linux/drivers/scsi/mac_esp.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/* mac_esp.c: ESP front-end for Macintosh Quadra systems.
   3 *
   4 * Adapted from jazz_esp.c and the old mac_esp.c.
   5 *
   6 * The pseudo DMA algorithm is based on the one used in NetBSD.
   7 * See sys/arch/mac68k/obio/esp.c for some background information.
   8 *
   9 * Copyright (C) 2007-2008 Finn Thain
  10 */
  11
  12#include <linux/kernel.h>
  13#include <linux/types.h>
  14#include <linux/module.h>
  15#include <linux/init.h>
  16#include <linux/interrupt.h>
  17#include <linux/platform_device.h>
  18#include <linux/dma-mapping.h>
  19#include <linux/scatterlist.h>
  20#include <linux/delay.h>
  21#include <linux/io.h>
  22#include <linux/nubus.h>
  23#include <linux/slab.h>
  24
  25#include <asm/irq.h>
  26#include <asm/dma.h>
  27#include <asm/macints.h>
  28#include <asm/macintosh.h>
  29#include <asm/mac_via.h>
  30
  31#include <scsi/scsi_host.h>
  32
  33#include "esp_scsi.h"
  34
  35#define DRV_MODULE_NAME     "mac_esp"
  36#define PFX                 DRV_MODULE_NAME ": "
  37#define DRV_VERSION         "1.000"
  38#define DRV_MODULE_RELDATE  "Sept 15, 2007"
  39
  40#define MAC_ESP_IO_BASE          0x50F00000
  41#define MAC_ESP_REGS_QUADRA      (MAC_ESP_IO_BASE + 0x10000)
  42#define MAC_ESP_REGS_QUADRA2     (MAC_ESP_IO_BASE + 0xF000)
  43#define MAC_ESP_REGS_QUADRA3     (MAC_ESP_IO_BASE + 0x18000)
  44#define MAC_ESP_REGS_SPACING     0x402
  45#define MAC_ESP_PDMA_REG         0xF9800024
  46#define MAC_ESP_PDMA_REG_SPACING 0x4
  47#define MAC_ESP_PDMA_IO_OFFSET   0x100
  48
  49#define esp_read8(REG)          mac_esp_read8(esp, REG)
  50#define esp_write8(VAL, REG)    mac_esp_write8(esp, VAL, REG)
  51
  52struct mac_esp_priv {
  53        struct esp *esp;
  54        void __iomem *pdma_regs;
  55        void __iomem *pdma_io;
  56};
  57static struct esp *esp_chips[2];
  58static DEFINE_SPINLOCK(esp_chips_lock);
  59
  60#define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \
  61                               dev_get_drvdata((esp)->dev))
  62
  63static inline void mac_esp_write8(struct esp *esp, u8 val, unsigned long reg)
  64{
  65        nubus_writeb(val, esp->regs + reg * 16);
  66}
  67
  68static inline u8 mac_esp_read8(struct esp *esp, unsigned long reg)
  69{
  70        return nubus_readb(esp->regs + reg * 16);
  71}
  72
  73static void mac_esp_reset_dma(struct esp *esp)
  74{
  75        /* Nothing to do. */
  76}
  77
  78static void mac_esp_dma_drain(struct esp *esp)
  79{
  80        /* Nothing to do. */
  81}
  82
  83static void mac_esp_dma_invalidate(struct esp *esp)
  84{
  85        /* Nothing to do. */
  86}
  87
  88static int mac_esp_dma_error(struct esp *esp)
  89{
  90        return esp->send_cmd_error;
  91}
  92
  93static inline int mac_esp_wait_for_empty_fifo(struct esp *esp)
  94{
  95        int i = 500000;
  96
  97        do {
  98                if (!(esp_read8(ESP_FFLAGS) & ESP_FF_FBYTES))
  99                        return 0;
 100
 101                if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
 102                        return 1;
 103
 104                udelay(2);
 105        } while (--i);
 106
 107        printk(KERN_ERR PFX "FIFO is not empty (sreg %02x)\n",
 108               esp_read8(ESP_STATUS));
 109        esp->send_cmd_error = 1;
 110        return 1;
 111}
 112
 113static inline int mac_esp_wait_for_dreq(struct esp *esp)
 114{
 115        struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
 116        int i = 500000;
 117
 118        do {
 119                if (mep->pdma_regs == NULL) {
 120                        if (via2_scsi_drq_pending())
 121                                return 0;
 122                } else {
 123                        if (nubus_readl(mep->pdma_regs) & 0x200)
 124                                return 0;
 125                }
 126
 127                if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
 128                        return 1;
 129
 130                udelay(2);
 131        } while (--i);
 132
 133        printk(KERN_ERR PFX "PDMA timeout (sreg %02x)\n",
 134               esp_read8(ESP_STATUS));
 135        esp->send_cmd_error = 1;
 136        return 1;
 137}
 138
 139#define MAC_ESP_PDMA_LOOP(operands) \
 140        asm volatile ( \
 141             "       tstw %1                   \n" \
 142             "       jbeq 20f                  \n" \
 143             "1:     movew " operands "        \n" \
 144             "2:     movew " operands "        \n" \
 145             "3:     movew " operands "        \n" \
 146             "4:     movew " operands "        \n" \
 147             "5:     movew " operands "        \n" \
 148             "6:     movew " operands "        \n" \
 149             "7:     movew " operands "        \n" \
 150             "8:     movew " operands "        \n" \
 151             "9:     movew " operands "        \n" \
 152             "10:    movew " operands "        \n" \
 153             "11:    movew " operands "        \n" \
 154             "12:    movew " operands "        \n" \
 155             "13:    movew " operands "        \n" \
 156             "14:    movew " operands "        \n" \
 157             "15:    movew " operands "        \n" \
 158             "16:    movew " operands "        \n" \
 159             "       subqw #1,%1               \n" \
 160             "       jbne 1b                   \n" \
 161             "20:    tstw %2                   \n" \
 162             "       jbeq 30f                  \n" \
 163             "21:    movew " operands "        \n" \
 164             "       subqw #1,%2               \n" \
 165             "       jbne 21b                  \n" \
 166             "30:    tstw %3                   \n" \
 167             "       jbeq 40f                  \n" \
 168             "31:    moveb " operands "        \n" \
 169             "32:    nop                       \n" \
 170             "40:                              \n" \
 171             "                                 \n" \
 172             "       .section __ex_table,\"a\" \n" \
 173             "       .align  4                 \n" \
 174             "       .long   1b,40b            \n" \
 175             "       .long   2b,40b            \n" \
 176             "       .long   3b,40b            \n" \
 177             "       .long   4b,40b            \n" \
 178             "       .long   5b,40b            \n" \
 179             "       .long   6b,40b            \n" \
 180             "       .long   7b,40b            \n" \
 181             "       .long   8b,40b            \n" \
 182             "       .long   9b,40b            \n" \
 183             "       .long  10b,40b            \n" \
 184             "       .long  11b,40b            \n" \
 185             "       .long  12b,40b            \n" \
 186             "       .long  13b,40b            \n" \
 187             "       .long  14b,40b            \n" \
 188             "       .long  15b,40b            \n" \
 189             "       .long  16b,40b            \n" \
 190             "       .long  21b,40b            \n" \
 191             "       .long  31b,40b            \n" \
 192             "       .long  32b,40b            \n" \
 193             "       .previous                 \n" \
 194             : "+a" (addr), "+r" (count32), "+r" (count2) \
 195             : "g" (count1), "a" (mep->pdma_io))
 196
 197static void mac_esp_send_pdma_cmd(struct esp *esp, u32 addr, u32 esp_count,
 198                                  u32 dma_count, int write, u8 cmd)
 199{
 200        struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
 201
 202        esp->send_cmd_error = 0;
 203
 204        if (!write)
 205                scsi_esp_cmd(esp, ESP_CMD_FLUSH);
 206
 207        esp_write8((esp_count >> 0) & 0xFF, ESP_TCLOW);
 208        esp_write8((esp_count >> 8) & 0xFF, ESP_TCMED);
 209
 210        scsi_esp_cmd(esp, cmd);
 211
 212        do {
 213                unsigned int count32 = esp_count >> 5;
 214                unsigned int count2 = (esp_count & 0x1F) >> 1;
 215                unsigned int count1 = esp_count & 1;
 216                unsigned int start_addr = addr;
 217
 218                if (mac_esp_wait_for_dreq(esp))
 219                        break;
 220
 221                if (write) {
 222                        MAC_ESP_PDMA_LOOP("%4@,%0@+");
 223
 224                        esp_count -= addr - start_addr;
 225                } else {
 226                        unsigned int n;
 227
 228                        MAC_ESP_PDMA_LOOP("%0@+,%4@");
 229
 230                        if (mac_esp_wait_for_empty_fifo(esp))
 231                                break;
 232
 233                        n = (esp_read8(ESP_TCMED) << 8) + esp_read8(ESP_TCLOW);
 234                        addr = start_addr + esp_count - n;
 235                        esp_count = n;
 236                }
 237        } while (esp_count);
 238}
 239
 240static int mac_esp_irq_pending(struct esp *esp)
 241{
 242        if (esp_read8(ESP_STATUS) & ESP_STAT_INTR)
 243                return 1;
 244        return 0;
 245}
 246
 247static u32 mac_esp_dma_length_limit(struct esp *esp, u32 dma_addr, u32 dma_len)
 248{
 249        return dma_len > 0xFFFF ? 0xFFFF : dma_len;
 250}
 251
 252static irqreturn_t mac_scsi_esp_intr(int irq, void *dev_id)
 253{
 254        int got_intr;
 255
 256        /*
 257         * This is an edge triggered IRQ, so we have to be careful to
 258         * avoid missing a transition when it is shared by two ESP devices.
 259         */
 260
 261        do {
 262                got_intr = 0;
 263                if (esp_chips[0] &&
 264                    (mac_esp_read8(esp_chips[0], ESP_STATUS) & ESP_STAT_INTR)) {
 265                        (void)scsi_esp_intr(irq, esp_chips[0]);
 266                        got_intr = 1;
 267                }
 268                if (esp_chips[1] &&
 269                    (mac_esp_read8(esp_chips[1], ESP_STATUS) & ESP_STAT_INTR)) {
 270                        (void)scsi_esp_intr(irq, esp_chips[1]);
 271                        got_intr = 1;
 272                }
 273        } while (got_intr);
 274
 275        return IRQ_HANDLED;
 276}
 277
 278static struct esp_driver_ops mac_esp_ops = {
 279        .esp_write8       = mac_esp_write8,
 280        .esp_read8        = mac_esp_read8,
 281        .irq_pending      = mac_esp_irq_pending,
 282        .dma_length_limit = mac_esp_dma_length_limit,
 283        .reset_dma        = mac_esp_reset_dma,
 284        .dma_drain        = mac_esp_dma_drain,
 285        .dma_invalidate   = mac_esp_dma_invalidate,
 286        .send_dma_cmd     = mac_esp_send_pdma_cmd,
 287        .dma_error        = mac_esp_dma_error,
 288};
 289
 290static int esp_mac_probe(struct platform_device *dev)
 291{
 292        struct scsi_host_template *tpnt = &scsi_esp_template;
 293        struct Scsi_Host *host;
 294        struct esp *esp;
 295        int err;
 296        struct mac_esp_priv *mep;
 297
 298        if (!MACH_IS_MAC)
 299                return -ENODEV;
 300
 301        if (dev->id > 1)
 302                return -ENODEV;
 303
 304        host = scsi_host_alloc(tpnt, sizeof(struct esp));
 305
 306        err = -ENOMEM;
 307        if (!host)
 308                goto fail;
 309
 310        host->max_id = 8;
 311        host->dma_boundary = PAGE_SIZE - 1;
 312        esp = shost_priv(host);
 313
 314        esp->host = host;
 315        esp->dev = &dev->dev;
 316
 317        esp->command_block = kzalloc(16, GFP_KERNEL);
 318        if (!esp->command_block)
 319                goto fail_unlink;
 320        esp->command_block_dma = (dma_addr_t)esp->command_block;
 321
 322        esp->scsi_id = 7;
 323        host->this_id = esp->scsi_id;
 324        esp->scsi_id_mask = 1 << esp->scsi_id;
 325
 326        mep = kzalloc(sizeof(struct mac_esp_priv), GFP_KERNEL);
 327        if (!mep)
 328                goto fail_free_command_block;
 329        mep->esp = esp;
 330        platform_set_drvdata(dev, mep);
 331
 332        switch (macintosh_config->scsi_type) {
 333        case MAC_SCSI_QUADRA:
 334                esp->cfreq     = 16500000;
 335                esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA;
 336                mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
 337                mep->pdma_regs = NULL;
 338                break;
 339        case MAC_SCSI_QUADRA2:
 340                esp->cfreq     = 25000000;
 341                esp->regs      = (void __iomem *)(MAC_ESP_REGS_QUADRA2 +
 342                                 dev->id * MAC_ESP_REGS_SPACING);
 343                mep->pdma_io   = esp->regs + MAC_ESP_PDMA_IO_OFFSET;
 344                mep->pdma_regs = (void __iomem *)(MAC_ESP_PDMA_REG +
 345                                 dev->id * MAC_ESP_PDMA_REG_SPACING);
 346                nubus_writel(0x1d1, mep->pdma_regs);
 347                break;
 348        case MAC_SCSI_QUADRA3:
 349                /* These quadras have a real DMA controller (the PSC) but we
 350                 * don't know how to drive it so we must use PIO instead.
 351                 */
 352                esp->cfreq     = 25000000;
 353                esp->regs      = (void __iomem *)MAC_ESP_REGS_QUADRA3;
 354                mep->pdma_io   = NULL;
 355                mep->pdma_regs = NULL;
 356                break;
 357        }
 358        esp->fifo_reg = esp->regs + ESP_FDATA * 16;
 359
 360        esp->ops = &mac_esp_ops;
 361        esp->flags = ESP_FLAG_NO_DMA_MAP;
 362        if (mep->pdma_io == NULL) {
 363                printk(KERN_INFO PFX "using PIO for controller %d\n", dev->id);
 364                esp_write8(0, ESP_TCLOW);
 365                esp_write8(0, ESP_TCMED);
 366                esp->flags |= ESP_FLAG_DISABLE_SYNC;
 367                mac_esp_ops.send_dma_cmd = esp_send_pio_cmd;
 368        } else {
 369                printk(KERN_INFO PFX "using PDMA for controller %d\n", dev->id);
 370        }
 371
 372        host->irq = IRQ_MAC_SCSI;
 373
 374        /* The request_irq() call is intended to succeed for the first device
 375         * and fail for the second device.
 376         */
 377        err = request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL);
 378        spin_lock(&esp_chips_lock);
 379        if (err < 0 && esp_chips[!dev->id] == NULL) {
 380                spin_unlock(&esp_chips_lock);
 381                goto fail_free_priv;
 382        }
 383        esp_chips[dev->id] = esp;
 384        spin_unlock(&esp_chips_lock);
 385
 386        err = scsi_esp_register(esp);
 387        if (err)
 388                goto fail_free_irq;
 389
 390        return 0;
 391
 392fail_free_irq:
 393        spin_lock(&esp_chips_lock);
 394        esp_chips[dev->id] = NULL;
 395        if (esp_chips[!dev->id] == NULL) {
 396                spin_unlock(&esp_chips_lock);
 397                free_irq(host->irq, NULL);
 398        } else
 399                spin_unlock(&esp_chips_lock);
 400fail_free_priv:
 401        kfree(mep);
 402fail_free_command_block:
 403        kfree(esp->command_block);
 404fail_unlink:
 405        scsi_host_put(host);
 406fail:
 407        return err;
 408}
 409
 410static int esp_mac_remove(struct platform_device *dev)
 411{
 412        struct mac_esp_priv *mep = platform_get_drvdata(dev);
 413        struct esp *esp = mep->esp;
 414        unsigned int irq = esp->host->irq;
 415
 416        scsi_esp_unregister(esp);
 417
 418        spin_lock(&esp_chips_lock);
 419        esp_chips[dev->id] = NULL;
 420        if (esp_chips[!dev->id] == NULL) {
 421                spin_unlock(&esp_chips_lock);
 422                free_irq(irq, NULL);
 423        } else
 424                spin_unlock(&esp_chips_lock);
 425
 426        kfree(mep);
 427
 428        kfree(esp->command_block);
 429
 430        scsi_host_put(esp->host);
 431
 432        return 0;
 433}
 434
 435static struct platform_driver esp_mac_driver = {
 436        .probe    = esp_mac_probe,
 437        .remove   = esp_mac_remove,
 438        .driver   = {
 439                .name   = DRV_MODULE_NAME,
 440        },
 441};
 442
 443static int __init mac_esp_init(void)
 444{
 445        return platform_driver_register(&esp_mac_driver);
 446}
 447
 448static void __exit mac_esp_exit(void)
 449{
 450        platform_driver_unregister(&esp_mac_driver);
 451}
 452
 453MODULE_DESCRIPTION("Mac ESP SCSI driver");
 454MODULE_AUTHOR("Finn Thain");
 455MODULE_LICENSE("GPL v2");
 456MODULE_VERSION(DRV_VERSION);
 457MODULE_ALIAS("platform:" DRV_MODULE_NAME);
 458
 459module_init(mac_esp_init);
 460module_exit(mac_esp_exit);
 461