mesh.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * 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 <linux/spinlock.h>
#include <asm/dbdma.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/hydra.h>
#include <asm/processor.h>
#include <asm/feature.h>

#include "scsi.h"
#include "hosts.h"
#include "mesh.h"

/*
 * To do:
 * - handle aborts correctly
 * - retry arbitration if lost (unless higher levels do this for us)
 */

#define MESH_NEW_STYLE_EH

#if 1
#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 */
unsigned char use_active_neg = 0;  /* bit mask for SEQ_ACTIVE_NEG if used */

#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))

#undef MESH_DBG
#define N_DBG_LOG	50
#define N_DBG_SLOG	20
#define NUM_DBG_EVENTS	13
#undef	DBG_USE_TB		/* bombs on 601 */

struct dbglog {
	char	*fmt;
	u32	tb;
	u8	phase;
	u8	bs0;
	u8	bs1;
	u8	tgt;
	int	d;
};

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,
	msg_in_bad,
};

enum sdtr_phase {
	do_sdtr,
	sdtr_sent,
	sdtr_done
};

struct mesh_target {
	enum sdtr_phase sdtr_state;
	int	sync_params;
	int	data_goes_out;		/* guess as to data direction */
	Scsi_Cmnd *current_req;
	u32	saved_ptr;
	int	want_abort;
#ifdef MESH_DBG
	int	log_ix;
	int	n_log;
	struct dbglog log[N_DBG_LOG];
#endif
};

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	dma_started;
	int	dma_count;
	int	stat;
	int	aborting;
	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];
	void	*dma_cmd_space;
	struct device_node *ofnode;
#ifndef MESH_NEW_STYLE_EH
	Scsi_Cmnd *completed_q;
	Scsi_Cmnd *completed_qtail;
	struct tq_struct tqueue;
#endif
#ifdef MESH_DBG
	int	log_ix;
	int	n_log;
	struct dbglog log[N_DBG_SLOG];
#endif
};

#ifdef MESH_DBG

static void dlog(struct mesh_state *ms, char *fmt, int a);
static void dumplog(struct mesh_state *ms, int tgt);
static void dumpslog(struct mesh_state *ms);

#else
static inline void dlog(struct mesh_state *ms, char *fmt, int a)
{}
static inline void dumplog(struct mesh_state *ms, int tgt)
{}
static inline void dumpslog(struct mesh_state *ms)
{}

#endif /* MESH_DBG */
#define MKWORD(a, b, c, d)	(((a) << 24) + ((b) << 16) + ((c) << 8) + (d))

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 mesh_start_cmd(struct mesh_state *, Scsi_Cmnd *);
#ifndef MESH_NEW_STYLE_EH
static void finish_cmds(void *);
#endif
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 handle_error(struct mesh_state *);
static void handle_exception(struct mesh_state *);
static void mesh_interrupt(int, void *, struct pt_regs *);
static void do_mesh_interrupt(int, void *, struct pt_regs *);
static void handle_msgin(struct mesh_state *);
static void mesh_done(struct mesh_state *, int);
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 void do_abort(struct mesh_state *ms);

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;

	if (_machine == _MACH_Pmac) {
	    use_active_neg = (find_devices("mac-io") ? 0 : SEQ_ACTIVE_NEG);
	} else {
	    /* CHRP mac-io */
	    use_active_neg = SEQ_ACTIVE_NEG;
	}

	nmeshes = 0;
	prev_statep = &all_meshes;
	/*
	 * On powermacs, the MESH node has device_type "mesh".
	 * On chrp machines, its device_type is "scsi" with
	 * "chrp,mesh0" as its `compatible' property.
	 */
	mesh = find_devices("mesh");
	if (mesh == 0)
		mesh = find_compatible_devices("scsi", "chrp,mesh0");
	for (; mesh != 0; mesh = mesh->next) {
		if (mesh->n_addrs != 2 || mesh->n_intrs != 2) {
			printk(KERN_ERR "mesh: expected 2 addrs and 2 intrs"
			       " (got %d,%d)", mesh->n_addrs, mesh->n_intrs);
			continue;
		}
		mesh_host = scsi_register(tp, sizeof(struct mesh_state));
		if (mesh_host == 0) {
			printk(KERN_ERR "mesh: couldn't register host");
			continue;
		}
		mesh_host->unique_id = nmeshes;
#if !defined(MODULE)
		note_scsi_host(mesh, mesh_host);
#endif

		ms = (struct mesh_state *) mesh_host->hostdata;
		if (ms == 0)
			panic("no mesh state");
		memset(ms, 0, sizeof(*ms));
		ms->host = mesh_host;
		ms->ofnode = mesh;
		ms->mesh = (volatile struct mesh_regs *)
			ioremap(mesh->addrs[0].address, 0x1000);
		ms->dma = (volatile struct dbdma_regs *)
			ioremap(mesh->addrs[1].address, 0x1000);
		ms->meshintr = mesh->intrs[0].line;
		ms->dmaintr = mesh->intrs[1].line;

		/* 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->dma_cmd_space = dma_cmd_space;

		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;
		}
#ifndef MESH_NEW_STYLE_EH
		ms->tqueue.routine = finish_cmds;
		ms->tqueue.data = ms;
#endif
		*prev_statep = ms;
		prev_statep = &ms->next;

		if ((cfp = (int *) get_property(mesh, "clock-frequency",
						NULL))) {
			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;

		feature_set(mesh, FEATURE_MESH_enable);
		mdelay(200);

		mesh_init(ms);

		if (request_irq(ms->meshintr, do_mesh_interrupt, 0, "MESH", ms)) {
			printk(KERN_ERR "MESH: can't get irq %d\n", ms->meshintr);
		}

		++nmeshes;
	}

	if ((_machine == _MACH_Pmac) && (nmeshes > 0))
		register_reboot_notifier(&mesh_notifier);

	return nmeshes;
}

int
mesh_release(struct Scsi_Host *host)
{
	struct mesh_state *ms = (struct mesh_state *) host->hostdata;

	if (ms == 0)
		return 0;
	if (ms->mesh)
		iounmap((void *) ms->mesh);
	if (ms->dma)
		iounmap((void *) ms->dma);
	kfree(ms->dma_cmd_space);
	free_irq(ms->meshintr, ms);
	feature_clear(ms->ofnode, FEATURE_MESH_enable);
	return 0;
}

int
mesh_queue(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
{
	unsigned long flags;
	struct mesh_state *ms;

	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)
{
	struct mesh_state *ms = (struct mesh_state *) cmd->host->hostdata;

	printk(KERN_DEBUG "mesh_abort(%p)\n", cmd);
	mesh_dump_regs(ms);
	dumplog(ms, cmd->target);
	dumpslog(ms);
	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 im=%2x int=%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->intr_mask, mr->interrupt,
	       mr->sync_params);
	while(in_8(&mr->fifo_count))
		printk(KERN_DEBUG " fifo data=%.2x\n",in_8(&mr->fifo));
	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 "    dma_st=%d dma_ct=%d n_msgout=%d\n",
	       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 goes_out=%d saved_ptr=%d\n",
		       t, tp->current_req, tp->data_goes_out, 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_le32(&md->control, (RUN|PAUSE|FLUSH|WAKE) << 16);	/* stop dma */
	out_8(&mr->exception, 0xff);	/* clear all exception bits */
	out_8(&mr->error, 0xff);	/* clear all error bits */
	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->source_id, ms->host->this_id);
		out_8(&mr->sel_timeout, 25);	/* 250ms */
		out_8(&mr->sync_params, ASYNC_PARAMS);
	}
	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
	{
		handle_reset(ms);
		restore_flags(flags);
#ifndef MESH_NEW_STYLE_EH
		finish_cmds(ms);
#endif
		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) {
		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);
		}
	}