linux/drivers/scsi/mac53c94.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * SCSI low-level driver for the 53c94 SCSI bus adaptor found
   4 * on Power Macintosh computers, controlling the external SCSI chain.
   5 * We assume the 53c94 is connected to a DBDMA (descriptor-based DMA)
   6 * controller.
   7 *
   8 * Paul Mackerras, August 1996.
   9 * Copyright (C) 1996 Paul Mackerras.
  10 */
  11#include <linux/kernel.h>
  12#include <linux/delay.h>
  13#include <linux/types.h>
  14#include <linux/string.h>
  15#include <linux/slab.h>
  16#include <linux/blkdev.h>
  17#include <linux/proc_fs.h>
  18#include <linux/stat.h>
  19#include <linux/spinlock.h>
  20#include <linux/interrupt.h>
  21#include <linux/module.h>
  22#include <linux/pci.h>
  23#include <linux/pgtable.h>
  24#include <asm/dbdma.h>
  25#include <asm/io.h>
  26#include <asm/prom.h>
  27#include <asm/macio.h>
  28
  29#include <scsi/scsi.h>
  30#include <scsi/scsi_cmnd.h>
  31#include <scsi/scsi_device.h>
  32#include <scsi/scsi_host.h>
  33
  34#include "mac53c94.h"
  35
  36enum fsc_phase {
  37        idle,
  38        selecting,
  39        dataing,
  40        completing,
  41        busfreeing,
  42};
  43
  44struct fsc_state {
  45        struct  mac53c94_regs __iomem *regs;
  46        int     intr;
  47        struct  dbdma_regs __iomem *dma;
  48        int     dmaintr;
  49        int     clk_freq;
  50        struct  Scsi_Host *host;
  51        struct scsi_cmnd *request_q;
  52        struct scsi_cmnd *request_qtail;
  53        struct scsi_cmnd *current_req;          /* req we're currently working on */
  54        enum fsc_phase phase;           /* what we're currently trying to do */
  55        struct dbdma_cmd *dma_cmds;     /* space for dbdma commands, aligned */
  56        void    *dma_cmd_space;
  57        struct  pci_dev *pdev;
  58        dma_addr_t dma_addr;
  59        struct macio_dev *mdev;
  60};
  61
  62static void mac53c94_init(struct fsc_state *);
  63static void mac53c94_start(struct fsc_state *);
  64static void mac53c94_interrupt(int, void *);
  65static irqreturn_t do_mac53c94_interrupt(int, void *);
  66static void cmd_done(struct fsc_state *, int result);
  67static void set_dma_cmds(struct fsc_state *, struct scsi_cmnd *);
  68
  69
  70static int mac53c94_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
  71{
  72        struct fsc_state *state;
  73
  74#if 0
  75        if (cmd->sc_data_direction == DMA_TO_DEVICE) {
  76                int i;
  77                printk(KERN_DEBUG "mac53c94_queue %p: command is", cmd);
  78                for (i = 0; i < cmd->cmd_len; ++i)
  79                        printk(KERN_CONT " %.2x", cmd->cmnd[i]);
  80                printk(KERN_CONT "\n");
  81                printk(KERN_DEBUG "use_sg=%d request_bufflen=%d request_buffer=%p\n",
  82                       scsi_sg_count(cmd), scsi_bufflen(cmd), scsi_sglist(cmd));
  83        }
  84#endif
  85
  86        cmd->scsi_done = done;
  87        cmd->host_scribble = NULL;
  88
  89        state = (struct fsc_state *) cmd->device->host->hostdata;
  90
  91        if (state->request_q == NULL)
  92                state->request_q = cmd;
  93        else
  94                state->request_qtail->host_scribble = (void *) cmd;
  95        state->request_qtail = cmd;
  96
  97        if (state->phase == idle)
  98                mac53c94_start(state);
  99
 100        return 0;
 101}
 102
 103static DEF_SCSI_QCMD(mac53c94_queue)
 104
 105static int mac53c94_host_reset(struct scsi_cmnd *cmd)
 106{
 107        struct fsc_state *state = (struct fsc_state *) cmd->device->host->hostdata;
 108        struct mac53c94_regs __iomem *regs = state->regs;
 109        struct dbdma_regs __iomem *dma = state->dma;
 110        unsigned long flags;
 111
 112        spin_lock_irqsave(cmd->device->host->host_lock, flags);
 113
 114        writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
 115        writeb(CMD_SCSI_RESET, &regs->command); /* assert RST */
 116        udelay(100);                    /* leave it on for a while (>= 25us) */
 117        writeb(CMD_RESET, &regs->command);
 118        udelay(20);
 119        mac53c94_init(state);
 120        writeb(CMD_NOP, &regs->command);
 121
 122        spin_unlock_irqrestore(cmd->device->host->host_lock, flags);
 123        return SUCCESS;
 124}
 125
 126static void mac53c94_init(struct fsc_state *state)
 127{
 128        struct mac53c94_regs __iomem *regs = state->regs;
 129        struct dbdma_regs __iomem *dma = state->dma;
 130        int x;
 131
 132        writeb(state->host->this_id | CF1_PAR_ENABLE, &regs->config1);
 133        writeb(TIMO_VAL(250), &regs->sel_timeout);      /* 250ms */
 134        writeb(CLKF_VAL(state->clk_freq), &regs->clk_factor);
 135        writeb(CF2_FEATURE_EN, &regs->config2);
 136        writeb(0, &regs->config3);
 137        writeb(0, &regs->sync_period);
 138        writeb(0, &regs->sync_offset);
 139        x = readb(&regs->interrupt);
 140        writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
 141}
 142
 143/*
 144 * Start the next command for a 53C94.
 145 * Should be called with interrupts disabled.
 146 */
 147static void mac53c94_start(struct fsc_state *state)
 148{
 149        struct scsi_cmnd *cmd;
 150        struct mac53c94_regs __iomem *regs = state->regs;
 151        int i;
 152
 153        if (state->phase != idle || state->current_req != NULL)
 154                panic("inappropriate mac53c94_start (state=%p)", state);
 155        if (state->request_q == NULL)
 156                return;
 157        state->current_req = cmd = state->request_q;
 158        state->request_q = (struct scsi_cmnd *) cmd->host_scribble;
 159
 160        /* Off we go */
 161        writeb(0, &regs->count_lo);
 162        writeb(0, &regs->count_mid);
 163        writeb(0, &regs->count_hi);
 164        writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
 165        udelay(1);
 166        writeb(CMD_FLUSH, &regs->command);
 167        udelay(1);
 168        writeb(cmd->device->id, &regs->dest_id);
 169        writeb(0, &regs->sync_period);
 170        writeb(0, &regs->sync_offset);
 171
 172        /* load the command into the FIFO */
 173        for (i = 0; i < cmd->cmd_len; ++i)
 174                writeb(cmd->cmnd[i], &regs->fifo);
 175
 176        /* do select without ATN XXX */
 177        writeb(CMD_SELECT, &regs->command);
 178        state->phase = selecting;
 179
 180        set_dma_cmds(state, cmd);
 181}
 182
 183static irqreturn_t do_mac53c94_interrupt(int irq, void *dev_id)
 184{
 185        unsigned long flags;
 186        struct Scsi_Host *dev = ((struct fsc_state *) dev_id)->current_req->device->host;
 187        
 188        spin_lock_irqsave(dev->host_lock, flags);
 189        mac53c94_interrupt(irq, dev_id);
 190        spin_unlock_irqrestore(dev->host_lock, flags);
 191        return IRQ_HANDLED;
 192}
 193
 194static void mac53c94_interrupt(int irq, void *dev_id)
 195{
 196        struct fsc_state *state = (struct fsc_state *) dev_id;
 197        struct mac53c94_regs __iomem *regs = state->regs;
 198        struct dbdma_regs __iomem *dma = state->dma;
 199        struct scsi_cmnd *cmd = state->current_req;
 200        int nb, stat, seq, intr;
 201        static int mac53c94_errors;
 202
 203        /*
 204         * Apparently, reading the interrupt register unlatches
 205         * the status and sequence step registers.
 206         */
 207        seq = readb(&regs->seqstep);
 208        stat = readb(&regs->status);
 209        intr = readb(&regs->interrupt);
 210
 211#if 0
 212        printk(KERN_DEBUG "mac53c94_intr, intr=%x stat=%x seq=%x phase=%d\n",
 213               intr, stat, seq, state->phase);
 214#endif
 215
 216        if (intr & INTR_RESET) {
 217                /* SCSI bus was reset */
 218                printk(KERN_INFO "external SCSI bus reset detected\n");
 219                writeb(CMD_NOP, &regs->command);
 220                writel(RUN << 16, &dma->control);       /* stop dma */
 221                cmd_done(state, DID_RESET << 16);
 222                return;
 223        }
 224        if (intr & INTR_ILL_CMD) {
 225                printk(KERN_ERR "53c94: invalid cmd, intr=%x stat=%x seq=%x phase=%d\n",
 226                       intr, stat, seq, state->phase);
 227                cmd_done(state, DID_ERROR << 16);
 228                return;
 229        }
 230        if (stat & STAT_ERROR) {
 231#if 0
 232                /* XXX these seem to be harmless? */
 233                printk("53c94: bad error, intr=%x stat=%x seq=%x phase=%d\n",
 234                       intr, stat, seq, state->phase);
 235#endif
 236                ++mac53c94_errors;
 237                writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
 238        }
 239        if (cmd == 0) {
 240                printk(KERN_DEBUG "53c94: interrupt with no command active?\n");
 241                return;
 242        }
 243        if (stat & STAT_PARITY) {
 244                printk(KERN_ERR "mac53c94: parity error\n");
 245                cmd_done(state, DID_PARITY << 16);
 246                return;
 247        }
 248        switch (state->phase) {
 249        case selecting:
 250                if (intr & INTR_DISCONNECT) {
 251                        /* selection timed out */
 252                        cmd_done(state, DID_BAD_TARGET << 16);
 253                        return;
 254                }
 255                if (intr != INTR_BUS_SERV + INTR_DONE) {
 256                        printk(KERN_DEBUG "got intr %x during selection\n", intr);
 257                        cmd_done(state, DID_ERROR << 16);
 258                        return;
 259                }
 260                if ((seq & SS_MASK) != SS_DONE) {
 261                        printk(KERN_DEBUG "seq step %x after command\n", seq);
 262                        cmd_done(state, DID_ERROR << 16);
 263                        return;
 264                }
 265                writeb(CMD_NOP, &regs->command);
 266                /* set DMA controller going if any data to transfer */
 267                if ((stat & (STAT_MSG|STAT_CD)) == 0
 268                    && (scsi_sg_count(cmd) > 0 || scsi_bufflen(cmd))) {
 269                        nb = cmd->SCp.this_residual;
 270                        if (nb > 0xfff0)
 271                                nb = 0xfff0;
 272                        cmd->SCp.this_residual -= nb;
 273                        writeb(nb, &regs->count_lo);
 274                        writeb(nb >> 8, &regs->count_mid);
 275                        writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
 276                        writel(virt_to_phys(state->dma_cmds), &dma->cmdptr);
 277                        writel((RUN << 16) | RUN, &dma->control);
 278                        writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
 279                        state->phase = dataing;
 280                        break;
 281                } else if ((stat & STAT_PHASE) == STAT_CD + STAT_IO) {
 282                        /* up to status phase already */
 283                        writeb(CMD_I_COMPLETE, &regs->command);
 284                        state->phase = completing;
 285                } else {
 286                        printk(KERN_DEBUG "in unexpected phase %x after cmd\n",
 287                               stat & STAT_PHASE);
 288                        cmd_done(state, DID_ERROR << 16);
 289                        return;
 290                }
 291                break;
 292
 293        case dataing:
 294                if (intr != INTR_BUS_SERV) {
 295                        printk(KERN_DEBUG "got intr %x before status\n", intr);
 296                        cmd_done(state, DID_ERROR << 16);
 297                        return;
 298                }
 299                if (cmd->SCp.this_residual != 0
 300                    && (stat & (STAT_MSG|STAT_CD)) == 0) {
 301                        /* Set up the count regs to transfer more */
 302                        nb = cmd->SCp.this_residual;
 303                        if (nb > 0xfff0)
 304                                nb = 0xfff0;
 305                        cmd->SCp.this_residual -= nb;
 306                        writeb(nb, &regs->count_lo);
 307                        writeb(nb >> 8, &regs->count_mid);
 308                        writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
 309                        writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
 310                        break;
 311                }
 312                if ((stat & STAT_PHASE) != STAT_CD + STAT_IO) {
 313                        printk(KERN_DEBUG "intr %x before data xfer complete\n", intr);
 314                }
 315                writel(RUN << 16, &dma->control);       /* stop dma */
 316                scsi_dma_unmap(cmd);
 317                /* should check dma status */
 318                writeb(CMD_I_COMPLETE, &regs->command);
 319                state->phase = completing;
 320                break;
 321        case completing:
 322                if (intr != INTR_DONE) {
 323                        printk(KERN_DEBUG "got intr %x on completion\n", intr);
 324                        cmd_done(state, DID_ERROR << 16);
 325                        return;
 326                }
 327                cmd->SCp.Status = readb(&regs->fifo);
 328                cmd->SCp.Message = readb(&regs->fifo);
 329                writeb(CMD_ACCEPT_MSG, &regs->command);
 330                state->phase = busfreeing;
 331                break;
 332        case busfreeing:
 333                if (intr != INTR_DISCONNECT) {
 334                        printk(KERN_DEBUG "got intr %x when expected disconnect\n", intr);
 335                }
 336                cmd_done(state, (DID_OK << 16) + (cmd->SCp.Message << 8)
 337                         + cmd->SCp.Status);
 338                break;
 339        default:
 340                printk(KERN_DEBUG "don't know about phase %d\n", state->phase);
 341        }
 342}
 343
 344static void cmd_done(struct fsc_state *state, int result)
 345{
 346        struct scsi_cmnd *cmd;
 347
 348        cmd = state->current_req;
 349        if (cmd) {
 350                cmd->result = result;
 351                (*cmd->scsi_done)(cmd);
 352                state->current_req = NULL;
 353        }
 354        state->phase = idle;
 355        mac53c94_start(state);
 356}
 357
 358/*
 359 * Set up DMA commands for transferring data.
 360 */
 361static void set_dma_cmds(struct fsc_state *state, struct scsi_cmnd *cmd)
 362{
 363        int i, dma_cmd, total, nseg;
 364        struct scatterlist *scl;
 365        struct dbdma_cmd *dcmds;
 366        dma_addr_t dma_addr;
 367        u32 dma_len;
 368
 369        nseg = scsi_dma_map(cmd);
 370        BUG_ON(nseg < 0);
 371        if (!nseg)
 372                return;
 373
 374        dma_cmd = cmd->sc_data_direction == DMA_TO_DEVICE ?
 375                        OUTPUT_MORE : INPUT_MORE;
 376        dcmds = state->dma_cmds;
 377        total = 0;
 378
 379        scsi_for_each_sg(cmd, scl, nseg, i) {
 380                dma_addr = sg_dma_address(scl);
 381                dma_len = sg_dma_len(scl);
 382                if (dma_len > 0xffff)
 383                        panic("mac53c94: scatterlist element >= 64k");
 384                total += dma_len;
 385                dcmds->req_count = cpu_to_le16(dma_len);
 386                dcmds->command = cpu_to_le16(dma_cmd);
 387                dcmds->phy_addr = cpu_to_le32(dma_addr);
 388                dcmds->xfer_status = 0;
 389                ++dcmds;
 390        }
 391
 392        dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
 393        dcmds[-1].command = cpu_to_le16(dma_cmd);
 394        dcmds->command = cpu_to_le16(DBDMA_STOP);
 395        cmd->SCp.this_residual = total;
 396}
 397
 398static struct scsi_host_template mac53c94_template = {
 399        .proc_name      = "53c94",
 400        .name           = "53C94",
 401        .queuecommand   = mac53c94_queue,
 402        .eh_host_reset_handler = mac53c94_host_reset,
 403        .can_queue      = 1,
 404        .this_id        = 7,
 405        .sg_tablesize   = SG_ALL,
 406        .max_segment_size = 65535,
 407};
 408
 409static int mac53c94_probe(struct macio_dev *mdev, const struct of_device_id *match)
 410{
 411        struct device_node *node = macio_get_of_node(mdev);
 412        struct pci_dev *pdev = macio_get_pci_dev(mdev);
 413        struct fsc_state *state;
 414        struct Scsi_Host *host;
 415        void *dma_cmd_space;
 416        const unsigned char *clkprop;
 417        int proplen, rc = -ENODEV;
 418
 419        if (macio_resource_count(mdev) != 2 || macio_irq_count(mdev) != 2) {
 420                printk(KERN_ERR "mac53c94: expected 2 addrs and intrs"
 421                       " (got %d/%d)\n",
 422                       macio_resource_count(mdev), macio_irq_count(mdev));
 423                return -ENODEV;
 424        }
 425
 426        if (macio_request_resources(mdev, "mac53c94") != 0) {
 427                printk(KERN_ERR "mac53c94: unable to request memory resources");
 428                return -EBUSY;
 429        }
 430
 431        host = scsi_host_alloc(&mac53c94_template, sizeof(struct fsc_state));
 432        if (host == NULL) {
 433                printk(KERN_ERR "mac53c94: couldn't register host");
 434                rc = -ENOMEM;
 435                goto out_release;
 436        }
 437
 438        state = (struct fsc_state *) host->hostdata;
 439        macio_set_drvdata(mdev, state);
 440        state->host = host;
 441        state->pdev = pdev;
 442        state->mdev = mdev;
 443
 444        state->regs = (struct mac53c94_regs __iomem *)
 445                ioremap(macio_resource_start(mdev, 0), 0x1000);
 446        state->intr = macio_irq(mdev, 0);
 447        state->dma = (struct dbdma_regs __iomem *)
 448                ioremap(macio_resource_start(mdev, 1), 0x1000);
 449        state->dmaintr = macio_irq(mdev, 1);
 450        if (state->regs == NULL || state->dma == NULL) {
 451                printk(KERN_ERR "mac53c94: ioremap failed for %pOF\n", node);
 452                goto out_free;
 453        }
 454
 455        clkprop = of_get_property(node, "clock-frequency", &proplen);
 456        if (clkprop == NULL || proplen != sizeof(int)) {
 457                printk(KERN_ERR "%pOF: can't get clock frequency, "
 458                       "assuming 25MHz\n", node);
 459                state->clk_freq = 25000000;
 460        } else
 461                state->clk_freq = *(int *)clkprop;
 462
 463        /* Space for dma command list: +1 for stop command,
 464         * +1 to allow for aligning.
 465         * XXX FIXME: Use DMA consistent routines
 466         */
 467        dma_cmd_space = kmalloc_array(host->sg_tablesize + 2,
 468                                             sizeof(struct dbdma_cmd),
 469                                             GFP_KERNEL);
 470        if (!dma_cmd_space) {
 471                printk(KERN_ERR "mac53c94: couldn't allocate dma "
 472                       "command space for %pOF\n", node);
 473                rc = -ENOMEM;
 474                goto out_free;
 475        }
 476
 477        state->dma_cmds = (struct dbdma_cmd *)DBDMA_ALIGN(dma_cmd_space);
 478        memset(state->dma_cmds, 0, (host->sg_tablesize + 1)
 479               * sizeof(struct dbdma_cmd));
 480        state->dma_cmd_space = dma_cmd_space;
 481
 482        mac53c94_init(state);
 483
 484        if (request_irq(state->intr, do_mac53c94_interrupt, 0, "53C94",state)) {
 485                printk(KERN_ERR "mac53C94: can't get irq %d for %pOF\n",
 486                       state->intr, node);
 487                goto out_free_dma;
 488        }
 489
 490        rc = scsi_add_host(host, &mdev->ofdev.dev);
 491        if (rc != 0)
 492                goto out_release_irq;
 493
 494        scsi_scan_host(host);
 495        return 0;
 496
 497 out_release_irq:
 498        free_irq(state->intr, state);
 499 out_free_dma:
 500        kfree(state->dma_cmd_space);
 501 out_free:
 502        if (state->dma != NULL)
 503                iounmap(state->dma);
 504        if (state->regs != NULL)
 505                iounmap(state->regs);
 506        scsi_host_put(host);
 507 out_release:
 508        macio_release_resources(mdev);
 509
 510        return rc;
 511}
 512
 513static int mac53c94_remove(struct macio_dev *mdev)
 514{
 515        struct fsc_state *fp = (struct fsc_state *)macio_get_drvdata(mdev);
 516        struct Scsi_Host *host = fp->host;
 517
 518        scsi_remove_host(host);
 519
 520        free_irq(fp->intr, fp);
 521
 522        if (fp->regs)
 523                iounmap(fp->regs);
 524        if (fp->dma)
 525                iounmap(fp->dma);
 526        kfree(fp->dma_cmd_space);
 527
 528        scsi_host_put(host);
 529
 530        macio_release_resources(mdev);
 531
 532        return 0;
 533}
 534
 535
 536static struct of_device_id mac53c94_match[] = 
 537{
 538        {
 539        .name           = "53c94",
 540        },
 541        {},
 542};
 543MODULE_DEVICE_TABLE (of, mac53c94_match);
 544
 545static struct macio_driver mac53c94_driver = 
 546{
 547        .driver = {
 548                .name           = "mac53c94",
 549                .owner          = THIS_MODULE,
 550                .of_match_table = mac53c94_match,
 551        },
 552        .probe          = mac53c94_probe,
 553        .remove         = mac53c94_remove,
 554};
 555
 556
 557static int __init init_mac53c94(void)
 558{
 559        return macio_register_driver(&mac53c94_driver);
 560}
 561
 562static void __exit exit_mac53c94(void)
 563{
 564        return macio_unregister_driver(&mac53c94_driver);
 565}
 566
 567module_init(init_mac53c94);
 568module_exit(exit_mac53c94);
 569
 570MODULE_DESCRIPTION("PowerMac 53c94 SCSI driver");
 571MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 572MODULE_LICENSE("GPL");
 573
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