// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * eisa_enumerator.c - provide support for EISA adapters in PA-RISC machines
 *
 * Copyright (c) 2002 Daniel Engstrom <5116@telia.com>
 */

#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <asm/byteorder.h>

#include <asm/eisa_bus.h>
#include <asm/eisa_eeprom.h>


/*
 * Todo:
 * 
 * PORT init with MASK attr and other size than byte
 * MEMORY with other decode than 20 bit
 * CRC stuff
 * FREEFORM stuff
 */

#define EPI 0xc80
#define NUM_SLOT 16
#define SLOT2PORT(x) (x<<12)


/* macros to handle unaligned accesses and 
 * byte swapping. The data in the EEPROM is
 * little-endian on the big-endian PAROSC */
#define get_8(x) (*(u_int8_t*)(x))

static inline u_int16_t get_16(const unsigned char *x)
{ 
        return (x[1] << 8) | x[0];
}

static inline u_int32_t get_32(const unsigned char *x)
{
        return (x[3] << 24) | (x[2] << 16) | (x[1] << 8) | x[0];
}

static inline u_int32_t get_24(const unsigned char *x)
{
        return (x[2] << 24) | (x[1] << 16) | (x[0] << 8);
}

static void print_eisa_id(char *s, u_int32_t id)
{
        char vendor[4];
        int rev;
        int device;
        
        rev = id & 0xff;
        id >>= 8;
        device = id & 0xff;
        id >>= 8;
        vendor[3] = '\0';
        vendor[2] = '@' + (id & 0x1f);
        id >>= 5;       
        vendor[1] = '@' + (id & 0x1f);
        id >>= 5;       
        vendor[0] = '@' + (id & 0x1f);
        id >>= 5;       
        
        sprintf(s, "%s%02X%02X", vendor, device, rev);
}
       
static int configure_memory(const unsigned char *buf, 
                       struct resource *mem_parent,
                       char *name)
{
        int len;
        u_int8_t c;
        int i;
        struct resource *res;
        
        len=0;
        
        for (i=0;i<HPEE_MEMORY_MAX_ENT;i++) {
                c = get_8(buf+len);
                
                if (NULL != (res = kzalloc_obj(struct resource))) {
                        int result;
                        
                        res->name = name;
                        res->start = mem_parent->start + get_24(buf+len+2);
                        res->end = res->start + get_16(buf+len+5)*1024;
                        res->flags = IORESOURCE_MEM;
                        pr_cont("memory %pR ", res);
                        result = request_resource(mem_parent, res);
                        if (result < 0) {
                                printk(KERN_ERR "EISA Enumerator: failed to claim EISA Bus address space!\n");
                                return result;
                        }
                }
                        
                len+=7;      
        
                if (!(c & HPEE_MEMORY_MORE)) {
                        break;
                }
        }
        
        return len;
}


static int configure_irq(const unsigned char *buf)
{
        int len;
        u_int8_t c;
        int i;
        
        len=0;
        
        for (i=0;i<HPEE_IRQ_MAX_ENT;i++) {
                c = get_8(buf+len);
                
                pr_cont("IRQ %d ", c & HPEE_IRQ_CHANNEL_MASK);
                if (c & HPEE_IRQ_TRIG_LEVEL) {
                        eisa_make_irq_level(c & HPEE_IRQ_CHANNEL_MASK);
                } else {
                        eisa_make_irq_edge(c & HPEE_IRQ_CHANNEL_MASK);
                }
                
                len+=2; 
                /* hpux seems to allow for
                 * two bytes of irq data but only defines one of
                 * them, I think */
                if  (!(c & HPEE_IRQ_MORE)) {
                        break;
                }
        }
        
        return len;
}


static int configure_dma(const unsigned char *buf)
{
        int len;
        u_int8_t c;
        int i;
        
        len=0;
        
        for (i=0;i<HPEE_DMA_MAX_ENT;i++) {
                c = get_8(buf+len);
                pr_cont("DMA %d ", c&HPEE_DMA_CHANNEL_MASK);
                /* fixme: maybe initialize the dma channel withthe timing ? */
                len+=2;      
                if (!(c & HPEE_DMA_MORE)) {
                        break;
                }
        }
        
        return len;
}

static int configure_port(const unsigned char *buf, struct resource *io_parent,
                     char *board)
{
        int len;
        u_int8_t c;
        int i;
        struct resource *res;
        int result;
        
        len=0;
        
        for (i=0;i<HPEE_PORT_MAX_ENT;i++) {
                c = get_8(buf+len);
                
                if (NULL != (res = kzalloc_obj(struct resource))) {
                        res->name = board;
                        res->start = get_16(buf+len+1);
                        res->end = get_16(buf+len+1)+(c&HPEE_PORT_SIZE_MASK)+1;
                        res->flags = IORESOURCE_IO;
                        pr_cont("ioports %pR ", res);
                        result = request_resource(io_parent, res);
                        if (result < 0) {
                                printk(KERN_ERR "EISA Enumerator: failed to claim EISA Bus address space!\n");
                                return result;
                        }
                }

                len+=3;      
                if (!(c & HPEE_PORT_MORE)) {
                        break;
                }
        }
        
        return len;
}


/* byte 1 and 2 is the port number to write
 * and at byte 3 the value to write starts.
 * I assume that there are and- and or- masks
 * here when HPEE_PORT_INIT_MASK is set but I have 
 * not yet encountered this. */
static int configure_port_init(const unsigned char *buf)
{
        int len=0;
        u_int8_t c;
        
        while (len<HPEE_PORT_INIT_MAX_LEN) {
                int s=0;
                c = get_8(buf+len);
                
                switch (c & HPEE_PORT_INIT_WIDTH_MASK)  {
                 case HPEE_PORT_INIT_WIDTH_BYTE:
                        s=1;
                        if (c & HPEE_PORT_INIT_MASK) {
                                printk(KERN_WARNING "port_init: unverified mask attribute\n");
                                outb((inb(get_16(buf+len+1) & 
                                          get_8(buf+len+3)) | 
                                      get_8(buf+len+4)), get_16(buf+len+1));
                                      
                        } else {
                                outb(get_8(buf+len+3), get_16(buf+len+1));
                                      
                        }
                        break;
                 case HPEE_PORT_INIT_WIDTH_WORD:
                        s=2;
                        if (c & HPEE_PORT_INIT_MASK) {
                                printk(KERN_WARNING "port_init: unverified mask attribute\n");
                                       outw((inw(get_16(buf+len+1)) &
                                             get_16(buf+len+3)) |
                                            get_16(buf+len+5), 
                                            get_16(buf+len+1));
                        } else {
                                outw(cpu_to_le16(get_16(buf+len+3)), get_16(buf+len+1));
                        }
                        break;
                 case HPEE_PORT_INIT_WIDTH_DWORD:
                        s=4;
                        if (c & HPEE_PORT_INIT_MASK) {
                                printk(KERN_WARNING "port_init: unverified mask attribute\n");
                                outl((inl(get_16(buf+len+1) &
                                          get_32(buf+len+3)) |
                                      get_32(buf+len+7)), get_16(buf+len+1));
                        } else {
                                outl(cpu_to_le32(get_32(buf+len+3)), get_16(buf+len+1));
                        }

                        break;
                 default:
                        printk(KERN_ERR "Invalid port init word %02x\n", c);
                        return 0;
                }
                
                if (c & HPEE_PORT_INIT_MASK) {   
                        s*=2;
                }
                
                len+=s+3;
                if (!(c & HPEE_PORT_INIT_MORE)) {
                        break;
                }
        }
        
        return len;
}

static int configure_choise(const unsigned char *buf, u_int8_t *info)
{
        int len;
        
        /* theis record contain the value of the functions
         * configuration choises and an info byte which 
         * describes which other records to expect in this 
         * function */
        len = get_8(buf);
        *info=get_8(buf+len+1);
         
        return len+2;
}

static int configure_type_string(const unsigned char *buf) 
{
        int len;
        
        /* just skip past the type field */
        len = get_8(buf);
        if (len > 80) {
                printk(KERN_ERR "eisa_enumerator: type info field too long (%d, max is 80)\n", len);
        }
        
        return 1+len;
}

static int configure_function(const unsigned char *buf, int *more) 
{
        /* the init field seems to be a two-byte field
         * which is non-zero if there are an other function following
         * I think it is the length of the function def 
         */
        *more = get_16(buf);
        
        return 2;
}

static int parse_slot_config(int slot,
                             const unsigned char *buf,
                             struct eeprom_eisa_slot_info *es, 
                             struct resource *io_parent,
                             struct resource *mem_parent)
{
        int res=0;
        int function_len;
        unsigned int pos=0;
        unsigned int maxlen;
        int num_func=0;
        u_int8_t flags;
        int p0;
        
        char *board;
        int id_string_used=0;
        
        if (NULL == (board = kmalloc(8, GFP_KERNEL))) {
                return -1;
        }
        print_eisa_id(board, es->eisa_slot_id);
        printk(KERN_INFO "EISA slot %d: %s %s ", 
               slot, board, es->flags&HPEE_FLAG_BOARD_IS_ISA ? "ISA" : "EISA");
        
        maxlen = es->config_data_length < HPEE_MAX_LENGTH ?
                         es->config_data_length : HPEE_MAX_LENGTH;
        while ((pos < maxlen) && (num_func <= es->num_functions)) {
                pos+=configure_function(buf+pos, &function_len); 
                
                if (!function_len) {
                        break;
                }
                num_func++;
                p0 = pos;
                pos += configure_choise(buf+pos, &flags);

                if (flags & HPEE_FUNCTION_INFO_F_DISABLED) {
                        /* function disabled, skip silently */
                        pos = p0 + function_len;
                        continue;
                }
                if (flags & HPEE_FUNCTION_INFO_CFG_FREE_FORM) {
                        /* I have no idea how to handle this */
                        printk("function %d have free-form configuration, skipping ",
                                num_func);
                        pos = p0 + function_len;
                        continue;
                }

                /* the ordering of the sections need
                 * more investigation.
                 * Currently I think that memory comaed before IRQ
                 * I assume the order is LSB to MSB in the 
                 * info flags 
                 * eg type, memory, irq, dma, port, HPEE_PORT_init 
                 */

                if (flags & HPEE_FUNCTION_INFO_HAVE_TYPE) {
                        pos += configure_type_string(buf+pos);
                }
                
                if (flags & HPEE_FUNCTION_INFO_HAVE_MEMORY) {
                        id_string_used=1;
                        pos += configure_memory(buf+pos, mem_parent, board);
                } 
                
                if (flags & HPEE_FUNCTION_INFO_HAVE_IRQ) {
                        pos += configure_irq(buf+pos);
                } 
                
                if (flags & HPEE_FUNCTION_INFO_HAVE_DMA) {
                        pos += configure_dma(buf+pos);
                } 
                
                if (flags & HPEE_FUNCTION_INFO_HAVE_PORT) {
                        id_string_used=1;
                        pos += configure_port(buf+pos, io_parent, board);
                } 
                
                if (flags &  HPEE_FUNCTION_INFO_HAVE_PORT_INIT) {
                        pos += configure_port_init(buf+pos);
                }
                
                if (p0 + function_len < pos) {
                        printk(KERN_ERR "eisa_enumerator: function %d length mismatch "
                               "got %d, expected %d\n",
                               num_func, pos-p0, function_len);
                        res=-1;
                        break;
                }
                pos = p0 + function_len;
        }
        pr_cont("\n");
        if (!id_string_used) {
                kfree(board);
        }
        
        if (pos != es->config_data_length) {
                printk(KERN_ERR "eisa_enumerator: config data length mismatch got %d, expected %d\n",
                        pos, es->config_data_length);
                res=-1;
        }
        
        if (num_func != es->num_functions) {
                printk(KERN_ERR "eisa_enumerator: number of functions mismatch got %d, expected %d\n",
                        num_func, es->num_functions);
                res=-2;
        }
        
        return res;
        
}

static int init_slot(int slot, struct eeprom_eisa_slot_info *es)
{
        unsigned int id;
        
        char id_string[8];
        
        if (!(es->slot_info&HPEE_SLOT_INFO_NO_READID)) {
                /* try to read the id of the board in the slot */
                id = le32_to_cpu(inl(SLOT2PORT(slot)+EPI));
                
                if (0xffffffff == id) {
                        /* Maybe we didn't expect a card to be here... */
                        if (es->eisa_slot_id == 0xffffffff)
                                return -1;
                        
                        /* this board is not here or it does not 
                         * support readid 
                         */
                        printk(KERN_ERR "EISA slot %d a configured board was not detected (", 
                               slot);
                        
                        print_eisa_id(id_string, es->eisa_slot_id);
                        printk(" expected %s)\n", id_string);
                
                        return -1;      

                }
                if (es->eisa_slot_id != id) {
                        print_eisa_id(id_string, id);
                        printk(KERN_ERR "EISA slot %d id mismatch: got %s",
                               slot, id_string);
                        
                        print_eisa_id(id_string, es->eisa_slot_id);
                        printk(" expected %s\n", id_string);
                
                        return -1;      
                        
                }
        }
        
        /* now: we need to enable the board if 
         * it supports enabling and run through
         * the port init sction if present
         * and finally record any interrupt polarity
         */
        if (es->slot_features & HPEE_SLOT_FEATURES_ENABLE) {
                /* enable board */
                outb(0x01| inb(SLOT2PORT(slot)+EPI+4),
                     SLOT2PORT(slot)+EPI+4);
        }
        
        return 0;
}


int eisa_enumerator(unsigned long eeprom_addr,
                    struct resource *io_parent, struct resource *mem_parent) 
{
        int i;
        struct eeprom_header *eh;
        static char eeprom_buf[HPEE_MAX_LENGTH];
        
        for (i=0; i < HPEE_MAX_LENGTH; i++) {
                eeprom_buf[i] = gsc_readb(eeprom_addr+i);
        }
        
        printk(KERN_INFO "Enumerating EISA bus\n");
                        
        eh = (struct eeprom_header*)(eeprom_buf);
        for (i=0;i<eh->num_slots;i++) {
                struct eeprom_eisa_slot_info *es;
                
                es = (struct eeprom_eisa_slot_info*)
                        (&eeprom_buf[HPEE_SLOT_INFO(i)]);
                
                if (-1==init_slot(i+1, es)) {
                        continue;
                }
                
                if (es->config_data_offset < HPEE_MAX_LENGTH) {
                        if (parse_slot_config(i+1, &eeprom_buf[es->config_data_offset],
                                              es, io_parent, mem_parent)) {
                                return -1;
                        }
                } else {
                        printk (KERN_WARNING "EISA EEPROM offset 0x%x out of range\n",es->config_data_offset);
                        return -1;
                }
        }
        return eh->num_slots;
}