ata: pata_cswarp: Add Amiga cslab ata support

Driver for the on-board IDE interface on CS-Lab Warp Expansion Card
(NOTE that idemode=native has to be set in Warp Configuration)

Assisted-by: Claude_Code:claude-opus-5
Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20260826160911.460165-2-p.pisati@gmail.com
Signed-off-by: Niklas Cassel <cassel@kernel.org>

drivers/ata/Kconfig

@@ -1040,6 +1040,16 @@ config PATA_GAYLE
 
 	  If unsure, say N.
 
+config PATA_CSWARP
+	tristate "Amiga CS Warp PATA support"
+	depends on M68K && AMIGA && ZORRO
+	help
+	  This option enables support for the on-board IDE interface on
+	  CS-Lab Warp Expansion Card (NOTE that idemode=native has to be
+	  set in Warp Configuration)
+
+	  If unsure, say N.
+
 config PATA_BUDDHA
 	tristate "Buddha/Catweasel/X-Surf PATA support"
 	depends on ZORRO

drivers/ata/Makefile

@@ -100,6 +100,7 @@ obj-$(CONFIG_PATA_WINBOND)	+= pata_sl82c105.o
 obj-$(CONFIG_PATA_CMD640_PCI)	+= pata_cmd640.o
 obj-$(CONFIG_PATA_FALCON)	+= pata_falcon.o
 obj-$(CONFIG_PATA_GAYLE)	+= pata_gayle.o
+obj-$(CONFIG_PATA_CSWARP)	+= pata_cswarp.o
 obj-$(CONFIG_PATA_BUDDHA)	+= pata_buddha.o
 obj-$(CONFIG_PATA_ISAPNP)	+= pata_isapnp.o
 obj-$(CONFIG_PATA_IXP4XX_CF)	+= pata_ixp4xx_cf.o

drivers/ata/pata_cswarp.c

@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Amiga CS Warp PATA controller driver
+ *
+ * Copyright (c) 2024 CS-Lab s.c.
+ *		http://www.cs-lab.eu
+ *
+ * Based on pata_gayle.c, pata_buddha.c and warpATA.device:
+ *
+ *     Created 2 Jun 2024 by Andrzej Rogozynski
+ */
+
+#include <linux/ata.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/device-id/zorro.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/libata.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/zorro.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+
+#include <asm/amigahw.h>
+#include <asm/amigaints.h>
+#include <asm/amigayle.h>
+#include <asm/setup.h>
+
+#define DRV_NAME "pata_cswarp"
+
+#define WARP_OFFSET_ATA         0x6000
+
+static const struct scsi_host_template pata_cswarp_sht = {
+	ATA_PIO_SHT(DRV_NAME),
+};
+
+static unsigned int pata_cswarp_data_xfer(struct ata_queued_cmd *qc,
+					  unsigned char *buf,
+					  unsigned int buflen, int rw)
+{
+	struct ata_device *dev = qc->dev;
+	struct ata_port *ap = dev->link->ap;
+	void __iomem *data_addr = ap->ioaddr.data_addr;
+	unsigned int words = buflen >> 1;
+	u16 *buf16 = (u16 *)buf;
+
+	/* Transfer multiple of 2 bytes */
+	if (rw == READ)
+		raw_insw(data_addr, buf16, words);
+	else
+		raw_outsw(data_addr, buf16, words);
+
+	/* Transfer trailing byte, if any. */
+	if (unlikely(buflen & 0x01)) {
+		if (rw == READ)
+			buf[buflen - 1] = raw_inw(data_addr) >> 8;
+		else
+			raw_outw(buf[buflen - 1] << 8, data_addr);
+		words++;
+	}
+
+	return words << 1;
+}
+
+/*
+ * Provide our own set_mode() as we don't want to change anything that has
+ * already been configured..
+ */
+static int pata_cswarp_set_mode(struct ata_link *link,
+				struct ata_device **unused)
+{
+	struct ata_device *dev;
+
+	ata_for_each_dev(dev, link, ENABLED) {
+		/* We don't really care */
+		dev->pio_mode = dev->xfer_mode = XFER_PIO_0;
+		dev->xfer_shift = ATA_SHIFT_PIO;
+		dev->flags |= ATA_DFLAG_PIO;
+		ata_dev_info(dev, "configured for PIO\n");
+	}
+	return 0;
+}
+
+static struct ata_port_operations pata_cswarp_ops = {
+	.inherits	= &ata_sff_port_ops,
+	.sff_data_xfer	= pata_cswarp_data_xfer,
+	.cable_detect	= ata_cable_unknown,
+	.set_mode	= pata_cswarp_set_mode,
+};
+
+static int pata_cswarp_probe(struct zorro_dev *z,
+			     const struct zorro_device_id *ent)
+{
+	static const char board_name[] = "csWarp";
+	struct ata_host *host;
+	struct ata_port *ap;
+	struct resource *res;
+	void __iomem *base;
+	unsigned long board = z->resource.start;
+
+	dev_info(&z->dev, "%s IDE controller (board: 0x%lx)\n", board_name,
+		 board);
+
+	res = devm_request_mem_region(&z->dev, board + WARP_OFFSET_ATA, 0x1800,
+				      DRV_NAME);
+	if (!res)
+		return -ENXIO;
+
+	host = ata_host_alloc(&z->dev, 1);
+	if (!host)
+		return -ENXIO;
+
+	ap = host->ports[0];
+	base = devm_ioremap(&z->dev, board + WARP_OFFSET_ATA, 0x1800);
+	if (!base)
+		return -ENOMEM;
+
+	ap->ops = &pata_cswarp_ops;
+
+	ap->pio_mask = ATA_PIO4;
+	ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY |
+		ATA_FLAG_PIO_POLLING;
+
+	ap->ioaddr.data_addr		= base;
+	ap->ioaddr.error_addr		= base + 1 * 4;
+	ap->ioaddr.feature_addr		= base + 1 * 4;
+	ap->ioaddr.nsect_addr		= base + 2 * 4;
+	ap->ioaddr.lbal_addr		= base + 3 * 4;
+	ap->ioaddr.lbam_addr		= base + 4 * 4;
+	ap->ioaddr.lbah_addr		= base + 5 * 4;
+	ap->ioaddr.device_addr		= base + 6 * 4;
+	ap->ioaddr.status_addr		= base + 7 * 4;
+	ap->ioaddr.command_addr		= base + 7 * 4;
+
+	ap->ioaddr.altstatus_addr	= base + (0x1000 | (6UL << 2));
+	ap->ioaddr.ctl_addr		= base + (0x1000 | (6UL << 2));
+
+	ata_port_desc(ap, "mmio %pR", res);
+
+	return ata_host_activate(host, 0, NULL,
+			  IRQF_SHARED, &pata_cswarp_sht);
+}
+
+static void pata_cswarp_remove(struct zorro_dev *z)
+{
+	struct ata_host *host = dev_get_drvdata(&z->dev);
+
+	ata_host_detach(host);
+}
+
+static const struct zorro_device_id pata_cswarp_zorro_tbl[] = {
+	{ .id = ZORRO_PROD_CSLAB_WARP_1260 },
+	{ }
+};
+MODULE_DEVICE_TABLE(zorro, pata_cswarp_zorro_tbl);
+
+static struct zorro_driver pata_cswarp_driver = {
+	.name           = "pata_cswarp",
+	.id_table       = pata_cswarp_zorro_tbl,
+	.probe          = pata_cswarp_probe,
+	.remove         = pata_cswarp_remove,
+};
+
+static int __init pata_cswarp_init(void)
+{
+	return zorro_register_driver(&pata_cswarp_driver);
+}
+
+static void __exit pata_cswarp_unregister(void)
+{
+	zorro_unregister_driver(&pata_cswarp_driver);
+}
+
+module_init(pata_cswarp_init);
+module_exit(pata_cswarp_unregister);
+
+MODULE_AUTHOR("Andrzej Rogozynski");
+MODULE_DESCRIPTION("low-level driver for CSWarp PATA");
+MODULE_LICENSE("GPL");