mac53c94.c

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/*
 * SCSI low-level driver for the 53c94 SCSI bus adaptor found
 * on Power Macintosh computers, controlling the external SCSI chain.
 * We assume the 53c94 is connected to a DBDMA (descriptor-based DMA)
 * controller.
 *
 * Paul Mackerras, August 1996.
 * Copyright (C) 1996 Paul Mackerras.
 */
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/dbdma.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/pci-bridge.h>
#include <asm/macio.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include "mac53c94.h"

enum fsc_phase {
    idle,
    selecting,
    dataing,
    completing,
    busfreeing,
};

struct fsc_state {
    struct  mac53c94_regs __iomem *regs;
    int intr;
    struct  dbdma_regs __iomem *dma;
    int dmaintr;
    int clk_freq;
    struct  Scsi_Host *host;
    struct scsi_cmnd *request_q;
    struct scsi_cmnd *request_qtail;
    struct scsi_cmnd *current_req;      /* req we're currently working on */
    enum fsc_phase phase;       /* what we're currently trying to do */
    struct dbdma_cmd *dma_cmds; /* space for dbdma commands, aligned */
    void    *dma_cmd_space;
    struct  pci_dev *pdev;
    dma_addr_t dma_addr;
    struct macio_dev *mdev;
};

static void mac53c94_init(struct fsc_state *);
static void mac53c94_start(struct fsc_state *);
static void mac53c94_interrupt(int, void *);
static irqreturn_t do_mac53c94_interrupt(int, void *);
static void cmd_done(struct fsc_state *, int result);
static void set_dma_cmds(struct fsc_state *, struct scsi_cmnd *);


static int mac53c94_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
    struct fsc_state *state;

#if 0
    if (cmd->sc_data_direction == DMA_TO_DEVICE) {
        int i;
        printk(KERN_DEBUG "mac53c94_queue %p: command is", cmd);
        for (i = 0; i < cmd->cmd_len; ++i)
            printk(KERN_CONT " %.2x", cmd->cmnd[i]);
        printk(KERN_CONT "\n");
        printk(KERN_DEBUG "use_sg=%d request_bufflen=%d request_buffer=%p\n",
               scsi_sg_count(cmd), scsi_bufflen(cmd), scsi_sglist(cmd));
    }
#endif

    cmd->scsi_done = done;
    cmd->host_scribble = NULL;

    state = (struct fsc_state *) cmd->device->host->hostdata;

    if (state->request_q == NULL)
        state->request_q = cmd;
    else
        state->request_qtail->host_scribble = (void *) cmd;
    state->request_qtail = cmd;

    if (state->phase == idle)
        mac53c94_start(state);

    return 0;
}

static DEF_SCSI_QCMD(mac53c94_queue)

static int mac53c94_host_reset(struct scsi_cmnd *cmd)
{
    struct fsc_state *state = (struct fsc_state *) cmd->device->host->hostdata;
    struct mac53c94_regs __iomem *regs = state->regs;
    struct dbdma_regs __iomem *dma = state->dma;
    unsigned long flags;

    spin_lock_irqsave(cmd->device->host->host_lock, flags);

    writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
    writeb(CMD_SCSI_RESET, &regs->command); /* assert RST */
    udelay(100);            /* leave it on for a while (>= 25us) */
    writeb(CMD_RESET, &regs->command);
    udelay(20);
    mac53c94_init(state);
    writeb(CMD_NOP, &regs->command);

    spin_unlock_irqrestore(cmd->device->host->host_lock, flags);
    return SUCCESS;
}

static void mac53c94_init(struct fsc_state *state)
{
    struct mac53c94_regs __iomem *regs = state->regs;
    struct dbdma_regs __iomem *dma = state->dma;
    int x;

    writeb(state->host->this_id | CF1_PAR_ENABLE, &regs->config1);
    writeb(TIMO_VAL(250), &regs->sel_timeout);  /* 250ms */
    writeb(CLKF_VAL(state->clk_freq), &regs->clk_factor);
    writeb(CF2_FEATURE_EN, &regs->config2);
    writeb(0, &regs->config3);
    writeb(0, &regs->sync_period);
    writeb(0, &regs->sync_offset);
    x = readb(&regs->interrupt);
    writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
}

/*
 * Start the next command for a 53C94.
 * Should be called with interrupts disabled.
 */
static void mac53c94_start(struct fsc_state *state)
{
    struct scsi_cmnd *cmd;
    struct mac53c94_regs __iomem *regs = state->regs;
    int i;

    if (state->phase != idle || state->current_req != NULL)
        panic("inappropriate mac53c94_start (state=%p)", state);
    if (state->request_q == NULL)
        return;
    state->current_req = cmd = state->request_q;
    state->request_q = (struct scsi_cmnd *) cmd->host_scribble;

    /* Off we go */
    writeb(0, &regs->count_lo);
    writeb(0, &regs->count_mid);
    writeb(0, &regs->count_hi);
    writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
    udelay(1);
    writeb(CMD_FLUSH, &regs->command);
    udelay(1);
    writeb(cmd->device->id, &regs->dest_id);
    writeb(0, &regs->sync_period);
    writeb(0, &regs->sync_offset);

    /* load the command into the FIFO */
    for (i = 0; i < cmd->cmd_len; ++i)
        writeb(cmd->cmnd[i], &regs->fifo);

    /* do select without ATN XXX */
    writeb(CMD_SELECT, &regs->command);
    state->phase = selecting;

    set_dma_cmds(state, cmd);
}

static irqreturn_t do_mac53c94_interrupt(int irq, void *dev_id)
{
    unsigned long flags;
    struct Scsi_Host *dev = ((struct fsc_state *) dev_id)->current_req->device->host;
    
    spin_lock_irqsave(dev->host_lock, flags);
    mac53c94_interrupt(irq, dev_id);
    spin_unlock_irqrestore(dev->host_lock, flags);
    return IRQ_HANDLED;
}

static void mac53c94_interrupt(int irq, void *dev_id)
{
    struct fsc_state *state = (struct fsc_state *) dev_id;
    struct mac53c94_regs __iomem *regs = state->regs;
    struct dbdma_regs __iomem *dma = state->dma;
    struct scsi_cmnd *cmd = state->current_req;
    int nb, stat, seq, intr;
    static int mac53c94_errors;

    /*
     * Apparently, reading the interrupt register unlatches
     * the status and sequence step registers.
     */
    seq = readb(&regs->seqstep);
    stat = readb(&regs->status);
    intr = readb(&regs->interrupt);

#if 0
    printk(KERN_DEBUG "mac53c94_intr, intr=%x stat=%x seq=%x phase=%d\n",
           intr, stat, seq, state->phase);
#endif

    if (intr & INTR_RESET) {
        /* SCSI bus was reset */
        printk(KERN_INFO "external SCSI bus reset detected\n");
        writeb(CMD_NOP, &regs->command);
        writel(RUN << 16, &dma->control);   /* stop dma */
        cmd_done(state, DID_RESET << 16);
        return;
    }
    if (intr & INTR_ILL_CMD) {
        printk(KERN_ERR "53c94: invalid cmd, intr=%x stat=%x seq=%x phase=%d\n",
               intr, stat, seq, state->phase);
        cmd_done(state, DID_ERROR << 16);
        return;
    }
    if (stat & STAT_ERROR) {
#if 0
        /* XXX these seem to be harmless? */
        printk("53c94: bad error, intr=%x stat=%x seq=%x phase=%d\n",
               intr, stat, seq, state->phase);
#endif
        ++mac53c94_errors;
        writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
    }
    if (cmd == 0) {
        printk(KERN_DEBUG "53c94: interrupt with no command active?\n");
        return;
    }
    if (stat & STAT_PARITY) {
        printk(KERN_ERR "mac53c94: parity error\n");
        cmd_done(state, DID_PARITY << 16);
        return;
    }
    switch (state->phase) {
    case selecting:
        if (intr & INTR_DISCONNECT) {
            /* selection timed out */
            cmd_done(state, DID_BAD_TARGET << 16);
            return;
        }
        if (intr != INTR_BUS_SERV + INTR_DONE) {
            printk(KERN_DEBUG "got intr %x during selection\n", intr);
            cmd_done(state, DID_ERROR << 16);
            return;
        }
        if ((seq & SS_MASK) != SS_DONE) {
            printk(KERN_DEBUG "seq step %x after command\n", seq);
            cmd_done(state, DID_ERROR << 16);
            return;
        }
        writeb(CMD_NOP, &regs->command);
        /* set DMA controller going if any data to transfer */
        if ((stat & (STAT_MSG|STAT_CD)) == 0
            && (scsi_sg_count(cmd) > 0 || scsi_bufflen(cmd))) {
            nb = cmd->SCp.this_residual;
            if (nb > 0xfff0)
                nb = 0xfff0;
            cmd->SCp.this_residual -= nb;
            writeb(nb, &regs->count_lo);
            writeb(nb >> 8, &regs->count_mid);
            writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
            writel(virt_to_phys(state->dma_cmds), &dma->cmdptr);
            writel((RUN << 16) | RUN, &dma->control);
            writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
            state->phase = dataing;
            break;
        } else if ((stat & STAT_PHASE) == STAT_CD + STAT_IO) {
            /* up to status phase already */
            writeb(CMD_I_COMPLETE, &regs->command);
            state->phase = completing;
        } else {
            printk(KERN_DEBUG "in unexpected phase %x after cmd\n",
                   stat & STAT_PHASE);
            cmd_done(state, DID_ERROR << 16);
            return;
        }
        break;

    case dataing:
        if (intr != INTR_BUS_SERV) {
            printk(KERN_DEBUG "got intr %x before status\n", intr);
            cmd_done(state, DID_ERROR << 16);
            return;
        }
        if (cmd->SCp.this_residual != 0
            && (stat & (STAT_MSG|STAT_CD)) == 0) {
            /* Set up the count regs to transfer more */
            nb = cmd->SCp.this_residual;
            if (nb > 0xfff0)
                nb = 0xfff0;
            cmd->SCp.this_residual -= nb;
            writeb(nb, &regs->count_lo);
            writeb(nb >> 8, &regs->count_mid);
            writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
            writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
            break;
        }
        if ((stat & STAT_PHASE) != STAT_CD + STAT_IO) {
            printk(KERN_DEBUG "intr %x before data xfer complete\n", intr);
        }
        writel(RUN << 16, &dma->control);   /* stop dma */
        scsi_dma_unmap(cmd);
        /* should check dma status */
        writeb(CMD_I_COMPLETE, &regs->command);
        state->phase = completing;
        break;
    case completing:
        if (intr != INTR_DONE) {
            printk(KERN_DEBUG "got intr %x on completion\n", intr);
            cmd_done(state, DID_ERROR << 16);
            return;
        }
        cmd->SCp.Status = readb(&regs->fifo);
        cmd->SCp.Message = readb(&regs->fifo);
        cmd->result = CMD_ACCEPT_MSG;
        writeb(CMD_ACCEPT_MSG, &regs->command);
        state->phase = busfreeing;
        break;
    case busfreeing:
        if (intr != INTR_DISCONNECT) {
            printk(KERN_DEBUG "got intr %x when expected disconnect\n", intr);
        }
        cmd_done(state, (DID_OK << 16) + (cmd->SCp.Message << 8)
             + cmd->SCp.Status);
        break;
    default:
        printk(KERN_DEBUG "don't know about phase %d\n", state->phase);
    }
}

static void cmd_done(struct fsc_state *state, int result)
{
    struct scsi_cmnd *cmd;

    cmd = state->current_req;
    if (cmd != 0) {
        cmd->result = result;
        (*cmd->scsi_done)(cmd);
        state->current_req = NULL;
    }
    state->phase = idle;
    mac53c94_start(state);
}

/*
 * Set up DMA commands for transferring data.
 */
static void set_dma_cmds(struct fsc_state *state, struct scsi_cmnd *cmd)
{
    int i, dma_cmd, total, nseg;
    struct scatterlist *scl;
    struct dbdma_cmd *dcmds;
    dma_addr_t dma_addr;
    u32 dma_len;

    nseg = scsi_dma_map(cmd);
    BUG_ON(nseg < 0);
    if (!nseg)
        return;

    dma_cmd = cmd->sc_data_direction == DMA_TO_DEVICE ?
            OUTPUT_MORE : INPUT_MORE;
    dcmds = state->dma_cmds;
    total = 0;

    scsi_for_each_sg(cmd, scl, nseg, i) {
        dma_addr = sg_dma_address(scl);
        dma_len = sg_dma_len(scl);
        if (dma_len > 0xffff)
            panic("mac53c94: scatterlist element >= 64k");
        total += dma_len;
        st_le16(&dcmds->req_count, dma_len);
        st_le16(&dcmds->command, dma_cmd);
        st_le32(&dcmds->phy_addr, dma_addr);
        dcmds->xfer_status = 0;
        ++dcmds;
    }

    dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
    st_le16(&dcmds[-1].command, dma_cmd);
    st_le16(&dcmds->command, DBDMA_STOP);
    cmd->SCp.this_residual = total;
}

static struct scsi_host_template mac53c94_template = {
    .proc_name  = "53c94",
    .name       = "53C94",
    .queuecommand   = mac53c94_queue,
    .eh_host_reset_handler = mac53c94_host_reset,
    .can_queue  = 1,
    .this_id    = 7,
    .sg_tablesize   = SG_ALL,
    .cmd_per_lun    = 1,
    .use_clustering = DISABLE_CLUSTERING,
};

static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
{
    struct device_node *node = macio_get_of_node(mdev);
    struct pci_dev *pdev = macio_get_pci_dev(mdev);
    struct fsc_state *state;
    struct Scsi_Host *host;
    void *dma_cmd_space;
    const unsigned char *clkprop;
    int proplen, rc = -ENODEV;

    if (macio_resource_count(mdev) != 2 || macio_irq_count(mdev) != 2) {
        printk(KERN_ERR "mac53c94: expected 2 addrs and intrs"
               " (got %d/%d)\n",
               macio_resource_count(mdev), macio_irq_count(mdev));
        return -ENODEV;
    }

    if (macio_request_resources(mdev, "mac53c94") != 0) {
            printk(KERN_ERR "mac53c94: unable to request memory resources");
        return -EBUSY;
    }

        host = scsi_host_alloc(&mac53c94_template, sizeof(struct fsc_state));
    if (host == NULL) {
        printk(KERN_ERR "mac53c94: couldn't register host");
        rc = -ENOMEM;
        goto out_release;
    }

    state = (struct fsc_state *) host->hostdata;
    macio_set_drvdata(mdev, state);
    state->host = host;
    state->pdev = pdev;
    state->mdev = mdev;

    state->regs = (struct mac53c94_regs __iomem *)
        ioremap(macio_resource_start(mdev, 0), 0x1000);
    state->intr = macio_irq(mdev, 0);
    state->dma = (struct dbdma_regs __iomem *)
        ioremap(macio_resource_start(mdev, 1), 0x1000);
    state->dmaintr = macio_irq(mdev, 1);
    if (state->regs == NULL || state->dma == NULL) {
        printk(KERN_ERR "mac53c94: ioremap failed for %s\n",
               node->full_name);
        goto out_free;
    }

    clkprop = of_get_property(node, "clock-frequency", &proplen);
        if (clkprop == NULL || proplen != sizeof(int)) {
            printk(KERN_ERR "%s: can't get clock frequency, "
                   "assuming 25MHz\n", node->full_name);
            state->clk_freq = 25000000;
        } else
            state->clk_freq = *(int *)clkprop;

        /* Space for dma command list: +1 for stop command,
         * +1 to allow for aligning.
     * XXX FIXME: Use DMA consistent routines
     */
        dma_cmd_space = kmalloc((host->sg_tablesize + 2) *
                    sizeof(struct dbdma_cmd), GFP_KERNEL);
        if (dma_cmd_space == 0) {
            printk(KERN_ERR "mac53c94: couldn't allocate dma "
                   "command space for %s\n", node->full_name);
        rc = -ENOMEM;
            goto out_free;
        }
    state->dma_cmds = (struct dbdma_cmd *)DBDMA_ALIGN(dma_cmd_space);
    memset(state->dma_cmds, 0, (host->sg_tablesize + 1)
           * sizeof(struct dbdma_cmd));
    state->dma_cmd_space = dma_cmd_space;

    mac53c94_init(state);

    if (request_irq(state->intr, do_mac53c94_interrupt, 0, "53C94",state)) {
        printk(KERN_ERR "mac53C94: can't get irq %d for %s\n",
               state->intr, node->full_name);
        goto out_free_dma;
    }

    rc = scsi_add_host(host, &mdev->ofdev.dev);
    if (rc != 0)
        goto out_release_irq;

    scsi_scan_host(host);
    return 0;

 out_release_irq:
    free_irq(state->intr, state);
 out_free_dma:
    kfree(state->dma_cmd_space);
 out_free:
    if (state->dma != NULL)
        iounmap(state->dma);
    if (state->regs != NULL)
        iounmap(state->regs);
    scsi_host_put(host);
 out_release:
    macio_release_resources(mdev);

    return rc;
}

static int mac53c94_remove(struct macio_dev *mdev)
{
    struct fsc_state *fp = (struct fsc_state *)macio_get_drvdata(mdev);
    struct Scsi_Host *host = fp->host;

    scsi_remove_host(host);

    free_irq(fp->intr, fp);

    if (fp->regs)
        iounmap(fp->regs);
    if (fp->dma)
        iounmap(fp->dma);
    kfree(fp->dma_cmd_space);

    scsi_host_put(host);

    macio_release_resources(mdev);

    return 0;
}


static struct of_device_id mac53c94_match[] = 
{
    {
    .name       = "53c94",
    },
    {},
};
MODULE_DEVICE_TABLE (of, mac53c94_match);

static struct macio_driver mac53c94_driver = 
{
    .driver = {
        .name       = "mac53c94",
        .owner      = THIS_MODULE,
        .of_match_table = mac53c94_match,
    },
    .probe      = mac53c94_probe,
    .remove     = mac53c94_remove,
};


static int __init init_mac53c94(void)
{
    return macio_register_driver(&mac53c94_driver);
}

static void __exit exit_mac53c94(void)
{
    return macio_unregister_driver(&mac53c94_driver);
}

module_init(init_mac53c94);
module_exit(exit_mac53c94);

MODULE_DESCRIPTION("PowerMac 53c94 SCSI driver");
MODULE_AUTHOR("Paul Mackerras <[email protected]>");
MODULE_LICENSE("GPL");