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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 01/16] pata_parport: add core driver (PARIDE replacement)
Date:   Sat,  5 Mar 2022 21:13:56 +0100
Message-Id: <20220305201411.501-2-linux@zary.sk>
In-Reply-To: <20220305201411.501-1-linux@zary.sk>
References: <20220305201411.501-1-linux@zary.sk>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Add pata_parport (PARIDE replacement) core libata driver.

Signed-off-by: Ondrej Zary <linux@zary.sk>
---
 drivers/ata/Kconfig                     |  25 +
 drivers/ata/Makefile                    |   2 +
 drivers/ata/pata_parport/Kconfig        |  10 +
 drivers/ata/pata_parport/Makefile       |   9 +
 drivers/ata/pata_parport/pata_parport.c | 809 ++++++++++++++++++++++++
 drivers/ata/pata_parport/pata_parport.h | 110 ++++
 6 files changed, 965 insertions(+)
 create mode 100644 drivers/ata/pata_parport/Kconfig
 create mode 100644 drivers/ata/pata_parport/Makefile
 create mode 100644 drivers/ata/pata_parport/pata_parport.c
 create mode 100644 drivers/ata/pata_parport/pata_parport.h

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index cb54631fd950..de4548471398 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -1161,6 +1161,31 @@ config PATA_WINBOND_VLB
 	  Support for the Winbond W83759A controller on Vesa Local Bus
 	  systems.
 
+config PATA_PARPORT
+	tristate "Parallel port IDE device support (PARIDE replacement)"
+	depends on PARPORT_PC
+	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.
+
+	  If you have said Y to the "Parallel-port support" configuration
+	  option, you may share a single port between your printer and other
+	  parallel port devices. Answer Y to build PATA_PARPORT support into your
+	  kernel, or M if you would like to build it as a loadable module. If
+	  your parallel port support is in a loadable module, you must build
+	  PATA_PARPORT as a module. If you built PATA_PARPORT support into your kernel,
+	  you may still build the individual protocol modules as loadable
+	  modules. If you build this support as a module, it will be called pata_parport.
+
+	  Unlike the old PARIDE, there are no high-level drivers needed.
+	  The IDE devices behind parallel port adapters are handled by the
+	  ATA layer.
+
+source "drivers/ata/pata_parport/Kconfig"
+
 comment "Generic fallback / legacy drivers"
 
 config PATA_ACPI
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index b8aebfb14e82..bd6b5fdc004e 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-$(CONFIG_PATA_PARPORT)	+= pata_parport/
+
 # Should be last but two libata driver
 obj-$(CONFIG_PATA_ACPI)		+= pata_acpi.o
 # Should be last but one libata driver
diff --git a/drivers/ata/pata_parport/Kconfig b/drivers/ata/pata_parport/Kconfig
new file mode 100644
index 000000000000..56dc6b25d5fa
--- /dev/null
+++ b/drivers/ata/pata_parport/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# PATA_PARPORT configuration
+#
+# PATA_PARPORT doesn't need PARPORT, but if PARPORT is configured as a module,
+# PATA_PARPORT must also be a module.
+# PATA_PARPORT only supports PC style parports. Tough for USB or other parports...
+
+comment "Parallel IDE protocol modules"
+	depends on PATA_PARPORT
diff --git a/drivers/ata/pata_parport/Makefile b/drivers/ata/pata_parport/Makefile
new file mode 100644
index 000000000000..b105e1cb8dc6
--- /dev/null
+++ b/drivers/ata/pata_parport/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Parallel port IDE device drivers.
+#
+# 7 October 2000, Bartlomiej Zolnierkiewicz <bkz@linux-ide.org>
+# Rewritten to use lists instead of if-statements.
+#
+
+obj-$(CONFIG_PATA_PARPORT)		+= pata_parport.o
diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c
new file mode 100644
index 000000000000..7f814062cedd
--- /dev/null
+++ b/drivers/ata/pata_parport/pata_parport.c
@@ -0,0 +1,809 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/parport.h>
+#include "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 = 1;
+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)
+		return;
+	pi->claimed = 1;
+	parport_claim_or_block(pi->pardev);
+	pi->proto->connect(pi);
+}
+
+static void pi_disconnect_later(struct pi_adapter *pi)
+{
+	mod_timer(&pi->timer, jiffies + DISCONNECT_TIMEOUT);
+}
+
+static void pi_disconnect_timer(struct timer_list *t)
+{
+	struct pi_adapter *pi = from_timer(pi, t, timer);
+
+	if (!pi->claimed)
+		return;
+	pi->proto->disconnect(pi);
+	parport_release(pi->pardev);
+	pi->claimed = 0;
+}
+
+/* functions taken from libata-sff.c and converted from direct port I/O */
+static unsigned int pata_parport_devchk(struct ata_port *ap, unsigned int device)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+	u8 nsect, lbal;
+
+	ap->ops->sff_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);
+	pi_disconnect_later(pi);
+
+	if ((nsect == 0x55) && (lbal == 0xaa))
+		return 1;	/* we found a device */
+
+	return 0;		/* 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);	/* FIXME: flush */
+	pi->proto->write_regr(pi, 1, 6, ap->ctl | ATA_SRST);
+	udelay(20);	/* FIXME: flush */
+	pi->proto->write_regr(pi, 1, 6, ap->ctl);
+	ap->last_ctl = ap->ctl;
+	pi_disconnect_later(pi);
+
+	/* 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 slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
+	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 (slave_possible && pata_parport_devchk(ap, 1))
+		devmask |= (1 << 1);
+
+	/* select device 0 again */
+	ap->ops->sff_dev_select(ap, 0);
+
+	/* issue bus reset */
+	rc = pata_parport_bus_softreset(ap, devmask, deadline);
+	/* if link is occupied, -ENODEV too is an error */
+	if (rc && (rc != -ENODEV || sata_scr_valid(link))) {
+		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 (slave_possible && 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);
+	pi_disconnect_later(pi);
+
+	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);
+	pi_disconnect_later(pi);
+
+	return altstatus;
+}
+
+static void pata_parport_dev_select(struct ata_port *ap, unsigned int device)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+	u8 tmp;
+
+	pi_connect(pi);
+	if (device == 0)
+		tmp = ATA_DEVICE_OBS;
+	else
+		tmp = ATA_DEVICE_OBS | ATA_DEV1;
+
+	pi->proto->write_regr(pi, 0, ATA_REG_DEVICE, tmp);
+	pi_disconnect_later(pi);
+	ata_sff_pause(ap);	/* needed; also flushes, for mmio */
+}
+
+static void pata_parport_tf_load(struct ata_port *ap, const struct ata_taskfile *tf)
+{
+	struct pi_adapter *pi = ap->host->private_data;
+	unsigned int is_addr = tf->flags & ATA_TFLAG_ISADDR;
+
+	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 (is_addr && (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);
+	}
+
+	if (is_addr) {
+		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);
+	pi_disconnect_later(pi);
+}
+
+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->command = pi->proto->read_regr(pi, 0, ATA_REG_STATUS);
+	tf->feature = 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;
+	}
+	pi_disconnect_later(pi);
+}
+
+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);
+	pi_disconnect_later(pi);
+}
+
+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);
+	pi_disconnect_later(pi);
+
+	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; (ap->ops->sff_check_status(ap) & ATA_DRQ)
+						&& count < 65536; count += 2) {
+		pi_connect(pi);
+		pi->proto->read_block(pi, junk, 2);
+		pi_disconnect_later(pi);
+	}
+
+	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 = {
+	.qc_prep		= ata_noop_qc_prep,
+	.qc_issue		= ata_sff_qc_issue,
+	.qc_fill_rtf		= ata_sff_qc_fill_rtf,
+
+	.freeze			= ata_sff_freeze,
+	.thaw			= ata_sff_thaw,
+	.prereset		= ata_sff_prereset,
+	.softreset		= pata_parport_softreset,
+	.postreset		= ata_sff_postreset,
+	.error_handler		= ata_sff_error_handler,
+	.sched_eh		= ata_std_sched_eh,
+	.end_eh			= ata_std_end_eh,
+
+	.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,
+};
+
+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 int pi_probe_mode(struct pi_adapter *pi, int max, char *scratch)
+{
+	int best, range;
+
+	if (pi->mode != -1) {
+		if (pi->mode >= max)
+			return 0;
+		range = 3;
+		if (pi->mode >= pi->proto->epp_first)
+			range = 8;
+		if ((range == 8) && (pi->port % 8))
+			return 0;
+		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 int 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);
+				if (pi_probe_mode(pi, max, scratch))
+					return 1;
+				return 0;
+			}
+		parport_release(pi->pardev);
+		return 0;
+	}
+
+	if (!pi_probe_mode(pi, max, scratch))
+		return 0;
+	return 1;
+}
+
+static void pata_parport_dev_release(struct device *dev)
+{
+	struct pi_adapter *pi = container_of(dev, struct pi_adapter, dev);
+
+	kfree(pi);
+}
+
+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,
+};
+
+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 = 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;
+
+	/* still racy */
+	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, dev_name(&pi->dev),
+						&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->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, &pi->proto->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);
+	pr_info("pata_parport: protocol %s removed\n", pr->name);
+	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);
+	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];
+	int fields;
+
+	fields = sscanf(buf, "%31s", device_name);
+	if (fields < 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);
+		return 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/ata/pata_parport/pata_parport.h b/drivers/ata/pata_parport/pata_parport.h
new file mode 100644
index 000000000000..c4201b809b20
--- /dev/null
+++ b/drivers/ata/pata_parport/pata_parport.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *	paride.h	(c) 1997-8  Grant R. Guenther <grant@torque.net>
+ *				    Under the terms of the GPL.
+ *
+ * This file defines the interface for adapter chip drivers.
+ */
+
+#include <linux/libata.h>
+
+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 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 */
+	int claimed;			/* parport has already been claimed */
+	struct timer_list timer;	/* disconnect timer */
+};
+
+/* 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];		/* name for this protocol */
+
+	int max_mode;		/* max mode number */
+	int epp_first;		/* modes >= this use 8 ports */
+
+	int default_delay;	/* delay parameter if not specified */
+	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
+
+extern int pata_parport_register_driver(struct pi_protocol *pr);
+extern void pata_parport_unregister_driver(struct pi_protocol *pr);
+
+/**
+ * module_pata_parport_driver() - Helper macro for registering a pata_parport driver
+ * @__pi_protocol: pi_protocol struct
+ *
+ * Helper macro for pata_parport drivers which do not do anything special in module
+ * init/exit. This eliminates a lot of boilerplate. Each module may only
+ * use this macro once, and calling it replaces module_init() and module_exit()
+ */
+#define module_pata_parport_driver(__pi_protocol) \
+	module_driver(__pi_protocol, pata_parport_register_driver, pata_parport_unregister_driver)
-- 
Ondrej Zary