#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <scsi/scsi_host.h>
#include <linux/ata.h>
#include <linux/libata.h>

#include <asm/dma.h>
#include <asm/ecard.h>

#define DRV_NAME	"pata_icside"

#define ICS_IDENT_OFFSET		0x2280

#define ICS_ARCIN_V5_INTRSTAT		0x0000
#define ICS_ARCIN_V5_INTROFFSET		0x0004

#define ICS_ARCIN_V6_INTROFFSET_1	0x2200
#define ICS_ARCIN_V6_INTRSTAT_1		0x2290
#define ICS_ARCIN_V6_INTROFFSET_2	0x3200
#define ICS_ARCIN_V6_INTRSTAT_2		0x3290

struct portinfo {
	unsigned int dataoffset;
	unsigned int ctrloffset;
	unsigned int stepping;
};

static const struct portinfo pata_icside_portinfo_v5 = {
	.dataoffset	= 0x2800,
	.ctrloffset	= 0x2b80,
	.stepping	= 6,
};

static const struct portinfo pata_icside_portinfo_v6_1 = {
	.dataoffset	= 0x2000,
	.ctrloffset	= 0x2380,
	.stepping	= 6,
};

static const struct portinfo pata_icside_portinfo_v6_2 = {
	.dataoffset	= 0x3000,
	.ctrloffset	= 0x3380,
	.stepping	= 6,
};

#define PATA_ICSIDE_MAX_SG	128

struct pata_icside_state {
	void __iomem *irq_port;
	void __iomem *ioc_base;
	unsigned int type;
	unsigned int dma;
	struct {
		u8 port_sel;
		u8 disabled;
		unsigned int speed[ATA_MAX_DEVICES];
	} port[2];
	struct scatterlist sg[PATA_ICSIDE_MAX_SG];
};

struct pata_icside_info {
	struct pata_icside_state *state;
	struct expansion_card	*ec;
	void __iomem		*base;
	void __iomem		*irqaddr;
	unsigned int		irqmask;
	const expansioncard_ops_t *irqops;
	unsigned int		mwdma_mask;
	unsigned int		nr_ports;
	const struct portinfo	*port[2];
};

#define ICS_TYPE_A3IN	0
#define ICS_TYPE_A3USER	1
#define ICS_TYPE_V6	3
#define ICS_TYPE_V5	15
#define ICS_TYPE_NOTYPE	((unsigned int)-1)

/* ---------------- Version 5 PCB Support Functions --------------------- */
/* Prototype: pata_icside_irqenable_arcin_v5 (struct expansion_card *ec, int irqnr)
 * Purpose  : enable interrupts from card
 */
static void pata_icside_irqenable_arcin_v5 (struct expansion_card *ec, int irqnr)
{
	struct pata_icside_state *state = ec->irq_data;

	writeb(0, state->irq_port + ICS_ARCIN_V5_INTROFFSET);
}

/* Prototype: pata_icside_irqdisable_arcin_v5 (struct expansion_card *ec, int irqnr)
 * Purpose  : disable interrupts from card
 */
static void pata_icside_irqdisable_arcin_v5 (struct expansion_card *ec, int irqnr)
{
	struct pata_icside_state *state = ec->irq_data;

	readb(state->irq_port + ICS_ARCIN_V5_INTROFFSET);
}

static const expansioncard_ops_t pata_icside_ops_arcin_v5 = {
	.irqenable	= pata_icside_irqenable_arcin_v5,
	.irqdisable	= pata_icside_irqdisable_arcin_v5,
};


/* ---------------- Version 6 PCB Support Functions --------------------- */
/* Prototype: pata_icside_irqenable_arcin_v6 (struct expansion_card *ec, int irqnr)
 * Purpose  : enable interrupts from card
 */
static void pata_icside_irqenable_arcin_v6 (struct expansion_card *ec, int irqnr)
{
	struct pata_icside_state *state = ec->irq_data;
	void __iomem *base = state->irq_port;

	if (!state->port[0].disabled)
		writeb(0, base + ICS_ARCIN_V6_INTROFFSET_1);
	if (!state->port[1].disabled)
		writeb(0, base + ICS_ARCIN_V6_INTROFFSET_2);
}

/* Prototype: pata_icside_irqdisable_arcin_v6 (struct expansion_card *ec, int irqnr)
 * Purpose  : disable interrupts from card
 */
static void pata_icside_irqdisable_arcin_v6 (struct expansion_card *ec, int irqnr)
{
	struct pata_icside_state *state = ec->irq_data;

	readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_1);
	readb(state->irq_port + ICS_ARCIN_V6_INTROFFSET_2);
}

/* Prototype: pata_icside_irqprobe(struct expansion_card *ec)
 * Purpose  : detect an active interrupt from card
 */
static int pata_icside_irqpending_arcin_v6(struct expansion_card *ec)
{
	struct pata_icside_state *state = ec->irq_data;

	return readb(state->irq_port + ICS_ARCIN_V6_INTRSTAT_1) & 1 ||
	       readb(state->irq_port + ICS_ARCIN_V6_INTRSTAT_2) & 1;
}

static const expansioncard_ops_t pata_icside_ops_arcin_v6 = {
	.irqenable	= pata_icside_irqenable_arcin_v6,
	.irqdisable	= pata_icside_irqdisable_arcin_v6,
	.irqpending	= pata_icside_irqpending_arcin_v6,
};


/*
 * SG-DMA support.
 *
 * Similar to the BM-DMA, but we use the RiscPCs IOMD DMA controllers.
 * There is only one DMA controller per card, which means that only
 * one drive can be accessed at one time.  NOTE! We do not enforce that
 * here, but we rely on the main IDE driver spotting that both
 * interfaces use the same IRQ, which should guarantee this.
 */

/*
 * Configure the IOMD to give the appropriate timings for the transfer
 * mode being requested.  We take the advice of the ATA standards, and
 * calculate the cycle time based on the transfer mode, and the EIDE
 * MW DMA specs that the drive provides in the IDENTIFY command.
 *
 * We have the following IOMD DMA modes to choose from:
 *
 *	Type	Active		Recovery	Cycle
 *	A	250 (250)	312 (550)	562 (800)
 *	B	187 (200)	250 (550)	437 (750)
 *	C	125 (125)	125 (375)	250 (500)
 *	D	62  (50)	125 (375)	187 (425)
 *
 * (figures in brackets are actual measured timings on DIOR/DIOW)
 *
 * However, we also need to take care of the read/write active and
 * recovery timings:
 *
 *			Read	Write
 *  	Mode	Active	-- Recovery --	Cycle	IOMD type
 *	MW0	215	50	215	480	A
 *	MW1	80	50	50	150	C
 *	MW2	70	25	25	120	C
 */
static void pata_icside_set_dmamode(struct ata_port *ap, struct ata_device *adev)
{
	struct pata_icside_state *state = ap->host->private_data;
	struct ata_timing t;
	unsigned int cycle;
	char iomd_type;

	/*
	 * DMA is based on a 16MHz clock
	 */
	if (ata_timing_compute(adev, adev->dma_mode, &t, 1000, 1))
		return;

	/*
	 * Choose the IOMD cycle timing which ensure that the interface
	 * satisfies the measured active, recovery and cycle times.
	 */
	if (t.active <= 50 && t.recover <= 375 && t.cycle <= 425)
		iomd_type = 'D', cycle = 187;
	else if (t.active <= 125 && t.recover <= 375 && t.cycle <= 500)
		iomd_type = 'C', cycle = 250;
	else if (t.active <= 200 && t.recover <= 550 && t.cycle <= 750)
		iomd_type = 'B', cycle = 437;
	else
		iomd_type = 'A', cycle = 562;

	ata_dev_printk(adev, KERN_INFO, "timings: act %dns rec %dns cyc %dns (%c)\n",
		t.active, t.recover, t.cycle, iomd_type);

	state->port[ap->port_no].speed[adev->devno] = cycle;
}

static void pata_icside_bmdma_setup(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct pata_icside_state *state = ap->host->private_data;
	struct scatterlist *sg, *rsg = state->sg;
	unsigned int write = qc->tf.flags & ATA_TFLAG_WRITE;

	/*
	 * We are simplex; BUG if we try to fiddle with DMA
	 * while it's active.
	 */
	BUG_ON(dma_channel_active(state->dma));

	/*
	 * Copy ATAs scattered sg list into a contiguous array of sg
	 */
	ata_for_each_sg(sg, qc) {
		memcpy(rsg, sg, sizeof(*sg));
		rsg++;
	}

	/*
	 * Route the DMA signals to the correct interface
	 */
	writeb(state->port[ap->port_no].port_sel, state->ioc_base);