/*
 * Calxeda Highbank AHCI SATA platform driver
 * Copyright 2012 Calxeda, Inc.
 *
 * based on the AHCI SATA platform driver by Jeff Garzik and Anton Vorontsov
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/libata.h>
#include <linux/ahci_platform.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/export.h>
#include "ahci.h"

#define CPHY_MAP(dev, addr) ((((dev) & 0x1f) << 7) | (((addr) >> 9) & 0x7f))
#define CPHY_ADDR(addr) (((addr) & 0x1ff) << 2)
#define SERDES_CR_CTL			0x80a0
#define SERDES_CR_ADDR			0x80a1
#define SERDES_CR_DATA			0x80a2
#define CR_BUSY				0x0001
#define CR_START			0x0001
#define CR_WR_RDN			0x0002
#define CPHY_RX_INPUT_STS		0x2002
#define CPHY_SATA_OVERRIDE	 	0x4000
#define CPHY_OVERRIDE			0x2005
#define SPHY_LANE			0x100
#define SPHY_HALF_RATE			0x0001
#define CPHY_SATA_DPLL_MODE		0x0700
#define CPHY_SATA_DPLL_SHIFT		8
#define CPHY_SATA_DPLL_RESET		(1 << 11)
#define CPHY_PHY_COUNT			6
#define CPHY_LANE_COUNT			4
#define CPHY_PORT_COUNT			(CPHY_PHY_COUNT * CPHY_LANE_COUNT)

static DEFINE_SPINLOCK(cphy_lock);
/* Each of the 6 phys can have up to 4 sata ports attached to i. Map 0-based
 * sata ports to their phys and then to their lanes within the phys
 */
struct phy_lane_info {
	void __iomem *phy_base;
	u8 lane_mapping;
	u8 phy_devs;
};
static struct phy_lane_info port_data[CPHY_PORT_COUNT];

static u32 __combo_phy_reg_read(u8 sata_port, u32 addr)
{
	u32 data;
	u8 dev = port_data[sata_port].phy_devs;
	spin_lock(&cphy_lock);
	writel(CPHY_MAP(dev, addr), port_data[sata_port].phy_base + 0x800);
	data = readl(port_data[sata_port].phy_base + CPHY_ADDR(addr));
	spin_unlock(&cphy_lock);
	return data;
}

static void __combo_phy_reg_write(u8 sata_port, u32 addr, u32 data)
{
	u8 dev = port_data[sata_port].phy_devs;
	spin_lock(&cphy_lock);
	writel(CPHY_MAP(dev, addr), port_data[sata_port].phy_base + 0x800);
	writel(data, port_data[sata_port].phy_base + CPHY_ADDR(addr));
	spin_unlock(&cphy_lock);
}

static void combo_phy_wait_for_ready(u8 sata_port)
{
	while (__combo_phy_reg_read(sata_port, SERDES_CR_CTL) & CR_BUSY)
		udelay(5);
}

static u32 combo_phy_read(u8 sata_port, u32 addr)
{
	combo_phy_wait_for_ready(sata_port);
	__combo_phy_reg_write(sata_port, SERDES_CR_ADDR, addr);
	__combo_phy_reg_write(sata_port, SERDES_CR_CTL, CR_START);
	combo_phy_wait_for_ready(sata_port);
	return __combo_phy_reg_read(sata_port, SERDES_CR_DATA);
}

static void combo_phy_write(u8 sata_port, u32 addr, u32 data)
{
	combo_phy_wait_for_ready(sata_port);
	__combo_phy_reg_write(sata_port, SERDES_CR_ADDR, addr);
	__combo_phy_reg_write(sata_port, SERDES_CR_DATA, data);
	__combo_phy_reg_write(sata_port, SERDES_CR_CTL, CR_WR_RDN | CR_START);
}

static void highbank_cphy_disable_overrides(u8 sata_port)
{
	u8 lane = port_data[sata_port].lane_mapping;
	u32 tmp;
	if (unlikely(port_data[sata_port].phy_base == NULL))
		return;
	tmp = combo_phy_read(sata_port, CPHY_RX_INPUT_STS + lane * SPHY_LANE);
	tmp &= ~CPHY_SATA_OVERRIDE;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);
}

static void cphy_override_rx_mode(u8 sata_port, u32 val)
{
	u8 lane = port_data[sata_port].lane_mapping;
	u32 tmp;
	tmp = combo_phy_read(sata_port, CPHY_RX_INPUT_STS + lane * SPHY_LANE);
	tmp &= ~CPHY_SATA_OVERRIDE;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);

	tmp |= CPHY_SATA_OVERRIDE;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);

	tmp &= ~CPHY_SATA_DPLL_MODE;
	tmp |= val << CPHY_SATA_DPLL_SHIFT;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);

	tmp |= CPHY_SATA_DPLL_RESET;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);

	tmp &= ~CPHY_SATA_DPLL_RESET;
	combo_phy_write(sata_port, CPHY_OVERRIDE + lane * SPHY_LANE, tmp);

	msleep(15);
}

static void highbank_cphy_override_lane(u8 sata_port)
{
	u8 lane = port_data[sata_port].lane_mapping;
	u32 tmp, k = 0;

	if (unlikely(port_data[sata_port].phy_base == NULL))
		return;
	do {
		tmp = combo_phy_read(sata_port, CPHY_RX_INPUT_STS +
						lane * SPHY_LANE);
	} while ((tmp & SPHY_HALF_RATE) && (k++ < 1000));
	cphy_override_rx_mode(sata_port, 3);
}

static int highbank_initialize_phys(struct device *dev, void __iomem *addr)
{
	struct device_node *sata_node = dev->of_node;
	int phy_count = 0, phy, port = 0;
	void __iomem *cphy_base[CPHY_PHY_COUNT];
	struct device_node *phy_nodes[CPHY_PHY_COUNT];
	memset(port_data, 0, sizeof(struct phy_lane_info) * CPHY_PORT_COUNT);
	memset(phy_nodes, 0, sizeof(struct device_node*) * CPHY_PHY_COUNT);

	do {
		u32 tmp;
		struct of_phandle_args phy_data;
		if (of_parse_phandle_with_args(sata_node,
				"calxeda,port-phys", "#phy-cells",
				port, &phy_data))
			break;
		for (phy = 0; phy < phy_count; phy++) {
			if (phy_nodes[phy] == phy_data.np)
				break;
		}
		if (phy_nodes[phy] == NULL) {
			phy_nodes[phy] = phy_data.np;
			cphy_base[phy] = of_iomap(phy_nodes[phy], 0);
			if (cphy_base[phy] == NULL) {
				return 0;
			}
			phy_count += 1;
		}
		port_data[port].lane_mapping = phy_data.args[0];
		of_property_read_u32(phy_nodes[phy], "phydev", &tmp);
		port_data[port].phy_devs = tmp;
		port_data[port].phy_base = cphy_base[phy];
		of_node_put(phy_data.np);
		port += 1;
	} while (port < CPHY_PORT_COUNT);
	return 0;
}

/*
 * The Calxeda SATA phy intermittently fails to bring up a link with Gen3
 * Retrying the phy hard reset can work around the issue, but the drive
 * may fail again. In less than 150 out of 15000 test runs, it took more
 * than 10 tries for the link to be established (but never more than 35).
 * Triple the maximum observed retry count to provide plenty of margin for
 * rare events and to guarantee that the link is established.
 *
 * Also, the default 2 second time-out on a failed drive is too long in
 * this situation. The uboot implementation of the same driver function
 * uses a much shorter time-out period and never experiences a time out
 * issue. Reducing the time-out to 500ms improves the responsiveness.
 * The other timing constants were kept the same as the stock AHCI driver.
 * This change was also tested 15000 times on 24 drives and none of them
 * experienced a time out.
 */
static int ahci_highbank_hardreset(struct ata_link *link, unsigned int *class,
				unsigned long deadline)
{
	static const unsigned long timing[] = { 5, 100, 500};
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
	struct ata_taskfile tf;
	bool online;
	u32 sstatus;
	int rc;
	int retry = 100;

	ahci_stop_engine(ap);

	/* clear D2H reception area to properly wait for D2H FIS */
	ata_tf_init(link->device, &tf);
	tf.command = ATA_BUSY;
	ata_tf_to_fis(&tf, 0, 0, d2h_fis);

	do {
		highbank_cphy_disable_overrides(link->ap->port_no);
		rc = sata_link_hardreset(link, timing, deadline, &online, NULL);
		highbank_cphy_override_lane(link->ap->port_no);

		/* If the status is 1, we are connected, but the link did not
		 * come up. So retry resetting the link again.
		 */
		if (sata_scr_read(link, SCR_STATUS, &sstatus))
			break;
		if (!(sstatus & 0x3))
			break;
	} while (!online && retry--);

	ahci_start_engine(ap);

	if (online)
		*class = ahci_dev_classify(ap);

	return rc;
}

static struct ata_port_operations ahci_highbank_ops = {
	.inherits		= &ahci_ops,
	.hardreset		= ahci_highbank_hardreset,
};

static const struct ata_port_info ahci_highbank_port_info = {
	.flags          = AHCI_FLAG_COMMON,
	.pio_mask       = ATA_PIO4,
	.udma_mask      = ATA_UDMA6,
	.port_ops       = &ahci_highbank_ops,
};

static struct scsi_host_template ahci_highbank_platform_sht = {
	AHCI_SHT("sata_highbank"),
};

static const struct of_device_id ahci_of_match[] = {
	{ .compatible = "calxeda,hb-ahci" },
	{},
};
MODULE_DEVICE_TABLE(of, ahci_of_match);

static int ahci_highbank_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct ahci_host_priv *hpriv;
	struct ata_host *host;
	struct resource *mem;
	int irq;
	int n_ports;
	int i;
	int rc;
	struct ata_port_info pi = ahci_highbank_port_info;
	const struct ata_port_info *ppi[] = { &pi, NULL };

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		dev_err(dev, "no mmio space\n");
		return -EINVAL;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
		dev_err(dev, "no irq\n");
		return -EINVAL;
	}

	hpriv = devm_kzalloc(dev, sizeof(*hpriv), GFP_KERNEL);
	if (!hpriv) {
		dev_err(dev, "can't alloc ahci_host_priv\n");
		return -ENOMEM;
	}

	hpriv->flags |= (unsigned long)pi.private_data;

	hpriv->mmio = devm_ioremap(dev, mem->start, resource_size(mem));
	if (!hpriv->mmio) {
		dev_err(dev, "can't map %pR\n", mem);
		return -ENOMEM;
	}

	rc = highbank_initialize_phys(dev, hpriv->mmio);
	if (rc)
		return rc;


	ahci_save_initial_config(dev, hpriv, 0, 0);

	/* prepare host */
	if (hpriv->cap & HOST_CAP_NCQ)
		pi.flags |= ATA_FLAG_NCQ;

	if (hpriv->cap & HOST_CAP_PMP)
		pi.flags |= ATA_FLAG_PMP;

	ahci_set_em_messages(hpriv, &pi);

	/* CAP.NP sometimes indicate the index of the last enabled
	 * port, at other times, that of the last possible port, so
	 * determining the maximum port number requires looking at
	 * both CAP.NP and port_map.
	 */
	n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));

	host = ata_host_alloc_pinfo(dev, ppi, n_ports);
	if (!host) {
		rc = -ENOMEM;
		goto err0;
	}

	host->private_data = hpriv;

	if (!(hpriv->cap & HOST_CAP_SSS) || ahci_ignore_sss)
		host->flags |= ATA_HOST_PARALLEL_SCAN;

	if (pi.flags & ATA_FLAG_EM)
		ahci_reset_em(host);

	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap = host->ports[i];

		ata_port_desc(ap, "mmio %pR", mem);
		ata_port_desc(ap, "port 0x%x", 0x100 + ap->port_no * 0x80);

		/* set enclosure management message type */
		if (ap->flags & ATA_FLAG_EM)
			ap->em_message_type = hpriv->em_msg_type;

		/* disabled/not-implemented port */
		if (!(hpriv->port_map & (1 << i)))
			ap->ops = &ata_dummy_port_ops;
	}

	rc = ahci_reset_controller(host);
	if (rc)
		goto err0;

	ahci_init_controller(host);
	ahci_print_info(host, "platform");

	rc = ata_host_activate(host, irq, ahci_interrupt, 0,
					&ahci_highbank_platform_sht);
	if (rc)
		goto err0;

	return 0;
err0:
	return rc;
}

#ifdef CONFIG_PM_SLEEP
static int ahci_highbank_suspend(struct device *dev)
{
	struct ata_host *host = dev_get_drvdata(dev);
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;
	u32 ctl;
	int rc;

	if (hpriv->flags & AHCI_HFLAG_NO_SUSPEND) {
		dev_err(dev, "firmware update required for suspend/resume\n");
		return -EIO;
	}

	/*
	 * AHCI spec rev1.1 section 8.3.3:
	 * Software must disable interrupts prior to requesting a
	 * transition of the HBA to D3 state.
	 */
	ctl = readl(mmio + HOST_CTL);
	ctl &= ~HOST_IRQ_EN;
	writel(ctl, mmio + HOST_CTL);
	readl(mmio + HOST_CTL); /* flush */

	rc = ata_host_suspend(host, PMSG_SUSPEND);
	if (rc)
		return rc;

	return 0;
}

static int ahci_highbank_resume(struct device *dev)
{
	struct ata_host *host = dev_get_drvdata(dev);
	int rc;

	if (dev->power.power_state.event == PM_EVENT_SUSPEND) {
		rc = ahci_reset_controller(host);
		if (rc)
			return rc;

		ahci_init_controller(host);
	}

	ata_host_resume(host);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(ahci_highbank_pm_ops,
		  ahci_highbank_suspend, ahci_highbank_resume);

static struct platform_driver ahci_highbank_driver = {
	.remove = ata_platform_remove_one,
        .driver = {
                .name = "highbank-ahci",
                .owner = THIS_MODULE,
                .of_match_table = ahci_of_match,
                .pm = &ahci_highbank_pm_ops,
        },
	.probe = ahci_highbank_probe,
};

module_platform_driver(ahci_highbank_driver);

MODULE_DESCRIPTION("Calxeda Highbank AHCI SATA platform driver");
MODULE_AUTHOR("Mark Langsdorf <mark.langsdorf@calxeda.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("sata:highbank");