// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/sys_cabriolet.c
 *
 *      Copyright (C) 1995 David A Rusling
 *      Copyright (C) 1996 Jay A Estabrook
 *      Copyright (C) 1998, 1999, 2000 Richard Henderson
 *
 * Code supporting the PC164 and LX164.
 */

#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_cia.h>
#include <asm/tlbflush.h>

#include "proto.h"
#include "irq_impl.h"
#include "pci_impl.h"
#include "machvec_impl.h"
#include "pc873xx.h"

/* Note mask bit is true for DISABLED irqs.  */
static unsigned long cached_irq_mask = ~0UL;

static inline void
cabriolet_update_irq_hw(unsigned int irq, unsigned long mask)
{
        int ofs = (irq - 16) / 8;
        outb(mask >> (16 + ofs * 8), 0x804 + ofs);
}

static inline void
cabriolet_enable_irq(struct irq_data *d)
{
        cabriolet_update_irq_hw(d->irq, cached_irq_mask &= ~(1UL << d->irq));
}

static void
cabriolet_disable_irq(struct irq_data *d)
{
        cabriolet_update_irq_hw(d->irq, cached_irq_mask |= 1UL << d->irq);
}

static struct irq_chip cabriolet_irq_type = {
        .name           = "CABRIOLET",
        .irq_unmask     = cabriolet_enable_irq,
        .irq_mask       = cabriolet_disable_irq,
        .irq_mask_ack   = cabriolet_disable_irq,
};

static void 
cabriolet_device_interrupt(unsigned long v)
{
        unsigned long pld;
        unsigned int i;

        /* Read the interrupt summary registers */
        pld = inb(0x804) | (inb(0x805) << 8) | (inb(0x806) << 16);

        /*
         * 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 == 4) {
                        isa_device_interrupt(v);
                } else {
                        handle_irq(16 + i);
                }
        }
}

static void __init
common_init_irq(void (*srm_dev_int)(unsigned long v))
{
        init_i8259a_irqs();

        if (alpha_using_srm) {
                alpha_mv.device_interrupt = srm_dev_int;
                init_srm_irqs(35, 0);
        }
        else {
                long i;

                outb(0xff, 0x804);
                outb(0xff, 0x805);
                outb(0xff, 0x806);

                for (i = 16; i < 35; ++i) {
                        irq_set_chip_and_handler(i, &cabriolet_irq_type,
                                                 handle_level_irq);
                        irq_set_status_flags(i, IRQ_LEVEL);
                }
        }

        common_init_isa_dma();
        if (request_irq(16 + 4, no_action, 0, "isa-cascade", NULL))
                pr_err("Failed to register isa-cascade interrupt\n");
}

#ifndef CONFIG_ALPHA_PC164
static void __init
cabriolet_init_irq(void)
{
        common_init_irq(srm_device_interrupt);
}
#endif

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_PC164)
/* In theory, the PC164 has the same interrupt hardware as the other
   Cabriolet based systems.  However, something got screwed up late
   in the development cycle which broke the interrupt masking hardware.
   Repeat, it is not possible to mask and ack interrupts.  At all.

   In an attempt to work around this, while processing interrupts,
   we do not allow the IPL to drop below what it is currently.  This
   prevents the possibility of recursion.  

   ??? Another option might be to force all PCI devices to use edge
   triggered rather than level triggered interrupts.  That might be
   too invasive though.  */

static void
pc164_srm_device_interrupt(unsigned long v)
{
        __min_ipl = getipl();
        srm_device_interrupt(v);
        __min_ipl = 0;
}

static void
pc164_device_interrupt(unsigned long v)
{
        __min_ipl = getipl();
        cabriolet_device_interrupt(v);
        __min_ipl = 0;
}

static void __init
pc164_init_irq(void)
{
        common_init_irq(pc164_srm_device_interrupt);
}
#endif

/*
 * The EB66+ is very similar to the EB66 except that it does not have
 * the on-board NCR and Tulip chips.  In the code below, I have used
 * slot number to refer to the id select line and *not* the slot
 * number used in the EB66+ documentation.  However, in the table,
 * I've given the slot number, the id select line and the Jxx number
 * that's printed on the board.  The interrupt pins from the PCI slots
 * are wired into 3 interrupt summary registers at 0x804, 0x805 and
 * 0x806 ISA.
 *
 * In the table, -1 means don't assign an IRQ number.  This is usually
 * because it is the Saturn IO (SIO) PCI/ISA Bridge Chip.
 */

static inline int
eb66p_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        static char irq_tab[5][5] = {
                /*INT  INTA  INTB  INTC   INTD */
                {16+0, 16+0, 16+5,  16+9, 16+13},  /* IdSel 6,  slot 0, J25 */
                {16+1, 16+1, 16+6, 16+10, 16+14},  /* IdSel 7,  slot 1, J26 */
                {  -1,   -1,   -1,    -1,    -1},  /* IdSel 8,  SIO         */
                {16+2, 16+2, 16+7, 16+11, 16+15},  /* IdSel 9,  slot 2, J27 */
                {16+3, 16+3, 16+8, 16+12,  16+6}   /* IdSel 10, slot 3, J28 */
        };
        const long min_idsel = 6, max_idsel = 10, irqs_per_slot = 5;
        return COMMON_TABLE_LOOKUP;
}


/*
 * The AlphaPC64 is very similar to the EB66+ except that its slots
 * are numbered differently.  In the code below, I have used slot
 * number to refer to the id select line and *not* the slot number
 * used in the AlphaPC64 documentation.  However, in the table, I've
 * given the slot number, the id select line and the Jxx number that's
 * printed on the board.  The interrupt pins from the PCI slots are
 * wired into 3 interrupt summary registers at 0x804, 0x805 and 0x806
 * ISA.
 *
 * In the table, -1 means don't assign an IRQ number.  This is usually
 * because it is the Saturn IO (SIO) PCI/ISA Bridge Chip.
 */

static inline int
cabriolet_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        static char irq_tab[5][5] = {
                /*INT   INTA  INTB  INTC   INTD */
                { 16+2, 16+2, 16+7, 16+11, 16+15}, /* IdSel 5,  slot 2, J21 */
                { 16+0, 16+0, 16+5,  16+9, 16+13}, /* IdSel 6,  slot 0, J19 */
                { 16+1, 16+1, 16+6, 16+10, 16+14}, /* IdSel 7,  slot 1, J20 */
                {   -1,   -1,   -1,    -1,    -1}, /* IdSel 8,  SIO         */
                { 16+3, 16+3, 16+8, 16+12, 16+16}  /* IdSel 9,  slot 3, J22 */
        };
        const long min_idsel = 5, max_idsel = 9, irqs_per_slot = 5;
        return COMMON_TABLE_LOOKUP;
}

static inline void __init
cabriolet_enable_ide(void)
{
        if (pc873xx_probe() == -1) {
                printk(KERN_ERR "Probing for PC873xx Super IO chip failed.\n");
         } else {
                printk(KERN_INFO "Found %s Super IO chip at 0x%x\n",
                        pc873xx_get_model(), pc873xx_get_base());

                pc873xx_enable_ide();
        }
}

static inline void __init
cia_cab_init_pci(void)
{
        cia_init_pci();
        cabriolet_enable_ide();
}

/*
 * The PC164 and LX164 have 19 PCI interrupts, four from each of the four
 * PCI slots, the SIO, PCI/IDE, and USB.
 * 
 * Each of the interrupts can be individually masked. This is
 * accomplished by setting the appropriate bit in the mask register.
 * A bit is set by writing a "1" to the desired position in the mask
 * register and cleared by writing a "0". There are 3 mask registers
 * located at ISA address 804h, 805h and 806h.
 * 
 * An I/O read at ISA address 804h, 805h, 806h will return the
 * state of the 11 PCI interrupts and not the state of the MASKED
 * interrupts.
 * 
 * Note: A write to I/O 804h, 805h, and 806h the mask register will be
 * updated.
 * 
 * 
 *                              ISA DATA<7:0>
 * ISA     +--------------------------------------------------------------+
 * ADDRESS |   7   |   6   |   5   |   4   |   3   |   2  |   1   |   0   |
 *         +==============================================================+
 * 0x804   | INTB0 |  USB  |  IDE  |  SIO  | INTA3 |INTA2 | INTA1 | INTA0 |
 *         +--------------------------------------------------------------+
 * 0x805   | INTD0 | INTC3 | INTC2 | INTC1 | INTC0 |INTB3 | INTB2 | INTB1 |
 *         +--------------------------------------------------------------+
 * 0x806   | Rsrv  | Rsrv  | Rsrv  | Rsrv  | Rsrv  |INTD3 | INTD2 | INTD1 |
 *         +--------------------------------------------------------------+
 *         * Rsrv = reserved bits
 *         Note: The mask register is write-only.
 * 
 * IdSel        
 *   5   32 bit PCI option slot 2
 *   6   64 bit PCI option slot 0
 *   7   64 bit PCI option slot 1
 *   8   Saturn I/O
 *   9   32 bit PCI option slot 3
 *  10   USB
 *  11   IDE
 * 
 */

static inline int
alphapc164_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
{
        static char irq_tab[7][5] = {
                /*INT   INTA  INTB   INTC   INTD */
                { 16+2, 16+2, 16+9,  16+13, 16+17}, /* IdSel  5, slot 2, J20 */
                { 16+0, 16+0, 16+7,  16+11, 16+15}, /* IdSel  6, slot 0, J29 */
                { 16+1, 16+1, 16+8,  16+12, 16+16}, /* IdSel  7, slot 1, J26 */
                {   -1,   -1,   -1,    -1,    -1},  /* IdSel  8, SIO */
                { 16+3, 16+3, 16+10, 16+14, 16+18}, /* IdSel  9, slot 3, J19 */
                { 16+6, 16+6, 16+6,  16+6,  16+6},  /* IdSel 10, USB */
                { 16+5, 16+5, 16+5,  16+5,  16+5}   /* IdSel 11, IDE */
        };
        const long min_idsel = 5, max_idsel = 11, irqs_per_slot = 5;
        return COMMON_TABLE_LOOKUP;
}

static inline void __init
alphapc164_init_pci(void)
{
        cia_init_pci();
        SMC93x_Init();
}


/*
 * The System Vector
 */

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_LX164)
struct alpha_machine_vector lx164_mv __initmv = {
        .vector_name            = "LX164",
        DO_EV5_MMU,
        DO_DEFAULT_RTC,
        DO_PYXIS_IO,
        .machine_check          = cia_machine_check,
        .max_isa_dma_address    = ALPHA_MAX_ISA_DMA_ADDRESS,
        .min_io_address         = DEFAULT_IO_BASE,
        .min_mem_address        = DEFAULT_MEM_BASE,
        .pci_dac_offset         = PYXIS_DAC_OFFSET,

        .nr_irqs                = 35,
        .device_interrupt       = cabriolet_device_interrupt,

        .init_arch              = pyxis_init_arch,
        .init_irq               = cabriolet_init_irq,
        .init_rtc               = common_init_rtc,
        .init_pci               = alphapc164_init_pci,
        .kill_arch              = cia_kill_arch,
        .pci_map_irq            = alphapc164_map_irq,
        .pci_swizzle            = common_swizzle,
};
ALIAS_MV(lx164)
#endif

#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_PC164)
struct alpha_machine_vector pc164_mv __initmv = {
        .vector_name            = "PC164",
        DO_EV5_MMU,
        DO_DEFAULT_RTC,
        DO_CIA_IO,
        .machine_check          = cia_machine_check,
        .max_isa_dma_address    = ALPHA_MAX_ISA_DMA_ADDRESS,
        .min_io_address         = DEFAULT_IO_BASE,
        .min_mem_address        = CIA_DEFAULT_MEM_BASE,

        .nr_irqs                = 35,
        .device_interrupt       = pc164_device_interrupt,

        .init_arch              = cia_init_arch,
        .init_irq               = pc164_init_irq,
        .init_rtc               = common_init_rtc,
        .init_pci               = alphapc164_init_pci,
        .kill_arch              = cia_kill_arch,
        .pci_map_irq            = alphapc164_map_irq,
        .pci_swizzle            = common_swizzle,
};
ALIAS_MV(pc164)
#endif