// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/sys_rx164.c
 *
 *      Copyright (C) 1995 David A Rusling
 *      Copyright (C) 1996 Jay A Estabrook
 *      Copyright (C) 1998, 1999 Richard Henderson
 *
 * Code supporting the RX164 (PCA56+POLARIS).
 */

#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 <linux/bitops.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_polaris.h>
#include <asm/tlbflush.h>

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


/* Note mask bit is true for ENABLED irqs.  */
static unsigned long cached_irq_mask;

static inline void
rx164_update_irq_hw(unsigned long mask)
{
        volatile unsigned int *irq_mask;

        irq_mask = (void *)(POLARIS_DENSE_CONFIG_BASE + 0x74);
        *irq_mask = mask;
        mb();
        *irq_mask;
}

static inline void
rx164_enable_irq(struct irq_data *d)
{
        rx164_update_irq_hw(cached_irq_mask |= 1UL << (d->irq - 16));
}

static void
rx164_disable_irq(struct irq_data *d)
{
        rx164_update_irq_hw(cached_irq_mask &= ~(1UL << (d->irq - 16)));
}

static struct irq_chip rx164_irq_type = {
        .name           = "RX164",
        .irq_unmask     = rx164_enable_irq,
        .irq_mask       = rx164_disable_irq,
        .irq_mask_ack   = rx164_disable_irq,
};

static void 
rx164_device_interrupt(unsigned long vector)
{
        unsigned long pld;
        volatile unsigned int *dirr;
        long i;

        /* Read the interrupt summary register.  On Polaris, this is
           the DIRR register in PCI config space (offset 0x84).  */
        dirr = (void *)(POLARIS_DENSE_CONFIG_BASE + 0x84);
        pld = *dirr;

        /*
         * Now for every possible bit set, work through them and call
         * the appropriate interrupt handler.
         */
        while (pld) {
                i = ffz(~pld);
                pld &= pld - 1; /* clear least bit set */
                if (i == 20) {
                        isa_no_iack_sc_device_interrupt(vector);
                } else {
                        handle_irq(16+i);
                }
        }
}

static void __init
rx164_init_irq(void)
{
        long i;

        rx164_update_irq_hw(0);
        for (i = 16; i < 40; ++i) {
                irq_set_chip_and_handler(i, &rx164_irq_type, handle_level_irq);
                irq_set_status_flags(i, IRQ_LEVEL);
        }

        init_i8259a_irqs();
        common_init_isa_dma();

        if (request_irq(16 + 20, no_action, 0, "isa-cascade", NULL))
                pr_err("Failed to register isa-cascade interrupt\n");
}


/*
 * The RX164 changed its interrupt routing between pass1 and pass2...
 *
 * PASS1:
 *
 *      Slot    IDSEL   INTA    INTB    INTC    INTD    
 *      0       6       5       10      15      20
 *      1       7       4       9       14      19
 *      2       5       3       8       13      18
 *      3       9       2       7       12      17
 *      4       10      1       6       11      16
 *
 * PASS2:
 *      Slot    IDSEL   INTA    INTB    INTC    INTD    
 *      0       5       1       7       12      17
 *      1       6       2       8       13      18
 *      2       8       3       9       14      19
 *      3       9       4       10      15      20
 *      4       10      5       11      16      6
 *      
 */

/*
 * IdSel       
 *   5  32 bit PCI option slot 0
 *   6  64 bit PCI option slot 1
 *   7  PCI-ISA bridge
 *   7  64 bit PCI option slot 2
 *   9  32 bit PCI option slot 3
 *  10  PCI-PCI bridge
 * 
 */

static int
rx164_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
#if 0
        static char irq_tab_pass1[6][5] __initdata = {
          /*INT   INTA  INTB  INTC   INTD */
          { 16+3, 16+3, 16+8, 16+13, 16+18},      /* IdSel 5,  slot 2 */
          { 16+5, 16+5, 16+10, 16+15, 16+20},     /* IdSel 6,  slot 0 */
          { 16+4, 16+4, 16+9, 16+14, 16+19},      /* IdSel 7,  slot 1 */
          { -1,     -1,    -1,    -1,   -1},      /* IdSel 8, PCI/ISA bridge */
          { 16+2, 16+2, 16+7, 16+12, 16+17},      /* IdSel 9,  slot 3 */
          { 16+1, 16+1, 16+6, 16+11, 16+16},      /* IdSel 10, slot 4 */
        };
#else
        static char irq_tab[6][5] = {
          /*INT   INTA  INTB  INTC   INTD */
          { 16+0, 16+0, 16+6, 16+11, 16+16},      /* IdSel 5,  slot 0 */
          { 16+1, 16+1, 16+7, 16+12, 16+17},      /* IdSel 6,  slot 1 */
          { -1,     -1,    -1,    -1,   -1},      /* IdSel 7, PCI/ISA bridge */
          { 16+2, 16+2, 16+8, 16+13, 16+18},      /* IdSel 8,  slot 2 */
          { 16+3, 16+3, 16+9, 16+14, 16+19},      /* IdSel 9,  slot 3 */
          { 16+4, 16+4, 16+10, 16+15, 16+5},      /* IdSel 10, PCI-PCI */
        };
#endif
        const long min_idsel = 5, max_idsel = 10, irqs_per_slot = 5;

        /* JRP - Need to figure out how to distinguish pass1 from pass2,
           and use the correct table.  */
        return COMMON_TABLE_LOOKUP;
}


/*
 * The System Vector
 */

struct alpha_machine_vector rx164_mv __initmv = {
        .vector_name            = "RX164",
        DO_EV5_MMU,
        DO_DEFAULT_RTC,
        DO_POLARIS_IO,
        .machine_check          = polaris_machine_check,
        .max_isa_dma_address    = ALPHA_MAX_ISA_DMA_ADDRESS,
        .min_io_address         = DEFAULT_IO_BASE,
        .min_mem_address        = DEFAULT_MEM_BASE,

        .nr_irqs                = 40,
        .device_interrupt       = rx164_device_interrupt,

        .init_arch              = polaris_init_arch,
        .init_irq               = rx164_init_irq,
        .init_rtc               = common_init_rtc,
        .init_pci               = common_init_pci,
        .kill_arch              = NULL,
        .pci_map_irq            = rx164_map_irq,
        .pci_swizzle            = common_swizzle,
};
ALIAS_MV(rx164)