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From:   Ondrej Zary <linux@zary.sk>
To:     Damien Le Moal <damien.lemoal@opensource.wdc.com>
Cc:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Tim Waugh <tim@cyberelk.net>, linux-block@vger.kernel.org,
        linux-parport@lists.infradead.org, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] pata_parport: add driver (PARIDE replacement)
Date:   Sat, 12 Mar 2022 15:44:15 +0100
Message-Id: <20220312144415.20010-1-linux@zary.sk>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The pata_parport is a libata-based replacement of the old PARIDE
subsystem - driver for parallel port IDE devices.
It uses the original paride low-level protocol drivers but does not
need the high-level drivers (pd, pcd, pf, pt, pg). The IDE devices
behind parallel port adapters are handled by the ATA layer.

This will allow paride and its high-level drivers to be removed.

paride and pata_parport are mutually exclusive because the compiled
protocol drivers are incompatible.

Tested with Imation SuperDisk LS-120 and HP C4381A (both use EPAT
chip).

Note: EPP-32 mode is buggy in EPAT - and also in all other protocol
drivers - they don't handle non-multiple-of-4 block transfers
correctly. This causes problems with LS-120 drive.
There is also another bug in EPAT: EPP modes don't work unless a 4-bit
or 8-bit mode is used first (probably some initialization missing?).
Once the device is initialized, EPP works until power cycle.

So after device power on, you have to:
echo "parport0 epat 0" >/sys/bus/pata_parport/new_device
echo pata_parport.0 >/sys/bus/pata_parport/delete_device
echo "parport0 epat 4" >/sys/bus/pata_parport/new_device
(autoprobe will initialize correctly as it tries the slowest modes
first but you'll get the broken EPP-32 mode)

Signed-off-by: Ondrej Zary <linux@zary.sk>
---
 Documentation/admin-guide/blockdev/paride.rst |  52 ++
 drivers/Makefile                              |   2 +-
 drivers/ata/Kconfig                           |  14 +
 drivers/ata/Makefile                          |   2 +
 drivers/ata/pata_parport.c                    | 819 ++++++++++++++++++
 drivers/block/paride/Kconfig                  |  32 +-
 drivers/block/paride/paride.h                 |  13 +
 include/linux/pata_parport.h                  | 108 +++
 8 files changed, 1025 insertions(+), 17 deletions(-)
 create mode 100644 drivers/ata/pata_parport.c
 create mode 100644 include/linux/pata_parport.h

diff --git a/Documentation/admin-guide/blockdev/paride.rst b/Documentation/admin-guide/blockdev/paride.rst
index e1ce90af602a..e431a1ef41eb 100644
--- a/Documentation/admin-guide/blockdev/paride.rst
+++ b/Documentation/admin-guide/blockdev/paride.rst
@@ -2,6 +2,9 @@
 Linux and parallel port IDE devices
 ===================================
 
+Most of this document describes the old paride driver. For the new libata
+pata_parport drivrer, jump to the section 4 at the end.
+
 PARIDE v1.03   (c) 1997-8  Grant Guenther <grant@torque.net>
 
 1. Introduction
@@ -437,3 +440,52 @@ You might also find some useful information on the linux-parport
 web pages (although they are not always up to date) at
 
 	http://web.archive.org/web/%2E/http://www.torque.net/parport/
+
+4. pata_parport driver
+======================
+pata_parport is a libata-based driver that uses the same low-level protocol
+drivers as PARIDE but there are no high-level drivers (pd, pcd, pf, pt, pg).
+The IDE devices behind parallel port adapters are handled by the ATA layer.
+
+The device creation is also changed - no protocol numbers or parport I/O
+addresses are used.
+
+All parports and all protocol drivers are probed automatically unless probe=0
+parameter is used. So just "modprobe epat" is enough for a Imation SuperDisk
+drive to work.
+
+Manual device creation::
+
+	# echo "port protocol mode unit delay" >/sys/bus/pata_parport/new_device
+
+where:
+
+	======== ================================================
+	port	 parport name (or "auto" for all parports)
+	protocol protocol name (or "auto" for all protocols)
+	mode	 mode number (protocol-specific) or -1 for probe
+	unit	 unit number (see the paride documentation above)
+	delay	 I/O delay (see the paride documentation above)
+	======== ================================================
+
+If you omit the parameters from the end, defaults will be used, e.g.:
+
+Probe all parports with all protocols::
+
+	# echo auto >/sys/bus/pata_parport/new_device
+
+Probe parport0 using protocol epat and mode 4 (EPP-16)::
+
+	# echo "parport0 epat 4" >/sys/bus/pata_parport/new_device
+
+Probe parport0 using all protocols::
+
+	# echo "parport0 auto" >/sys/bus/pata_parport/new_device
+
+Probe all parports using protoocol epat::
+
+	# echo "auto epat" >/sys/bus/pata_parport/new_device
+
+Deleting devices::
+
+	# echo pata_parport.0 >/sys/bus/pata_parport/delete_device
diff --git a/drivers/Makefile b/drivers/Makefile
index a110338c860c..8ec515f3614e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -98,7 +98,7 @@ obj-$(CONFIG_DIO)		+= dio/
 obj-$(CONFIG_SBUS)		+= sbus/
 obj-$(CONFIG_ZORRO)		+= zorro/
 obj-$(CONFIG_ATA_OVER_ETH)	+= block/aoe/
-obj-$(CONFIG_PARIDE) 		+= block/paride/
+obj-y		 		+= block/paride/
 obj-$(CONFIG_TC)		+= tc/
 obj-$(CONFIG_USB_PHY)		+= usb/
 obj-$(CONFIG_USB)		+= usb/
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index e5641e6c52ee..ccbf6114fd53 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -1161,6 +1161,20 @@ config PATA_WINBOND_VLB
 	  Support for the Winbond W83759A controller on Vesa Local Bus
 	  systems.
 
+config PATA_PARPORT
+	tristate "Parallel port IDE device support"
+	depends on PARPORT_PC && PARIDE=n
+	help
+	  There are many external CD-ROM and disk devices that connect through
+	  your computer's parallel port. Most of them are actually IDE devices
+	  using a parallel port IDE adapter. This option enables the
+	  PATA_PARPORT subsystem which contains drivers for many of these
+	  external drives.
+	  Read <file:Documentation/admin-guide/blockdev/paride.rst> for more
+	  information.
+
+	  Use the old PARIDE protocol modules.
+
 comment "Generic fallback / legacy drivers"
 
 config PATA_ACPI
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index b8aebfb14e82..77145834a585 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -114,6 +114,8 @@ obj-$(CONFIG_PATA_SAMSUNG_CF)	+= pata_samsung_cf.o
 
 obj-$(CONFIG_PATA_PXA)		+= pata_pxa.o
 
+obj-$(CONFIG_PATA_PARPORT)	+= pata_parport.o
+
 # Should be last but two libata driver
 obj-$(CONFIG_PATA_ACPI)		+= pata_acpi.o
 # Should be last but one libata driver
diff --git a/drivers/ata/pata_parport.c b/drivers/ata/pata_parport.c
new file mode 100644
index 000000000000..783764626a27
--- /dev/null
+++ b/drivers/ata/pata_parport.c
@@ -0,0 +1,819 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022 Ondrej Zary
+ * based on paride.c by Grant R. Guenther <grant@torque.net>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/parport.h>
+#include <linux/pata_parport.h>
+
+#define DRV_NAME "pata_parport"
+
+static DEFINE_IDR(parport_list);
+static DEFINE_IDR(protocols);
+static DEFINE_IDA(pata_parport_bus_dev_ids);
+static DEFINE_MUTEX(pi_mutex);
+
+static bool probe = true;
+module_param(probe, bool, 0644);
+MODULE_PARM_DESC(probe, "Enable automatic device probing (0=off, 1=on [default])");
+
+static bool verbose;
+module_param(verbose, bool, 0644);
+MODULE_PARM_DESC(verbose, "Enable verbose messages (0=off [default], 1=on)");
+
+#define DISCONNECT_TIMEOUT	(HZ / 10)
+
+static void pi_connect(struct pi_adapter *pi)
+{
+	del_timer_sync(&pi->timer);
+	if (!pi->claimed) {
+		pi->claimed = true;
+		parport_claim_or_block(pi->pardev);
+		pi->proto->connect(pi);
+	}
+}
+
+static void pi_disconnect_timer(struct timer_list *t)
+{
+	struct pi_adapter *pi = from_timer(pi, t, timer);
+
+	if (pi->claimed) {
+		pi->proto->disconnect(pi);
+		parport_release(pi->pardev);
+		pi->claimed = false;
+	}
+}
+
+/* functions taken from libata-sff.c and converted from direct port I/O */
+static void pata_parport_dev_select(struct ata_port *ap, unsigned int device)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+	u8 tmp;
+
+	if (device == 0)
+		tmp = ATA_DEVICE_OBS;
+	else
+		tmp = ATA_DEVICE_OBS | ATA_DEV1;
+
+	pi_connect(pi);
+	pi->proto->write_regr(pi, 0, ATA_REG_DEVICE, tmp);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+	ata_sff_pause(ap);
+}
+
+static bool pata_parport_devchk(struct ata_port *ap, unsigned int device)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+	u8 nsect, lbal;
+
+	pata_parport_dev_select(ap, device);
+
+	pi_connect(pi);
+	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 0x55);
+	pi->proto->write_regr(pi, 0, ATA_REG_LBAL, 0xaa);
+
+	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 0xaa);
+	pi->proto->write_regr(pi, 0, ATA_REG_LBAL, 0x55);
+
+	pi->proto->write_regr(pi, 0, ATA_REG_NSECT, 055);
+	pi->proto->write_regr(pi, 0, ATA_REG_LBAL, 0xaa);
+
+	nsect = pi->proto->read_regr(pi, 0, ATA_REG_NSECT);
+	lbal = pi->proto->read_regr(pi, 0, ATA_REG_LBAL);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+
+	if ((nsect == 0x55) && (lbal == 0xaa))
+		return true;	/* we found a device */
+
+	return false;		/* nothing found */
+}
+
+static int pata_parport_bus_softreset(struct ata_port *ap, unsigned int devmask,
+				      unsigned long deadline)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	/* software reset.  causes dev0 to be selected */
+	pi->proto->write_regr(pi, 1, 6, ap->ctl);
+	udelay(20);
+	pi->proto->write_regr(pi, 1, 6, ap->ctl | ATA_SRST);
+	udelay(20);
+	pi->proto->write_regr(pi, 1, 6, ap->ctl);
+	ap->last_ctl = ap->ctl;
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+
+	/* wait the port to become ready */
+	return ata_sff_wait_after_reset(&ap->link, devmask, deadline);
+}
+
+static int pata_parport_softreset(struct ata_link *link, unsigned int *classes,
+				  unsigned long deadline)
+{
+	struct ata_port *ap = link->ap;
+	unsigned int devmask = 0;
+	int rc;
+	u8 err;
+
+	/* determine if device 0/1 are present */
+	if (pata_parport_devchk(ap, 0))
+		devmask |= (1 << 0);
+	if (pata_parport_devchk(ap, 1))
+		devmask |= (1 << 1);
+
+	/* select device 0 again */
+	pata_parport_dev_select(ap, 0);
+
+	/* issue bus reset */
+	rc = pata_parport_bus_softreset(ap, devmask, deadline);
+	if (rc && rc != -ENODEV) {
+		ata_link_err(link, "SRST failed (errno=%d)\n", rc);
+		return rc;
+	}
+
+	/* determine by signature whether we have ATA or ATAPI devices */
+	classes[0] = ata_sff_dev_classify(&link->device[0],
+					  devmask & (1 << 0), &err);
+	if (err != 0x81)
+		classes[1] = ata_sff_dev_classify(&link->device[1],
+						  devmask & (1 << 1), &err);
+
+	return 0;
+}
+
+static u8 pata_parport_check_status(struct ata_port *ap)
+{
+	u8 status;
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	status = pi->proto->read_regr(pi, 0, ATA_REG_STATUS);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+
+	return status;
+}
+
+static u8 pata_parport_check_altstatus(struct ata_port *ap)
+{
+	u8 altstatus;
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	altstatus = pi->proto->read_regr(pi, 1, 6);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+
+	return altstatus;
+}
+
+static void pata_parport_tf_load(struct ata_port *ap,
+				 const struct ata_taskfile *tf)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	if (tf->ctl != ap->last_ctl) {
+		pi->proto->write_regr(pi, 1, 6, tf->ctl);
+		ap->last_ctl = tf->ctl;
+		ata_wait_idle(ap);
+	}
+
+	if (tf->flags & ATA_TFLAG_ISADDR) {
+		if (tf->flags & ATA_TFLAG_LBA48) {
+			pi->proto->write_regr(pi, 0, ATA_REG_FEATURE,
+					      tf->hob_feature);
+			pi->proto->write_regr(pi, 0, ATA_REG_NSECT,
+					      tf->hob_nsect);
+			pi->proto->write_regr(pi, 0, ATA_REG_LBAL,
+					      tf->hob_lbal);
+			pi->proto->write_regr(pi, 0, ATA_REG_LBAM,
+					      tf->hob_lbam);
+			pi->proto->write_regr(pi, 0, ATA_REG_LBAH,
+					      tf->hob_lbah);
+		}
+		pi->proto->write_regr(pi, 0, ATA_REG_FEATURE, tf->feature);
+		pi->proto->write_regr(pi, 0, ATA_REG_NSECT, tf->nsect);
+		pi->proto->write_regr(pi, 0, ATA_REG_LBAL, tf->lbal);
+		pi->proto->write_regr(pi, 0, ATA_REG_LBAM, tf->lbam);
+		pi->proto->write_regr(pi, 0, ATA_REG_LBAH, tf->lbah);
+	}
+
+	if (tf->flags & ATA_TFLAG_DEVICE)
+		pi->proto->write_regr(pi, 0, ATA_REG_DEVICE, tf->device);
+
+	ata_wait_idle(ap);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+}
+
+static void pata_parport_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	tf->status = pi->proto->read_regr(pi, 0, ATA_REG_STATUS);
+	tf->error = pi->proto->read_regr(pi, 0, ATA_REG_ERR);
+	tf->nsect = pi->proto->read_regr(pi, 0, ATA_REG_NSECT);
+	tf->lbal = pi->proto->read_regr(pi, 0, ATA_REG_LBAL);
+	tf->lbam = pi->proto->read_regr(pi, 0, ATA_REG_LBAM);
+	tf->lbah = pi->proto->read_regr(pi, 0, ATA_REG_LBAH);
+	tf->device = pi->proto->read_regr(pi, 0, ATA_REG_DEVICE);
+
+	if (tf->flags & ATA_TFLAG_LBA48) {
+		pi->proto->write_regr(pi, 1, 6, tf->ctl | ATA_HOB);
+		tf->hob_feature = pi->proto->read_regr(pi, 0, ATA_REG_ERR);
+		tf->hob_nsect = pi->proto->read_regr(pi, 0, ATA_REG_NSECT);
+		tf->hob_lbal = pi->proto->read_regr(pi, 0, ATA_REG_LBAL);
+		tf->hob_lbam = pi->proto->read_regr(pi, 0, ATA_REG_LBAM);
+		tf->hob_lbah = pi->proto->read_regr(pi, 0, ATA_REG_LBAH);
+		pi->proto->write_regr(pi, 1, 6, tf->ctl);
+		ap->last_ctl = tf->ctl;
+	}
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+}
+
+static void pata_parport_exec_command(struct ata_port *ap,
+				      const struct ata_taskfile *tf)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	pi->proto->write_regr(pi, 0, ATA_REG_CMD, tf->command);
+	ata_sff_pause(ap);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+}
+
+static unsigned int pata_parport_data_xfer(struct ata_queued_cmd *qc,
+				unsigned char *buf, unsigned int buflen, int rw)
+{
+	struct ata_port *ap = qc->dev->link->ap;
+	struct pi_adapter *pi = ap->host->private_data;
+
+	pi_connect(pi);
+	if (rw == READ)
+		pi->proto->read_block(pi, buf, buflen);
+	else
+		pi->proto->write_block(pi, buf, buflen);
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+
+	return buflen;
+}
+
+static void pata_parport_drain_fifo(struct ata_queued_cmd *qc)
+{
+	int count;
+	struct ata_port *ap;
+	struct pi_adapter *pi;
+	char junk[2];
+
+	/* We only need to flush incoming data when a command was running */
+	if (qc == NULL || qc->dma_dir == DMA_TO_DEVICE)
+		return;
+
+	ap = qc->ap;
+	pi = ap->host->private_data;
+	/* Drain up to 64K of data before we give up this recovery method */
+	for (count = 0; (pata_parport_check_status(ap) & ATA_DRQ)
+						&& count < 65536; count += 2) {
+		pi_connect(pi);
+		pi->proto->read_block(pi, junk, 2);
+		mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+	}
+
+	if (count)
+		ata_port_dbg(ap, "drained %d bytes to clear DRQ\n", count);
+}
+
+static void pata_parport_lost_interrupt(struct ata_port *ap)
+{
+	u8 status;
+	struct ata_queued_cmd *qc;
+
+	/* Only one outstanding command per SFF channel */
+	qc = ata_qc_from_tag(ap, ap->link.active_tag);
+	/* We cannot lose an interrupt on a non-existent or polled command */
+	if (!qc || qc->tf.flags & ATA_TFLAG_POLLING)
+		return;
+	/*
+	 * See if the controller thinks it is still busy - if so the command
+	 * isn't a lost IRQ but is still in progress
+	 */
+	status = pata_parport_check_altstatus(ap);
+	if (status & ATA_BUSY)
+		return;
+
+	/*
+	 * There was a command running, we are no longer busy and we have
+	 * no interrupt.
+	 */
+	ata_port_warn(ap, "lost interrupt (Status 0x%x)\n", status);
+	/* Run the host interrupt logic as if the interrupt had not been lost */
+	ata_sff_port_intr(ap, qc);
+}
+
+static struct ata_port_operations pata_parport_port_ops = {
+	.inherits		= &ata_sff_port_ops,
+
+	.softreset		= pata_parport_softreset,
+	.hardreset		= NULL,
+
+	.sff_dev_select		= pata_parport_dev_select,
+	.sff_check_status	= pata_parport_check_status,
+	.sff_check_altstatus	= pata_parport_check_altstatus,
+	.sff_tf_load		= pata_parport_tf_load,
+	.sff_tf_read		= pata_parport_tf_read,
+	.sff_exec_command	= pata_parport_exec_command,
+	.sff_data_xfer		= pata_parport_data_xfer,
+	.sff_drain_fifo		= pata_parport_drain_fifo,
+
+	.lost_interrupt		= pata_parport_lost_interrupt,
+};
+
+static const struct ata_port_info pata_parport_port_info = {
+	.flags		= ATA_FLAG_SLAVE_POSS | ATA_FLAG_PIO_POLLING,
+	.pio_mask	= ATA_PIO0,
+	/* No DMA */
+	.port_ops	= &pata_parport_port_ops,
+};
+
+static void pi_release(struct pi_adapter *pi)
+{
+	parport_unregister_device(pi->pardev);
+	if (pi->proto->release_proto)
+		pi->proto->release_proto(pi);
+	module_put(pi->proto->owner);
+}
+
+static int default_test_proto(struct pi_adapter *pi, char *scratch)
+{
+	int j, k;
+	int e[2] = { 0, 0 };
+
+	pi->proto->connect(pi);
+
+	for (j = 0; j < 2; j++) {
+		pi->proto->write_regr(pi, 0, 6, 0xa0 + j * 0x10);
+		for (k = 0; k < 256; k++) {
+			pi->proto->write_regr(pi, 0, 2, k ^ 0xaa);
+			pi->proto->write_regr(pi, 0, 3, k ^ 0x55);
+			if (pi->proto->read_regr(pi, 0, 2) != (k ^ 0xaa))
+				e[j]++;
+		}
+	}
+	pi->proto->disconnect(pi);
+
+	if (verbose)
+		dev_info(&pi->dev, "%s: port 0x%x, mode %d, test=(%d,%d)\n",
+		       pi->proto->name, pi->port,
+		       pi->mode, e[0], e[1]);
+
+	return e[0] && e[1];	/* not here if both > 0 */
+}
+
+static int pi_test_proto(struct pi_adapter *pi, char *scratch)
+{
+	int res;
+
+	parport_claim_or_block(pi->pardev);
+	if (pi->proto->test_proto)
+		res = pi->proto->test_proto(pi, scratch, verbose);
+	else
+		res = default_test_proto(pi, scratch);
+	parport_release(pi->pardev);
+
+	return res;
+}
+
+static bool pi_probe_mode(struct pi_adapter *pi, int max, char *scratch)
+{
+	int best, range;
+
+	if (pi->mode != -1) {
+		if (pi->mode >= max)
+			return false;
+		range = 3;
+		if (pi->mode >= pi->proto->epp_first)
+			range = 8;
+		if (range == 8 && pi->port % 8)
+			return false;
+		return !pi_test_proto(pi, scratch);
+	}
+	best = -1;
+	for (pi->mode = 0; pi->mode < max; pi->mode++) {
+		range = 3;
+		if (pi->mode >= pi->proto->epp_first)
+			range = 8;
+		if (range == 8 && pi->port % 8)
+			break;
+		if (!pi_test_proto(pi, scratch))
+			best = pi->mode;
+	}
+	pi->mode = best;
+	return best > -1;
+}
+
+static bool pi_probe_unit(struct pi_adapter *pi, int unit, char *scratch)
+{
+	int max, s, e;
+
+	s = unit;
+	e = s + 1;
+
+	if (s == -1) {
+		s = 0;
+		e = pi->proto->max_units;
+	}
+
+	if (pi->proto->test_port) {
+		parport_claim_or_block(pi->pardev);
+		max = pi->proto->test_port(pi);
+		parport_release(pi->pardev);
+	} else {
+		max = pi->proto->max_mode;
+	}
+
+	if (pi->proto->probe_unit) {
+		parport_claim_or_block(pi->pardev);
+		for (pi->unit = s; pi->unit < e; pi->unit++) {
+			if (pi->proto->probe_unit(pi)) {
+				parport_release(pi->pardev);
+				return pi_probe_mode(pi, max, scratch);
+			}
+		}
+		parport_release(pi->pardev);
+		return false;
+	}
+
+	return pi_probe_mode(pi, max, scratch);
+}
+
+static void pata_parport_dev_release(struct device *dev)
+{
+	struct pi_adapter *pi = container_of(dev, struct pi_adapter, dev);
+
+	kfree(pi);
+}
+
+static void pata_parport_bus_release(struct device *dev)
+{
+	/* nothing to do here but required to avoid warning on device removal */
+}
+
+static struct bus_type pata_parport_bus_type = {
+	.name = DRV_NAME,
+};
+
+static struct device pata_parport_bus = {
+	.init_name = DRV_NAME,
+	.release = pata_parport_bus_release,
+};
+
+/* temporary for old paride protocol modules */
+static struct scsi_host_template pata_parport_sht = {
+	PATA_PARPORT_SHT("pata_parport")
+};
+
+static struct pi_adapter *pi_init_one(struct parport *parport,
+			struct pi_protocol *pr, int mode, int unit, int delay)
+{
+	struct pardev_cb par_cb = { };
+	char scratch[512];
+	const struct ata_port_info *ppi[] = { &pata_parport_port_info };
+	struct ata_host *host;
+	struct pi_adapter *pi;
+
+	pi = kzalloc(sizeof(struct pi_adapter), GFP_KERNEL);
+	if (!pi)
+		return NULL;
+
+	/* set up pi->dev before pi_probe_unit() so it can use dev_printk() */
+	pi->dev.parent = &pata_parport_bus;
+	pi->dev.bus = &pata_parport_bus_type;
+	pi->dev.driver = &pr->driver;
+	pi->dev.release = pata_parport_dev_release;
+	pi->dev.id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL);
+	if (pi->dev.id < 0)
+		return NULL; /* pata_parport_dev_release will do kfree(pi) */
+	dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id);
+	if (device_register(&pi->dev)) {
+		put_device(&pi->dev);
+		goto out_ida_free;
+	}
+
+	pi->proto = pr;
+
+	if (!try_module_get(pi->proto->owner))
+		goto out_unreg_dev;
+	if (pi->proto->init_proto && pi->proto->init_proto(pi) < 0)
+		goto out_module_put;
+
+	pi->delay = (delay == -1) ? pi->proto->default_delay : delay;
+	pi->mode = mode;
+	pi->port = parport->base;
+
+	par_cb.private = pi;
+	pi->pardev = parport_register_dev_model(parport, DRV_NAME, &par_cb,
+						pi->dev.id);
+	if (!pi->pardev)
+		goto out_module_put;
+
+	if (!pi_probe_unit(pi, unit, scratch)) {
+		dev_info(&pi->dev, "Adapter not found\n");
+		goto out_unreg_parport;
+	}
+
+	pi->proto->log_adapter(pi, scratch, verbose);
+
+	host = ata_host_alloc_pinfo(&pi->pardev->dev, ppi, 1);
+	if (!host)
+		goto out_unreg_parport;
+	dev_set_drvdata(&pi->dev, host);
+	host->private_data = pi;
+
+	ata_port_desc(host->ports[0], "port %s", pi->pardev->port->name);
+	ata_port_desc(host->ports[0], "protocol %s", pi->proto->name);
+
+	timer_setup(&pi->timer, pi_disconnect_timer, 0);
+
+	if (ata_host_activate(host, 0, NULL, 0, &pata_parport_sht))
+		goto out_unreg_parport;
+
+	return pi;
+
+out_unreg_parport:
+	parport_unregister_device(pi->pardev);
+	if (pi->proto->release_proto)
+		pi->proto->release_proto(pi);
+out_module_put:
+	module_put(pi->proto->owner);
+out_unreg_dev:
+	device_unregister(&pi->dev);
+out_ida_free:
+	ida_free(&pata_parport_bus_dev_ids, pi->dev.id);
+	return NULL;
+}
+
+int pata_parport_register_driver(struct pi_protocol *pr)
+{
+	int error;
+	struct parport *parport;
+	int port_num;
+
+	pr->driver.bus = &pata_parport_bus_type;
+	pr->driver.name = pr->name;
+	error = driver_register(&pr->driver);
+	if (error)
+		return error;
+
+	mutex_lock(&pi_mutex);
+	error = idr_alloc(&protocols, pr, 0, 0, GFP_KERNEL);
+	if (error < 0) {
+		driver_unregister(&pr->driver);
+		mutex_unlock(&pi_mutex);
+		return error;
+	}
+
+	pr_info("pata_parport: protocol %s registered\n", pr->name);
+
+	if (probe) {
+		/* probe all parports using this protocol */
+		idr_for_each_entry(&parport_list, parport, port_num)
+			pi_init_one(parport, pr, -1, 0, -1);
+	}
+	mutex_unlock(&pi_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL(pata_parport_register_driver);
+
+void pata_parport_unregister_driver(struct pi_protocol *pr)
+{
+	struct pi_protocol *pr_iter;
+	int id = -1;
+
+	mutex_lock(&pi_mutex);
+	idr_for_each_entry(&protocols, pr_iter, id) {
+		if (pr_iter == pr)
+			break;
+	}
+	idr_remove(&protocols, id);
+	mutex_unlock(&pi_mutex);
+	driver_unregister(&pr->driver);
+}
+EXPORT_SYMBOL(pata_parport_unregister_driver);
+
+static ssize_t new_device_store(struct bus_type *bus, const char *buf,
+				size_t count)
+{
+	char port[12] = "auto";
+	char protocol[8] = "auto";
+	int mode = -1, unit = -1, delay = -1;
+	struct pi_protocol *pr, *pr_wanted;
+	struct device_driver *drv;
+	struct parport *parport;
+	int port_num, port_wanted, pr_num;
+	bool ok = false;
+
+	if (sscanf(buf, "%11s %7s %d %d %d",
+			port, protocol, &mode, &unit, &delay) < 1)
+		return -EINVAL;
+
+	if (sscanf(port, "parport%u", &port_wanted) < 1) {
+		if (!strcmp(port, "auto")) {
+			port_wanted = -1;
+		} else {
+			pr_err("invalid port name %s\n", port);
+			return -EINVAL;
+		}
+	}
+
+	drv = driver_find(protocol, &pata_parport_bus_type);
+	if (!drv) {
+		if (!strcmp(protocol, "auto")) {
+			pr_wanted = NULL;
+		} else {
+			pr_err("protocol %s not found\n", protocol);
+			return -EINVAL;
+		}
+	} else {
+		pr_wanted = container_of(drv, struct pi_protocol, driver);
+	}
+
+	mutex_lock(&pi_mutex);
+	/* walk all parports */
+	idr_for_each_entry(&parport_list, parport, port_num) {
+		if (port_num == port_wanted || port_wanted == -1) {
+			parport = parport_find_number(port_num);
+			if (!parport) {
+				pr_err("no such port %s\n", port);
+				mutex_unlock(&pi_mutex);
+				return -ENODEV;
+			}
+			/* walk all protocols */
+			idr_for_each_entry(&protocols, pr, pr_num) {
+				if (pr == pr_wanted || !pr_wanted)
+					if (pi_init_one(parport, pr, mode, unit,
+							delay))
+						ok = true;
+			}
+			parport_put_port(parport);
+		}
+	}
+	mutex_unlock(&pi_mutex);
+	if (!ok)
+		return -ENODEV;
+
+	return count;
+}
+static BUS_ATTR_WO(new_device);
+
+static void pi_remove_one(struct device *dev)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pi_adapter *pi = host->private_data;
+
+	ata_host_detach(host);
+	del_timer_sync(&pi->timer);
+	if (pi->claimed) {
+		pi->proto->disconnect(pi);
+		parport_release(pi->pardev);
+	}
+	pi_release(pi);
+	device_unregister(dev);
+	ida_free(&pata_parport_bus_dev_ids, dev->id);
+	/* pata_parport_dev_release will do kfree(pi) */
+}
+
+static ssize_t delete_device_store(struct bus_type *bus, const char *buf,
+				   size_t count)
+{
+	struct device *dev;
+	char device_name[32];
+
+	if (sscanf(buf, "%31s", device_name) < 1)
+		return -EINVAL;
+
+	mutex_lock(&pi_mutex);
+	dev = bus_find_device_by_name(bus, NULL, device_name);
+	if (!dev) {
+		mutex_unlock(&pi_mutex);
+		return -ENODEV;
+	}
+
+	pi_remove_one(dev);
+	mutex_unlock(&pi_mutex);
+
+	return count;
+}
+static BUS_ATTR_WO(delete_device);
+
+static void pata_parport_attach(struct parport *port)
+{
+	struct pi_protocol *pr;
+	int pr_num, id;
+
+	mutex_lock(&pi_mutex);
+	id = idr_alloc(&parport_list, port, port->number, port->number,
+		       GFP_KERNEL);
+	if (id < 0) {
+		mutex_unlock(&pi_mutex);
+		return;
+	}
+
+	if (probe) {
+		/* probe this port using all protocols */
+		idr_for_each_entry(&protocols, pr, pr_num)
+			pi_init_one(port, pr, -1, 0, -1);
+	}
+	mutex_unlock(&pi_mutex);
+}
+
+static int pi_remove_port(struct device *dev, void *p)
+{
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct pi_adapter *pi = host->private_data;
+
+	if (pi->pardev->port == p)
+		pi_remove_one(dev);
+
+	return 0;
+}
+
+static void pata_parport_detach(struct parport *port)
+{
+	mutex_lock(&pi_mutex);
+	bus_for_each_dev(&pata_parport_bus_type, NULL, port, pi_remove_port);
+	idr_remove(&parport_list, port->number);
+	mutex_unlock(&pi_mutex);
+}
+
+static struct parport_driver pata_parport_driver = {
+	.name = DRV_NAME,
+	.match_port = pata_parport_attach,
+	.detach = pata_parport_detach,
+	.devmodel = true,
+};
+
+static __init int pata_parport_init(void)
+{
+	int error;
+
+	error = bus_register(&pata_parport_bus_type);
+	if (error) {
+		pr_err("failed to register pata_parport bus, error: %d\n", error);
+		return error;
+	}
+
+	error = device_register(&pata_parport_bus);
+	if (error) {
+		pr_err("failed to register pata_parport bus, error: %d\n", error);
+		goto out_unregister_bus;
+	}
+
+	error = bus_create_file(&pata_parport_bus_type, &bus_attr_new_device);
+	if (error) {
+		pr_err("unable to create sysfs file, error: %d\n", error);
+		goto out_unregister_dev;
+	}
+
+	error = bus_create_file(&pata_parport_bus_type, &bus_attr_delete_device);
+	if (error) {
+		pr_err("unable to create sysfs file, error: %d\n", error);
+		goto out_remove_new;
+	}
+
+	error = parport_register_driver(&pata_parport_driver);
+	if (error) {
+		pr_err("unable to register parport driver, error: %d\n", error);
+		goto out_remove_del;
+	}
+
+	return 0;
+
+out_remove_del:
+	bus_remove_file(&pata_parport_bus_type, &bus_attr_delete_device);
+out_remove_new:
+	bus_remove_file(&pata_parport_bus_type, &bus_attr_new_device);
+out_unregister_dev:
+	device_unregister(&pata_parport_bus);
+out_unregister_bus:
+	bus_unregister(&pata_parport_bus_type);
+	return error;
+}
+
+static __exit void pata_parport_exit(void)
+{
+	parport_unregister_driver(&pata_parport_driver);
+	bus_remove_file(&pata_parport_bus_type, &bus_attr_new_device);
+	bus_remove_file(&pata_parport_bus_type, &bus_attr_delete_device);
+	device_unregister(&pata_parport_bus);
+	bus_unregister(&pata_parport_bus_type);
+}
+
+MODULE_AUTHOR("Ondrej Zary");
+MODULE_DESCRIPTION("driver for parallel port ATA adapters");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("paride");
+
+module_init(pata_parport_init);
+module_exit(pata_parport_exit);
diff --git a/drivers/block/paride/Kconfig b/drivers/block/paride/Kconfig
index a295634597ba..01e4ef3655c1 100644
--- a/drivers/block/paride/Kconfig
+++ b/drivers/block/paride/Kconfig
@@ -92,11 +92,11 @@ config PARIDE_PG
 	  later fully support this driver.
 
 comment "Parallel IDE protocol modules"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 
 config PARIDE_ATEN
 	tristate "ATEN EH-100 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the ATEN EH-100 parallel port IDE
 	  protocol. This protocol is used in some inexpensive low performance
@@ -109,7 +109,7 @@ config PARIDE_ATEN
 
 config PARIDE_BPCK
 	tristate "MicroSolutions backpack (Series 5) protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the Micro Solutions BACKPACK
 	  parallel port Series 5 IDE protocol.  (Most BACKPACK drives made
@@ -127,7 +127,7 @@ config PARIDE_BPCK
 
 config PARIDE_BPCK6
 	tristate "MicroSolutions backpack (Series 6) protocol"
-	depends on PARIDE && !64BIT
+	depends on (PARIDE || PATA_PARPORT) && !64BIT
 	help
 	  This option enables support for the Micro Solutions BACKPACK
 	  parallel port Series 6 IDE protocol.  (Most BACKPACK drives made
@@ -146,7 +146,7 @@ config PARIDE_BPCK6
 
 config PARIDE_COMM
 	tristate "DataStor Commuter protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the Commuter parallel port IDE
 	  protocol from DataStor. If you chose to build PARIDE support
@@ -157,7 +157,7 @@ config PARIDE_COMM
 
 config PARIDE_DSTR
 	tristate "DataStor EP-2000 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the EP-2000 parallel port IDE
 	  protocol from DataStor. If you chose to build PARIDE support
@@ -168,7 +168,7 @@ config PARIDE_DSTR
 
 config PARIDE_FIT2
 	tristate "FIT TD-2000 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the TD-2000 parallel port IDE
 	  protocol from Fidelity International Technology. This is a simple
@@ -181,7 +181,7 @@ config PARIDE_FIT2
 
 config PARIDE_FIT3
 	tristate "FIT TD-3000 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the TD-3000 parallel port IDE
 	  protocol from Fidelity International Technology. This protocol is
@@ -194,7 +194,7 @@ config PARIDE_FIT3
 
 config PARIDE_EPAT
 	tristate "Shuttle EPAT/EPEZ protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the EPAT parallel port IDE protocol.
 	  EPAT is a parallel port IDE adapter manufactured by Shuttle
@@ -216,7 +216,7 @@ config PARIDE_EPATC8
 
 config PARIDE_EPIA
 	tristate "Shuttle EPIA protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the (obsolete) EPIA parallel port
 	  IDE protocol from Shuttle Technology. This adapter can still be
@@ -228,7 +228,7 @@ config PARIDE_EPIA
 
 config PARIDE_FRIQ
 	tristate "Freecom IQ ASIC-2 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for version 2 of the Freecom IQ parallel
 	  port IDE adapter.  This adapter is used by the Maxell Superdisk
@@ -240,7 +240,7 @@ config PARIDE_FRIQ
 
 config PARIDE_FRPW
 	tristate "FreeCom power protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the Freecom power parallel port IDE
 	  protocol. If you chose to build PARIDE support into your kernel, you
@@ -251,7 +251,7 @@ config PARIDE_FRPW
 
 config PARIDE_KBIC
 	tristate "KingByte KBIC-951A/971A protocols"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the KBIC-951A and KBIC-971A parallel
 	  port IDE protocols from KingByte Information Corp. KingByte's
@@ -264,7 +264,7 @@ config PARIDE_KBIC
 
 config PARIDE_KTTI
 	tristate "KT PHd protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the "PHd" parallel port IDE protocol
 	  from KT Technology. This is a simple (low speed) adapter that is
@@ -277,7 +277,7 @@ config PARIDE_KTTI
 
 config PARIDE_ON20
 	tristate "OnSpec 90c20 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the (obsolete) 90c20 parallel port
 	  IDE protocol from OnSpec (often marketed under the ValuStore brand
@@ -289,7 +289,7 @@ config PARIDE_ON20
 
 config PARIDE_ON26
 	tristate "OnSpec 90c26 protocol"
-	depends on PARIDE
+	depends on PARIDE || PATA_PARPORT
 	help
 	  This option enables support for the 90c26 parallel port IDE protocol
 	  from OnSpec Electronics (often marketed under the ValuStore brand
diff --git a/drivers/block/paride/paride.h b/drivers/block/paride/paride.h
index ddb9e589da7f..24dcfadb782d 100644
--- a/drivers/block/paride/paride.h
+++ b/drivers/block/paride/paride.h
@@ -1,3 +1,15 @@
+/*
+ * The low-level protocol modules are used by either paride or pata_parport.
+ * These two are mutually exclusive because the compiled low-level protocol
+ * modules are not compatible.
+ * When PATA_PARPORT is enabled, include pata_parport.h instead of the rest
+ * of this file.
+ */
+
+#if IS_ENABLED(CONFIG_PATA_PARPORT)
+#include <linux/pata_parport.h>
+
+#else
 #ifndef __DRIVERS_PARIDE_H__
 #define __DRIVERS_PARIDE_H__
 
@@ -170,3 +182,4 @@ void pi_unregister_driver(void *);
 
 #endif /* __DRIVERS_PARIDE_H__ */
 /* end of paride.h */
+#endif /* IS_ENABLED(CONFIG_PATA_PARPORT) */
diff --git a/include/linux/pata_parport.h b/include/linux/pata_parport.h
new file mode 100644
index 000000000000..f1ba57bb319c
--- /dev/null
+++ b/include/linux/pata_parport.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *	pata_parport.h	(c) 1997-8  Grant R. Guenther <grant@torque.net>
+ *				    Under the terms of the GPL.
+ *
+ * This file defines the interface for parallel port IDE adapter chip drivers.
+ */
+
+#include <linux/libata.h>
+
+#define PI_PCD	1	/* dummy for paride protocol modules */
+
+struct pi_adapter {
+	struct device dev;
+	struct pi_protocol *proto;	/* adapter protocol */
+	int port;			/* base address of parallel port */
+	int mode;			/* transfer mode in use */
+	int delay;			/* adapter delay setting */
+	int devtype;			/* dummy for paride protocol modules */
+	char *device;			/* dummy for paride protocol modules */
+	int unit;			/* unit number for chained adapters */
+	int saved_r0;			/* saved port state */
+	int saved_r2;			/* saved port state */
+	unsigned long private;		/* for protocol module */
+	struct pardevice *pardev;	/* pointer to pardevice */
+	bool claimed;			/* parport has already been claimed */
+	struct timer_list timer;	/* disconnect timer */
+};
+
+typedef struct pi_adapter PIA;	/* for paride protocol modules */
+
+/* registers are addressed as (cont,regr)
+ *	cont: 0 for command register file, 1 for control register(s)
+ *	regr: 0-7 for register number.
+ */
+
+/* macros and functions exported to the protocol modules */
+#define delay_p			(pi->delay ? udelay(pi->delay) : (void)0)
+#define out_p(offs, byte)	do { outb(byte, pi->port + offs); delay_p; } while (0)
+#define in_p(offs)		(delay_p, inb(pi->port + offs))
+
+#define w0(byte)		out_p(0, byte)
+#define r0()			(in_p(0) & 0xff)
+#define w1(byte)		out_p(1, byte)
+#define r1()			(in_p(1) & 0xff)
+#define w2(byte)		out_p(2, byte)
+#define r2()			(in_p(2) & 0xff)
+#define w3(byte)		out_p(3, byte)
+#define w4(byte)		out_p(4, byte)
+#define r4()			(in_p(4) & 0xff)
+#define w4w(data)		do { outw(data, pi->port + 4); delay_p; } while (0)
+#define w4l(data)		do { outl(data, pi->port + 4); delay_p; } while (0)
+#define r4w()			(delay_p, inw(pi->port + 4) & 0xffff)
+#define r4l()			(delay_p, inl(pi->port + 4) & 0xffffffff)
+
+static inline u16 pi_swab16(char *b, int k)
+{
+	union { u16 u; char t[2]; } r;
+
+	r.t[0] = b[2 * k + 1]; r.t[1] = b[2 * k];
+	return r.u;
+}
+
+static inline u32 pi_swab32(char *b, int k)
+{
+	union { u32 u; char f[4]; } r;
+
+	r.f[0] = b[4 * k + 1]; r.f[1] = b[4 * k];
+	r.f[2] = b[4 * k + 3]; r.f[3] = b[4 * k + 2];
+	return r.u;
+}
+
+struct pi_protocol {
+	char name[8];
+
+	int max_mode;
+	int epp_first;		/* modes >= this use 8 ports */
+
+	int default_delay;
+	int max_units;		/* max chained units probed for */
+
+	void (*write_regr)(struct pi_adapter *pi, int cont, int regr, int val);
+	int (*read_regr)(struct pi_adapter *pi, int cont, int regr);
+	void (*write_block)(struct pi_adapter *pi, char *buf, int count);
+	void (*read_block)(struct pi_adapter *pi, char *buf, int count);
+
+	void (*connect)(struct pi_adapter *pi);
+	void (*disconnect)(struct pi_adapter *pi);
+
+	int (*test_port)(struct pi_adapter *pi);
+	int (*probe_unit)(struct pi_adapter *pi);
+	int (*test_proto)(struct pi_adapter *pi, char *scratch, int verbose);
+	void (*log_adapter)(struct pi_adapter *pi, char *scratch, int verbose);
+
+	int (*init_proto)(struct pi_adapter *pi);
+	void (*release_proto)(struct pi_adapter *pi);
+	struct module *owner;
+	struct device_driver driver;
+	struct scsi_host_template sht;
+};
+
+#define PATA_PARPORT_SHT ATA_PIO_SHT
+
+int pata_parport_register_driver(struct pi_protocol *pr);
+void pata_parport_unregister_driver(struct pi_protocol *pr);
+/* defines for old paride protocol modules */
+#define paride_register pata_parport_register_driver
+#define paride_unregister pata_parport_unregister_driver
-- 
Ondrej Zary