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 /*
  * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
  *
  * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
  *
  *   Loosely based on the work of Robert De Vries' team and added:
  *    - working real DMA
  *    - Falcon support (untested yet!)   ++bjoern fixed and now it works
  *    - lots of extensions and bug fixes.
  *
  * 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.
  *
  */
 
 /*
  * Notes for Falcon SCSI DMA
  *
  * The 5380 device is one of several that all share the DMA chip. Hence
  * "locking" and "unlocking" access to this chip is required.
  *
  * Two possible schemes for ST DMA acquisition by atari_scsi are:
  * 1) The lock is taken for each command separately (i.e. can_queue == 1).
  * 2) The lock is taken when the first command arrives and released
  * when the last command is finished (i.e. can_queue > 1).
  *
  * The first alternative limits SCSI bus utilization, since interleaving
  * commands is not possible. The second gives better performance but is
  * unfair to other drivers needing to use the ST DMA chip. In order to
  * allow the IDE and floppy drivers equal access to the ST DMA chip
  * the default is can_queue == 1.
  */
 
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/blkdev.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/nvram.h>
 #include <linux/bitops.h>
 #include <linux/wait.h>
 #include <linux/platform_device.h>
 
 #include <asm/setup.h>
 #include <asm/atarihw.h>
 #include <asm/atariints.h>
 #include <asm/atari_stdma.h>
 #include <asm/atari_stram.h>
 #include <asm/io.h>
 
 #include <scsi/scsi_host.h>
 
 #define DMA_MIN_SIZE                    32
 
 /* Definitions for the core NCR5380 driver. */
 
 #define NCR5380_implementation_fields   /* none */
 
 static u8 (*atari_scsi_reg_read)(unsigned int);
 static void (*atari_scsi_reg_write)(unsigned int, u8);
 
 #define NCR5380_read(reg)               atari_scsi_reg_read(reg)
 #define NCR5380_write(reg, value)       atari_scsi_reg_write(reg, value)
 
 #define NCR5380_queue_command           atari_scsi_queue_command
 #define NCR5380_abort                   atari_scsi_abort
 #define NCR5380_info                    atari_scsi_info
 
 #define NCR5380_dma_xfer_len            atari_scsi_dma_xfer_len
 #define NCR5380_dma_recv_setup          atari_scsi_dma_recv_setup
 #define NCR5380_dma_send_setup          atari_scsi_dma_send_setup
 #define NCR5380_dma_residual            atari_scsi_dma_residual
 
 #define NCR5380_acquire_dma_irq(instance)      falcon_get_lock(instance)
 #define NCR5380_release_dma_irq(instance)      falcon_release_lock()
 
 #include "NCR5380.h"
 
 
 #define IS_A_TT()   ATARIHW_PRESENT(TT_SCSI)
 
 #define SCSI_DMA_WRITE_P(elt,val)               \
     do {                            \
         unsigned long v = val;              \
         tt_scsi_dma.elt##_lo = v & 0xff;        \
         v >>= 8;                    \
         tt_scsi_dma.elt##_lmd = v & 0xff;       \
         v >>= 8;                    \
         tt_scsi_dma.elt##_hmd = v & 0xff;       \
         v >>= 8;                    \
         tt_scsi_dma.elt##_hi = v & 0xff;        \
     } while(0)
 
 #define SCSI_DMA_READ_P(elt)                    \
     (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) |   \
          (unsigned long)tt_scsi_dma.elt##_hmd) << 8) |  \
        (unsigned long)tt_scsi_dma.elt##_lmd) << 8) |    \
      (unsigned long)tt_scsi_dma.elt##_lo)
 
 
 static inline void SCSI_DMA_SETADR(unsigned long adr)
 {
     st_dma.dma_lo = (unsigned char)adr;
     MFPDELAY();
     adr >>= 8;
     st_dma.dma_md = (unsigned char)adr;
     MFPDELAY();
     adr >>= 8;
     st_dma.dma_hi = (unsigned char)adr;
     MFPDELAY();
 }
 
 static inline unsigned long SCSI_DMA_GETADR(void)
 {
     unsigned long adr;
     adr = st_dma.dma_lo;
     MFPDELAY();
     adr |= (st_dma.dma_md & 0xff) << 8;
     MFPDELAY();
     adr |= (st_dma.dma_hi & 0xff) << 16;
     MFPDELAY();
     return adr;
 }
 
 static void atari_scsi_fetch_restbytes(void);
 
 static unsigned long    atari_dma_residual, atari_dma_startaddr;
 static short        atari_dma_active;
 /* pointer to the dribble buffer */
 static char     *atari_dma_buffer;
 /* precalculated physical address of the dribble buffer */
 static unsigned long    atari_dma_phys_buffer;
 /* != 0 tells the Falcon int handler to copy data from the dribble buffer */
 static char     *atari_dma_orig_addr;
 /* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
  * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
  * cases where requests to physical contiguous buffers have been merged, this
  * request is <= 4k (one page). So I don't think we have to split transfers
  * just due to this buffer size...
  */
 #define STRAM_BUFFER_SIZE   (4096)
 /* mask for address bits that can't be used with the ST-DMA */
 static unsigned long    atari_dma_stram_mask;
 #define STRAM_ADDR(a)   (((a) & atari_dma_stram_mask) == 0)
 
 static int setup_can_queue = -1;
 module_param(setup_can_queue, int, 0);
 static int setup_cmd_per_lun = -1;
 module_param(setup_cmd_per_lun, int, 0);
 static int setup_sg_tablesize = -1;
 module_param(setup_sg_tablesize, int, 0);
 static int setup_hostid = -1;
 module_param(setup_hostid, int, 0);
 static int setup_toshiba_delay = -1;
 module_param(setup_toshiba_delay, int, 0);
 
 
 static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
 {
     int i;
     unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
 
     if (dma_stat & 0x01) {
 
         /* A bus error happens when DMA-ing from the last page of a
          * physical memory chunk (DMA prefetch!), but that doesn't hurt.
          * Check for this case:
          */
 
         for (i = 0; i < m68k_num_memory; ++i) {
             end_addr = m68k_memory[i].addr + m68k_memory[i].size;
             if (end_addr <= addr && addr <= end_addr + 4)
                 return 1;
         }
     }
     return 0;
 }
 
 
 static irqreturn_t scsi_tt_intr(int irq, void *dev)
 {
     struct Scsi_Host *instance = dev;
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int dma_stat;
 
     dma_stat = tt_scsi_dma.dma_ctrl;
 
     dsprintk(NDEBUG_INTR, instance, "NCR5380 interrupt, DMA status = %02x\n",
              dma_stat & 0xff);
 
     /* Look if it was the DMA that has interrupted: First possibility
      * is that a bus error occurred...
      */
     if (dma_stat & 0x80) {
         if (!scsi_dma_is_ignored_buserr(dma_stat)) {
             printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
                    SCSI_DMA_READ_P(dma_addr));
             printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
         }
     }
 
     /* If the DMA is active but not finished, we have the case
      * that some other 5380 interrupt occurred within the DMA transfer.
      * This means we have residual bytes, if the desired end address
      * is not yet reached. Maybe we have to fetch some bytes from the
      * rest data register, too. The residual must be calculated from
      * the address pointer, not the counter register, because only the
      * addr reg counts bytes not yet written and pending in the rest
      * data reg!
      */
     if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
         atari_dma_residual = hostdata->dma_len -
             (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
 
         dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
                atari_dma_residual);
 
         if ((signed int)atari_dma_residual < 0)
             atari_dma_residual = 0;
         if ((dma_stat & 1) == 0) {
             /*
              * After read operations, we maybe have to
              * transport some rest bytes
              */
             atari_scsi_fetch_restbytes();
         } else {
             /*
              * There seems to be a nasty bug in some SCSI-DMA/NCR
              * combinations: If a target disconnects while a write
              * operation is going on, the address register of the
              * DMA may be a few bytes farer than it actually read.
              * This is probably due to DMA prefetching and a delay
              * between DMA and NCR.  Experiments showed that the
              * dma_addr is 9 bytes to high, but this could vary.
              * The problem is, that the residual is thus calculated
              * wrong and the next transfer will start behind where
              * it should.  So we round up the residual to the next
              * multiple of a sector size, if it isn't already a
              * multiple and the originally expected transfer size
              * was.  The latter condition is there to ensure that
              * the correction is taken only for "real" data
              * transfers and not for, e.g., the parameters of some
              * other command.  These shouldn't disconnect anyway.
              */
             if (atari_dma_residual & 0x1ff) {
                 dprintk(NDEBUG_DMA, "SCSI DMA: DMA bug corrected, "
                        "difference %ld bytes\n",
                        512 - (atari_dma_residual & 0x1ff));
                 atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
             }
         }
         tt_scsi_dma.dma_ctrl = 0;
     }
 
     /* If the DMA is finished, fetch the rest bytes and turn it off */
     if (dma_stat & 0x40) {
         atari_dma_residual = 0;
         if ((dma_stat & 1) == 0)
             atari_scsi_fetch_restbytes();
         tt_scsi_dma.dma_ctrl = 0;
     }
 
     NCR5380_intr(irq, dev);
 
     return IRQ_HANDLED;
 }
 
 
 static irqreturn_t scsi_falcon_intr(int irq, void *dev)
 {
     struct Scsi_Host *instance = dev;
     struct NCR5380_hostdata *hostdata = shost_priv(instance);
     int dma_stat;
 
     /* Turn off DMA and select sector counter register before
      * accessing the status register (Atari recommendation!)
      */
     st_dma.dma_mode_status = 0x90;
     dma_stat = st_dma.dma_mode_status;
 
     /* Bit 0 indicates some error in the DMA process... don't know
      * what happened exactly (no further docu).
      */
     if (!(dma_stat & 0x01)) {
         /* DMA error */
         printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
     }
 
     /* If the DMA was active, but now bit 1 is not clear, it is some
      * other 5380 interrupt that finishes the DMA transfer. We have to
      * calculate the number of residual bytes and give a warning if
      * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
      */
     if (atari_dma_active && (dma_stat & 0x02)) {
         unsigned long transferred;
 
         transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
         /* The ST-DMA address is incremented in 2-byte steps, but the
          * data are written only in 16-byte chunks. If the number of
          * transferred bytes is not divisible by 16, the remainder is
          * lost somewhere in outer space.
          */
         if (transferred & 15)
             printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
                    "ST-DMA fifo\n", transferred & 15);
 
         atari_dma_residual = hostdata->dma_len - transferred;
         dprintk(NDEBUG_DMA, "SCSI DMA: There are %ld residual bytes.\n",
                atari_dma_residual);
     } else
         atari_dma_residual = 0;
     atari_dma_active = 0;
 
     if (atari_dma_orig_addr) {
         /* If the dribble buffer was used on a read operation, copy the DMA-ed
          * data to the original destination address.
          */
         memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
                hostdata->dma_len - atari_dma_residual);
         atari_dma_orig_addr = NULL;
     }
 
     NCR5380_intr(irq, dev);
 
     return IRQ_HANDLED;
 }
 
 
 static void atari_scsi_fetch_restbytes(void)
 {
     int nr;
     char *src, *dst;
     unsigned long phys_dst;
 
     /* fetch rest bytes in the DMA register */
     phys_dst = SCSI_DMA_READ_P(dma_addr);
     nr = phys_dst & 3;
     if (nr) {
         /* there are 'nr' bytes left for the last long address
            before the DMA pointer */
         phys_dst ^= nr;
         dprintk(NDEBUG_DMA, "SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
                nr, phys_dst);
         /* The content of the DMA pointer is a physical address!  */
         dst = phys_to_virt(phys_dst);
         dprintk(NDEBUG_DMA, " = virt addr %p\n", dst);
         for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
             *dst++ = *src++;
     }
 }
 
 
 /* This function releases the lock on the DMA chip if there is no
  * connected command and the disconnected queue is empty.
  */
 
 static void falcon_release_lock(void)
 {
     if (IS_A_TT())
         return;
 
     if (stdma_is_locked_by(scsi_falcon_intr))
         stdma_release();
 }
 
 /* This function manages the locking of the ST-DMA.
  * If the DMA isn't locked already for SCSI, it tries to lock it by
  * calling stdma_lock(). But if the DMA is locked by the SCSI code and
  * there are other drivers waiting for the chip, we do not issue the
  * command immediately but tell the SCSI mid-layer to defer.
  */
 
 static int falcon_get_lock(struct Scsi_Host *instance)
 {
     if (IS_A_TT())
         return 1;
 
     if (stdma_is_locked_by(scsi_falcon_intr))
         return 1;
 
     /* stdma_lock() may sleep which means it can't be used here */
     return stdma_try_lock(scsi_falcon_intr, instance);
 }
 
 #ifndef MODULE
 static int __init atari_scsi_setup(char *str)
 {
     /* Format of atascsi parameter is:
      *   atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
      * Defaults depend on TT or Falcon, determined at run time.
      * Negative values mean don't change.
      */
     int ints[8];
 
     get_options(str, ARRAY_SIZE(ints), ints);
 
     if (ints[0] < 1) {
         printk("atari_scsi_setup: no arguments!\n");
         return 0;
     }
     if (ints[0] >= 1)
         setup_can_queue = ints[1];
     if (ints[0] >= 2)
         setup_cmd_per_lun = ints[2];
     if (ints[0] >= 3)
         setup_sg_tablesize = ints[3];
     if (ints[0] >= 4)
         setup_hostid = ints[4];
     /* ints[5] (use_tagged_queuing) is ignored */
     /* ints[6] (use_pdma) is ignored */
     if (ints[0] >= 7)
         setup_toshiba_delay = ints[7];
 
     return 1;
 }
 
 __setup("atascsi=", atari_scsi_setup);
 #endif /* !MODULE */
 
 static unsigned long atari_scsi_dma_setup(struct NCR5380_hostdata *hostdata,
                       void *data, unsigned long count,
                       int dir)
 {
     unsigned long addr = virt_to_phys(data);
 
     dprintk(NDEBUG_DMA, "scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, dir = %d\n",
             hostdata->host->host_no, data, addr, count, dir);
 
     if (!IS_A_TT() && !STRAM_ADDR(addr)) {
         /* If we have a non-DMAable address on a Falcon, use the dribble
          * buffer; 'orig_addr' != 0 in the read case tells the interrupt
          * handler to copy data from the dribble buffer to the originally
          * wanted address.
          */
         if (dir)
             memcpy(atari_dma_buffer, data, count);
         else
             atari_dma_orig_addr = data;
         addr = atari_dma_phys_buffer;
     }
 
     atari_dma_startaddr = addr; /* Needed for calculating residual later. */
 
     /* Cache cleanup stuff: On writes, push any dirty cache out before sending
      * it to the peripheral. (Must be done before DMA setup, since at least
      * the ST-DMA begins to fill internal buffers right after setup. For
      * reads, invalidate any cache, may be altered after DMA without CPU
      * knowledge.
      *
      * ++roman: For the Medusa, there's no need at all for that cache stuff,
      * because the hardware does bus snooping (fine!).
      */
     dma_cache_maintenance(addr, count, dir);
 
     if (IS_A_TT()) {
         tt_scsi_dma.dma_ctrl = dir;
         SCSI_DMA_WRITE_P(dma_addr, addr);
         SCSI_DMA_WRITE_P(dma_cnt, count);
         tt_scsi_dma.dma_ctrl = dir | 2;
     } else { /* ! IS_A_TT */
 
         /* set address */
         SCSI_DMA_SETADR(addr);
 
         /* toggle direction bit to clear FIFO and set DMA direction */
         dir <<= 8;
         st_dma.dma_mode_status = 0x90 | dir;
         st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
         st_dma.dma_mode_status = 0x90 | dir;
         udelay(40);
         /* On writes, round up the transfer length to the next multiple of 512
          * (see also comment at atari_dma_xfer_len()). */
         st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
         udelay(40);
         st_dma.dma_mode_status = 0x10 | dir;
         udelay(40);
         /* need not restore value of dir, only boolean value is tested */
         atari_dma_active = 1;
     }
 
     return count;
 }
 
 static inline int atari_scsi_dma_recv_setup(struct NCR5380_hostdata *hostdata,
                                             unsigned char *data, int count)
 {
     return atari_scsi_dma_setup(hostdata, data, count, 0);
 }
 
 static inline int atari_scsi_dma_send_setup(struct NCR5380_hostdata *hostdata,
                                             unsigned char *data, int count)
 {
     return atari_scsi_dma_setup(hostdata, data, count, 1);
 }
 
 static int atari_scsi_dma_residual(struct NCR5380_hostdata *hostdata)
 {
     return atari_dma_residual;
 }
 
 
 #define CMD_SURELY_BLOCK_MODE   0
 #define CMD_SURELY_BYTE_MODE    1
 #define CMD_MODE_UNKNOWN        2
 
 static int falcon_classify_cmd(struct scsi_cmnd *cmd)
 {
     unsigned char opcode = cmd->cmnd[0];
 
     if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
         opcode == READ_BUFFER)
         return CMD_SURELY_BYTE_MODE;
     else if (opcode == READ_6 || opcode == READ_10 ||
          opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
          opcode == RECOVER_BUFFERED_DATA) {
         /* In case of a sequential-access target (tape), special care is
          * needed here: The transfer is block-mode only if the 'fixed' bit is
          * set! */
         if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
             return CMD_SURELY_BYTE_MODE;
         else
             return CMD_SURELY_BLOCK_MODE;
     } else
         return CMD_MODE_UNKNOWN;
 }
 
 
 /* This function calculates the number of bytes that can be transferred via
  * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
  * ST-DMA chip. There are only multiples of 512 bytes possible and max.
  * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
  * possible on the Falcon, since that would require to program the DMA for
  * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
  * the overrun problem, so this question is academic :-)
  */
 
 static int atari_scsi_dma_xfer_len(struct NCR5380_hostdata *hostdata,
                                    struct scsi_cmnd *cmd)
 {
     int wanted_len = NCR5380_to_ncmd(cmd)->this_residual;
     int possible_len, limit;
 
     if (wanted_len < DMA_MIN_SIZE)
         return 0;
 
     if (IS_A_TT())
         /* TT SCSI DMA can transfer arbitrary #bytes */
         return wanted_len;
 
     /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
      * 255*512 bytes, but this should be enough)
      *
      * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
      * that return a number of bytes which cannot be known beforehand. In this
      * case, the given transfer length is an "allocation length". Now it
      * can happen that this allocation length is a multiple of 512 bytes and
      * the DMA is used. But if not n*512 bytes really arrive, some input data
      * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
      * between commands that do block transfers and those that do byte
      * transfers. But this isn't easy... there are lots of vendor specific
      * commands, and the user can issue any command via the
      * SCSI_IOCTL_SEND_COMMAND.
      *
      * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
      * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
      * and 3), the thing to do is obvious: allow any number of blocks via DMA
      * or none. In case 2), we apply some heuristic: Byte mode is assumed if
      * the transfer (allocation) length is < 1024, hoping that no cmd. not
      * explicitly known as byte mode have such big allocation lengths...
      * BTW, all the discussion above applies only to reads. DMA writes are
      * unproblematic anyways, since the targets aborts the transfer after
      * receiving a sufficient number of bytes.
      *
      * Another point: If the transfer is from/to an non-ST-RAM address, we
      * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
      */
 
     if (cmd->sc_data_direction == DMA_TO_DEVICE) {
         /* Write operation can always use the DMA, but the transfer size must
          * be rounded up to the next multiple of 512 (atari_dma_setup() does
          * this).
          */
         possible_len = wanted_len;
     } else {
         /* Read operations: if the wanted transfer length is not a multiple of
          * 512, we cannot use DMA, since the ST-DMA cannot split transfers
          * (no interrupt on DMA finished!)
          */
         if (wanted_len & 0x1ff)
             possible_len = 0;
         else {
             /* Now classify the command (see above) and decide whether it is
              * allowed to do DMA at all */
             switch (falcon_classify_cmd(cmd)) {
             case CMD_SURELY_BLOCK_MODE:
                 possible_len = wanted_len;
                 break;
             case CMD_SURELY_BYTE_MODE:
                 possible_len = 0; /* DMA prohibited */
                 break;
             case CMD_MODE_UNKNOWN:
             default:
                 /* For unknown commands assume block transfers if the transfer
                  * size/allocation length is >= 1024 */
                 possible_len = (wanted_len < 1024) ? 0 : wanted_len;
                 break;
             }
         }
     }
 
     /* Last step: apply the hard limit on DMA transfers */
     limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(NCR5380_to_ncmd(cmd)->ptr))) ?
             STRAM_BUFFER_SIZE : 255*512;
     if (possible_len > limit)
         possible_len = limit;
 
     if (possible_len != wanted_len)
         dprintk(NDEBUG_DMA, "DMA transfer now %d bytes instead of %d\n",
                 possible_len, wanted_len);
 
     return possible_len;
 }
 
 
 /* NCR5380 register access functions
  *
  * There are separate functions for TT and Falcon, because the access
  * methods are quite different. The calling macros NCR5380_read and
  * NCR5380_write call these functions via function pointers.
  */
 
 static u8 atari_scsi_tt_reg_read(unsigned int reg)
 {
     return tt_scsi_regp[reg * 2];
 }
 
 static void atari_scsi_tt_reg_write(unsigned int reg, u8 value)
 {
     tt_scsi_regp[reg * 2] = value;
 }
 
 static u8 atari_scsi_falcon_reg_read(unsigned int reg)
 {
     unsigned long flags;
     u8 result;
 
     reg += 0x88;
     local_irq_save(flags);
     dma_wd.dma_mode_status = (u_short)reg;
     result = (u8)dma_wd.fdc_acces_seccount;
     local_irq_restore(flags);
     return result;
 }
 
 static void atari_scsi_falcon_reg_write(unsigned int reg, u8 value)
 {
     unsigned long flags;
 
     reg += 0x88;
     local_irq_save(flags);
     dma_wd.dma_mode_status = (u_short)reg;
     dma_wd.fdc_acces_seccount = (u_short)value;
     local_irq_restore(flags);
 }
 
 
 #include "NCR5380.c"
 
 static int atari_scsi_host_reset(struct scsi_cmnd *cmd)
 {
     int rv;
     unsigned long flags;
 
     local_irq_save(flags);
 
     /* Abort a maybe active DMA transfer */
     if (IS_A_TT()) {
         tt_scsi_dma.dma_ctrl = 0;
     } else {
         if (stdma_is_locked_by(scsi_falcon_intr))
             st_dma.dma_mode_status = 0x90;
         atari_dma_active = 0;
         atari_dma_orig_addr = NULL;
     }
 
     rv = NCR5380_host_reset(cmd);
 
     /* The 5380 raises its IRQ line while _RST is active but the ST DMA
      * "lock" has been released so this interrupt may end up handled by
      * floppy or IDE driver (if one of them holds the lock). The NCR5380
      * interrupt flag has been cleared already.
      */
 
     local_irq_restore(flags);
 
     return rv;
 }
 
 #define DRV_MODULE_NAME         "atari_scsi"
 #define PFX                     DRV_MODULE_NAME ": "
 
 static struct scsi_host_template atari_scsi_template = {
     .module         = THIS_MODULE,
     .proc_name      = DRV_MODULE_NAME,
     .name           = "Atari native SCSI",
     .info           = atari_scsi_info,
     .queuecommand       = atari_scsi_queue_command,
     .eh_abort_handler   = atari_scsi_abort,
     .eh_host_reset_handler  = atari_scsi_host_reset,
     .this_id        = 7,
     .cmd_per_lun        = 2,
     .dma_boundary       = PAGE_SIZE - 1,
     .cmd_size       = sizeof(struct NCR5380_cmd),
 };
 
 static int __init atari_scsi_probe(struct platform_device *pdev)
 {
     struct Scsi_Host *instance;
     int error;
     struct resource *irq;
     int host_flags = 0;
 
     irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
     if (!irq)
         return -ENODEV;
 
     if (ATARIHW_PRESENT(TT_SCSI)) {
         atari_scsi_reg_read  = atari_scsi_tt_reg_read;
         atari_scsi_reg_write = atari_scsi_tt_reg_write;
     } else {
         atari_scsi_reg_read  = atari_scsi_falcon_reg_read;
         atari_scsi_reg_write = atari_scsi_falcon_reg_write;
     }
 
     if (ATARIHW_PRESENT(TT_SCSI)) {
         atari_scsi_template.can_queue    = 16;
         atari_scsi_template.sg_tablesize = SG_ALL;
     } else {
         atari_scsi_template.can_queue    = 1;
         atari_scsi_template.sg_tablesize = 1;
     }
 
     if (setup_can_queue > 0)
         atari_scsi_template.can_queue = setup_can_queue;
 
     if (setup_cmd_per_lun > 0)
         atari_scsi_template.cmd_per_lun = setup_cmd_per_lun;
 
     /* Don't increase sg_tablesize on Falcon! */
     if (ATARIHW_PRESENT(TT_SCSI) && setup_sg_tablesize > 0)
         atari_scsi_template.sg_tablesize = setup_sg_tablesize;
 
     if (setup_hostid >= 0) {
         atari_scsi_template.this_id = setup_hostid & 7;
     } else if (IS_REACHABLE(CONFIG_NVRAM)) {
         /* Test if a host id is set in the NVRam */
         if (ATARIHW_PRESENT(TT_CLK)) {
             unsigned char b;
             loff_t offset = 16;
             ssize_t count = nvram_read(&b, 1, &offset);
 
             /* Arbitration enabled? (for TOS)
              * If yes, use configured host ID
              */
             if ((count == 1) && (b & 0x80))
                 atari_scsi_template.this_id = b & 7;
         }
     }
 
     /* If running on a Falcon and if there's TT-Ram (i.e., more than one
      * memory block, since there's always ST-Ram in a Falcon), then
      * allocate a STRAM_BUFFER_SIZE byte dribble buffer for transfers
      * from/to alternative Ram.
      */
     if (ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) &&
         m68k_realnum_memory > 1) {
         atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
         if (!atari_dma_buffer) {
             pr_err(PFX "can't allocate ST-RAM double buffer\n");
             return -ENOMEM;
         }
         atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
         atari_dma_orig_addr = NULL;
     }
 
     instance = scsi_host_alloc(&atari_scsi_template,
                                sizeof(struct NCR5380_hostdata));
     if (!instance) {
         error = -ENOMEM;
         goto fail_alloc;
     }
 
     instance->irq = irq->start;
 
     host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP;
     host_flags |= setup_toshiba_delay > 0 ? FLAG_TOSHIBA_DELAY : 0;
 
     error = NCR5380_init(instance, host_flags);
     if (error)
         goto fail_init;
 
     if (IS_A_TT()) {
         error = request_irq(instance->irq, scsi_tt_intr, 0,
                             "NCR5380", instance);
         if (error) {
             pr_err(PFX "request irq %d failed, aborting\n",
                    instance->irq);
             goto fail_irq;
         }
         tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */
 
         tt_scsi_dma.dma_ctrl = 0;
         atari_dma_residual = 0;
 
         /* While the read overruns (described by Drew Eckhardt in
          * NCR5380.c) never happened on TTs, they do in fact on the
          * Medusa (This was the cause why SCSI didn't work right for
          * so long there.) Since handling the overruns slows down
          * a bit, I turned the #ifdef's into a runtime condition.
          *
          * In principle it should be sufficient to do max. 1 byte with
          * PIO, but there is another problem on the Medusa with the DMA
          * rest data register. So read_overruns is currently set
          * to 4 to avoid having transfers that aren't a multiple of 4.
          * If the rest data bug is fixed, this can be lowered to 1.
          */
         if (MACH_IS_MEDUSA) {
             struct NCR5380_hostdata *hostdata =
                 shost_priv(instance);
 
             hostdata->read_overruns = 4;
         }
     } else {
         /* Nothing to do for the interrupt: the ST-DMA is initialized
          * already.
          */
         atari_dma_residual = 0;
         atari_dma_active = 0;
         atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
                     : 0xff000000);
     }
 
     NCR5380_maybe_reset_bus(instance);
 
     error = scsi_add_host(instance, NULL);
     if (error)
         goto fail_host;
 
     platform_set_drvdata(pdev, instance);
 
     scsi_scan_host(instance);
     return 0;
 
 fail_host:
     if (IS_A_TT())
         free_irq(instance->irq, instance);
 fail_irq:
     NCR5380_exit(instance);
 fail_init:
     scsi_host_put(instance);
 fail_alloc:
     if (atari_dma_buffer)
         atari_stram_free(atari_dma_buffer);
     return error;
 }
 
 static int __exit atari_scsi_remove(struct platform_device *pdev)
 {
     struct Scsi_Host *instance = platform_get_drvdata(pdev);
 
     scsi_remove_host(instance);
     if (IS_A_TT())
         free_irq(instance->irq, instance);
     NCR5380_exit(instance);
     scsi_host_put(instance);
     if (atari_dma_buffer)
         atari_stram_free(atari_dma_buffer);
     return 0;
 }
 
 static struct platform_driver atari_scsi_driver = {
     .remove = __exit_p(atari_scsi_remove),
     .driver = {
         .name   = DRV_MODULE_NAME,
     },
 };
 
 module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
 
 MODULE_ALIAS("platform:" DRV_MODULE_NAME);
 MODULE_LICENSE("GPL");

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