mac53c94.c

Linux Kernel 2.6.9 for OMAP1710

/*
 * SCSI low-level driver for the 53c94 SCSI bus adaptor found
 * on Power Macintosh computers, controlling the external SCSI chain.
 * We assume the 53c94 is connected to a DBDMA (descriptor-based DMA)
 * controller.
 *
 * Paul Mackerras, August 1996.
 * Copyright (C) 1996 Paul Mackerras.
 */
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/dbdma.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/system.h>
#include <asm/pci-bridge.h>
#include <asm/macio.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include "mac53c94.h"

enum fsc_phase {
	idle,
	selecting,
	dataing,
	completing,
	busfreeing,
};

struct fsc_state {
	struct	mac53c94_regs *regs;
	int	intr;
	struct	dbdma_regs *dma;
	int	dmaintr;
	int	clk_freq;
	struct	Scsi_Host *host;
	struct scsi_cmnd *request_q;
	struct scsi_cmnd *request_qtail;
	struct scsi_cmnd *current_req;		/* req we're currently working on */
	enum fsc_phase phase;		/* what we're currently trying to do */
	struct dbdma_cmd *dma_cmds;	/* space for dbdma commands, aligned */
	void	*dma_cmd_space;
	struct	pci_dev *pdev;
	dma_addr_t dma_addr;
	struct macio_dev *mdev;
};

static void mac53c94_init(struct fsc_state *);
static void mac53c94_start(struct fsc_state *);
static void mac53c94_interrupt(int, void *, struct pt_regs *);
static irqreturn_t do_mac53c94_interrupt(int, void *, struct pt_regs *);
static void cmd_done(struct fsc_state *, int result);
static void set_dma_cmds(struct fsc_state *, struct scsi_cmnd *);


static int mac53c94_queue(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
	struct fsc_state *state;

#if 0
	if (cmd->sc_data_direction == DMA_TO_DEVICE) {
		int i;
		printk(KERN_DEBUG "mac53c94_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;

	state = (struct fsc_state *) cmd->device->host->hostdata;

	if (state->request_q == NULL)
		state->request_q = cmd;
	else
		state->request_qtail->host_scribble = (void *) cmd;
	state->request_qtail = cmd;

	if (state->phase == idle)
		mac53c94_start(state);

	return 0;
}

static int mac53c94_abort(struct scsi_cmnd *cmd)
{
	return FAILED;
}

static int mac53c94_host_reset(struct scsi_cmnd *cmd)
{
	struct fsc_state *state = (struct fsc_state *) cmd->device->host->hostdata;
	struct mac53c94_regs *regs = state->regs;
	struct dbdma_regs *dma = state->dma;

	st_le32(&dma->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
	writeb(CMD_SCSI_RESET, &regs->command);	/* assert RST */
	udelay(100);			/* leave it on for a while (>= 25us) */
	writeb(CMD_RESET, &regs->command);
	udelay(20);
	mac53c94_init(state);
	writeb(CMD_NOP, &regs->command);
	return SUCCESS;
}

static void mac53c94_init(struct fsc_state *state)
{
	struct mac53c94_regs *regs = state->regs;
	struct dbdma_regs *dma = state->dma;
	int x;

	writeb(state->host->this_id | CF1_PAR_ENABLE, &regs->config1);
	writeb(TIMO_VAL(250), &regs->sel_timeout);	/* 250ms */
	writeb(CLKF_VAL(state->clk_freq), &regs->clk_factor);
	writeb(CF2_FEATURE_EN, &regs->config2);
	writeb(0, &regs->config3);
	writeb(0, &regs->sync_period);
	writeb(0, &regs->sync_offset);
	x = readb(&regs->interrupt);
	writel((RUN|PAUSE|FLUSH|WAKE) << 16, &dma->control);
}

/*
 * Start the next command for a 53C94.
 * Should be called with interrupts disabled.
 */
static void mac53c94_start(struct fsc_state *state)
{
	struct scsi_cmnd *cmd;
	struct mac53c94_regs *regs = state->regs;
	int i;

	if (state->phase != idle || state->current_req != NULL)
		panic("inappropriate mac53c94_start (state=%p)", state);
	if (state->request_q == NULL)
		return;
	state->current_req = cmd = state->request_q;
	state->request_q = (struct scsi_cmnd *) cmd->host_scribble;

	/* Off we go */
	writeb(0, &regs->count_lo);
	writeb(0, &regs->count_mid);
	writeb(0, &regs->count_hi);
	writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
	udelay(1);
	writeb(CMD_FLUSH, &regs->command);
	udelay(1);
	writeb(cmd->device->id, &regs->dest_id);
	writeb(0, &regs->sync_period);
	writeb(0, &regs->sync_offset);

	/* load the command into the FIFO */
	for (i = 0; i < cmd->cmd_len; ++i)
		writeb(cmd->cmnd[i], &regs->fifo);

	/* do select without ATN XXX */
	writeb(CMD_SELECT, &regs->command);
	state->phase = selecting;

	if (cmd->use_sg > 0 || cmd->request_bufflen != 0)
		set_dma_cmds(state, cmd);
}

static irqreturn_t do_mac53c94_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
{
	unsigned long flags;
	struct Scsi_Host *dev = ((struct fsc_state *) dev_id)->current_req->device->host;
	
	spin_lock_irqsave(dev->host_lock, flags);
	mac53c94_interrupt(irq, dev_id, ptregs);
	spin_unlock_irqrestore(dev->host_lock, flags);
	return IRQ_HANDLED;
}

static void mac53c94_interrupt(int irq, void *dev_id, struct pt_regs *ptregs)
{
	struct fsc_state *state = (struct fsc_state *) dev_id;
	struct mac53c94_regs *regs = state->regs;
	struct dbdma_regs *dma = state->dma;
	struct scsi_cmnd *cmd = state->current_req;
	int nb, stat, seq, intr;
	static int mac53c94_errors;

	/*
	 * Apparently, reading the interrupt register unlatches
	 * the status and sequence step registers.
	 */
	seq = readb(&regs->seqstep);
	stat = readb(&regs->status);
	intr = readb(&regs->interrupt);

#if 0
	printk(KERN_DEBUG "mac53c94_intr, intr=%x stat=%x seq=%x phase=%d\n",
	       intr, stat, seq, state->phase);
#endif

	if (intr & INTR_RESET) {
		/* SCSI bus was reset */
		printk(KERN_INFO "external SCSI bus reset detected\n");
		writeb(CMD_NOP, &regs->command);
		writel(RUN << 16, &dma->control);	/* stop dma */
		cmd_done(state, DID_RESET << 16);
		return;
	}
	if (intr & INTR_ILL_CMD) {
		printk(KERN_ERR "53c94: invalid cmd, intr=%x stat=%x seq=%x phase=%d\n",
		       intr, stat, seq, state->phase);
		cmd_done(state, DID_ERROR << 16);
		return;
	}
	if (stat & STAT_ERROR) {
#if 0
		/* XXX these seem to be harmless? */
		printk("53c94: bad error, intr=%x stat=%x seq=%x phase=%d\n",
		       intr, stat, seq, state->phase);
#endif
		++mac53c94_errors;
		writeb(CMD_NOP + CMD_DMA_MODE, &regs->command);
	}
	if (cmd == 0) {
		printk(KERN_DEBUG "53c94: interrupt with no command active?\n");
		return;
	}
	if (stat & STAT_PARITY) {
		printk(KERN_ERR "mac53c94: parity error\n");
		cmd_done(state, DID_PARITY << 16);
		return;
	}
	switch (state->phase) {
	case selecting:
		if (intr & INTR_DISCONNECT) {
			/* selection timed out */
			cmd_done(state, DID_BAD_TARGET << 16);
			return;
		}
		if (intr != INTR_BUS_SERV + INTR_DONE) {
			printk(KERN_DEBUG "got intr %x during selection\n", intr);
			cmd_done(state, DID_ERROR << 16);
			return;
		}
		if ((seq & SS_MASK) != SS_DONE) {
			printk(KERN_DEBUG "seq step %x after command\n", seq);
			cmd_done(state, DID_ERROR << 16);
			return;
		}
		writeb(CMD_NOP, &regs->command);
		/* set DMA controller going if any data to transfer */
		if ((stat & (STAT_MSG|STAT_CD)) == 0
		    && (cmd->use_sg > 0 || cmd->request_bufflen != 0)) {
			nb = cmd->SCp.this_residual;
			if (nb > 0xfff0)
				nb = 0xfff0;
			cmd->SCp.this_residual -= nb;
			writeb(nb, &regs->count_lo);
			writeb(nb >> 8, &regs->count_mid);
			writeb(CMD_DMA_MODE + CMD_NOP, &regs->command);
			writel(virt_to_phys(state->dma_cmds), &dma->cmdptr);
			writel((RUN << 16) | RUN, &dma->control);
			writeb(CMD_DMA_MODE + CMD_XFER_DATA, &regs->command);
			state->phase = dataing;
			break;
		} else if ((stat & STAT_PHASE) == STAT_CD + STAT_IO) {
			/* up to status phase already */
			writeb(CMD_I_COMPLETE, &regs->command);
			state->phase = completing;
		} else {
			printk(KERN_DEBUG "in unexpected phase %x after cmd\n",
			       stat & STAT_PHASE);
			cmd_done(state, DID_ERROR << 16);
			return;
		}
		break;

	case dataing:
		if (intr != INTR_BUS_SERV) {
			printk(KERN_DEBUG "got intr %x before status\n", intr);