ata: add Atari Falcon PATA controller driver

Add Atari Falcon PATA controller driver.  The major difference
when compared to legacy IDE's falconide host driver is that we
are using polled PIO mode and thus avoiding the need for STDMA
locking magic altogether.

Tested under ARAnyM emulator.
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/Kconfig

@@ -902,6 +902,15 @@ config PATA_CMD640_PCI
 
 	  If unsure, say N.
 
+config PATA_FALCON
+	tristate "Atari Falcon PATA support"
+	depends on M68K && ATARI
+	help
+	  This option enables support for the on-board IDE
+	  interface on the Atari Falcon.
+
+	  If unsure, say N.
+
 config PATA_ISAPNP
 	tristate "ISA Plug and Play PATA support"
 	depends on ISAPNP

drivers/ata/Makefile

@@ -93,6 +93,7 @@ obj-$(CONFIG_PATA_WINBOND)	+= pata_sl82c105.o
 obj-$(CONFIG_PATA_AT32)		+= pata_at32.o
 obj-$(CONFIG_PATA_AT91)		+= pata_at91.o
 obj-$(CONFIG_PATA_CMD640_PCI)	+= pata_cmd640.o
+obj-$(CONFIG_PATA_FALCON)	+= pata_falcon.o
 obj-$(CONFIG_PATA_ISAPNP)	+= pata_isapnp.o
 obj-$(CONFIG_PATA_IXP4XX_CF)	+= pata_ixp4xx_cf.o
 obj-$(CONFIG_PATA_MPIIX)	+= pata_mpiix.o

drivers/ata/pata_falcon.c

+/*
+ * Atari Falcon PATA controller driver
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Based on falconide.c:
+ *
+ *     Created 12 Jul 1997 by Geert Uytterhoeven
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_cmnd.h>
+#include <linux/ata.h>
+#include <linux/libata.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <asm/setup.h>
+#include <asm/atarihw.h>
+#include <asm/atariints.h>
+#include <asm/atari_stdma.h>
+#include <asm/ide.h>
+
+#define DRV_NAME "pata_falcon"
+#define DRV_VERSION "0.1.0"
+
+#define ATA_HD_BASE	0xfff00000
+#define ATA_HD_CONTROL	0x39
+
+static struct scsi_host_template pata_falcon_sht = {
+	ATA_PIO_SHT(DRV_NAME),
+};
+
+static unsigned int pata_falcon_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;
+	struct scsi_cmnd *cmd = qc->scsicmd;
+	bool swap = 1;
+
+	if (dev->class == ATA_DEV_ATA && cmd && cmd->request &&
+	    cmd->request->cmd_type == REQ_TYPE_FS)
+		swap = 0;
+
+	/* Transfer multiple of 2 bytes */
+	if (rw == READ) {
+		if (swap)
+			raw_insw_swapw((u16 *)data_addr, (u16 *)buf, words);
+		else
+			raw_insw((u16 *)data_addr, (u16 *)buf, words);
+	} else {
+		if (swap)
+			raw_outsw_swapw((u16 *)data_addr, (u16 *)buf, words);
+		else
+			raw_outsw((u16 *)data_addr, (u16 *)buf, words);
+	}
+
+	/* Transfer trailing byte, if any. */
+	if (unlikely(buflen & 0x01)) {
+		unsigned char pad[2] = { };
+
+		/* Point buf to the tail of buffer */
+		buf += buflen - 1;
+
+		if (rw == READ) {
+			if (swap)
+				raw_insw_swapw((u16 *)data_addr, (u16 *)pad, 1);
+			else
+				raw_insw((u16 *)data_addr, (u16 *)pad, 1);
+			*buf = pad[0];
+		} else {
+			pad[0] = *buf;
+			if (swap)
+				raw_outsw_swapw((u16 *)data_addr, (u16 *)pad, 1);
+			else
+				raw_outsw((u16 *)data_addr, (u16 *)pad, 1);
+		}
+		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_falcon_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_falcon_ops = {
+	.inherits	= &ata_sff_port_ops,
+	.sff_data_xfer	= pata_falcon_data_xfer,
+	.cable_detect	= ata_cable_unknown,
+	.set_mode	= pata_falcon_set_mode,
+};
+
+static int pata_falcon_init_one(void)
+{
+	struct ata_host *host;
+	struct ata_port *ap;
+	struct platform_device *pdev;
+	void __iomem *base;
+
+	if (!MACH_IS_ATARI || !ATARIHW_PRESENT(IDE))
+		return -ENODEV;
+
+	pr_info(DRV_NAME ": Atari Falcon PATA controller\n");
+
+	pdev = platform_device_register_simple(DRV_NAME, 0, NULL, 0);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	if (!devm_request_mem_region(&pdev->dev, ATA_HD_BASE, 0x40, DRV_NAME)) {
+		pr_err(DRV_NAME ": resources busy\n");
+		return -EBUSY;
+	}
+
+	/* allocate host */
+	host = ata_host_alloc(&pdev->dev, 1);
+	if (!host)
+		return -ENOMEM;
+	ap = host->ports[0];
+
+	ap->ops = &pata_falcon_ops;
+	ap->pio_mask = ATA_PIO4;
+	ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY;
+	ap->flags |= ATA_FLAG_PIO_POLLING;
+
+	base = (void __iomem *)ATA_HD_BASE;
+	ap->ioaddr.data_addr		= base;
+	ap->ioaddr.error_addr		= base + 1 + 1 * 4;
+	ap->ioaddr.feature_addr		= base + 1 + 1 * 4;
+	ap->ioaddr.nsect_addr		= base + 1 + 2 * 4;
+	ap->ioaddr.lbal_addr		= base + 1 + 3 * 4;
+	ap->ioaddr.lbam_addr		= base + 1 + 4 * 4;
+	ap->ioaddr.lbah_addr		= base + 1 + 5 * 4;
+	ap->ioaddr.device_addr		= base + 1 + 6 * 4;
+	ap->ioaddr.status_addr		= base + 1 + 7 * 4;
+	ap->ioaddr.command_addr		= base + 1 + 7 * 4;
+
+	ap->ioaddr.altstatus_addr	= base + ATA_HD_CONTROL;
+	ap->ioaddr.ctl_addr		= base + ATA_HD_CONTROL;
+
+	ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", (unsigned long)base,
+		      (unsigned long)base + ATA_HD_CONTROL);
+
+	/* activate */
+	return ata_host_activate(host, 0, NULL, 0, &pata_falcon_sht);
+}
+
+module_init(pata_falcon_init_one);
+
+MODULE_AUTHOR("Bartlomiej Zolnierkiewicz");
+MODULE_DESCRIPTION("low-level driver for Atari Falcon PATA");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);