[06/16] pata_parport: add dstr protocol driver

diff --git a/drivers/ata/pata_parport/Kconfig b/drivers/ata/pata_parport/Kconfig
index 3cc3d6ae4d45..67f203dfbdca 100644
--- a/drivers/ata/pata_parport/Kconfig
+++ b/drivers/ata/pata_parport/Kconfig
@@ -64,3 +64,13 @@  config PATA_PARPORT_COMM
 	  into your kernel, you may answer Y here to build in the protocol
 	  driver, otherwise you should answer M to build it as a loadable
 	  module. The module will be called comm.
+
+config PATA_PARPORT_DSTR
+	tristate "DataStor EP-2000 protocol"
+	depends on PATA_PARPORT
+	help
+	  This option enables support for the EP-2000 parallel port IDE
+	  protocol from DataStor. If you chose to build PATA_PARPORT support
+	  into your kernel, you may answer Y here to build in the protocol
+	  driver, otherwise you should answer M to build it as a loadable
+	  module. The module will be called dstr.
diff --git a/drivers/ata/pata_parport/Makefile b/drivers/ata/pata_parport/Makefile
index fcb77a855ef6..bf81c4ca32ab 100644
--- a/drivers/ata/pata_parport/Makefile
+++ b/drivers/ata/pata_parport/Makefile
@@ -11,3 +11,4 @@  obj-$(CONFIG_PATA_PARPORT_ATEN)		+= aten.o
 obj-$(CONFIG_PATA_PARPORT_BPCK)		+= bpck.o
 obj-$(CONFIG_PATA_PARPORT_BPCK6)	+= bpck6.o
 obj-$(CONFIG_PATA_PARPORT_COMM)		+= comm.o
+obj-$(CONFIG_PATA_PARPORT_DSTR)		+= dstr.o
diff --git a/drivers/ata/pata_parport/dstr.c b/drivers/ata/pata_parport/dstr.c
new file mode 100644
index 000000000000..2e1e078fa467
--- /dev/null
+++ b/drivers/ata/pata_parport/dstr.c
@@ -0,0 +1,226 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	dstr.c    (c) 1997-8  Grant R. Guenther <grant@torque.net>
+ *			      Under the terms of the GNU General Public License.
+ *
+ *	dstr.c is a low-level protocol driver for the
+ *	DataStor EP2000 parallel to IDE adapter chip.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/io.h>
+
+#include "pata_parport.h"
+
+/* mode codes:  0  nybble reads, 8-bit writes
+ *		1  8-bit reads and writes
+ *		2  8-bit EPP mode
+ *		3  EPP-16
+ *		4  EPP-32
+ */
+
+#define j44(a, b)  (((a >> 3) & 0x07) | ((~a >> 4) & 0x08) | ((b << 1) & 0x70) | ((~b) & 0x80))
+
+#define P1	do { w2(5); w2(0xd); w2(5); w2(4); } while (0)
+#define P2	do { w2(5); w2(7); w2(5); w2(4); } while (0)
+#define P3      do { w2(6); w2(4); w2(6); w2(4); } while (0)
+
+/* cont = 0 - access the IDE register file
+ * cont = 1 - access the IDE command set
+ */
+
+static int cont_map[2] = { 0x20, 0x40 };
+
+static int dstr_read_regr(struct pi_adapter *pi, int cont, int regr)
+{
+	int a, b, r;
+
+	r = regr + cont_map[cont];
+
+	w0(0x81); P1;
+	if (pi->mode)
+		w0(0x11);
+	else
+		w0(1);
+	P2; w0(r); P1;
+
+	switch (pi->mode) {
+	case 0:
+		w2(6); a = r1(); w2(4); w2(6); b = r1(); w2(4);
+		return j44(a, b);
+	case 1:
+		w0(0); w2(0x26); a = r0(); w2(4);
+		return a;
+	case 2:
+	case 3:
+	case 4:
+		w2(0x24); a = r4(); w2(4);
+		return a;
+	}
+	return -1;
+}
+
+static void dstr_write_regr(struct pi_adapter *pi, int cont, int regr, int val)
+{
+	int r = regr + cont_map[cont];
+
+	w0(0x81); P1;
+	if (pi->mode >= 2)
+		w0(0x11);
+	else
+		w0(1);
+	P2; w0(r); P1;
+
+	switch (pi->mode)  {
+	case 0:
+	case 1:
+		w0(val); w2(5); w2(7); w2(5); w2(4);
+		break;
+	case 2:
+	case 3:
+	case 4:
+		w4(val);
+		break;
+	}
+}
+
+#define CCP(x)	do { w0(0xff); w2(0xc); w2(4);\
+		     w0(0xaa); w0(0x55); w0(0); w0(0xff); w0(0x87); w0(0x78);\
+		     w0(x); w2(5); w2(4);\
+		} while (0)
+
+static void dstr_connect(struct pi_adapter *pi)
+{
+	pi->saved_r0 = r0();
+	pi->saved_r2 = r2();
+	w2(4); CCP(0xe0); w0(0xff);
+}
+
+static void dstr_disconnect(struct pi_adapter *pi)
+{
+	CCP(0x30);
+	w0(pi->saved_r0);
+	w2(pi->saved_r2);
+}
+
+static void dstr_read_block(struct pi_adapter *pi, char *buf, int count)
+{
+	int k, a, b;
+
+	w0(0x81); P1;
+	if (pi->mode)
+		w0(0x19);
+	else
+		w0(9);
+	P2; w0(0x82); P1; P3; w0(0x20); P1;
+
+	switch (pi->mode) {
+	case 0:
+		for (k = 0; k < count; k++) {
+			w2(6); a = r1(); w2(4);
+			w2(6); b = r1(); w2(4);
+			buf[k] = j44(a, b);
+		}
+		break;
+	case 1:
+		w0(0);
+		for (k = 0; k < count; k++) {
+			w2(0x26); buf[k] = r0(); w2(0x24);
+		}
+		w2(4);
+		break;
+	case 2:
+		w2(0x24);
+		for (k = 0; k < count; k++)
+			buf[k] = r4();
+		w2(4);
+		break;
+	case 3:
+		w2(0x24);
+		for (k = 0; k < count / 2; k++)
+			((u16 *)buf)[k] = r4w();
+		w2(4);
+		break;
+	case 4:
+		w2(0x24);
+		for (k = 0; k < count / 4; k++)
+			((u32 *)buf)[k] = r4l();
+		w2(4);
+		break;
+	}
+}
+
+static void dstr_write_block(struct pi_adapter *pi, char *buf, int count)
+{
+	int k;
+
+	w0(0x81); P1;
+	if (pi->mode)
+		w0(0x19);
+	else
+		w0(9);
+	P2; w0(0x82); P1; P3; w0(0x20); P1;
+
+	switch (pi->mode) {
+	case 0:
+	case 1:
+		for (k = 0; k < count; k++) {
+			w2(5); w0(buf[k]); w2(7);
+		}
+		w2(5); w2(4);
+		break;
+	case 2:
+		w2(0xc5);
+		for (k = 0; k < count; k++)
+			w4(buf[k]);
+		w2(0xc4);
+		break;
+	case 3:
+		w2(0xc5);
+		for (k = 0; k < count / 2; k++)
+			w4w(((u16 *)buf)[k]);
+		w2(0xc4);
+		break;
+	case 4:
+		w2(0xc5);
+		for (k = 0; k < count / 4; k++)
+			w4l(((u32 *)buf)[k]);
+		w2(0xc4);
+		break;
+	}
+}
+
+
+static void dstr_log_adapter(struct pi_adapter *pi, char *scratch, int verbose)
+{
+	static char * const mode_string[] = {
+		"4-bit", "8-bit", "EPP-8", "EPP-16", "EPP-32" };
+
+	dev_info(&pi->dev, "dstr, DataStor EP2000 at 0x%x, mode %d (%s), delay %d\n",
+		pi->port, pi->mode, mode_string[pi->mode], pi->delay);
+}
+
+static struct pi_protocol dstr = {
+	.owner		= THIS_MODULE,
+	.name		= "dstr",
+	.max_mode	= 5,
+	.epp_first	= 2,
+	.default_delay	= 1,
+	.max_units	= 1,
+	.write_regr	= dstr_write_regr,
+	.read_regr	= dstr_read_regr,
+	.write_block	= dstr_write_block,
+	.read_block	= dstr_read_block,
+	.connect	= dstr_connect,
+	.disconnect	= dstr_disconnect,
+	.log_adapter	= dstr_log_adapter,
+	.sht		= { PATA_PARPORT_SHT("pata_parport-dstr") },
+};
+
+MODULE_LICENSE("GPL");
+module_pata_parport_driver(dstr);