/*
 * mm.c - Micro Memory(tm) PCI memory board block device driver - v2.3
 *
 * (C) 2001 San Mehat <nettwerk@valinux.com>
 * (C) 2001 Johannes Erdfelt <jerdfelt@valinux.com>
 * (C) 2001 NeilBrown <neilb@cse.unsw.edu.au>
 *
 * This driver for the Micro Memory PCI Memory Module with Battery Backup
 * is Copyright Micro Memory Inc 2001-2002.  All rights reserved.
 *
 * This driver is released to the public under the terms of the
 *  GNU GENERAL PUBLIC LICENSE version 2
 * See the file COPYING for details.
 *
 * This driver provides a standard block device interface for Micro Memory(tm)
 * PCI based RAM boards.
 * 10/05/01: Phap Nguyen - Rebuilt the driver
 * 10/22/01: Phap Nguyen - v2.1 Added disk partitioning
 * 29oct2001:NeilBrown   - Use make_request_fn instead of request_fn
 *                       - use stand disk partitioning (so fdisk works).
 * 08nov2001:NeilBrown   - change driver name from "mm" to "umem"
 *                       - incorporate into main kernel
 * 08apr2002:NeilBrown   - Move some of interrupt handle to tasklet
 *                       - use spin_lock_bh instead of _irq
 *                       - Never block on make_request.  queue
 *                         bh's instead.
 *                       - unregister umem from devfs at mod unload
 *                       - Change version to 2.3
 * 07Nov2001:Phap Nguyen - Select pci read command: 06, 12, 15 (Decimal)
 * 07Jan2002: P. Nguyen  - Used PCI Memory Write & Invalidate for DMA
 * 15May2002:NeilBrown   - convert to bio for 2.5
 * 17May2002:NeilBrown   - remove init_mem initialisation.  Instead detect
 *                       - a sequence of writes that cover the card, and
 *                       - set initialised bit then.
 */

#undef DEBUG    /* #define DEBUG if you want debugging info (pr_debug) */
#include <linux/fs.h>
#include <linux/bio.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/gfp.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>

#include <linux/fcntl.h>        /* O_ACCMODE */
#include <linux/hdreg.h>  /* HDIO_GETGEO */

#include "umem.h"

#include <asm/uaccess.h>
#include <asm/io.h>

#define MM_MAXCARDS 4
#define MM_RAHEAD 2      /* two sectors */
#define MM_BLKSIZE 1024  /* 1k blocks */
#define MM_HARDSECT 512  /* 512-byte hardware sectors */
#define MM_SHIFT 6       /* max 64 partitions on 4 cards  */

/*
 * Version Information
 */

#define DRIVER_NAME     "umem"
#define DRIVER_VERSION  "v2.3"
#define DRIVER_AUTHOR   "San Mehat, Johannes Erdfelt, NeilBrown"
#define DRIVER_DESC     "Micro Memory(tm) PCI memory board block driver"

static int debug;
/* #define HW_TRACE(x)     writeb(x,cards[0].csr_remap + MEMCTRLSTATUS_MAGIC) */
#define HW_TRACE(x)

#define DEBUG_LED_ON_TRANSFER   0x01
#define DEBUG_BATTERY_POLLING   0x02

module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Debug bitmask");

static int pci_read_cmd = 0x0C;         /* Read Multiple */
module_param(pci_read_cmd, int, 0);
MODULE_PARM_DESC(pci_read_cmd, "PCI read command");

static int pci_write_cmd = 0x0F;        /* Write and Invalidate */
module_param(pci_write_cmd, int, 0);
MODULE_PARM_DESC(pci_write_cmd, "PCI write command");

static int pci_cmds;

static int major_nr;

#include <linux/blkdev.h>
#include <linux/blkpg.h>

struct cardinfo {
        struct pci_dev  *dev;

        unsigned char   __iomem *csr_remap;
        unsigned int    mm_size;  /* size in kbytes */

        unsigned int    init_size; /* initial segment, in sectors,
                                    * that we know to
                                    * have been written
                                    */
        struct bio      *bio, *currentbio, **biotail;
        struct bvec_iter current_iter;

        struct request_queue *queue;

        struct mm_page {
                dma_addr_t              page_dma;
                struct mm_dma_desc      *desc;
                int                     cnt, headcnt;
                struct bio              *bio, **biotail;
                struct bvec_iter        iter;
        } mm_pages[2];
#define DESC_PER_PAGE ((PAGE_SIZE*2)/sizeof(struct mm_dma_desc))

        int  Active, Ready;

        struct tasklet_struct   tasklet;
        unsigned int dma_status;

        struct {
                int             good;
                int             warned;
                unsigned long   last_change;
        } battery[2];

        spinlock_t      lock;
        int             check_batteries;

        int             flags;
};

static struct cardinfo cards[MM_MAXCARDS];
static struct timer_list battery_timer;

static int num_cards;

static struct gendisk *mm_gendisk[MM_MAXCARDS];

static void check_batteries(struct cardinfo *card);

static int get_userbit(struct cardinfo *card, int bit)
{
        unsigned char led;

        led = readb(card->csr_remap + MEMCTRLCMD_LEDCTRL);
        return led & bit;
}

static int set_userbit(struct cardinfo *card, int bit, unsigned char state)
{
        unsigned char led;

        led = readb(card->csr_remap + MEMCTRLCMD_LEDCTRL);
        if (state)
                led |= bit;
        else
                led &= ~bit;
        writeb(led, card->csr_remap + MEMCTRLCMD_LEDCTRL);

        return 0;
}

/*
 * NOTE: For the power LED, use the LED_POWER_* macros since they differ
 */
static void set_led(struct cardinfo *card, int shift, unsigned char state)
{
        unsigned char led;

        led = readb(card->csr_remap + MEMCTRLCMD_LEDCTRL);
        if (state == LED_FLIP)
                led ^= (1<<shift);
        else {
                led &= ~(0x03 << shift);
                led |= (state << shift);
        }
        writeb(led, card->csr_remap + MEMCTRLCMD_LEDCTRL);

}

#ifdef MM_DIAG
static void dump_regs(struct cardinfo *card)
{
        unsigned char *p;
        int i, i1;

        p = card->csr_remap;
        for (i = 0; i < 8; i++) {
                printk(KERN_DEBUG "%p   ", p);

                for (i1 = 0; i1 < 16; i1++)
                        printk("%02x ", *p++);

                printk("\n");
        }
}
#endif

static void dump_dmastat(struct cardinfo *card, unsigned int dmastat)
{
        dev_printk(KERN_DEBUG, &card->dev->dev, "DMAstat - ");
        if (dmastat & DMASCR_ANY_ERR)
                printk(KERN_CONT "ANY_ERR ");
        if (dmastat & DMASCR_MBE_ERR)
                printk(KERN_CONT "MBE_ERR ");
        if (dmastat & DMASCR_PARITY_ERR_REP)
                printk(KERN_CONT "PARITY_ERR_REP ");
        if (dmastat & DMASCR_PARITY_ERR_DET)
                printk(KERN_CONT "PARITY_ERR_DET ");
        if (dmastat & DMASCR_SYSTEM_ERR_SIG)
                printk(KERN_CONT "SYSTEM_ERR_SIG ");
        if (dmastat & DMASCR_TARGET_ABT)
                printk(KERN_CONT "TARGET_ABT ");
        if (dmastat & DMASCR_MASTER_ABT)
                printk(KERN_CONT "MASTER_ABT ");
        if (dmastat & DMASCR_CHAIN_COMPLETE)
                printk(KERN_CONT "CHAIN_COMPLETE ");
        if (dmastat & DMASCR_DMA_COMPLETE)
                printk(KERN_CONT "DMA_COMPLETE ");
        printk("\n");
}

/*
 * Theory of request handling
 *
 * Each bio is assigned to one mm_dma_desc - which may not be enough FIXME
 * We have two pages of mm_dma_desc, holding about 64 descriptors
 * each.  These are allocated at init time.
 * One page is "Ready" and is either full, or can have request added.
 * The other page might be "Active", which DMA is happening on it.
 *
 * Whenever IO on the active page completes, the Ready page is activated
 * and the ex-Active page is clean out and made Ready.
 * Otherwise the Ready page is only activated when it becomes full.
 *
 * If a request arrives while both pages a full, it is queued, and b_rdev is
 * overloaded to record whether it was a read or a write.
 *
 * The interrupt handler only polls the device to clear the interrupt.
 * The processing of the result is done in a tasklet.
 */

static void mm_start_io(struct cardinfo *card)
{
        /* we have the lock, we know there is
         * no IO active, and we know that card->Active
         * is set
         */
        struct mm_dma_desc *desc;
        struct mm_page *page;
        int offset;

        /* make the last descriptor end the chain */
        page = &card->mm_pages[card->Active];
        pr_debug("start_io: %d %d->%d\n",
                card->Active, page->headcnt, page->cnt - 1);
        desc = &page->desc[page->cnt-1];

        desc->control_bits |= cpu_to_le32(DMASCR_CHAIN_COMP_EN);
        desc->control_bits &= ~cpu_to_le32(DMASCR_CHAIN_EN);
        desc->sem_control_bits = desc->control_bits;


        if (debug & DEBUG_LED_ON_TRANSFER)
                set_led(card, LED_REMOVE, LED_ON);

        desc = &page->desc[page->headcnt];
        writel(0, card->csr_remap + DMA_PCI_ADDR);
        writel(0, card->csr_remap + DMA_PCI_ADDR + 4);

        writel(0, card->csr_remap + DMA_LOCAL_ADDR);
        writel(0, card->csr_remap + DMA_LOCAL_ADDR + 4);

        writel(0, card->csr_remap + DMA_TRANSFER_SIZE);
        writel(0, card->csr_remap + DMA_TRANSFER_SIZE + 4);

        writel(0, card->csr_remap + DMA_SEMAPHORE_ADDR);
        writel(0, card->csr_remap + DMA_SEMAPHORE_ADDR + 4);

        offset = ((char *)desc) - ((char *)page->desc);
        writel(cpu_to_le32((page->page_dma+offset) & 0xffffffff),
               card->csr_remap + DMA_DESCRIPTOR_ADDR);
        /* Force the value to u64 before shifting otherwise >> 32 is undefined C
         * and on some ports will do nothing ! */
        writel(cpu_to_le32(((u64)page->page_dma)>>32),
               card->csr_remap + DMA_DESCRIPTOR_ADDR + 4);

        /* Go, go, go */
        writel(cpu_to_le32(DMASCR_GO | DMASCR_CHAIN_EN | pci_cmds),
               card->csr_remap + DMA_STATUS_CTRL);
}

static int add_bio(struct cardinfo *card);

static void activate(struct cardinfo *card)
{
        /* if No page is Active, and Ready is
         * not empty, then switch Ready page
         * to active and start IO.
         * Then add any bh's that are available to Ready
         */

        do {
                while (add_bio(card))
                        ;

                if (card->Active == -1 &&
                    card->mm_pages[card->Ready].cnt > 0) {
                        card->Active = card->Ready;
                        card->Ready = 1-card->Ready;
                        mm_start_io(card);
                }

        } while (card->Active == -1 && add_bio(card));
}

static inline void reset_page(struct mm_page *page)
{
        page->cnt = 0;
        page->headcnt = 0;
        page->bio = NULL;
        page->biotail = &page->bio;
}

/*
 * If there is room on Ready page, take
 * one bh off list and add it.
 * return 1 if there was room, else 0.
 */
static int add_bio(struct cardinfo *card)
{
        struct mm_page *p;
        struct mm_dma_desc *desc;
        dma_addr_t dma_handle;
        int offset;
        struct bio *bio;
        struct bio_vec vec;
        int rw;

        bio = card->currentbio;
        if (!bio && card->bio) {
                card->currentbio = card->bio;
                card->current_iter = card->bio->bi_iter;
                card->bio = card->bio->bi_next;
                if (card->bio == NULL)
                        card->biotail = &card->bio;
                card->currentbio->bi_next = NULL;
                return 1;
        }
        if (!bio)
                return 0;

        rw = bio_rw(bio);
        if (card->mm_pages[card->Ready].cnt >= DESC_PER_PAGE)
                return 0;

        vec = bio_iter_iovec(bio, card->current_iter);

        dma_handle = pci_map_page(card->dev,
                                  vec.bv_page,
                                  vec.bv_offset,
                                  vec.bv_len,
                                  (rw == READ) ?
                                  PCI_DMA_FROMDEVICE : PCI_DMA_TODEVICE);

        p = &card->mm_pages[card->Ready];
        desc = &p->desc[p->cnt];
        p->cnt++;
        if (p->bio == NULL)
                p->iter = card->current_iter;
        if ((p->biotail) != &bio->bi_next) {
                *(p->biotail) = bio;
                p->biotail = &(bio->bi_next);
                bio->bi_next = NULL;
        }

        desc->data_dma_handle = dma_handle;

        desc->pci_addr = cpu_to_le64((u64)desc->data_dma_handle);
        desc->local_addr = cpu_to_le64(card->current_iter.bi_sector << 9);
        desc->transfer_size = cpu_to_le32(vec.bv_len);
        offset = (((char *)&desc->sem_control_bits) - ((char *)p->desc));
        desc->sem_addr = cpu_to_le64((u64)(p->page_dma+offset));
        desc->zero1 = desc->zero2 = 0;
        offset = (((char *)(desc+1)) - ((char *)p->desc));
        desc->next_desc_addr = cpu_to_le64(p->page_dma+offset);
        desc->control_bits = cpu_to_le32(DMASCR_GO|DMASCR_ERR_INT_EN|
                                         DMASCR_PARITY_INT_EN|
                                         DMASCR_CHAIN_EN |
                                         DMASCR_SEM_EN |
                                         pci_cmds);
        if (rw == WRITE)
                desc->control_bits |= cpu_to_le32(DMASCR_TRANSFER_READ);
        desc->sem_control_bits = desc->control_bits;


        bio_advance_iter(bio, &card->current_iter, vec.bv_len);
        if (!card->current_iter.bi_size)
                card->currentbio = NULL;

        return 1;
}

static void process_page(unsigned long data)
{
        /* check if any of the requests in the page are DMA_COMPLETE,
         * and deal with them appropriately.
         * If we find a descriptor without DMA_COMPLETE in the semaphore, then
         * dma must have hit an error on that descriptor, so use dma_status
         * instead and assume that all following descriptors must be re-tried.
         */
        struct mm_page *page;
        struct bio *return_bio = NULL;
        struct cardinfo *card = (struct cardinfo *)data;
        unsigned int dma_status = card->dma_status;

        spin_lock_bh(&card->lock);
        if (card->Active < 0)
                goto out_unlock;
        page = &card->mm_pages[card->Active];

        while (page->headcnt < page->cnt) {
                struct bio *bio = page->bio;
                struct mm_dma_desc *desc = &page->desc[page->headcnt];
                int control = le32_to_cpu(desc->sem_control_bits);
                int last = 0;
                struct bio_vec vec;

                if (!(control & DMASCR_DMA_COMPLETE)) {
                        control = dma_status;
                        last = 1;
                }

                page->headcnt++;
                vec = bio_iter_iovec(bio, page->iter);
                bio_advance_iter(bio, &page->iter, vec.bv_len);

                if (!page->iter.bi_size) {
                        page->bio = bio->bi_next;
                        if (page->bio)
                                page->iter = page->bio->bi_iter;
                }

                pci_unmap_page(card->dev, desc->data_dma_handle,
                               vec.bv_len,
                                 (control & DMASCR_TRANSFER_READ) ?
                                PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
                if (control & DMASCR_HARD_ERROR) {
                        /* error */
                        clear_bit(BIO_UPTODATE, &bio->bi_flags);
                        dev_printk(KERN_WARNING, &card->dev->dev,
                                "I/O error on sector %d/%d\n",
                                le32_to_cpu(desc->local_addr)>>9,
                                le32_to_cpu(desc->transfer_size));
                        dump_dmastat(card, control);
                } else if ((bio->bi_rw & REQ_WRITE) &&
                           le32_to_cpu(desc->local_addr) >> 9 ==
                                card->init_size) {
                        card->init_size += le32_to_cpu(desc->transfer_size) >> 9;
                        if (card->init_size >> 1 >= card->mm_size) {
                                dev_printk(KERN_INFO, &card->dev->dev,
                                        "memory now initialised\n");
                                set_userbit(card, MEMORY_INITIALIZED, 1);
                        }
                }
                if (bio != page->bio) {
                        bio->bi_next = return_bio;
                        return_bio = bio;
                }

                if (last)
                        break;
        }

        if (debug & DEBUG_LED_ON_TRANSFER)
                set_led(card, LED_REMOVE, LED_OFF);

        if (card->check_batteries) {
                card->check_batteries = 0;
                check_batteries(card);
        }
        if (page->headcnt >= page->cnt) {
                reset_page(page);
                card->Active = -1;
                activate(card);
        } else {
                /* haven't finished with this one yet */
                pr_debug("do some more\n");
                mm_start_io(card);
        }
 out_unlock:
        spin_unlock_bh(&card->lock);

        while (return_bio) {
                struct bio *bio = return_bio;

                return_bio = bio->bi_next;
                bio->bi_next = NULL;
                bio_endio(bio, 0);
        }
}

static void mm_unplug(struct blk_plug_cb *cb, bool from_schedule)
{
        struct cardinfo *card = cb->data;

        spin_lock_irq(&card->lock);
        activate(card);
        spin_unlock_irq(&card->lock);
        kfree(cb);
}

static int mm_check_plugged(struct cardinfo *card)
{
        return !!blk_check_plugged(mm_unplug, card, sizeof(struct blk_plug_cb));
}

static void mm_make_request(struct request_queue *q, struct bio *bio)
{
        struct cardinfo *card = q->queuedata;
        pr_debug("mm_make_request %llu %u\n",
                 (unsigned long long)bio->bi_iter.bi_sector,
                 bio->bi_iter.bi_size);

        spin_lock_irq(&card->lock);
        *card->biotail = bio;
        bio->bi_next = NULL;
        card->biotail = &bio->bi_next;
        if (bio->bi_rw & REQ_SYNC || !mm_check_plugged(card))
                activate(card);
        spin_unlock_irq(&card->lock);

        return;
}

static irqreturn_t mm_interrupt(int irq, void *__card)
{
        struct cardinfo *card = (struct cardinfo *) __card;
        unsigned int dma_status;
        unsigned short cfg_status;

HW_TRACE(0x30);

        dma_status = le32_to_cpu(readl(card->csr_remap + DMA_STATUS_CTRL));

        if (!(dma_status & (DMASCR_ERROR_MASK | DMASCR_CHAIN_COMPLETE))) {
                /* interrupt wasn't for me ... */
                return IRQ_NONE;
        }

        /* clear COMPLETION interrupts */
        if (card->flags & UM_FLAG_NO_BYTE_STATUS)
                writel(cpu_to_le32(DMASCR_DMA_COMPLETE|DMASCR_CHAIN_COMPLETE),
                       card->csr_remap + DMA_STATUS_CTRL);
        else
                writeb((DMASCR_DMA_COMPLETE|DMASCR_CHAIN_COMPLETE) >> 16,
                       card->csr_remap + DMA_STATUS_CTRL + 2);

        /* log errors and clear interrupt status */
        if (dma_status & DMASCR_ANY_ERR) {
                unsigned int    data_log1, data_log2;
                unsigned int    addr_log1, addr_log2;
                unsigned char   stat, count, syndrome, check;

                stat = readb(card->csr_remap + MEMCTRLCMD_ERRSTATUS);

                data_log1 = le32_to_cpu(readl(card->csr_remap +
                                                ERROR_DATA_LOG));
                data_log2 = le32_to_cpu(readl(card->csr_remap +
                                                ERROR_DATA_LOG + 4));
                addr_log1 = le32_to_cpu(readl(card->csr_remap +
                                                ERROR_ADDR_LOG));
                addr_log2 = readb(card->csr_remap + ERROR_ADDR_LOG + 4);

                count = readb(card->csr_remap + ERROR_COUNT);
                syndrome = readb(card->csr_remap + ERROR_SYNDROME);
                check = readb(card->csr_remap + ERROR_CHECK);

                dump_dmastat(card, dma_status);

                if (stat & 0x01)
                        dev_printk(KERN_ERR, &card->dev->dev,
                                "Memory access error detected (err count %d)\n",
                                count);
                if (stat & 0x02)
                        dev_printk(KERN_ERR, &card->dev->dev,
                                "Multi-bit EDC error\n");

                dev_printk(KERN_ERR, &card->dev->dev,
                        "Fault Address 0x%02x%08x, Fault Data 0x%08x%08x\n",
                        addr_log2, addr_log1, data_log2, data_log1);
                dev_printk(KERN_ERR, &card->dev->dev,
                        "Fault Check 0x%02x, Fault Syndrome 0x%02x\n",
                        check, syndrome);

                writeb(0, card->csr_remap + ERROR_COUNT);
        }

        if (dma_status & DMASCR_PARITY_ERR_REP) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "PARITY ERROR REPORTED\n");
                pci_read_config_word(card->dev, PCI_STATUS, &cfg_status);
                pci_write_config_word(card->dev, PCI_STATUS, cfg_status);
        }

        if (dma_status & DMASCR_PARITY_ERR_DET) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "PARITY ERROR DETECTED\n");
                pci_read_config_word(card->dev, PCI_STATUS, &cfg_status);
                pci_write_config_word(card->dev, PCI_STATUS, cfg_status);
        }

        if (dma_status & DMASCR_SYSTEM_ERR_SIG) {
                dev_printk(KERN_ERR, &card->dev->dev, "SYSTEM ERROR\n");
                pci_read_config_word(card->dev, PCI_STATUS, &cfg_status);
                pci_write_config_word(card->dev, PCI_STATUS, cfg_status);
        }

        if (dma_status & DMASCR_TARGET_ABT) {
                dev_printk(KERN_ERR, &card->dev->dev, "TARGET ABORT\n");
                pci_read_config_word(card->dev, PCI_STATUS, &cfg_status);
                pci_write_config_word(card->dev, PCI_STATUS, cfg_status);
        }

        if (dma_status & DMASCR_MASTER_ABT) {
                dev_printk(KERN_ERR, &card->dev->dev, "MASTER ABORT\n");
                pci_read_config_word(card->dev, PCI_STATUS, &cfg_status);
                pci_write_config_word(card->dev, PCI_STATUS, cfg_status);
        }

        /* and process the DMA descriptors */
        card->dma_status = dma_status;
        tasklet_schedule(&card->tasklet);

HW_TRACE(0x36);

        return IRQ_HANDLED;
}

/*
 * If both batteries are good, no LED
 * If either battery has been warned, solid LED
 * If both batteries are bad, flash the LED quickly
 * If either battery is bad, flash the LED semi quickly
 */
static void set_fault_to_battery_status(struct cardinfo *card)
{
        if (card->battery[0].good && card->battery[1].good)
                set_led(card, LED_FAULT, LED_OFF);
        else if (card->battery[0].warned || card->battery[1].warned)
                set_led(card, LED_FAULT, LED_ON);
        else if (!card->battery[0].good && !card->battery[1].good)
                set_led(card, LED_FAULT, LED_FLASH_7_0);
        else
                set_led(card, LED_FAULT, LED_FLASH_3_5);
}

static void init_battery_timer(void);

static int check_battery(struct cardinfo *card, int battery, int status)
{
        if (status != card->battery[battery].good) {
                card->battery[battery].good = !card->battery[battery].good;
                card->battery[battery].last_change = jiffies;

                if (card->battery[battery].good) {
                        dev_printk(KERN_ERR, &card->dev->dev,
                                "Battery %d now good\n", battery + 1);
                        card->battery[battery].warned = 0;
                } else
                        dev_printk(KERN_ERR, &card->dev->dev,
                                "Battery %d now FAILED\n", battery + 1);

                return 1;
        } else if (!card->battery[battery].good &&
                   !card->battery[battery].warned &&
                   time_after_eq(jiffies, card->battery[battery].last_change +
                                 (HZ * 60 * 60 * 5))) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "Battery %d still FAILED after 5 hours\n", battery + 1);
                card->battery[battery].warned = 1;

                return 1;
        }

        return 0;
}

static void check_batteries(struct cardinfo *card)
{
        /* NOTE: this must *never* be called while the card
         * is doing (bus-to-card) DMA, or you will need the
         * reset switch
         */
        unsigned char status;
        int ret1, ret2;

        status = readb(card->csr_remap + MEMCTRLSTATUS_BATTERY);
        if (debug & DEBUG_BATTERY_POLLING)
                dev_printk(KERN_DEBUG, &card->dev->dev,
                        "checking battery status, 1 = %s, 2 = %s\n",
                       (status & BATTERY_1_FAILURE) ? "FAILURE" : "OK",
                       (status & BATTERY_2_FAILURE) ? "FAILURE" : "OK");

        ret1 = check_battery(card, 0, !(status & BATTERY_1_FAILURE));
        ret2 = check_battery(card, 1, !(status & BATTERY_2_FAILURE));

        if (ret1 || ret2)
                set_fault_to_battery_status(card);
}

static void check_all_batteries(unsigned long ptr)
{
        int i;

        for (i = 0; i < num_cards; i++)
                if (!(cards[i].flags & UM_FLAG_NO_BATT)) {
                        struct cardinfo *card = &cards[i];
                        spin_lock_bh(&card->lock);
                        if (card->Active >= 0)
                                card->check_batteries = 1;
                        else
                                check_batteries(card);
                        spin_unlock_bh(&card->lock);
                }

        init_battery_timer();
}

static void init_battery_timer(void)
{
        init_timer(&battery_timer);
        battery_timer.function = check_all_batteries;
        battery_timer.expires = jiffies + (HZ * 60);
        add_timer(&battery_timer);
}

static void del_battery_timer(void)
{
        del_timer(&battery_timer);
}

/*
 * Note no locks taken out here.  In a worst case scenario, we could drop
 * a chunk of system memory.  But that should never happen, since validation
 * happens at open or mount time, when locks are held.
 *
 *      That's crap, since doing that while some partitions are opened
 * or mounted will give you really nasty results.
 */
static int mm_revalidate(struct gendisk *disk)
{
        struct cardinfo *card = disk->private_data;
        set_capacity(disk, card->mm_size << 1);
        return 0;
}

static int mm_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
        struct cardinfo *card = bdev->bd_disk->private_data;
        int size = card->mm_size * (1024 / MM_HARDSECT);

        /*
         * get geometry: we have to fake one...  trim the size to a
         * multiple of 2048 (1M): tell we have 32 sectors, 64 heads,
         * whatever cylinders.
         */
        geo->heads     = 64;
        geo->sectors   = 32;
        geo->cylinders = size / (geo->heads * geo->sectors);
        return 0;
}

static const struct block_device_operations mm_fops = {
        .owner          = THIS_MODULE,
        .getgeo         = mm_getgeo,
        .revalidate_disk = mm_revalidate,
};

static int mm_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
        int ret = -ENODEV;
        struct cardinfo *card = &cards[num_cards];
        unsigned char   mem_present;
        unsigned char   batt_status;
        unsigned int    saved_bar, data;
        unsigned long   csr_base;
        unsigned long   csr_len;
        int             magic_number;
        static int      printed_version;

        if (!printed_version++)
                printk(KERN_INFO DRIVER_VERSION " : " DRIVER_DESC "\n");

        ret = pci_enable_device(dev);
        if (ret)
                return ret;

        pci_write_config_byte(dev, PCI_LATENCY_TIMER, 0xF8);
        pci_set_master(dev);

        card->dev         = dev;

        csr_base = pci_resource_start(dev, 0);
        csr_len  = pci_resource_len(dev, 0);
        if (!csr_base || !csr_len)
                return -ENODEV;

        dev_printk(KERN_INFO, &dev->dev,
          "Micro Memory(tm) controller found (PCI Mem Module (Battery Backup))\n");

        if (pci_set_dma_mask(dev, DMA_BIT_MASK(64)) &&
            pci_set_dma_mask(dev, DMA_BIT_MASK(32))) {
                dev_printk(KERN_WARNING, &dev->dev, "NO suitable DMA found\n");
                return  -ENOMEM;
        }

        ret = pci_request_regions(dev, DRIVER_NAME);
        if (ret) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "Unable to request memory region\n");
                goto failed_req_csr;
        }

        card->csr_remap = ioremap_nocache(csr_base, csr_len);
        if (!card->csr_remap) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "Unable to remap memory region\n");
                ret = -ENOMEM;

                goto failed_remap_csr;
        }

        dev_printk(KERN_INFO, &card->dev->dev,
                "CSR 0x%08lx -> 0x%p (0x%lx)\n",
               csr_base, card->csr_remap, csr_len);

        switch (card->dev->device) {
        case 0x5415:
                card->flags |= UM_FLAG_NO_BYTE_STATUS | UM_FLAG_NO_BATTREG;
                magic_number = 0x59;
                break;

        case 0x5425:
                card->flags |= UM_FLAG_NO_BYTE_STATUS;
                magic_number = 0x5C;
                break;

        case 0x6155:
                card->flags |= UM_FLAG_NO_BYTE_STATUS |
                                UM_FLAG_NO_BATTREG | UM_FLAG_NO_BATT;
                magic_number = 0x99;
                break;

        default:
                magic_number = 0x100;
                break;
        }

        if (readb(card->csr_remap + MEMCTRLSTATUS_MAGIC) != magic_number) {
                dev_printk(KERN_ERR, &card->dev->dev, "Magic number invalid\n");
                ret = -ENOMEM;
                goto failed_magic;
        }

        card->mm_pages[0].desc = pci_alloc_consistent(card->dev,
                                                PAGE_SIZE * 2,
                                                &card->mm_pages[0].page_dma);
        card->mm_pages[1].desc = pci_alloc_consistent(card->dev,
                                                PAGE_SIZE * 2,
                                                &card->mm_pages[1].page_dma);
        if (card->mm_pages[0].desc == NULL ||
            card->mm_pages[1].desc == NULL) {
                dev_printk(KERN_ERR, &card->dev->dev, "alloc failed\n");
                goto failed_alloc;
        }
        reset_page(&card->mm_pages[0]);
        reset_page(&card->mm_pages[1]);
        card->Ready = 0;        /* page 0 is ready */
        card->Active = -1;      /* no page is active */
        card->bio = NULL;
        card->biotail = &card->bio;

        card->queue = blk_alloc_queue(GFP_KERNEL);
        if (!card->queue)
                goto failed_alloc;

        blk_queue_make_request(card->queue, mm_make_request);
        card->queue->queue_lock = &card->lock;
        card->queue->queuedata = card;

        tasklet_init(&card->tasklet, process_page, (unsigned long)card);

        card->check_batteries = 0;

        mem_present = readb(card->csr_remap + MEMCTRLSTATUS_MEMORY);
        switch (mem_present) {
        case MEM_128_MB:
                card->mm_size = 1024 * 128;
                break;
        case MEM_256_MB:
                card->mm_size = 1024 * 256;
                break;
        case MEM_512_MB:
                card->mm_size = 1024 * 512;
                break;
        case MEM_1_GB:
                card->mm_size = 1024 * 1024;
                break;
        case MEM_2_GB:
                card->mm_size = 1024 * 2048;
                break;
        default:
                card->mm_size = 0;
                break;
        }

        /* Clear the LED's we control */
        set_led(card, LED_REMOVE, LED_OFF);
        set_led(card, LED_FAULT, LED_OFF);

        batt_status = readb(card->csr_remap + MEMCTRLSTATUS_BATTERY);

        card->battery[0].good = !(batt_status & BATTERY_1_FAILURE);
        card->battery[1].good = !(batt_status & BATTERY_2_FAILURE);
        card->battery[0].last_change = card->battery[1].last_change = jiffies;

        if (card->flags & UM_FLAG_NO_BATT)
                dev_printk(KERN_INFO, &card->dev->dev,
                        "Size %d KB\n", card->mm_size);
        else {
                dev_printk(KERN_INFO, &card->dev->dev,
                        "Size %d KB, Battery 1 %s (%s), Battery 2 %s (%s)\n",
                       card->mm_size,
                       batt_status & BATTERY_1_DISABLED ? "Disabled" : "Enabled",
                       card->battery[0].good ? "OK" : "FAILURE",
                       batt_status & BATTERY_2_DISABLED ? "Disabled" : "Enabled",
                       card->battery[1].good ? "OK" : "FAILURE");

                set_fault_to_battery_status(card);
        }

        pci_read_config_dword(dev, PCI_BASE_ADDRESS_1, &saved_bar);
        data = 0xffffffff;
        pci_write_config_dword(dev, PCI_BASE_ADDRESS_1, data);
        pci_read_config_dword(dev, PCI_BASE_ADDRESS_1, &data);
        pci_write_config_dword(dev, PCI_BASE_ADDRESS_1, saved_bar);
        data &= 0xfffffff0;
        data = ~data;
        data += 1;

        if (request_irq(dev->irq, mm_interrupt, IRQF_SHARED, DRIVER_NAME,
                        card)) {
                dev_printk(KERN_ERR, &card->dev->dev,
                        "Unable to allocate IRQ\n");
                ret = -ENODEV;
                goto failed_req_irq;
        }

        dev_printk(KERN_INFO, &card->dev->dev,
                "Window size %d bytes, IRQ %d\n", data, dev->irq);

        spin_lock_init(&card->lock);

        pci_set_drvdata(dev, card);

        if (pci_write_cmd != 0x0F)      /* If not Memory Write & Invalidate */
                pci_write_cmd = 0x07;   /* then Memory Write command */

        if (pci_write_cmd & 0x08) { /* use Memory Write and Invalidate */
                unsigned short cfg_command;
                pci_read_config_word(dev, PCI_COMMAND, &cfg_command);
                cfg_command |= 0x10; /* Memory Write & Invalidate Enable */
                pci_write_config_word(dev, PCI_COMMAND, cfg_command);
        }
        pci_cmds = (pci_read_cmd << 28) | (pci_write_cmd << 24);

        num_cards++;

        if (!get_userbit(card, MEMORY_INITIALIZED)) {
                dev_printk(KERN_INFO, &card->dev->dev,
                  "memory NOT initialized. Consider over-writing whole device.\n");
                card->init_size = 0;
        } else {
                dev_printk(KERN_INFO, &card->dev->dev,
                        "memory already initialized\n");
                card->init_size = card->mm_size;
        }

        /* Enable ECC */
        writeb(EDC_STORE_CORRECT, card->csr_remap + MEMCTRLCMD_ERRCTRL);

        return 0;

 failed_req_irq:
 failed_alloc:
        if (card->mm_pages[0].desc)
                pci_free_consistent(card->dev, PAGE_SIZE*2,
                                    card->mm_pages[0].desc,
                                    card->mm_pages[0].page_dma);
        if (card->mm_pages[1].desc)
                pci_free_consistent(card->dev, PAGE_SIZE*2,
                                    card->mm_pages[1].desc,
                                    card->mm_pages[1].page_dma);
 failed_magic:
        iounmap(card->csr_remap);
 failed_remap_csr:
        pci_release_regions(dev);
 failed_req_csr:

        return ret;
}

static void mm_pci_remove(struct pci_dev *dev)
{
        struct cardinfo *card = pci_get_drvdata(dev);

        tasklet_kill(&card->tasklet);
        free_irq(dev->irq, card);
        iounmap(card->csr_remap);

        if (card->mm_pages[0].desc)
                pci_free_consistent(card->dev, PAGE_SIZE*2,
                                    card->mm_pages[0].desc,
                                    card->mm_pages[0].page_dma);
        if (card->mm_pages[1].desc)
                pci_free_consistent(card->dev, PAGE_SIZE*2,
                                    card->mm_pages[1].desc,
                                    card->mm_pages[1].page_dma);
        blk_cleanup_queue(card->queue);

        pci_release_regions(dev);
        pci_disable_device(dev);
}

static const struct pci_device_id mm_pci_ids[] = {
    {PCI_DEVICE(PCI_VENDOR_ID_MICRO_MEMORY, PCI_DEVICE_ID_MICRO_MEMORY_5415CN)},
    {PCI_DEVICE(PCI_VENDOR_ID_MICRO_MEMORY, PCI_DEVICE_ID_MICRO_MEMORY_5425CN)},
    {PCI_DEVICE(PCI_VENDOR_ID_MICRO_MEMORY, PCI_DEVICE_ID_MICRO_MEMORY_6155)},
    {
        .vendor =       0x8086,
        .device =       0xB555,
        .subvendor =    0x1332,
        .subdevice =    0x5460,
        .class =        0x050000,
        .class_mask =   0,
    }, { /* end: all zeroes */ }
};

MODULE_DEVICE_TABLE(pci, mm_pci_ids);

static struct pci_driver mm_pci_driver = {
        .name           = DRIVER_NAME,
        .id_table       = mm_pci_ids,
        .probe          = mm_pci_probe,
        .remove         = mm_pci_remove,
};

static int __init mm_init(void)
{
        int retval, i;
        int err;

        retval = pci_register_driver(&mm_pci_driver);
        if (retval)
                return -ENOMEM;

        err = major_nr = register_blkdev(0, DRIVER_NAME);
        if (err < 0) {
                pci_unregister_driver(&mm_pci_driver);
                return -EIO;
        }

        for (i = 0; i < num_cards; i++) {
                mm_gendisk[i] = alloc_disk(1 << MM_SHIFT);
                if (!mm_gendisk[i])
                        goto out;
        }

        for (i = 0; i < num_cards; i++) {
                struct gendisk *disk = mm_gendisk[i];
                sprintf(disk->disk_name, "umem%c", 'a'+i);
                spin_lock_init(&cards[i].lock);
                disk->major = major_nr;
                disk->first_minor  = i << MM_SHIFT;
                disk->fops = &mm_fops;
                disk->private_data = &cards[i];
                disk->queue = cards[i].queue;
                set_capacity(disk, cards[i].mm_size << 1);
                add_disk(disk);
        }

        init_battery_timer();
        printk(KERN_INFO "MM: desc_per_page = %ld\n", DESC_PER_PAGE);
/* printk("mm_init: Done. 10-19-01 9:00\n"); */
        return 0;

out:
        pci_unregister_driver(&mm_pci_driver);
        unregister_blkdev(major_nr, DRIVER_NAME);
        while (i--)
                put_disk(mm_gendisk[i]);
        return -ENOMEM;
}

static void __exit mm_cleanup(void)
{
        int i;

        del_battery_timer();

        for (i = 0; i < num_cards ; i++) {
                del_gendisk(mm_gendisk[i]);
                put_disk(mm_gendisk[i]);
        }

        pci_unregister_driver(&mm_pci_driver);

        unregister_blkdev(major_nr, DRIVER_NAME);
}

module_init(mm_init);
module_exit(mm_cleanup);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");