esp.c

讲述linux的初始化过程

		bursts = (DMA_BURST32 - 1);

	esp->bursts = bursts;
}

static void __init esp_get_revision(struct esp *esp)
{
	u8 tmp;

	esp->config1 = (ESP_CONFIG1_PENABLE | (esp->scsi_id & 7));
	esp->config2 = (ESP_CONFIG2_SCSI2ENAB | ESP_CONFIG2_REGPARITY);
	sbus_writeb(esp->config2, esp->eregs + ESP_CFG2);

	tmp = sbus_readb(esp->eregs + ESP_CFG2);
	tmp &= ~ESP_CONFIG2_MAGIC;
	if (tmp != (ESP_CONFIG2_SCSI2ENAB | ESP_CONFIG2_REGPARITY)) {
		/* If what we write to cfg2 does not come back, cfg2
		 * is not implemented, therefore this must be a plain
		 * esp100.
		 */
		esp->erev = esp100;
		printk("NCR53C90(esp100)\n");
	} else {
		esp->config2 = 0;
		esp->prev_cfg3 = esp->config3[0] = 5;
		sbus_writeb(esp->config2, esp->eregs + ESP_CFG2);
		sbus_writeb(0, esp->eregs + ESP_CFG3);
		sbus_writeb(esp->prev_cfg3, esp->eregs + ESP_CFG3);

		tmp = sbus_readb(esp->eregs + ESP_CFG3);
		if (tmp != 5) {
			/* The cfg2 register is implemented, however
			 * cfg3 is not, must be esp100a.
			 */
			esp->erev = esp100a;
			printk("NCR53C90A(esp100a)\n");
		} else {
			int target;

			for (target = 0; target < 16; target++)
				esp->config3[target] = 0;
			esp->prev_cfg3 = 0;
			sbus_writeb(esp->prev_cfg3, esp->eregs + ESP_CFG3);

			/* All of cfg{1,2,3} implemented, must be one of
			 * the fas variants, figure out which one.
			 */
			if (esp->raw_cfact > ESP_CCF_F5) {
				esp->erev = fast;
				esp->sync_defp = SYNC_DEFP_FAST;
				printk("NCR53C9XF(espfast)\n");
			} else {
				esp->erev = esp236;
				printk("NCR53C9x(esp236)\n");
			}
			esp->config2 = 0;
			sbus_writeb(esp->config2, esp->eregs + ESP_CFG2);
		}
	}
}

static void __init esp_init_swstate(struct esp *esp)
{
	int i;

	/* Driver spinlock... */
	spin_lock_init(&esp->lock);

	/* Command queues... */
	esp->current_SC = NULL;
	esp->disconnected_SC = NULL;
	esp->issue_SC = NULL;

	/* Target and current command state... */
	esp->targets_present = 0;
	esp->resetting_bus = 0;
	esp->snip = 0;

	/* Debugging... */
	for(i = 0; i < 32; i++)
		esp->espcmdlog[i] = 0;
	esp->espcmdent = 0;

	/* MSG phase state... */
	for(i = 0; i < 16; i++) {
		esp->cur_msgout[i] = 0;
		esp->cur_msgin[i] = 0;
	}
	esp->prevmsgout = esp->prevmsgin = 0;
	esp->msgout_len = esp->msgin_len = 0;

	/* Clear the one behind caches to hold unmatchable values. */
	esp->prev_soff = esp->prev_stp = esp->prev_cfg3 = 0xff;
	esp->prev_hme_dmacsr = 0xffffffff;
}

static int __init detect_one_esp(Scsi_Host_Template *tpnt, struct sbus_dev *esp_dev,
				 struct sbus_dev *espdma, struct sbus_bus *sbus,
				 int id, int hme)
{
	struct Scsi_Host *esp_host = scsi_register(tpnt, sizeof(struct esp));
	struct esp *esp;
	
	if (!esp_host) {
		printk("ESP: Cannot register SCSI host\n");
		return -1;
	}
	if (hme)
		esp_host->max_id = 16;
	esp = (struct esp *) esp_host->hostdata;
	esp->ehost = esp_host;
	esp->sdev = esp_dev;
	esp->esp_id = id;
	esp->prom_node = esp_dev->prom_node;
	prom_getstring(esp->prom_node, "name", esp->prom_name,
		       sizeof(esp->prom_name));

	esp_chain_add(esp);
	if (esp_find_dvma(esp, espdma) < 0)
		goto fail_unlink;
	if (esp_map_regs(esp, hme) < 0) {
		printk("ESP registers unmappable");
		goto fail_dvma_release;
	}
	if (esp_map_cmdarea(esp) < 0) {
		printk("ESP DVMA transport area unmappable");
		goto fail_unmap_regs;
	}
	if (esp_register_irq(esp) < 0)
		goto fail_unmap_cmdarea;

	esp_get_scsi_id(esp);

	esp->diff = prom_getbool(esp->prom_node, "differential");
	if (esp->diff)
		printk("Differential ");

	esp_get_clock_params(esp);
	esp_get_bursts(esp, espdma);
	esp_get_revision(esp);
	esp_init_swstate(esp);

	esp_bootup_reset(esp);

	return 0;

fail_unmap_cmdarea:
	sbus_free_consistent(esp->sdev, 16,
			     (void *) esp->esp_command,
			     esp->esp_command_dvma);

fail_unmap_regs:
	sbus_iounmap(esp->eregs, ESP_REG_SIZE);

fail_dvma_release:
	esp->dma->allocated = 0;

fail_unlink:
	esp_chain_del(esp);
	scsi_unregister(esp_host);
	return -1;
}

/* Detecting ESP chips on the machine.  This is the simple and easy
 * version.
 */

#ifdef CONFIG_SUN4

#include <asm/sun4paddr.h>

int __init esp_detect(Scsi_Host_Template *tpnt)
{
	static struct sbus_dev esp_dev;
	int esps_in_use = 0;

	espchain = 0;

	if (sun4_esp_physaddr) {
		memset (&esp_dev, 0, sizeof(esp_dev));
		esp_dev.reg_addrs[0].phys_addr = sun4_esp_physaddr;
		esp_dev.irqs[0] = 4;
		esp_dev.resource[0].start = sun4_esp_physaddr;
		esp_dev.resource[0].end = sun4_esp_physaddr + ESP_REG_SIZE - 1;
		esp_dev.resource[0].flags = IORESOURCE_IO;

		if (!detect_one_esp(tpnt, &esp_dev, NULL, NULL, 0, 0))
			esps_in_use++;
		printk("ESP: Total of 1 ESP hosts found, %d actually in use.\n", esps_in_use);
		esps_running =  esps_in_use;
	}
	return esps_in_use;
}

#else /* !CONFIG_SUN4 */

int __init esp_detect(Scsi_Host_Template *tpnt)
{
	struct sbus_bus *sbus;
	struct sbus_dev *esp_dev, *sbdev_iter;
	int nesps = 0, esps_in_use = 0;

	espchain = 0;
	if (!sbus_root) {
#ifdef CONFIG_PCI
		return 0;
#else
		panic("No SBUS in esp_detect()");
#endif
	}
	for_each_sbus(sbus) {
		for_each_sbusdev(sbdev_iter, sbus) {
			struct sbus_dev *espdma = NULL;
			int hme = 0;

			/* Is it an esp sbus device? */
			esp_dev = sbdev_iter;
			if (strcmp(esp_dev->prom_name, "esp") &&
			    strcmp(esp_dev->prom_name, "SUNW,esp")) {
				if (!strcmp(esp_dev->prom_name, "SUNW,fas")) {
					hme = 1;
					espdma = esp_dev;
				} else {
					if (!esp_dev->child ||
					    (strcmp(esp_dev->prom_name, "espdma") &&
					     strcmp(esp_dev->prom_name, "dma")))
						continue; /* nope... */
					espdma = esp_dev;
					esp_dev = esp_dev->child;
					if (strcmp(esp_dev->prom_name, "esp") &&
					    strcmp(esp_dev->prom_name, "SUNW,esp"))
						continue; /* how can this happen? */
				}
			}
			
			if (detect_one_esp(tpnt, esp_dev, espdma, sbus, nesps++, hme) < 0)
				continue;
				
			esps_in_use++;
		} /* for each sbusdev */
	} /* for each sbus */
	printk("ESP: Total of %d ESP hosts found, %d actually in use.\n", nesps,
	       esps_in_use);
	esps_running = esps_in_use;
	return esps_in_use;
}

#endif /* !CONFIG_SUN4 */

/* The info function will return whatever useful
 * information the developer sees fit.  If not provided, then
 * the name field will be used instead.
 */
const char *esp_info(struct Scsi_Host *host)
{
	struct esp *esp;

	esp = (struct esp *) host->hostdata;
	switch (esp->erev) {
	case esp100:
		return "Sparc ESP100 (NCR53C90)";
	case esp100a:
		return "Sparc ESP100A (NCR53C90A)";
	case esp236:
		return "Sparc ESP236";
	case fas236:
		return "Sparc ESP236-FAST";
	case fashme:
		return "Sparc ESP366-HME";
	case fas100a:
		return "Sparc ESP100A-FAST";
	default:
		return "Bogon ESP revision";
	};
}

/* From Wolfgang Stanglmeier's NCR scsi driver. */
struct info_str
{
	char *buffer;
	int length;
	int offset;
	int pos;
};

static void copy_mem_info(struct info_str *info, char *data, int len)
{
	if (info->pos + len > info->length)
		len = info->length - info->pos;

	if (info->pos + len < info->offset) {
		info->pos += len;
		return;
	}
	if (info->pos < info->offset) {
		data += (info->offset - info->pos);
		len  -= (info->offset - info->pos);
	}

	if (len > 0) {
		memcpy(info->buffer + info->pos, data, len);
		info->pos += len;
	}
}

static int copy_info(struct info_str *info, char *fmt, ...)
{
	va_list args;
	char buf[81];
	int len;

	va_start(args, fmt);
	len = vsprintf(buf, fmt, args);
	va_end(args);

	copy_mem_info(info, buf, len);
	return len;
}

static int esp_host_info(struct esp *esp, char *ptr, off_t offset, int len)
{
	struct info_str info;
	int i;

	info.buffer	= ptr;
	info.length	= len;
	info.offset	= offset;
	info.pos	= 0;

	copy_info(&info, "Sparc ESP Host Adapter:\n");
	copy_info(&info, "\tPROM node\t\t%08x\n", (unsigned int) esp->prom_node);
	copy_info(&info, "\tPROM name\t\t%s\n", esp->prom_name);
	copy_info(&info, "\tESP Model\t\t");
	switch (esp->erev) {
	case esp100:
		copy_info(&info, "ESP100\n");
		break;
	case esp100a:
		copy_info(&info, "ESP100A\n");
		break;
	case esp236:
		copy_info(&info, "ESP236\n");
		break;
	case fas236:
		copy_info(&info, "FAS236\n");
		break;
	case fas100a:
		copy_info(&info, "FAS100A\n");
		break;
	case fast:
		copy_info(&info, "FAST\n");
		break;
	case fashme:
		copy_info(&info, "Happy Meal FAS\n");
		break;
	case espunknown:
	default:
		copy_info(&info, "Unknown!\n");
		break;
	};
	copy_info(&info, "\tDMA Revision\t\t");
	switch (esp->dma->revision) {
	case dvmarev0:
		copy_info(&info, "Rev 0\n");
		break;
	case dvmaesc1:
		copy_info(&info, "ESC Rev 1\n");
		break;
	case dvmarev1:
		copy_info(&info, "Rev 1\n");
		break;
	case dvmarev2:
		copy_info(&info, "Rev 2\n");
		break;
	case dvmarev3:
		copy_info(&info, "Rev 3\n");
		break;
	case dvmarevplus:
		copy_info(&info, "Rev 1+\n");
		break;
	case dvmahme:
		copy_info(&info, "Rev HME/FAS\n");
		break;
	default:
		copy_info(&info, "Unknown!\n");
		break;
	};
	copy_info(&info, "\tLive Targets\t\t[ ");
	for (i = 0; i < 15; i++) {
		if (esp->targets_present & (1 << i))
			copy_info(&info, "%d ", i);
	}
	copy_info(&info, "]\n\n");
	
	/* Now describe the state of each existing target. */
	copy_info(&info, "Target #\tconfig3\t\tSync Capabilities\tDisconnect\tWide\n");
	for (i = 0; i < 15; i++) {
		if (esp->targets_present & (1 << i)) {
			Scsi_Device *SDptr = esp->ehost->host_queue;

			while ((SDptr->host != esp->ehost) &&
			       (SDptr->id != i) &&
			       (SDptr->next))
				SDptr = SDptr->next;

			copy_info(&info, "%d\t\t", i);
			copy_info(&info, "%08lx\t", esp->config3[i]);
			copy_info(&info, "[%02lx,%02lx]\t\t\t", SDptr->sync_max_offset,
				  SDptr->sync_min_period);
			copy_info(&info, "%s\t\t", SDptr->disconnect ? "yes" : "no");
			copy_info(&info, "%s\n",
				  (esp->config3[i] & ESP_CONFIG3_EWIDE) ? "yes" : "no");
		}
	}
	return info.pos > info.offset? info.pos - info.offset : 0;
}

/* ESP proc filesystem code. */
int esp_proc_info(char *buffer, char **start, off_t offset, int length,
		  int hostno, int inout)
{
	struct esp *esp;

	if (inout)
		return -EINVAL; /* not yet */

	for_each_esp(esp) {
		if (esp->ehost->host_no == hostno)
			break;
	}
	if (!esp)
		return -EINVAL;

	if (start)
		*start = buffer;

	return esp_host_info(esp, buffer, offset, length);
}

static void esp_get_dmabufs(struct esp *esp, Scsi_Cmnd *sp)
{
	if (sp->use_sg == 0) {
		sp->SCp.this_residual = sp->request_bufflen;
		sp->SCp.buffer = (struct scatterlist *) sp->request_buffer;
		sp->SCp.buffers_residual = 0;
		if (sp->request_bufflen) {
			sp->SCp.have_data_in = sbus_map_single(esp->sdev, sp->SCp.buffer,
							       sp->SCp.this_residual,
							       scsi_to_sbus_dma_dir(sp->sc_data_direction));
			sp->SCp.ptr = (char *) ((unsigned long)sp->SCp.have_data_in);
		} else {
			sp->SCp.ptr = NULL;
		}
	} else {
		sp->SCp.buffer = (struct scatterlist *) sp->buffer;
		sp->SCp.buffers_residual = sbus_map_sg(esp->sdev,
						       sp->SCp.buffer,
						       sp->use_sg,
						       scsi_to_sbus_dma_dir(sp->sc_data_direction));
		sp->SCp.this_residual = sg_dma_len(sp->SCp.buffer);
		sp->SCp.ptr = (char *) ((unsigned long)sg_dma_address(sp->SCp.buffer));
	}
}

static void esp_release_dmabufs(struct esp *esp, Scsi_Cmnd *sp)
{
	if (sp->use_sg) {
		sbus_unmap_sg(esp->sdev, sp->buffer, sp->use_sg,
			      scsi_to_sbus_dma_dir(sp->sc_data_direction));
	} else if (sp->request_bufflen) {
		sbus_unmap_single(esp->sdev,
				  sp->SCp.have_data_in,
				  sp->request_bufflen,
				  scsi_to_sbus_dma_dir(sp->sc_data_direction));
	}
}

static void esp_restore_pointers(struct esp *esp, Scsi_Cmnd *sp)
{
	struct esp_pointers *ep = &esp->data_pointers[sp->target];

	sp->SCp.ptr = ep->saved_ptr;
	sp->SCp.buffer = ep->saved_buffer;
	sp->SCp.this_residual = ep->saved_this_residual;
	sp->SCp.buffers_residual = ep->saved_buffers_residual;
}