microsoft
/
WSL2-Linux-Kernel
зеркало из https://github.com/microsoft/WSL2-Linux-Kernel.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
WSL2-Linux-Kernel/drivers/scsi/atari_scsi.c

1025 строки
32 KiB
C
Исходник Ответственный История

/*
* 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()
#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(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;
}
#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 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 (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;
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,
.owner = THIS_MODULE,
},
};
module_platform_driver_probe(atari_scsi_driver, atari_scsi_probe);
MODULE_ALIAS("platform:" DRV_MODULE_NAME);
MODULE_LICENSE("GPL");
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку