sgiwd93.c

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1996 David S. Miller ([email protected])
 * Copyright (C) 1999 Andrew R. Baker ([email protected])
 * Copyright (C) 2001 Florian Lohoff ([email protected])
 * Copyright (C) 2003, 07 Ralf Baechle ([email protected])
 * 
 * (In all truth, Jed Schimmel wrote all this code.)
 */

#undef DEBUG

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>

#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>
#include <asm/sgi/wd.h>

#include "scsi.h"
#include "wd33c93.h"

struct ip22_hostdata {
    struct WD33C93_hostdata wh;
    dma_addr_t dma;
    void *cpu;
    struct device *dev;
};

#define host_to_hostdata(host) ((struct ip22_hostdata *)((host)->hostdata))

struct hpc_chunk {
    struct hpc_dma_desc desc;
    u32 _padding;   /* align to quadword boundary */
};

/* space for hpc dma descriptors */
#define HPC_DMA_SIZE   PAGE_SIZE

#define DMA_DIR(d)   ((d == DATA_OUT_DIR) ? DMA_TO_DEVICE : DMA_FROM_DEVICE)

static irqreturn_t sgiwd93_intr(int irq, void *dev_id)
{
    struct Scsi_Host * host = dev_id;
    unsigned long flags;

    spin_lock_irqsave(host->host_lock, flags);
    wd33c93_intr(host);
    spin_unlock_irqrestore(host->host_lock, flags);

    return IRQ_HANDLED;
}

static inline
void fill_hpc_entries(struct ip22_hostdata *hd, struct scsi_cmnd *cmd, int din)
{
    unsigned long len = cmd->SCp.this_residual;
    void *addr = cmd->SCp.ptr;
    dma_addr_t physaddr;
    unsigned long count;
    struct hpc_chunk *hcp;

    physaddr = dma_map_single(hd->dev, addr, len, DMA_DIR(din));
    cmd->SCp.dma_handle = physaddr;
    hcp = hd->cpu;

    while (len) {
        /*
         * even cntinfo could be up to 16383, without
         * magic only 8192 works correctly
         */
        count = len > 8192 ? 8192 : len;
        hcp->desc.pbuf = physaddr;
        hcp->desc.cntinfo = count;
        hcp++;
        len -= count;
        physaddr += count;
    }

    /*
     * To make sure, if we trip an HPC bug, that we transfer every single
     * byte, we tag on an extra zero length dma descriptor at the end of
     * the chain.
     */
    hcp->desc.pbuf = 0;
    hcp->desc.cntinfo = HPCDMA_EOX;
    dma_cache_sync(hd->dev, hd->cpu,
               (unsigned long)(hcp + 1) - (unsigned long)hd->cpu,
               DMA_TO_DEVICE);
}

static int dma_setup(struct scsi_cmnd *cmd, int datainp)
{
    struct ip22_hostdata *hdata = host_to_hostdata(cmd->device->host);
    struct hpc3_scsiregs *hregs =
        (struct hpc3_scsiregs *) cmd->device->host->base;

    pr_debug("dma_setup: datainp<%d> hcp<%p> ", datainp, hdata->cpu);

    hdata->wh.dma_dir = datainp;

    /*
     * wd33c93 shouldn't pass us bogus dma_setups, but it does:-(  The
     * other wd33c93 drivers deal with it the same way (which isn't that
     * obvious).  IMHO a better fix would be, not to do these dma setups
     * in the first place.
     */
    if (cmd->SCp.ptr == NULL || cmd->SCp.this_residual == 0)
        return 1;

    fill_hpc_entries(hdata, cmd, datainp);

    pr_debug(" HPCGO\n");

    /* Start up the HPC. */
    hregs->ndptr = hdata->dma;
    if (datainp)
        hregs->ctrl = HPC3_SCTRL_ACTIVE;
    else
        hregs->ctrl = HPC3_SCTRL_ACTIVE | HPC3_SCTRL_DIR;

    return 0;
}

static void dma_stop(struct Scsi_Host *instance, struct scsi_cmnd *SCpnt,
             int status)
{
    struct ip22_hostdata *hdata = host_to_hostdata(instance);
    struct hpc3_scsiregs *hregs;

    if (!SCpnt)
        return;

    if (SCpnt->SCp.ptr == NULL || SCpnt->SCp.this_residual == 0)
        return;

    hregs = (struct hpc3_scsiregs *) SCpnt->device->host->base;

    pr_debug("dma_stop: status<%d> ", status);

    /* First stop the HPC and flush it's FIFO. */
    if (hdata->wh.dma_dir) {
        hregs->ctrl |= HPC3_SCTRL_FLUSH;
        while (hregs->ctrl & HPC3_SCTRL_ACTIVE)
            barrier();
    }
    hregs->ctrl = 0;
    dma_unmap_single(hdata->dev, SCpnt->SCp.dma_handle,
             SCpnt->SCp.this_residual,
             DMA_DIR(hdata->wh.dma_dir));

    pr_debug("\n");
}

void sgiwd93_reset(unsigned long base)
{
    struct hpc3_scsiregs *hregs = (struct hpc3_scsiregs *) base;

    hregs->ctrl = HPC3_SCTRL_CRESET;
    udelay(50);
    hregs->ctrl = 0;
}
EXPORT_SYMBOL_GPL(sgiwd93_reset);

static inline void init_hpc_chain(struct ip22_hostdata *hdata)
{
    struct hpc_chunk *hcp = (struct hpc_chunk *)hdata->cpu;
    dma_addr_t dma = hdata->dma;
    unsigned long start, end;

    start = (unsigned long) hcp;
    end = start + HPC_DMA_SIZE;
    while (start < end) {
        hcp->desc.pnext = (u32) (dma + sizeof(struct hpc_chunk));
        hcp->desc.cntinfo = HPCDMA_EOX;
        hcp++;
        dma += sizeof(struct hpc_chunk);
        start += sizeof(struct hpc_chunk);
    };
    hcp--;
    hcp->desc.pnext = hdata->dma;
}

static int sgiwd93_bus_reset(struct scsi_cmnd *cmd)
{
    /* FIXME perform bus-specific reset */

    /* FIXME 2: kill this function, and let midlayer fallback
       to the same result, calling wd33c93_host_reset() */

    spin_lock_irq(cmd->device->host->host_lock);
    wd33c93_host_reset(cmd);
    spin_unlock_irq(cmd->device->host->host_lock);

    return SUCCESS;
}

/*
 * Kludge alert - the SCSI code calls the abort and reset method with int
 * arguments not with pointers.  So this is going to blow up beautyfully
 * on 64-bit systems with memory outside the compat address spaces.
 */
static struct scsi_host_template sgiwd93_template = {
    .module         = THIS_MODULE,
    .proc_name      = "SGIWD93",
    .name           = "SGI WD93",
    .queuecommand       = wd33c93_queuecommand,
    .eh_abort_handler   = wd33c93_abort,
    .eh_bus_reset_handler   = sgiwd93_bus_reset,
    .eh_host_reset_handler  = wd33c93_host_reset,
    .can_queue      = 16,
    .this_id        = 7,
    .sg_tablesize       = SG_ALL,
    .cmd_per_lun        = 8,
    .use_clustering     = DISABLE_CLUSTERING,
};

static int __devinit sgiwd93_probe(struct platform_device *pdev)
{
    struct sgiwd93_platform_data *pd = pdev->dev.platform_data;
    unsigned char *wdregs = pd->wdregs;
    struct hpc3_scsiregs *hregs = pd->hregs;
    struct ip22_hostdata *hdata;
    struct Scsi_Host *host;
    wd33c93_regs regs;
    unsigned int unit = pd->unit;
    unsigned int irq = pd->irq;
    int err;

    host = scsi_host_alloc(&sgiwd93_template, sizeof(struct ip22_hostdata));
    if (!host) {
        err = -ENOMEM;
        goto out;
    }

    host->base = (unsigned long) hregs;
    host->irq = irq;

    hdata = host_to_hostdata(host);
    hdata->dev = &pdev->dev;
    hdata->cpu = dma_alloc_noncoherent(&pdev->dev, HPC_DMA_SIZE,
                       &hdata->dma, GFP_KERNEL);
    if (!hdata->cpu) {
        printk(KERN_WARNING "sgiwd93: Could not allocate memory for "
               "host %d buffer.\n", unit);
        err = -ENOMEM;
        goto out_put;
    }

    init_hpc_chain(hdata);

    regs.SASR = wdregs + 3;
    regs.SCMD = wdregs + 7;

    hdata->wh.no_sync = 0;
    hdata->wh.fast = 1;
    hdata->wh.dma_mode = CTRL_BURST;

    wd33c93_init(host, regs, dma_setup, dma_stop, WD33C93_FS_MHZ(20));

    err = request_irq(irq, sgiwd93_intr, 0, "SGI WD93", host);
    if (err) {
        printk(KERN_WARNING "sgiwd93: Could not register irq %d "
               "for host %d.\n", irq, unit);
        goto out_free;
    }

    platform_set_drvdata(pdev, host);

    err = scsi_add_host(host, NULL);
    if (err)
        goto out_irq;

    scsi_scan_host(host);

    return 0;

out_irq:
    free_irq(irq, host);
out_free:
    dma_free_noncoherent(&pdev->dev, HPC_DMA_SIZE, hdata->cpu, hdata->dma);
out_put:
    scsi_host_put(host);
out:

    return err;
}

static int __exit sgiwd93_remove(struct platform_device *pdev)
{
    struct Scsi_Host *host = platform_get_drvdata(pdev);
    struct ip22_hostdata *hdata = (struct ip22_hostdata *) host->hostdata;
    struct sgiwd93_platform_data *pd = pdev->dev.platform_data;

    scsi_remove_host(host);
    free_irq(pd->irq, host);
    dma_free_noncoherent(&pdev->dev, HPC_DMA_SIZE, hdata->cpu, hdata->dma);
    scsi_host_put(host);
    return 0;
}

static struct platform_driver sgiwd93_driver = {
    .probe  = sgiwd93_probe,
    .remove = __devexit_p(sgiwd93_remove),
    .driver = {
        .name   = "sgiwd93",
        .owner  = THIS_MODULE,
    }
};

static int __init sgiwd93_module_init(void)
{
    return platform_driver_register(&sgiwd93_driver);
}

static void __exit sgiwd93_module_exit(void)
{
    return platform_driver_unregister(&sgiwd93_driver);
}

module_init(sgiwd93_module_init);
module_exit(sgiwd93_module_exit);

MODULE_DESCRIPTION("SGI WD33C93 driver");
MODULE_AUTHOR("Ralf Baechle <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sgiwd93");