diff options
Diffstat (limited to 'kernel/drivers/scsi/atari_scsi.c')
| -rw-r--r-- | kernel/drivers/scsi/atari_scsi.c | 1023 |
1 files changed, 1023 insertions, 0 deletions
diff --git a/kernel/drivers/scsi/atari_scsi.c b/kernel/drivers/scsi/atari_scsi.c new file mode 100644 index 000000000..5ede3daa9 --- /dev/null +++ b/kernel/drivers/scsi/atari_scsi.c @@ -0,0 +1,1023 @@ +/* + * 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: */ +/* ---------------------- */ +/* */ +/* 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 <linux/module.h> +#include <linux/types.h> +#include <linux/delay.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> + +/* Definitions for the core NCR5380 driver. */ + +#define REAL_DMA +#define SUPPORT_TAGS +#define MAX_TAGS 32 +#define DMA_MIN_SIZE 32 + +#define NCR5380_implementation_fields /* none */ + +#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_show_info atari_scsi_show_info +#define NCR5380_info atari_scsi_info + +#define NCR5380_dma_read_setup(instance, data, count) \ + atari_scsi_dma_setup(instance, data, count, 0) +#define NCR5380_dma_write_setup(instance, data, count) \ + atari_scsi_dma_setup(instance, data, count, 1) +#define NCR5380_dma_residual(instance) \ + atari_scsi_dma_residual(instance) +#define NCR5380_dma_xfer_len(instance, cmd, phase) \ + atari_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & SR_IO)) + +#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; +} + +#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 + +#ifdef REAL_DMA +static void atari_scsi_fetch_restbytes(void); +#endif + +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) +#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); + + 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 */ + + +/* 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 (in_interrupt()) + return stdma_try_lock(scsi_falcon_intr, instance); + + stdma_lock(scsi_falcon_intr, instance); + return 1; +} + +#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[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) + 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]; +#ifdef SUPPORT_TAGS + if (ints[0] >= 5) + 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; + unsigned long flags; + + local_irq_save(flags); + +#ifdef REAL_DMA + /* Abort a maybe active DMA transfer */ + if (IS_A_TT()) { + tt_scsi_dma.dma_ctrl = 0; + } else { + st_dma.dma_mode_status = 0x90; + atari_dma_active = 0; + atari_dma_orig_addr = NULL; + } +#endif + + rv = NCR5380_bus_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, + .show_info = atari_scsi_show_info, + .name = "Atari native SCSI", + .info = atari_scsi_info, + .queuecommand = atari_scsi_queue_command, + .eh_abort_handler = atari_scsi_abort, + .eh_bus_reset_handler = atari_scsi_bus_reset, + .this_id = 7, + .use_clustering = DISABLE_CLUSTERING +}; + +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; + } + + /* The values for CMD_PER_LUN and CAN_QUEUE are somehow arbitrary. + * Higher values should work, too; try it! + * (But cmd_per_lun costs memory!) + * + * But there seems to be a bug somewhere that requires CAN_QUEUE to be + * 2*CMD_PER_LUN. At least on a TT, no spurious timeouts seen since + * changed CMD_PER_LUN... + * + * Note: The Falcon currently uses 8/1 setting due to unsolved problems + * with cmd_per_lun != 1 + */ + if (ATARIHW_PRESENT(TT_SCSI)) { + atari_scsi_template.can_queue = 16; + atari_scsi_template.cmd_per_lun = 8; + atari_scsi_template.sg_tablesize = SG_ALL; + } else { + atari_scsi_template.can_queue = 8; + atari_scsi_template.cmd_per_lun = 1; + atari_scsi_template.sg_tablesize = SG_NONE; + } + + 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; + + /* Leave sg_tablesize at 0 on a 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 { + /* 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) + atari_scsi_template.this_id = b & 7; + } + } + + +#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 (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) { + 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 = 0; + } +#endif + + instance = scsi_host_alloc(&atari_scsi_template, + sizeof(struct NCR5380_hostdata)); + if (!instance) { + error = -ENOMEM; + goto fail_alloc; + } + atari_scsi_host = instance; + +#ifdef CONFIG_ATARI_SCSI_RESET_BOOT + atari_scsi_reset_boot(); +#endif + + instance->irq = irq->start; + + host_flags |= IS_A_TT() ? 0 : FLAG_LATE_DMA_SETUP; + +#ifdef SUPPORT_TAGS + host_flags |= setup_use_tagged_queuing > 0 ? FLAG_TAGGED_QUEUING : 0; +#endif + + NCR5380_init(instance, host_flags); + + 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 */ +#ifdef REAL_DMA + 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; + } +#endif + } else { + /* Nothing to do for the interrupt: the ST-DMA is initialized + * already. + */ +#ifdef REAL_DMA + atari_dma_residual = 0; + atari_dma_active = 0; + atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000 + : 0xff000000); +#endif + } + + 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); + 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"); |