/* * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port * * Copyright 1994 Roman Hodek * * 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: */ /* ---------------------- */ /* */ /* Since the Falcon SCSI uses the ST-DMA chip, that is shared among */ /* several device drivers, locking and unlocking the access to this */ /* chip is required. But locking is not possible from an interrupt, */ /* since it puts the process to sleep if the lock is not available. */ /* This prevents "late" locking of the DMA chip, i.e. locking it just */ /* before using it, since in case of disconnection-reconnection */ /* commands, the DMA is started from the reselection interrupt. */ /* */ /* Two possible schemes for ST-DMA-locking would be: */ /* 1) The lock is taken for each command separately and disconnecting */ /* is forbidden (i.e. can_queue = 1). */ /* 2) The DMA chip is locked when the first command comes in and */ /* released when the last command is finished and all queues are */ /* empty. */ /* The first alternative would result in bad performance, since the */ /* interleaving of commands would not be used. The second is unfair to */ /* other drivers using the ST-DMA, because the queues will seldom be */ /* totally empty if there is a lot of disk traffic. */ /* */ /* For this reasons I decided to employ a more elaborate scheme: */ /* - First, we give up the lock every time we can (for fairness), this */ /* means every time a command finishes and there are no other commands */ /* on the disconnected queue. */ /* - If there are others waiting to lock the DMA chip, we stop */ /* issuing commands, i.e. moving them onto the issue queue. */ /* Because of that, the disconnected queue will run empty in a */ /* while. Instead we go to sleep on a 'fairness_queue'. */ /* - If the lock is released, all processes waiting on the fairness */ /* queue will be woken. The first of them tries to re-lock the DMA, */ /* the others wait for the first to finish this task. After that, */ /* they can all run on and do their commands... */ /* This sounds complicated (and it is it :-(), but it seems to be a */ /* good compromise between fairness and performance: As long as no one */ /* else wants to work with the ST-DMA chip, SCSI can go along as */ /* usual. If now someone else comes, this behaviour is changed to a */ /* "fairness mode": just already initiated commands are finished and */ /* then the lock is released. The other one waiting will probably win */ /* the race for locking the DMA, since it was waiting for longer. And */ /* after it has finished, SCSI can go ahead again. Finally: I hope I */ /* have not produced any deadlock possibilities! */ /* */ /**************************************************************************/ #include /* For the Atari version, use only polled IO or REAL_DMA */ #define REAL_DMA /* Support tagged queuing? (on devices that are able to... :-) */ #define SUPPORT_TAGS #define MAX_TAGS 32 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "atari_scsi.h" #include "NCR5380.h" #include #include #include #include #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 inline void ENABLE_IRQ(void) { if (IS_A_TT()) atari_enable_irq(IRQ_TT_MFP_SCSI); else atari_enable_irq(IRQ_MFP_FSCSI); } static inline void DISABLE_IRQ(void) { if (IS_A_TT()) atari_disable_irq(IRQ_TT_MFP_SCSI); else atari_disable_irq(IRQ_MFP_FSCSI); } #define HOSTDATA_DMALEN (((struct NCR5380_hostdata *) \ (atari_scsi_host->hostdata))->dma_len) /* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms, * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more * need ten times the standard value... */ #ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY #define AFTER_RESET_DELAY (HZ/2) #else #define AFTER_RESET_DELAY (5*HZ/2) #endif /***************************** Prototypes *****************************/ #ifdef REAL_DMA static void atari_scsi_fetch_restbytes(void); #endif static irqreturn_t scsi_tt_intr(int irq, void *dummy); static irqreturn_t scsi_falcon_intr(int irq, void *dummy); static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata); static int falcon_get_lock(void); #ifdef CONFIG_ATARI_SCSI_RESET_BOOT static void atari_scsi_reset_boot(void); #endif static unsigned char atari_scsi_tt_reg_read(unsigned char reg); static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value); static unsigned char atari_scsi_falcon_reg_read(unsigned char reg); static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value); /************************* End of Prototypes **************************/ static struct Scsi_Host *atari_scsi_host; static unsigned char (*atari_scsi_reg_read)(unsigned char reg); static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value); #ifdef REAL_DMA 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) /* number of bytes to cut from a transfer to handle NCR overruns */ static int atari_read_overruns; #endif 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); #ifdef SUPPORT_TAGS static int setup_use_tagged_queuing = -1; module_param(setup_use_tagged_queuing, int, 0); #endif static int setup_hostid = -1; module_param(setup_hostid, int, 0); #if defined(REAL_DMA) 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; } #if 0 /* Dead code... wasn't called anyway :-) and causes some trouble, because at * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has * to clear the DMA int pending bit before it allows other level 6 interrupts. */ static void scsi_dma_buserr(int irq, void *dummy) { unsigned char dma_stat = tt_scsi_dma.dma_ctrl; /* Don't do anything if a NCR interrupt is pending. Probably it's just * masked... */ if (atari_irq_pending(IRQ_TT_MFP_SCSI)) return; printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n", SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt)); if (dma_stat & 0x80) { if (!scsi_dma_is_ignored_buserr(dma_stat)) printk("SCSI DMA bus error -- bad DMA programming!\n"); } else { /* Under normal circumstances we never should get to this point, * since both interrupts are triggered simultaneously and the 5380 * int has higher priority. When this irq is handled, that DMA * interrupt is cleared. So a warning message is printed here. */ printk("SCSI DMA intr ?? -- this shouldn't happen!\n"); } } #endif #endif static irqreturn_t scsi_tt_intr(int irq, void *dummy) { #ifdef REAL_DMA int dma_stat; dma_stat = tt_scsi_dma.dma_ctrl; dprintk(NDEBUG_INTR, "scsi%d: NCR5380 interrupt, DMA status = %02x\n", atari_scsi_host->host_no, 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_DMALEN - (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; } #endif /* REAL_DMA */ NCR5380_intr(irq, dummy); #if 0 /* To be sure the int is not masked */ atari_enable_irq(IRQ_TT_MFP_SCSI); #endif return IRQ_HANDLED; } static irqreturn_t scsi_falcon_intr(int irq, void *dummy) { #ifdef REAL_DMA 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_DMALEN - 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_DMALEN - atari_dma_residual); atari_dma_orig_addr = NULL; } #endif /* REAL_DMA */ NCR5380_intr(irq, dummy); return IRQ_HANDLED; } #ifdef REAL_DMA 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++; } } #endif /* REAL_DMA */ static int falcon_dont_release = 0; /* 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_if_possible(struct NCR5380_hostdata *hostdata) { unsigned long flags; if (IS_A_TT()) return; local_irq_save(flags); if (!hostdata->disconnected_queue && !hostdata->issue_queue && !hostdata->connected && !falcon_dont_release && stdma_is_locked_by(scsi_falcon_intr)) stdma_release(); local_irq_restore(flags); } /* 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(void) { if (IS_A_TT()) return 1; if (in_interrupt()) return stdma_try_lock(scsi_falcon_intr, NULL); stdma_lock(scsi_falcon_intr, NULL); return 1; } static int __init atari_scsi_detect(struct scsi_host_template *host) { static int called = 0; struct Scsi_Host *instance; if (!MACH_IS_ATARI || (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) || called) return 0; host->proc_name = "Atari"; atari_scsi_reg_read = IS_A_TT() ? atari_scsi_tt_reg_read : atari_scsi_falcon_reg_read; atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write : atari_scsi_falcon_reg_write; /* setup variables */ host->can_queue = (setup_can_queue > 0) ? setup_can_queue : IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE; host->cmd_per_lun = (setup_cmd_per_lun > 0) ? setup_cmd_per_lun : IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN; /* Force sg_tablesize to 0 on a Falcon! */ host->sg_tablesize = !IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE : (setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE; if (setup_hostid >= 0) host->this_id = setup_hostid; else { /* use 7 as default */ host->this_id = 7; /* Test if a host id is set in the NVRam */ if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) { unsigned char b = nvram_read_byte( 14 ); /* Arbitration enabled? (for TOS) If yes, use configured host ID */ if (b & 0x80) host->this_id = b & 7; } } #ifdef SUPPORT_TAGS if (setup_use_tagged_queuing < 0) setup_use_tagged_queuing = 0; #endif #ifdef REAL_DMA /* 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 (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) { atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI"); if (!atari_dma_buffer) { printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM " "double buffer\n"); return 0; } atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer); atari_dma_orig_addr = 0; } #endif instance = scsi_register(host, sizeof(struct NCR5380_hostdata)); if (instance == NULL) { atari_stram_free(atari_dma_buffer); atari_dma_buffer = 0; return 0; } atari_scsi_host = instance; /* * Set irq to 0, to avoid that the mid-level code disables our interrupt * during queue_command calls. This is completely unnecessary, and even * worse causes bad problems on the Falcon, where the int is shared with * IDE and floppy! */ instance->irq = 0; #ifdef CONFIG_ATARI_SCSI_RESET_BOOT atari_scsi_reset_boot(); #endif NCR5380_init(instance, 0); if (IS_A_TT()) { /* This int is actually "pseudo-slow", i.e. it acts like a slow * interrupt after having cleared the pending flag for the DMA * interrupt. */ if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW, "SCSI NCR5380", instance)) { printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI); scsi_unregister(atari_scsi_host); atari_stram_free(atari_dma_buffer); atari_dma_buffer = 0; return 0; } tt_mfp.active_edge |= 0x80; /* SCSI int on L->H */ #ifdef REAL_DMA tt_scsi_dma.dma_ctrl = 0; atari_dma_residual = 0; if (MACH_IS_MEDUSA) { /* 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 'atari_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. */ atari_read_overruns = 4; } #endif /*REAL_DMA*/ } else { /* ! IS_A_TT */ /* Nothing to do for the interrupt: the ST-DMA is initialized * already by atari_init_INTS() */ #ifdef REAL_DMA atari_dma_residual = 0; atari_dma_active = 0; atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 : 0xff000000); #endif } called = 1; return 1; } static int atari_scsi_release(struct Scsi_Host *sh) { if (IS_A_TT()) free_irq(IRQ_TT_MFP_SCSI, sh); if (atari_dma_buffer) atari_stram_free(atari_dma_buffer); NCR5380_exit(sh); return 1; } #ifndef MODULE static int __init atari_scsi_setup(char *str) { /* Format of atascsi parameter is: * atascsi=,,,, * Defaults depend on TT or Falcon, hostid determined at run time. * Negative values mean don't change. */ int ints[6]; get_options(str, ARRAY_SIZE(ints), ints); if (ints[0] < 1) { printk("atari_scsi_setup: no arguments!\n"); return 0; } if (ints[0] >= 1) { if (ints[1] > 0) /* no limits on this, just > 0 */ setup_can_queue = ints[1]; } if (ints[0] >= 2) { if (ints[2] > 0) setup_cmd_per_lun = ints[2]; } if (ints[0] >= 3) { if (ints[3] >= 0) { setup_sg_tablesize = ints[3]; /* Must be <= SG_ALL (255) */ if (setup_sg_tablesize > SG_ALL) setup_sg_tablesize = SG_ALL; } } if (ints[0] >= 4) { /* Must be between 0 and 7 */ if (ints[4] >= 0 && ints[4] <= 7) setup_hostid = ints[4]; else if (ints[4] > 7) printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]); } #ifdef SUPPORT_TAGS if (ints[0] >= 5) { if (ints[5] >= 0) setup_use_tagged_queuing = !!ints[5]; } #endif return 1; } __setup("atascsi=", atari_scsi_setup); #endif /* !MODULE */ #ifdef CONFIG_ATARI_SCSI_RESET_BOOT static void __init atari_scsi_reset_boot(void) { unsigned long end; /* * Do a SCSI reset to clean up the bus during initialization. No messing * with the queues, interrupts, or locks necessary here. */ printk("Atari SCSI: resetting the SCSI bus..."); /* get in phase */ NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG))); /* assert RST */ NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST); /* The min. reset hold time is 25us, so 40us should be enough */ udelay(50); /* reset RST and interrupt */ NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE); NCR5380_read(RESET_PARITY_INTERRUPT_REG); end = jiffies + AFTER_RESET_DELAY; while (time_before(jiffies, end)) barrier(); printk(" done\n"); } #endif #if defined(REAL_DMA) static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance, 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", instance->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 (count == 0) printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n"); 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 long atari_scsi_dma_residual(struct Scsi_Host *instance) { 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 unsigned long atari_dma_xfer_len(unsigned long wanted_len, struct scsi_cmnd *cmd, int write_flag) { unsigned long possible_len, limit; 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 (write_flag) { /* 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(cmd->SCp.ptr))) ? STRAM_BUFFER_SIZE : 255*512; if (possible_len > limit) possible_len = limit; if (possible_len != wanted_len) dprintk(NDEBUG_DMA, "Sorry, must cut DMA transfer size to %ld bytes " "instead of %ld\n", possible_len, wanted_len); return possible_len; } #endif /* REAL_DMA */ /* 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 unsigned char atari_scsi_tt_reg_read(unsigned char reg) { return tt_scsi_regp[reg * 2]; } static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value) { tt_scsi_regp[reg * 2] = value; } static unsigned char atari_scsi_falcon_reg_read(unsigned char reg) { dma_wd.dma_mode_status= (u_short)(0x88 + reg); return (u_char)dma_wd.fdc_acces_seccount; } static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value) { dma_wd.dma_mode_status = (u_short)(0x88 + reg); dma_wd.fdc_acces_seccount = (u_short)value; } #include "atari_NCR5380.c" static int atari_scsi_bus_reset(struct scsi_cmnd *cmd) { int rv; struct NCR5380_hostdata *hostdata = shost_priv(cmd->device->host); /* For doing the reset, SCSI interrupts must be disabled first, * since the 5380 raises its IRQ line while _RST is active and we * can't disable interrupts completely, since we need the timer. */ /* And abort a maybe active DMA transfer */ if (IS_A_TT()) { atari_turnoff_irq(IRQ_TT_MFP_SCSI); #ifdef REAL_DMA tt_scsi_dma.dma_ctrl = 0; #endif } else { atari_turnoff_irq(IRQ_MFP_FSCSI); #ifdef REAL_DMA st_dma.dma_mode_status = 0x90; atari_dma_active = 0; atari_dma_orig_addr = NULL; #endif } rv = NCR5380_bus_reset(cmd); if (IS_A_TT()) atari_turnon_irq(IRQ_TT_MFP_SCSI); else atari_turnon_irq(IRQ_MFP_FSCSI); if (rv == SUCCESS) falcon_release_lock_if_possible(hostdata); return rv; } static struct scsi_host_template driver_template = { .show_info = atari_scsi_show_info, .name = "Atari native SCSI", .detect = atari_scsi_detect, .release = atari_scsi_release, .info = atari_scsi_info, .queuecommand = atari_scsi_queue_command, .eh_abort_handler = atari_scsi_abort, .eh_bus_reset_handler = atari_scsi_bus_reset, .can_queue = 0, /* initialized at run-time */ .this_id = 0, /* initialized at run-time */ .sg_tablesize = 0, /* initialized at run-time */ .cmd_per_lun = 0, /* initialized at run-time */ .use_clustering = DISABLE_CLUSTERING }; #include "scsi_module.c" MODULE_LICENSE("GPL");