(void)
{
        struct pci_controller *hose;
        long i;

        mcpcia_init_hoses();

        /* Clear them all; only hoses that exist will be non-zero. */
        for (i = 0; i < MCPCIA_MAX_HOSES; i++) cached_irq_masks[i] = 0;

        for (hose = hose_head; hose; hose = hose->next) {
                unsigned int h = hose->index;
                unsigned int mask = hose_irq_masks[h];

                cached_irq_masks[h] = mask;
                *(vuip)MCPCIA_INT_MASK0(MCPCIA_HOSE2MID(h)) = mask;
                *(vuip)MCPCIA_INT_MASK1(MCPCIA_HOSE2MID(h)) = 0;
        }

        for (i = 16; i < 128; ++i) {
                irq_set_chip_and_handler(i, &rawhide_irq_type,
                                         handle_level_irq);
                irq_set_status_flags(i, IRQ_LEVEL);
        }

        init_i8259a_irqs();
        common_init_isa_dma();
}

/*
 * PCI Fixup configuration.
 *
 * Summary @ MCPCIA_PCI0_INT_REQ:
 * Bit      Meaning
 * 0        Interrupt Line A from slot 2 PCI0
 * 1        Interrupt Line B from slot 2 PCI0
 * 2        Interrupt Line C from slot 2 PCI0
 * 3        Interrupt Line D from slot 2 PCI0
 * 4        Interrupt Line A from slot 3 PCI0
 * 5        Interrupt Line B from slot 3 PCI0
 * 6        Interrupt Line C from slot 3 PCI0
 * 7        Interrupt Line D from slot 3 PCI0
 * 8        Interrupt Line A from slot 4 PCI0
 * 9        Interrupt Line B from slot 4 PCI0
 * 10       Interrupt Line C from slot 4 PCI0
 * 11       Interrupt Line D from slot 4 PCI0
 * 12       Interrupt Line A from slot 5 PCI0
 * 13       Interrupt Line B from slot 5 PCI0
 * 14       Interrupt Line C from slot 5 PCI0
 * 15       Interrupt Line D from slot 5 PCI0
 * 16       EISA interrupt (PCI 0) or SCSI interrupt (PCI 1)
 * 17-23    NA
 *
 * IdSel        
 *   1   EISA bridge (PCI bus 0 only)
 *   2   PCI option slot 2
 *   3   PCI option slot 3
 *   4   PCI option slot 4
 *   5   PCI option slot 5
 * 
 */

static int
rawhide_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        static char irq_tab[5][5] = {
                /*INT    INTA   INTB   INTC   INTD */
                { 16+16, 16+16, 16+16, 16+16, 16+16}, /* IdSel 1 SCSI PCI 1 */
                { 16+ 0, 16+ 0, 16+ 1, 16+ 2, 16+ 3}, /* IdSel 2 slot 2 */
                { 16+ 4, 16+ 4, 16+ 5, 16+ 6, 16+ 7}, /* IdSel 3 slot 3 */
                { 16+ 8, 16+ 8, 16+ 9, 16+10, 16+11}, /* IdSel 4 slot 4 */
                { 16+12, 16+12, 16+13, 16+14, 16+15}  /* IdSel 5 slot 5 */
        };
        const long min_idsel = 1, max_idsel = 5, irqs_per_slot = 5;

        struct pci_controller *hose = dev->sysdata;
        int irq = COMMON_TABLE_LOOKUP;
        if (irq >= 0)
                irq += 24 * hose->index;
        return irq;
}


/*
 * The System Vector
 */

struct alpha_machine_vector rawhide_mv __initmv = {
        .vector_name            = "Rawhide",
        DO_EV5_MMU,
        DO_DEFAULT_RTC,
        DO_MCPCIA_IO,
        .machine_check          = mcpcia_machine_check,
        .max_isa_dma_address    = ALPHA_MAX_ISA_DMA_ADDRESS,
        .min_io_address         = DEFAULT_IO_BASE,
        .min_mem_address        = MCPCIA_DEFAULT_MEM_BASE,
        .pci_dac_offset         = MCPCIA_DAC_OFFSET,

        .nr_irqs                = 128,
        .device_interrupt       = rawhide_srm_device_interrupt,

        .init_arch              = mcpcia_init_arch,
        .init_irq               = rawhide_init_irq,
        .init_rtc               = common_init_rtc,
        .init_pci               = common_init_pci,
        .kill_arch              = NULL,
        .pci_map_irq            = rawhide_map_irq,
        .pci_swizzle            = common_swizzle,
};
ALIAS_MV(rawhide)