path: root/drivers/s390/cio/css.c

// SPDX-License-Identifier: GPL-2.0
/*
 * driver for channel subsystem
 *
 * Copyright IBM Corp. 2002, 2010
 *
 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *	      Cornelia Huck (cornelia.huck@de.ibm.com)
 */

#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/export.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/proc_fs.h>
#include <linux/genalloc.h>
#include <linux/dma-mapping.h>
#include <asm/isc.h>
#include <asm/crw.h>

#include "css.h"
#include "cio.h"
#include "blacklist.h"
#include "cio_debug.h"
#include "ioasm.h"
#include "chsc.h"
#include "device.h"
#include "idset.h"
#include "chp.h"

int css_init_done = 0;
int max_ssid;

#define MAX_CSS_IDX 0
struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
static struct bus_type css_bus_type;

int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
	struct subchannel_id schid;
	int ret;

	init_subchannel_id(&schid);
	do {
		do {
			ret = fn(schid, data);
			if (ret)
				break;
		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
		schid.sch_no = 0;
	} while (schid.ssid++ < max_ssid);
	return ret;
}

struct cb_data {
	void *data;
	struct idset *set;
	int (*fn_known_sch)(struct subchannel *, void *);
	int (*fn_unknown_sch)(struct subchannel_id, void *);
};

static int call_fn_known_sch(struct device *dev, void *data)
{
	struct subchannel *sch = to_subchannel(dev);
	struct cb_data *cb = data;
	int rc = 0;

	if (cb->set)
		idset_sch_del(cb->set, sch->schid);
	if (cb->fn_known_sch)
		rc = cb->fn_known_sch(sch, cb->data);
	return rc;
}

static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	int rc = 0;

	if (idset_sch_contains(cb->set, schid))
		rc = cb->fn_unknown_sch(schid, cb->data);
	return rc;
}

static int call_fn_all_sch(struct subchannel_id schid, void *data)
{
	struct cb_data *cb = data;
	struct subchannel *sch;
	int rc = 0;

	sch = get_subchannel_by_schid(schid);
	if (sch) {
		if (cb->fn_known_sch)
			rc = cb->fn_known_sch(sch, cb->data);
		put_device(&sch->dev);
	} else {
		if (cb->fn_unknown_sch)
			rc = cb->fn_unknown_sch(schid, cb->data);
	}

	return rc;
}

int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
			       int (*fn_unknown)(struct subchannel_id,
			       void *), void *data)
{
	struct cb_data cb;
	int rc;

	cb.data = data;
	cb.fn_known_sch = fn_known;
	cb.fn_unknown_sch = fn_unknown;

	if (fn_known && !fn_unknown) {
		/* Skip idset allocation in case of known-only loop. */
		cb.set = NULL;
		return bus_for_each_dev(&css_bus_type, NULL, &cb,
					call_fn_known_sch);
	}

	cb.set = idset_sch_new();
	if (!cb.set)
		/* fall back to brute force scanning in case of oom */
		return for_each_subchannel(call_fn_all_sch, &cb);

	idset_fill(cb.set);

	/* Process registered subchannels. */
	rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
	if (rc)
		goto out;
	/* Process unregistered subchannels. */
	if (fn_unknown)
		rc = for_each_subchannel(call_fn_unknown_sch, &cb);
out:
	idset_free(cb.set);

	return rc;
}

static void css_sch_todo(struct work_struct *work);

static int css_sch_create_locks(struct subchannel *sch)
{
	sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
	if (!sch->lock)
		return -ENOMEM;

	spin_lock_init(sch->lock);
	mutex_init(&sch->reg_mutex);

	return 0;
}

static void css_subchannel_release(struct device *dev)
{
	struct subchannel *sch = to_subchannel(dev);

	sch->config.intparm = 0;
	cio_commit_config(sch);
	kfree(sch->driver_override);
	kfree(sch->lock);
	kfree(sch);
}

static int css_validate_subchannel(struct subchannel_id schid,
				   struct schib *schib)
{
	int err;

	switch (schib->pmcw.st) {
	case SUBCHANNEL_TYPE_IO:
	case SUBCHANNEL_TYPE_MSG:
		if (!css_sch_is_valid(schib))
			err = -ENODEV;
		else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
			CIO_MSG_EVENT(6, "Blacklisted device detected "
				      "at devno %04X, subchannel set %x\n",
				      schib->pmcw.dev, schid.ssid);
			err = -ENODEV;
		} else
			err = 0;
		break;
	default:
		err = 0;
	}
	if (err)
		goto out;

	CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
		      schid.ssid, schid.sch_no, schib->pmcw.st);
out:
	return err;
}

struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
					struct schib *schib)
{
	struct subchannel *sch;
	int ret;

	ret = css_validate_subchannel(schid, schib);
	if (ret < 0)
		return ERR_PTR(ret);

	sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
	if (!sch)
		return ERR_PTR(-ENOMEM);

	sch->schid = schid;
	sch->schib = *schib;
	sch->st = schib->pmcw.st;

	ret = css_sch_create_locks(sch);
	if (ret)
		goto err;

	INIT_WORK(&sch->todo_work, css_sch_todo);
	sch->dev.release = &css_subchannel_release;
	device_initialize(&sch->dev);
	/*
	 * The physical addresses of some the dma structures that can
	 * belong to a subchannel need to fit 31 bit width (e.g. ccw).
	 */
	sch->dev.coherent_dma_mask = DMA_BIT_MASK(31);
	sch->dev.dma_mask = &sch->dev.coherent_dma_mask;
	return sch;

err:
	kfree(sch);
	return ERR_PTR(ret);
}

static int css_sch_device_register(struct subchannel *sch)
{
	int ret;

	mutex_lock(&sch->reg_mutex);
	dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
		     sch->schid.sch_no);
	ret = device_add(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
	return ret;
}

/**
 * css_sch_device_unregister - unregister a subchannel
 * @sch: subchannel to be unregistered
 */
void css_sch_device_unregister(struct subchannel *sch)
{
	mutex_lock(&sch->reg_mutex);
	if (device_is_registered(&sch->dev))
		device_unregister(&sch->dev);
	mutex_unlock(&sch->reg_mutex);
}
EXPORT_SYMBOL_GPL(css_sch_device_unregister);

static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
{
	int i;
	int mask;

	memset(ssd, 0, sizeof(struct chsc_ssd_info));
	ssd->path_mask = pmcw->pim;
	for (i = 0; i < 8; i++) {
		mask = 0x80 >> i;
		if (pmcw->pim & mask) {
			chp_id_init(&ssd->chpid[i]);
			ssd->chpid[i].id = pmcw->chpid[i];