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authorRalf Baechle <ralf@linux-mips.org>1997-09-12 01:29:55 +0000
committerRalf Baechle <ralf@linux-mips.org>1997-09-12 01:29:55 +0000
commit545f435ebcfd94a1e7c20b46efe81b4d6ac4e698 (patch)
treee9ce4bc598d06374bda906f18365984bf22a526a /drivers/scsi/mesh.c
parent4291a610eef89d0d5c69d9a10ee6560e1aa36c74 (diff)
Merge with Linux 2.1.55. More bugfixes and goodies from my private
CVS archive.
Diffstat (limited to 'drivers/scsi/mesh.c')
-rw-r--r--drivers/scsi/mesh.c1319
1 files changed, 1319 insertions, 0 deletions
diff --git a/drivers/scsi/mesh.c b/drivers/scsi/mesh.c
new file mode 100644
index 000000000..501aff777
--- /dev/null
+++ b/drivers/scsi/mesh.c
@@ -0,0 +1,1319 @@
+/*
+ * SCSI low-level driver for the MESH (Macintosh Enhanced SCSI Hardware)
+ * bus adaptor found on Power Macintosh computers.
+ * We assume the MESH is connected to a DBDMA (descriptor-based DMA)
+ * controller.
+ *
+ * Paul Mackerras, August 1996.
+ * Copyright (C) 1996 Paul Mackerras.
+ */
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/malloc.h>
+#include <linux/blk.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/tqueue.h>
+#include <linux/interrupt.h>
+#include <linux/reboot.h>
+#include <asm/dbdma.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/system.h>
+
+#include "scsi.h"
+#include "hosts.h"
+#include "mesh.h"
+
+#if 0
+#undef KERN_DEBUG
+#define KERN_DEBUG KERN_WARNING
+#endif
+
+#if CONFIG_SCSI_MESH_SYNC_RATE == 0
+int mesh_sync_period = 100;
+int mesh_sync_offset = 0;
+#else
+int mesh_sync_period = 1000 / CONFIG_SCSI_MESH_SYNC_RATE; /* ns */
+int mesh_sync_offset = 15;
+#endif
+
+int mesh_sync_targets = 0xff; /* targets to set synchronous (bitmap) */
+int mesh_resel_targets = 0xff; /* targets that we let disconnect (bitmap) */
+int mesh_debug_targets = 0; /* print debug for these targets */
+
+#define ALLOW_SYNC(tgt) ((mesh_sync_targets >> (tgt)) & 1)
+#define ALLOW_RESEL(tgt) ((mesh_resel_targets >> (tgt)) & 1)
+#define ALLOW_DEBUG(tgt) ((mesh_debug_targets >> (tgt)) & 1)
+#define DEBUG_TARGET(cmd) ((cmd) && ALLOW_DEBUG((cmd)->target))
+
+struct proc_dir_entry proc_scsi_mesh = {
+ PROC_SCSI_MESH, 4, "mesh",
+ S_IFDIR | S_IRUGO | S_IXUGO, 2
+};
+
+enum mesh_phase {
+ idle,
+ arbitrating,
+ selecting,
+ commanding,
+ dataing,
+ statusing,
+ busfreeing,
+ disconnecting,
+ reselecting
+};
+
+enum msg_phase {
+ msg_none,
+ msg_out,
+ msg_out_xxx,
+ msg_out_last,
+ msg_in,
+};
+
+enum sdtr_phase {
+ do_sdtr,
+ sdtr_sent,
+ sdtr_done
+};
+
+struct mesh_target {
+ enum sdtr_phase sdtr_state;
+ enum mesh_phase phase;
+ int sync_params;
+ int data_goes_out;
+ Scsi_Cmnd *current_req;
+ u32 saved_ptr;
+};
+
+struct mesh_state {
+ volatile struct mesh_regs *mesh;
+ int meshintr;
+ volatile struct dbdma_regs *dma;
+ int dmaintr;
+ struct Scsi_Host *host;
+ struct mesh_state *next;
+ Scsi_Cmnd *request_q;
+ Scsi_Cmnd *request_qtail;
+ enum mesh_phase phase; /* what we're currently trying to do */
+ enum msg_phase msgphase;
+ int conn_tgt; /* target we're connected to */
+ Scsi_Cmnd *current_req; /* req we're currently working on */
+ int data_ptr;
+ int data_goes_out; /* guess as to data direction */
+ int dma_started;
+ int dma_count;
+ int expect_reply;
+ int n_msgin;
+ u8 msgin[16];
+ int n_msgout;
+ int last_n_msgout;
+ u8 msgout[16];
+ struct dbdma_cmd *dma_cmds; /* space for dbdma commands, aligned */
+ int clk_freq;
+ struct mesh_target tgts[8];
+ struct tq_struct tqueue;
+ Scsi_Cmnd *completed_q;
+ Scsi_Cmnd *completed_qtail;
+};
+
+static struct mesh_state *all_meshes;
+
+static void mesh_init(struct mesh_state *);
+static int mesh_notify_reboot(struct notifier_block *, unsigned long, void *);
+static void mesh_dump_regs(struct mesh_state *);
+static void mesh_start(struct mesh_state *);
+static void finish_cmds(void *);
+static void add_sdtr_msg(struct mesh_state *);
+static void set_sdtr(struct mesh_state *, int, int);
+static void start_phase(struct mesh_state *);
+static void get_msgin(struct mesh_state *);
+static int msgin_length(struct mesh_state *);
+static void cmd_complete(struct mesh_state *);
+static void phase_mismatch(struct mesh_state *);
+static void reselected(struct mesh_state *);
+static void handle_reset(struct mesh_state *);
+static void mesh_interrupt(int, void *, struct pt_regs *);
+static void handle_msgin(struct mesh_state *);
+static void mesh_done(struct mesh_state *);
+static void mesh_completed(struct mesh_state *, Scsi_Cmnd *);
+static void set_dma_cmds(struct mesh_state *, Scsi_Cmnd *);
+static void halt_dma(struct mesh_state *);
+static int data_goes_out(Scsi_Cmnd *);
+
+static struct notifier_block mesh_notifier = {
+ mesh_notify_reboot,
+ NULL,
+ 0
+};
+
+int
+mesh_detect(Scsi_Host_Template *tp)
+{
+ struct device_node *mesh;
+ int nmeshes, tgt, *cfp, minper;
+ struct mesh_state *ms, **prev_statep;
+ struct Scsi_Host *mesh_host;
+ void *dma_cmd_space;
+
+ nmeshes = 0;
+ prev_statep = &all_meshes;
+ for (mesh = find_devices("mesh"); mesh != 0; mesh = mesh->next) {
+ if (mesh->n_addrs != 2 || mesh->n_intrs != 2)
+ panic("mesh: expected 2 addrs and intrs (got %d/%d)",
+ mesh->n_addrs, mesh->n_intrs);
+ mesh_host = scsi_register(tp, sizeof(struct mesh_state));
+ if (mesh_host == 0)
+ panic("couldn't register mesh host");
+ mesh_host->unique_id = nmeshes;
+ note_scsi_host(mesh, mesh_host);
+
+ ms = (struct mesh_state *) mesh_host->hostdata;
+ if (ms == 0)
+ panic("no mesh state");
+ memset(ms, 0, sizeof(*ms));
+ ms->host = mesh_host;
+ ms->mesh = (volatile struct mesh_regs *)
+ mesh->addrs[0].address;
+ ms->meshintr = mesh->intrs[0];
+ ms->dma = (volatile struct dbdma_regs *)
+ mesh->addrs[1].address;
+ ms->dmaintr = mesh->intrs[1];
+
+ /* Space for dma command list: +1 for stop command,
+ +1 to allow for aligning. */
+ dma_cmd_space = kmalloc((mesh_host->sg_tablesize + 2) *
+ sizeof(struct dbdma_cmd), GFP_KERNEL);
+ if (dma_cmd_space == 0)
+ panic("mesh: couldn't allocate dma command space");
+ ms->dma_cmds = (struct dbdma_cmd *) DBDMA_ALIGN(dma_cmd_space);
+ memset(ms->dma_cmds, 0, (mesh_host->sg_tablesize + 1)
+ * sizeof(struct dbdma_cmd));
+
+ ms->current_req = 0;
+ for (tgt = 0; tgt < 8; ++tgt) {
+ ms->tgts[tgt].sdtr_state = do_sdtr;
+ ms->tgts[tgt].sync_params = ASYNC_PARAMS;
+ ms->tgts[tgt].current_req = 0;
+ }
+
+ ms->tqueue.routine = finish_cmds;
+ ms->tqueue.data = ms;
+
+ *prev_statep = ms;
+ prev_statep = &ms->next;
+
+ if (request_irq(ms->meshintr, mesh_interrupt, 0, "MESH", ms)) {
+ printk(KERN_ERR "MESH: can't get irq %d\n", ms->meshintr);
+ }
+
+ cfp = (int *) get_property(mesh, "clock-frequency", NULL);
+ if (cfp) {
+ ms->clk_freq = *cfp;
+ } else {
+ printk(KERN_INFO "mesh: assuming 50MHz clock frequency\n");
+ ms->clk_freq = 50000000;
+ }
+ /* The maximum sync rate is clock / 5; increase
+ mesh_sync_period if necessary. */
+ minper = 1000000000 / (ms->clk_freq / 5); /* ns */
+ if (mesh_sync_period < minper)
+ mesh_sync_period = minper;
+
+ mesh_init(ms);
+
+ ++nmeshes;
+ }
+ if (nmeshes > 0)
+ register_reboot_notifier(&mesh_notifier);
+
+ return nmeshes;
+}
+
+int
+mesh_queue(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
+{
+ unsigned long flags;
+ struct mesh_state *ms;
+
+#if 0
+ if (data_goes_out(cmd)) {
+ printk(KERN_DEBUG "mesh_queue %p: command is", cmd);
+ for (i = 0; i < cmd->cmd_len; ++i)
+ printk(" %.2x", cmd->cmnd[i]);
+ printk("\n" KERN_DEBUG "use_sg=%d request_bufflen=%d request_buffer=%p\n",
+ cmd->use_sg, cmd->request_bufflen, cmd->request_buffer);
+ }
+#endif
+
+ cmd->scsi_done = done;
+ cmd->host_scribble = NULL;
+
+ ms = (struct mesh_state *) cmd->host->hostdata;
+
+ save_flags(flags);
+ cli();
+ if (ms->request_q == NULL)
+ ms->request_q = cmd;
+ else
+ ms->request_qtail->host_scribble = (void *) cmd;
+ ms->request_qtail = cmd;
+
+ if (ms->phase == idle)
+ mesh_start(ms);
+
+ restore_flags(flags);
+ return 0;
+}
+
+int
+mesh_abort(Scsi_Cmnd *cmd)
+{
+ printk(KERN_DEBUG "mesh_abort(%p)\n", cmd);
+ mesh_dump_regs((struct mesh_state *)(cmd->host->hostdata));
+ return SCSI_ABORT_SNOOZE;
+}
+
+static void
+mesh_dump_regs(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ volatile struct dbdma_regs *md = ms->dma;
+ int t;
+ struct mesh_target *tp;
+
+ printk(KERN_DEBUG "mesh: state at %p, regs at %p, dma at %p\n",
+ ms, mr, md);
+ printk(KERN_DEBUG " ct=%4x seq=%2x bs=%4x fc=%2x exc=%2x err=%2x sp=%2x\n",
+ (mr->count_hi << 8) + mr->count_lo, mr->sequence,
+ (mr->bus_status1 << 8) + mr->bus_status0, mr->fifo_count,
+ mr->exception, mr->error, mr->sync_params);
+ printk(KERN_DEBUG " dma stat=%x cmdptr=%x\n",
+ in_le32(&md->status), in_le32(&md->cmdptr));
+ printk(KERN_DEBUG " phase=%d msgphase=%d conn_tgt=%d data_ptr=%d\n",
+ ms->phase, ms->msgphase, ms->conn_tgt, ms->data_ptr);
+ printk(KERN_DEBUG " goes_out=%d dma_st=%d dma_ct=%d n_msgout=%d\n",
+ ms->data_goes_out, ms->dma_started, ms->dma_count, ms->n_msgout);
+ for (t = 0; t < 8; ++t) {
+ tp = &ms->tgts[t];
+ if (tp->current_req == NULL)
+ continue;
+ printk(KERN_DEBUG " target %d: req=%p phase=%d saved_ptr=%d\n",
+ t, tp->current_req, tp->phase, tp->saved_ptr);
+ }
+}
+
+int
+mesh_reset(Scsi_Cmnd *cmd, unsigned how)
+{
+ struct mesh_state *ms = (struct mesh_state *) cmd->host->hostdata;
+ volatile struct mesh_regs *mr = ms->mesh;
+ volatile struct dbdma_regs *md = ms->dma;
+ unsigned long flags;
+ int ret;
+
+ printk(KERN_DEBUG "mesh_reset %x\n", how);
+ ret = SCSI_RESET_BUS_RESET;
+ save_flags(flags);
+ cli();
+ out_8(&mr->exception, 0xff); /* clear all exception bits */
+ out_8(&mr->error, 0xff); /* clear all error bits */
+ out_le32(&md->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
+ if (how & SCSI_RESET_SUGGEST_HOST_RESET) {
+ out_8(&mr->sequence, SEQ_RESETMESH);
+ ret |= SCSI_RESET_HOST_RESET;
+ udelay(1);
+ out_8(&mr->intr_mask, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
+ }
+ out_8(&mr->bus_status1, BS1_RST); /* assert RST */
+ udelay(30); /* leave it on for >= 25us */
+ out_8(&mr->bus_status1, 0); /* negate RST */
+#ifdef DO_ASYNC_RESET
+ if (how & SCSI_RESET_ASYNCHRONOUS) {
+ restore_flags(flags);
+ ret |= SCSI_RESET_PENDING;
+ } else
+#endif
+ {
+ out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
+ handle_reset(ms);
+ restore_flags(flags);
+ finish_cmds(ms);
+ ret |= SCSI_RESET_SUCCESS;
+ }
+ return ret;
+}
+
+/*
+ * If we leave drives set for synchronous transfers (especially
+ * CDROMs), and reboot to MacOS, it gets confused, poor thing.
+ * So, on reboot we reset the SCSI bus.
+ */
+static int
+mesh_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+ struct mesh_state *ms;
+ volatile struct mesh_regs *mr;
+
+ if (code == SYS_DOWN || code == SYS_HALT) {
+ printk(KERN_INFO "resetting MESH scsi bus(es)\n");
+ for (ms = all_meshes; ms != 0; ms = ms->next) {
+ mr = ms->mesh;
+ out_8(&mr->intr_mask, 0);
+ out_8(&mr->interrupt,
+ INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
+ out_8(&mr->bus_status1, BS1_RST);
+ udelay(30);
+ out_8(&mr->bus_status1, 0);
+ }
+ }
+ return NOTIFY_DONE;
+}
+
+int
+mesh_command(Scsi_Cmnd *cmd)
+{
+ printk(KERN_WARNING "whoops... mesh_command called\n");
+ return -1;
+}
+
+static void
+mesh_init(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ volatile struct dbdma_regs *md = ms->dma;
+
+ out_8(&mr->interrupt, 0xff); /* clear all interrupt bits */
+ out_8(&mr->intr_mask, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
+ out_8(&mr->source_id, ms->host->this_id);
+ out_8(&mr->sel_timeout, 25); /* 250ms */
+ out_8(&mr->sync_params, ASYNC_PARAMS); /* asynchronous initially */
+ out_le32(&md->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
+}
+
+/*
+ * Start the next command for a MESH.
+ * Should be called with interrupts disabled.
+ */
+static void
+mesh_start(struct mesh_state *ms)
+{
+ Scsi_Cmnd *cmd, *prev, *next;
+ volatile struct mesh_regs *mr = ms->mesh;
+
+ if (ms->phase != idle || ms->current_req != NULL)
+ panic("inappropriate mesh_start (ms=%p)", ms);
+
+ prev = NULL;
+ for (cmd = ms->request_q; ; cmd = (Scsi_Cmnd *) cmd->host_scribble) {
+ if (cmd == NULL)
+ return;
+ if (ms->tgts[cmd->target].current_req == NULL)
+ break;
+ prev = cmd;
+ }
+ next = (Scsi_Cmnd *) cmd->host_scribble;
+ if (prev == NULL)
+ ms->request_q = next;
+ else
+ prev->host_scribble = (void *) next;
+ if (next == NULL)
+ ms->request_qtail = prev;
+
+ ms->current_req = cmd;
+ ms->data_goes_out = data_goes_out(cmd);
+ ms->tgts[cmd->target].current_req = cmd;
+
+#if 1
+ if (DEBUG_TARGET(cmd)) {
+ int i;
+ printk(KERN_DEBUG "mesh_start: %p ser=%lu tgt=%d cmd=",
+ cmd, cmd->serial_number, cmd->target);
+ for (i = 0; i < cmd->cmd_len; ++i)
+ printk(" %x", cmd->cmnd[i]);
+ printk(" use_sg=%d buffer=%p bufflen=%u\n",
+ cmd->use_sg, cmd->request_buffer, cmd->request_bufflen);
+ }
+#endif
+
+ /* Off we go */
+ out_8(&mr->sequence, SEQ_ARBITRATE);
+
+ ms->phase = arbitrating;
+ ms->msgphase = msg_none;
+ ms->data_ptr = 0;
+ ms->dma_started = 0;
+ ms->n_msgout = 0;
+ ms->last_n_msgout = 0;
+ ms->expect_reply = 0;
+ ms->conn_tgt = cmd->target;
+ ms->tgts[cmd->target].saved_ptr = 0;
+}
+
+static void
+finish_cmds(void *data)
+{
+ struct mesh_state *ms = data;
+ Scsi_Cmnd *cmd;
+ unsigned long flags;
+
+ for (;;) {
+ save_flags(flags);
+ cli();
+ cmd = ms->completed_q;
+ if (cmd == NULL) {
+ restore_flags(flags);
+ break;
+ }
+ ms->completed_q = (Scsi_Cmnd *) cmd->host_scribble;
+ restore_flags(flags);
+ (*cmd->scsi_done)(cmd);
+ }
+}
+
+static inline void
+add_sdtr_msg(struct mesh_state *ms)
+{
+ int i = ms->n_msgout;
+
+ ms->msgout[i] = EXTENDED_MESSAGE;
+ ms->msgout[i+1] = 3;
+ ms->msgout[i+2] = EXTENDED_SDTR;
+ ms->msgout[i+3] = mesh_sync_period/4;
+ ms->msgout[i+4] = (ALLOW_SYNC(ms->conn_tgt)? mesh_sync_offset: 0);
+ ms->n_msgout = i + 5;
+}
+
+static void
+set_sdtr(struct mesh_state *ms, int period, int offset)
+{
+ struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
+ volatile struct mesh_regs *mr = ms->mesh;
+ int v, tr;
+
+ tp->sdtr_state = sdtr_done;
+ if (offset == 0) {
+ /* asynchronous */
+ if (SYNC_OFF(tp->sync_params))
+ printk(KERN_INFO "mesh: target %d now asynchronous\n",
+ ms->conn_tgt);
+ tp->sync_params = ASYNC_PARAMS;
+ out_8(&mr->sync_params, ASYNC_PARAMS);
+ return;
+ }
+ /*
+ * We need to compute ceil(clk_freq * period / 500e6) - 2
+ * without incurring overflow.
+ */
+ v = (ms->clk_freq / 5000) * period;
+ if (v <= 250000) {
+ /* special case: sync_period == 5 * clk_period */
+ v = 0;
+ /* units of tr are 100kB/s */
+ tr = (ms->clk_freq + 250000) / 500000;
+ } else {
+ /* sync_period == (v + 2) * 2 * clk_period */
+ v = (v + 99999) / 100000 - 2;
+ if (v > 15)
+ v = 15; /* oops */
+ tr = ((ms->clk_freq / (v + 2)) + 199999) / 200000;
+ }
+ if (offset > 15)
+ offset = 15; /* can't happen */
+ tp->sync_params = SYNC_PARAMS(offset, v);
+ out_8(&mr->sync_params, tp->sync_params);
+ printk(KERN_INFO "mesh: target %d synchronous at %d.%d MB/s\n",
+ ms->conn_tgt, tr/10, tr%10);
+}
+
+static void
+start_phase(struct mesh_state *ms)
+{
+ int i, seq, nb;
+ volatile struct mesh_regs *mr = ms->mesh;
+ volatile struct dbdma_regs *md = ms->dma;
+ Scsi_Cmnd *cmd = ms->current_req;
+ struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
+
+ if (cmd == 0) {
+ printk(KERN_ERR "mesh: start_phase but no cmd?\n");
+ return;
+ }
+ seq = SEQ_ACTIVE_NEG + (ms->n_msgout? SEQ_ATN: 0);
+ switch (ms->msgphase) {
+ case msg_none:
+ break;
+
+ case msg_in:
+ out_8(&mr->count_hi, 0);
+ out_8(&mr->count_lo, 1);
+ out_8(&mr->sequence, SEQ_MSGIN + seq);
+ ms->n_msgin = 0;
+ return;
+
+ case msg_out:
+ /*
+ * To make sure ATN drops before we assert ACK for
+ * the last byte of the message, we have to do the
+ * last byte specially.
+ */
+ if (DEBUG_TARGET(cmd)) {
+ printk(KERN_DEBUG "mesh: sending %d msg bytes:",
+ ms->n_msgout);
+ for (i = 0; i < ms->n_msgout; ++i)
+ printk(" %x", ms->msgout[i]);
+ printk("\n");
+ }
+ out_8(&mr->count_hi, 0);
+ if (ms->n_msgout == 1) {
+ out_8(&mr->count_lo, 1);
+ out_8(&mr->sequence, SEQ_MSGOUT + SEQ_ACTIVE_NEG);
+ udelay(1);
+ out_8(&mr->fifo, ms->msgout[0]);
+ ms->msgphase = msg_out_last;
+ } else {
+ out_8(&mr->count_lo, ms->n_msgout - 1);
+ out_8(&mr->sequence, SEQ_MSGOUT + seq);
+ for (i = 0; i < ms->n_msgout - 1; ++i)
+ out_8(&mr->fifo, ms->msgout[i]);
+ }
+ return;
+
+ default:
+ printk(KERN_ERR "mesh bug: start_phase msgphase=%d\n",
+ ms->msgphase);
+ }
+
+ switch (ms->phase) {
+ case selecting:
+ out_8(&mr->dest_id, cmd->target);
+ out_8(&mr->sequence, SEQ_SELECT + SEQ_ATN);
+ break;
+ case commanding:
+ out_8(&mr->sync_params, tp->sync_params);
+ out_8(&mr->count_hi, 0);
+ out_8(&mr->count_lo, cmd->cmd_len);
+ out_8(&mr->sequence, SEQ_COMMAND + seq);
+ for (i = 0; i < cmd->cmd_len; ++i)
+ out_8(&mr->fifo, cmd->cmnd[i]);
+ break;
+ case dataing:
+ /* transfer data, if any */
+ if (!ms->dma_started) {
+ set_dma_cmds(ms, cmd);
+ out_le32(&md->cmdptr, virt_to_phys(ms->dma_cmds));
+ out_le32(&md->control, (RUN << 16) | RUN);
+ ms->dma_started = 1;
+ }
+ nb = ms->dma_count;
+ if (nb > 0xfff0)
+ nb = 0xfff0;
+ ms->dma_count -= nb;
+ ms->data_ptr += nb;
+ out_8(&mr->count_lo, nb);
+ out_8(&mr->count_hi, nb >> 8);
+ out_8(&mr->sequence, (ms->data_goes_out?
+ SEQ_DATAOUT: SEQ_DATAIN) + SEQ_DMA_MODE + seq);
+ break;
+ case statusing:
+ out_8(&mr->count_hi, 0);
+ out_8(&mr->count_lo, 1);
+ out_8(&mr->sequence, SEQ_STATUS + seq);
+ break;
+ case busfreeing:
+ case disconnecting:
+ out_8(&mr->sequence, SEQ_ENBRESEL);
+ udelay(1);
+ out_8(&mr->sequence, SEQ_BUSFREE);
+ break;
+ default:
+ printk(KERN_ERR "mesh: start_phase called with phase=%d\n",
+ ms->phase);
+ }
+
+}
+
+static inline void
+get_msgin(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ int i, n;
+
+ n = mr->fifo_count;
+ if (n != 0) {
+ i = ms->n_msgin;
+ ms->n_msgin = i + n;
+ for (; n > 0; --n)
+ ms->msgin[i++] = in_8(&mr->fifo);
+ }
+}
+
+static inline int
+msgin_length(struct mesh_state *ms)
+{
+ int b, n;
+
+ n = 1;
+ if (ms->n_msgin > 0) {
+ b = ms->msgin[0];
+ if (b == 1) {
+ /* extended message */
+ n = ms->n_msgin < 2? 2: ms->msgin[1] + 2;
+ } else if (0x20 <= b && b <= 0x2f) {
+ /* 2-byte message */
+ n = 2;
+ }
+ }
+ return n;
+}
+
+static void
+cmd_complete(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ Scsi_Cmnd *cmd = ms->current_req;
+ struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
+ int seq, n, t;
+
+ seq = SEQ_ACTIVE_NEG + (ms->n_msgout? SEQ_ATN: 0);
+ switch (ms->msgphase) {
+ case msg_out_xxx:
+ /* huh? we expected a phase mismatch */
+ ms->n_msgin = 0;
+ ms->msgphase = msg_in;
+ /* fall through */
+
+ case msg_in:
+ /* should have some message bytes in fifo */
+ get_msgin(ms);
+ n = msgin_length(ms);
+ if (ms->n_msgin < n) {
+ out_8(&mr->count_lo, n - ms->n_msgin);
+ out_8(&mr->sequence, SEQ_MSGIN + seq);
+ } else {
+ ms->msgphase = msg_none;
+ handle_msgin(ms);
+ start_phase(ms);
+ }
+ break;
+
+ case msg_out:
+ /*
+ * To get the right timing on ATN wrt ACK, we have
+ * to get the MESH to drop ACK, wait until REQ gets
+ * asserted, then drop ATN. To do this we first
+ * issue a SEQ_MSGOUT with ATN and wait for REQ,
+ * then change the command to a SEQ_MSGOUT w/o ATN.
+ * If we don't see REQ in a reasonable time, we
+ * change the command to SEQ_MSGIN with ATN,
+ * wait for the phase mismatch interrupt, then
+ * issue the SEQ_MSGOUT without ATN.
+ */
+ out_8(&mr->count_lo, 1);
+ out_8(&mr->sequence, SEQ_MSGOUT + SEQ_ACTIVE_NEG + SEQ_ATN);
+ t = 30; /* wait up to 30us */
+ while ((mr->bus_status0 & BS0_REQ) == 0 && --t >= 0)
+ udelay(1);
+ if (mr->bus_status0 & BS0_REQ) {
+ out_8(&mr->sequence, SEQ_MSGOUT + SEQ_ACTIVE_NEG);
+ udelay(1);
+ out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
+ ms->msgphase = msg_out_last;
+ } else {
+ out_8(&mr->sequence, SEQ_MSGIN + SEQ_ACTIVE_NEG + SEQ_ATN);
+ ms->msgphase = msg_out_xxx;
+ }
+ break;
+
+ case msg_out_last:
+ ms->last_n_msgout = ms->n_msgout;
+ ms->n_msgout = 0;
+ ms->msgphase = ms->expect_reply? msg_in: msg_none;
+ start_phase(ms);
+ break;
+
+ case msg_none:
+ switch (ms->phase) {
+ case selecting:
+ ms->msgout[0] = IDENTIFY(ALLOW_RESEL(cmd->target), cmd->lun);
+ ms->n_msgout = 1;
+ ms->expect_reply = 0;
+ if (tp->sdtr_state == do_sdtr) {
+ /* add SDTR message */
+ add_sdtr_msg(ms);
+ ms->expect_reply = 1;
+ tp->sdtr_state = sdtr_sent;
+ }
+ ms->msgphase = msg_out;
+ /*
+ * We need to wait for REQ before dropping ATN.
+ * We wait for at most 30us, then fall back to
+ * a scheme where we issue a SEQ_COMMAND with ATN,
+ * which will give us a phase mismatch interrupt
+ * when REQ does come, and then we send the message.
+ */
+ t = 30; /* wait up to 30us */
+ while ((mr->bus_status0 & BS0_REQ) == 0) {
+ if (--t < 0) {
+ ms->msgphase = msg_none;
+ break;
+ }
+ udelay(1);
+ }
+ break;
+ case dataing:
+ if (ms->dma_count != 0) {
+ start_phase(ms);
+ return;
+ }
+ halt_dma(ms);
+ break;
+ case statusing:
+ cmd->SCp.Status = mr->fifo;
+ cmd->result = (DID_OK << 16) + cmd->SCp.Status;
+ ms->msgphase = msg_in;
+ if (DEBUG_TARGET(cmd))
+ printk(KERN_DEBUG "mesh: status is %x\n",
+ cmd->SCp.Status);
+ break;
+ case busfreeing:
+ mesh_done(ms);
+ return;
+ case disconnecting:
+ ms->current_req = 0;
+ ms->phase = idle;
+ mesh_start(ms);
+ return;
+ default:
+ break;
+ }
+ ++ms->phase;
+ start_phase(ms);
+ break;
+ }
+}
+
+static void phase_mismatch(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ int phase;
+
+ phase = mr->bus_status0 & BS0_PHASE;
+ if (ms->msgphase == msg_out_xxx && phase == BP_MSGOUT) {
+ /* output the last byte of the message, without ATN */
+ out_8(&mr->count_lo, 1);
+ out_8(&mr->sequence, SEQ_MSGOUT + SEQ_ACTIVE_NEG);
+ udelay(1);
+ out_8(&mr->fifo, ms->msgout[ms->n_msgout-1]);
+ ms->msgphase = msg_out_last;
+ return;
+ }
+
+ if (ms->msgphase == msg_in) {
+ get_msgin(ms);
+ if (ms->n_msgin)
+ handle_msgin(ms);
+ }
+
+ if (ms->dma_started)
+ halt_dma(ms);
+ if (mr->fifo_count) {
+ out_8(&mr->sequence, SEQ_FLUSHFIFO);
+ udelay(1);
+ }
+
+ ms->msgphase = msg_none;
+ switch (phase) {
+ case BP_DATAIN:
+ ms->data_goes_out = 0;
+ ms->phase = dataing;
+ break;
+ case BP_DATAOUT:
+ ms->data_goes_out = 1;
+ ms->phase = dataing;
+ break;
+ case BP_COMMAND:
+ ms->phase = commanding;
+ break;
+ case BP_STATUS:
+ ms->phase = statusing;
+ break;
+ case BP_MSGIN:
+ ms->msgphase = msg_in;
+ ms->n_msgin = 0;
+ break;
+ case BP_MSGOUT:
+ ms->msgphase = msg_out;
+ if (ms->n_msgout == 0) {
+ if (ms->last_n_msgout == 0) {
+ printk(KERN_DEBUG "mesh: no msg to repeat\n");
+ ms->msgout[0] = NOP;
+ ms->last_n_msgout = 1;
+ }
+ ms->n_msgout = ms->last_n_msgout;
+ }
+ break;
+ default:
+ printk(KERN_DEBUG "mesh: unknown scsi phase %x\n", phase);
+ ms->current_req->result = DID_ERROR << 16;
+ mesh_done(ms);
+ return;
+ }
+
+ start_phase(ms);
+}
+
+static void
+reselected(struct mesh_state *ms)
+{
+ volatile struct mesh_regs *mr = ms->mesh;
+ Scsi_Cmnd *cmd = ms->current_req;
+ struct mesh_target *tp;
+ int b, t;
+
+ switch (ms->phase) {
+ case idle:
+ case arbitrating:
+ break;
+ case busfreeing:
+ ms->phase = reselecting;
+ mesh_done(ms);
+ cmd = NULL;
+ break;
+ case disconnecting:
+ cmd = NULL;
+ break;
+ default:
+ printk(KERN_ERR "mesh: reselected in phase %d/%d\n",
+ ms->msgphase, ms->phase);
+ }
+ if (cmd) {
+ /* put the command back on the queue */
+ cmd->host_scribble = (void *) ms->request_q;
+ if (ms->request_q == NULL)
+ ms->request_qtail = cmd;
+ ms->request_q = cmd;
+ tp = &ms->tgts[cmd->target];
+ tp->current_req = NULL;
+ ms->current_req = NULL;
+ }
+
+ /*
+ * Find out who reselected us.
+ */
+ if (mr->fifo_count == 0) {
+ printk(KERN_ERR "mesh: reselection but nothing in fifo?\n");
+ return;
+ }
+ /* get the last byte in the fifo */
+ do {
+ b = in_8(&mr->fifo);
+ } while (in_8(&mr->fifo_count));
+ for (t = 0; t < 8; ++t)
+ if ((b & (1 << t)) != 0 && t != ms->host->this_id)
+ break;
+ if (b != (1 << t) + (1 << ms->host->this_id)) {
+ printk(KERN_ERR "mesh: bad reselection data %x\n", b);
+ return;
+ }
+
+ /*
+ * Set up to continue with that target's transfer.
+ */
+ tp = &ms->tgts[t];
+ if (ALLOW_DEBUG(t)) {
+ printk(KERN_DEBUG "mesh: reselected by target %d\n", t);
+ printk(KERN_DEBUG "mesh: saved_ptr=%x phase=%d cmd=%p\n",
+ tp->saved_ptr, tp->phase, tp->current_req);
+ }
+ if (tp->current_req == NULL) {
+ printk(KERN_ERR "mesh: reselected by tgt %d but no cmd!\n", t);
+ return;
+ }
+ ms->current_req = tp->current_req;
+ ms->phase = tp->phase;
+ ms->msgphase = msg_in;
+ ms->data_goes_out = tp->data_goes_out;
+ ms->data_ptr = tp->saved_ptr;
+ ms->conn_tgt = t;
+ ms->dma_started = 0;
+ ms->n_msgout = 0;
+ ms->last_n_msgout = 0;
+ out_8(&mr->sync_params, tp->sync_params);
+ start_phase(ms);
+}
+
+static void
+handle_reset(struct mesh_state *ms)
+{
+ int tgt;
+ struct mesh_target *tp;
+ Scsi_Cmnd *cmd;
+ volatile struct mesh_regs *mr = ms->mesh;
+
+ for (tgt = 0; tgt < 8; ++tgt) {
+ tp = &ms->tgts[tgt];
+ if ((cmd = tp->current_req) != NULL) {
+ cmd->result = DID_RESET << 16;
+ tp->current_req = NULL;
+ mesh_completed(ms, cmd);
+ }
+ ms->tgts[tgt].sdtr_state = do_sdtr;
+ ms->tgts[tgt].sync_params = ASYNC_PARAMS;
+ }
+ ms->current_req = NULL;
+ while ((cmd = ms->request_q) != NULL) {
+ ms->request_q = (Scsi_Cmnd *) cmd->host_scribble;
+ cmd->result = DID_RESET << 16;
+ mesh_completed(ms, cmd);
+ }
+ ms->phase = idle;
+ out_8(&mr->sync_params, ASYNC_PARAMS);
+}
+
+static void
+mesh_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
+{
+ struct mesh_state *ms = (struct mesh_state *) dev_id;
+ volatile struct mesh_regs *mr = ms->mesh;
+ Scsi_Cmnd *cmd = ms->current_req;
+ int stat, exc, err, intr;
+
+#if 0
+ if (DEBUG_TARGET(cmd))
+ printk(KERN_DEBUG "mesh_intr, bs0=%x int=%x exc=%x err=%x phase=%d msgphase=%d\n",
+ mr->bus_status0, mr->interrupt, mr->exception, mr->error, ms->phase, ms->msgphase);
+#endif
+ while ((intr = in_8(&mr->interrupt)) != 0) {
+ if (intr & INT_ERROR) {
+ stat = DID_BAD_INTR << 16;
+ err = in_8(&mr->error);
+ exc = in_8(&mr->exception);
+ out_8(&mr->interrupt, INT_ERROR | INT_EXCEPTION | INT_CMDDONE);
+ if (err & ERR_SCSIRESET) {
+ /* SCSI bus was reset */
+ printk(KERN_INFO "mesh: SCSI bus reset detected: "
+ "waiting for end...");
+ while ((mr->bus_status1 & BS1_RST) != 0)
+ udelay(1);
+ printk("done\n");
+ handle_reset(ms);
+ /* request_q is empty, no point in mesh_start() */
+ continue;
+ } else if (err & ERR_UNEXPDISC) {
+ /* Unexpected disconnect */
+ printk(KERN_WARNING "mesh: target %d aborted\n",
+ ms->conn_tgt);
+ stat = DID_ABORT << 16;
+ } else if (err & ERR_PARITY) {
+ printk(KERN_ERR "mesh: parity error\n");
+ stat = DID_PARITY << 16;
+ } else if ((err & ERR_SEQERR) && (exc & EXC_RESELECTED)
+ && ms->phase == arbitrating) {
+ /* This can happen if we issue a command to
+ get the bus just after the target
+ reselects us. */
+ static int mesh_resel_seqerr;
+ mesh_resel_seqerr++;
+ reselected(ms);
+ continue;
+ } else {
+ printk(KERN_ERR "mesh: error %x (exc = %x)\n",
+ err, exc);
+ mesh_dump_regs(ms);
+ }
+ if (cmd != 0) {
+ cmd->result = stat;
+ mesh_done(ms);
+ }
+
+ } else if (intr & INT_EXCEPTION) {
+ exc = in_8(&mr->exception);
+ out_8(&mr->interrupt, INT_EXCEPTION | INT_CMDDONE);
+ if (exc & EXC_RESELECTED) {
+ static int mesh_resel_exc;
+ mesh_resel_exc++;
+ reselected(ms);
+ } else if (cmd && exc == EXC_ARBLOST
+ && ms->phase == arbitrating) {
+ printk(KERN_DEBUG "mesh: lost arbitration\n");
+ cmd->result = DID_BUS_BUSY << 16;
+ mesh_done(ms);
+ } else if (cmd && exc == EXC_SELTO && ms->phase == selecting) {
+ /* selection timed out */
+ cmd->result = DID_BAD_TARGET << 16;
+ mesh_done(ms);
+ } else if (cmd && exc == EXC_PHASEMM
+ && (mr->bus_status0 & BS0_REQ) != 0) {
+ /* target wants to do something different:
+ find out what it wants and do it. */
+ phase_mismatch(ms);
+ } else {
+ printk(KERN_ERR "mesh: can't cope with exception %x\n",
+ exc);
+ cmd->result = DID_ERROR << 16;
+ mesh_done(ms);
+ }
+
+ } else if (intr & INT_CMDDONE) {
+ out_8(&mr->interrupt, INT_CMDDONE);
+ cmd_complete(ms);
+ }
+ }
+}
+
+static void
+handle_msgin(struct mesh_state *ms)
+{
+ int i;
+ Scsi_Cmnd *cmd = ms->current_req;
+ struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
+
+ if (ms->n_msgin == 0)
+ return;
+ if (DEBUG_TARGET(cmd)) {
+ printk(KERN_DEBUG "got %d message bytes:", ms->n_msgin);
+ for (i = 0; i < ms->n_msgin; ++i)
+ printk(" %x", ms->msgin[i]);
+ printk("\n");
+ }
+
+ ms->expect_reply = 0;
+ ms->n_msgout = 0;
+ if (ms->n_msgin < msgin_length(ms))
+ goto reject;
+ if (cmd)
+ cmd->SCp.Message = ms->msgin[0];
+ switch (ms->msgin[0]) {
+ case COMMAND_COMPLETE:
+ break;
+ case EXTENDED_MESSAGE:
+ switch (ms->msgin[2]) {
+ case EXTENDED_MODIFY_DATA_POINTER:
+ ms->data_ptr += (ms->msgin[3] << 24) + ms->msgin[6]
+ + (ms->msgin[4] << 16) + (ms->msgin[5] << 8);
+ break;
+ case EXTENDED_SDTR:
+ if (tp->sdtr_state != sdtr_sent) {
+ /* reply with an SDTR */
+ add_sdtr_msg(ms);
+ /* limit period to at least his value,
+ offset to no more than his */
+ if (ms->msgout[3] < ms->msgin[3])
+ ms->msgout[3] = ms->msgin[3];
+ if (ms->msgout[4] > ms->msgin[4])
+ ms->msgout[4] = ms->msgin[4];
+ set_sdtr(ms, ms->msgout[3], ms->msgout[4]);
+ ms->msgphase = msg_out;
+ } else {
+ set_sdtr(ms, ms->msgin[3], ms->msgin[4]);
+ }
+ break;
+ default:
+ goto reject;
+ }
+ break;
+ case SAVE_POINTERS:
+ tp->saved_ptr = ms->data_ptr;
+ break;
+ case RESTORE_POINTERS:
+ ms->data_ptr = tp->saved_ptr;
+ break;
+ case DISCONNECT:
+ tp->phase = ms->phase;
+ tp->data_goes_out = ms->data_goes_out;
+ ms->phase = disconnecting;
+ break;
+ case ABORT:
+ break;
+ case MESSAGE_REJECT:
+ if (tp->sdtr_state == sdtr_sent)
+ set_sdtr(ms, 0, 0);
+ break;
+ case NOP:
+ break;
+ default:
+ if (cmd && IDENTIFY_BASE <= ms->msgin[0]
+ && ms->msgin[0] <= IDENTIFY_BASE + 7) {
+ i = ms->msgin[0] - IDENTIFY_BASE;
+ if (i != cmd->lun)
+ printk(KERN_WARNING "mesh: lun mismatch "
+ "(%d != %d) on reselection from "
+ "target %d\n", i, cmd->lun,
+ ms->conn_tgt);
+ break;
+ }
+ goto reject;
+ }
+ return;
+
+ reject:
+ printk(KERN_WARNING "mesh: rejecting message %x from target %d\n",
+ ms->msgin[0], ms->conn_tgt);
+ ms->msgout[0] = MESSAGE_REJECT;
+ ms->n_msgout = 1;
+ ms->msgphase = msg_out;
+}
+
+static void
+mesh_done(struct mesh_state *ms)
+{
+ Scsi_Cmnd *cmd;
+ struct mesh_target *tp = &ms->tgts[ms->conn_tgt];
+
+ cmd = ms->current_req;
+ if (DEBUG_TARGET(cmd)) {
+ printk(KERN_DEBUG "mesh_done: result = %x, data_ptr=%d, buflen=%d\n",
+ cmd->result, ms->data_ptr, cmd->request_bufflen);
+ if ((cmd->cmnd[0] == 0 || cmd->cmnd[0] == 0x12 || cmd->cmnd[0] == 3)
+ && cmd->request_buffer != 0) {
+ unsigned char *b = cmd->request_buffer;
+ printk(KERN_DEBUG "buffer = %x %x %x %x %x %x %x %x\n",
+ b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7]);
+ }
+ }
+ tp->current_req = 0;
+ cmd->SCp.this_residual -= ms->data_ptr;
+ ms->current_req = NULL;
+ mesh_completed(ms, cmd);
+ if (ms->phase != reselecting) {
+ ms->phase = idle;
+ mesh_start(ms);
+ }
+}
+
+static void
+mesh_completed(struct mesh_state *ms, Scsi_Cmnd *cmd)
+{
+ if (ms->completed_q == NULL)
+ ms->completed_q = cmd;
+ else
+ ms->completed_qtail->host_scribble = (void *) cmd;
+ ms->completed_qtail = cmd;
+ cmd->host_scribble = NULL;
+ queue_task(&ms->tqueue, &tq_immediate);
+ mark_bh(IMMEDIATE_BH);
+}
+
+/*
+ * Set up DMA commands for transferring data.
+ */
+static void
+set_dma_cmds(struct mesh_state *ms, Scsi_Cmnd *cmd)
+{
+ int i, dma_cmd, total, off, dtot;
+ struct scatterlist *scl;
+ struct dbdma_cmd *dcmds;
+
+ dma_cmd = ms->data_goes_out? OUTPUT_MORE: INPUT_MORE;
+ dcmds = ms->dma_cmds;
+ dtot = 0;
+ cmd->SCp.this_residual = cmd->request_bufflen;
+ if (cmd->use_sg > 0) {
+ total = 0;
+ scl = (struct scatterlist *) cmd->buffer;
+ off = ms->data_ptr;
+ for (i = 0; i < cmd->use_sg; ++i, ++scl) {
+ total += scl->length;
+ if (off >= scl->length) {
+ off -= scl->length;
+ continue;
+ }
+ if (scl->length > 0xffff)
+ panic("mesh: scatterlist element >= 64k");
+ st_le16(&dcmds->req_count, scl->length - off);
+ st_le16(&dcmds->command, dma_cmd);
+ st_le32(&dcmds->phy_addr,
+ virt_to_phys(scl->address) + off);
+ dcmds->xfer_status = 0;
+ ++dcmds;
+ dtot += scl->length - off;
+ off = 0;
+ }
+ } else if (ms->data_ptr < cmd->request_bufflen) {
+ dtot = cmd->request_bufflen - ms->data_ptr;
+ if (dtot > 0xffff)
+ panic("mesh: transfer size >= 64k");
+ st_le16(&dcmds->req_count, dtot);
+ st_le32(&dcmds->phy_addr,
+ virt_to_phys(cmd->request_buffer) + ms->data_ptr);
+ dcmds->xfer_status = 0;
+ ++dcmds;
+ }
+ if (dtot == 0) {
+ /* Either the target has overrun our buffer,
+ or the caller didn't provide a buffer. */
+ static char mesh_extra_buf[64];
+
+ if (cmd->request_bufflen != 0)
+ printk(KERN_DEBUG "mesh: target %d overrun, "
+ "data_ptr=%x total=%x goes_out=%d\n",
+ ms->conn_tgt, ms->data_ptr,
+ cmd->request_bufflen, ms->data_goes_out);
+ dtot = sizeof(mesh_extra_buf);
+ st_le16(&dcmds->req_count, dtot);
+ st_le32(&dcmds->phy_addr, virt_to_phys(mesh_extra_buf));
+ dcmds->xfer_status = 0;
+ ++dcmds;
+ }
+ dma_cmd += OUTPUT_LAST - OUTPUT_MORE;
+ st_le16(&dcmds[-1].command, dma_cmd);
+ memset(dcmds, 0, sizeof(*dcmds));
+ st_le16(&dcmds->command, DBDMA_STOP);
+ ms->dma_count = dtot;
+}
+
+static void
+halt_dma(struct mesh_state *ms)
+{
+ volatile struct dbdma_regs *md = ms->dma;
+ volatile struct mesh_regs *mr = ms->mesh;
+ int t, nb;
+
+ if (!ms->data_goes_out) {
+ /* wait a little while until the fifo drains */
+ t = 50;
+ while (t > 0 && mr->fifo_count != 0
+ && (in_le32(&md->status) & ACTIVE) != 0) {
+ --t;
+ udelay(1);
+ }
+ }
+ out_le32(&md->control, RUN << 16); /* turn off RUN bit */
+ nb = (mr->count_hi << 8) + mr->count_lo;
+ if (ms->data_goes_out)
+ nb += mr->fifo_count;
+ /* nb is the number of bytes not yet transferred
+ to/from the target. */
+ ms->data_ptr -= nb;
+ if (ms->data_ptr < 0) {
+ printk(KERN_ERR "mesh: halt_dma: data_ptr=%d (nb=%d, ms=%p)\n",
+ ms->data_ptr, nb, ms);
+ ms->data_ptr = 0;
+ }
+ ms->dma_started = 0;
+}
+
+/*
+ * Work out whether we expect data to go out from the host adaptor or into it.
+ * (If this information is available from somewhere else in the scsi
+ * code, somebody please let me know :-)
+ */
+static int
+data_goes_out(Scsi_Cmnd *cmd)
+{
+ switch (cmd->cmnd[0]) {
+ case MODE_SELECT:
+ case MODE_SELECT_10:
+ case WRITE_6:
+ case WRITE_10:
+ case WRITE_12: /* any others? */
+ return 1;
+ default:
+ return 0;
+ }
+}