// SPDX-License-Identifier: GPL-2.0-only
/* OMAP SSI driver.
 *
 * Copyright (C) 2010 Nokia Corporation. All rights reserved.
 * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
 *
 * Contact: Carlos Chinea <carlos.chinea@nokia.com>
 */

#include <linux/compiler.h>
#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/delay.h>
#include <linux/hsi/ssi_protocol.h>
#include <linux/seq_file.h>
#include <linux/scatterlist.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/hsi/hsi.h>
#include <linux/idr.h>

#include "omap_ssi_regs.h"
#include "omap_ssi.h"

/* For automatically allocated device IDs */
static DEFINE_IDA(platform_omap_ssi_ida);

#ifdef CONFIG_DEBUG_FS
static int ssi_regs_show(struct seq_file *m, void *p __maybe_unused)
{
        struct hsi_controller *ssi = m->private;
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        void __iomem *sys = omap_ssi->sys;

        pm_runtime_get_sync(ssi->device.parent);
        seq_printf(m, "REVISION\t: 0x%08x\n",  readl(sys + SSI_REVISION_REG));
        seq_printf(m, "SYSCONFIG\t: 0x%08x\n", readl(sys + SSI_SYSCONFIG_REG));
        seq_printf(m, "SYSSTATUS\t: 0x%08x\n", readl(sys + SSI_SYSSTATUS_REG));
        pm_runtime_put(ssi->device.parent);

        return 0;
}

static int ssi_gdd_regs_show(struct seq_file *m, void *p __maybe_unused)
{
        struct hsi_controller *ssi = m->private;
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        void __iomem *gdd = omap_ssi->gdd;
        void __iomem *sys = omap_ssi->sys;
        int lch;

        pm_runtime_get_sync(ssi->device.parent);

        seq_printf(m, "GDD_MPU_STATUS\t: 0x%08x\n",
                readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG));
        seq_printf(m, "GDD_MPU_ENABLE\t: 0x%08x\n\n",
                readl(sys + SSI_GDD_MPU_IRQ_ENABLE_REG));
        seq_printf(m, "HW_ID\t\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_HW_ID_REG));
        seq_printf(m, "PPORT_ID\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_PPORT_ID_REG));
        seq_printf(m, "MPORT_ID\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_MPORT_ID_REG));
        seq_printf(m, "TEST\t\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_TEST_REG));
        seq_printf(m, "GCR\t\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_GCR_REG));

        for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
                seq_printf(m, "\nGDD LCH %d\n=========\n", lch);
                seq_printf(m, "CSDP\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CSDP_REG(lch)));
                seq_printf(m, "CCR\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CCR_REG(lch)));
                seq_printf(m, "CICR\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CICR_REG(lch)));
                seq_printf(m, "CSR\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CSR_REG(lch)));
                seq_printf(m, "CSSA\t\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_CSSA_REG(lch)));
                seq_printf(m, "CDSA\t\t: 0x%08x\n",
                                readl(gdd + SSI_GDD_CDSA_REG(lch)));
                seq_printf(m, "CEN\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CEN_REG(lch)));
                seq_printf(m, "CSAC\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CSAC_REG(lch)));
                seq_printf(m, "CDAC\t\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CDAC_REG(lch)));
                seq_printf(m, "CLNK_CTRL\t: 0x%04x\n",
                                readw(gdd + SSI_GDD_CLNK_CTRL_REG(lch)));
        }

        pm_runtime_put(ssi->device.parent);

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(ssi_regs);
DEFINE_SHOW_ATTRIBUTE(ssi_gdd_regs);

static int ssi_debug_add_ctrl(struct hsi_controller *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        struct dentry *dir;

        /* SSI controller */
        omap_ssi->dir = debugfs_create_dir(dev_name(&ssi->device), NULL);
        debugfs_create_file("regs", S_IRUGO, omap_ssi->dir, ssi, &ssi_regs_fops);

        /* SSI GDD (DMA) */
        dir = debugfs_create_dir("gdd", omap_ssi->dir);
        debugfs_create_file("regs", S_IRUGO, dir, ssi, &ssi_gdd_regs_fops);

        return 0;
}

static void ssi_debug_remove_ctrl(struct hsi_controller *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);

        debugfs_remove_recursive(omap_ssi->dir);
}
#endif /* CONFIG_DEBUG_FS */

/*
 * FIXME: Horrible HACK needed until we remove the useless wakeline test
 * in the CMT. To be removed !!!!
 */
void ssi_waketest(struct hsi_client *cl, unsigned int enable)
{
        struct hsi_port *port = hsi_get_port(cl);
        struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
        struct hsi_controller *ssi = to_hsi_controller(port->device.parent);
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);

        omap_port->wktest = !!enable;
        if (omap_port->wktest) {
                pm_runtime_get_sync(ssi->device.parent);
                writel_relaxed(SSI_WAKE(0),
                                omap_ssi->sys + SSI_SET_WAKE_REG(port->num));
        } else {
                writel_relaxed(SSI_WAKE(0),
                                omap_ssi->sys + SSI_CLEAR_WAKE_REG(port->num));
                pm_runtime_put(ssi->device.parent);
        }
}
EXPORT_SYMBOL_GPL(ssi_waketest);

static void ssi_gdd_complete(struct hsi_controller *ssi, unsigned int lch)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        struct hsi_msg *msg = omap_ssi->gdd_trn[lch].msg;
        struct hsi_port *port = to_hsi_port(msg->cl->device.parent);
        struct omap_ssi_port *omap_port = hsi_port_drvdata(port);
        unsigned int dir;
        u32 csr;
        u32 val;

        spin_lock(&omap_ssi->lock);

        val = readl(omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);
        val &= ~SSI_GDD_LCH(lch);
        writel_relaxed(val, omap_ssi->sys + SSI_GDD_MPU_IRQ_ENABLE_REG);

        if (msg->ttype == HSI_MSG_READ) {
                dir = DMA_FROM_DEVICE;
                val = SSI_DATAAVAILABLE(msg->channel);
                pm_runtime_put(omap_port->pdev);
        } else {
                dir = DMA_TO_DEVICE;
                val = SSI_DATAACCEPT(msg->channel);
                /* Keep clocks reference for write pio event */
        }
        dma_unmap_sg(&ssi->device, msg->sgt.sgl, msg->sgt.nents, dir);
        csr = readw(omap_ssi->gdd + SSI_GDD_CSR_REG(lch));
        omap_ssi->gdd_trn[lch].msg = NULL; /* release GDD lch */
        dev_dbg(&port->device, "DMA completed ch %d ttype %d\n",
                                msg->channel, msg->ttype);
        spin_unlock(&omap_ssi->lock);
        if (csr & SSI_CSR_TOUR) { /* Timeout error */
                msg->status = HSI_STATUS_ERROR;
                msg->actual_len = 0;
                spin_lock(&omap_port->lock);
                list_del(&msg->link); /* Dequeue msg */
                spin_unlock(&omap_port->lock);

                list_add_tail(&msg->link, &omap_port->errqueue);
                schedule_delayed_work(&omap_port->errqueue_work, 0);
                return;
        }
        spin_lock(&omap_port->lock);
        val |= readl(omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
        writel_relaxed(val, omap_ssi->sys + SSI_MPU_ENABLE_REG(port->num, 0));
        spin_unlock(&omap_port->lock);

        msg->status = HSI_STATUS_COMPLETED;
        msg->actual_len = sg_dma_len(msg->sgt.sgl);
}

static void ssi_gdd_tasklet(unsigned long dev)
{
        struct hsi_controller *ssi = (struct hsi_controller *)dev;
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        void __iomem *sys = omap_ssi->sys;
        unsigned int lch;
        u32 status_reg;

        pm_runtime_get(ssi->device.parent);

        if (!pm_runtime_active(ssi->device.parent)) {
                dev_warn(ssi->device.parent, "ssi_gdd_tasklet called without runtime PM!\n");
                pm_runtime_put(ssi->device.parent);
                return;
        }

        status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);
        for (lch = 0; lch < SSI_MAX_GDD_LCH; lch++) {
                if (status_reg & SSI_GDD_LCH(lch))
                        ssi_gdd_complete(ssi, lch);
        }
        writel_relaxed(status_reg, sys + SSI_GDD_MPU_IRQ_STATUS_REG);
        status_reg = readl(sys + SSI_GDD_MPU_IRQ_STATUS_REG);

        pm_runtime_put(ssi->device.parent);

        if (status_reg)
                tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
        else
                enable_irq(omap_ssi->gdd_irq);

}

static irqreturn_t ssi_gdd_isr(int irq, void *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);

        tasklet_hi_schedule(&omap_ssi->gdd_tasklet);
        disable_irq_nosync(irq);

        return IRQ_HANDLED;
}

static unsigned long ssi_get_clk_rate(struct hsi_controller *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        unsigned long rate = clk_get_rate(omap_ssi->fck);
        return rate;
}

static int ssi_clk_event(struct notifier_block *nb, unsigned long event,
                                                                void *data)
{
        struct omap_ssi_controller *omap_ssi = container_of(nb,
                                        struct omap_ssi_controller, fck_nb);
        struct hsi_controller *ssi = to_hsi_controller(omap_ssi->dev);
        struct clk_notifier_data *clk_data = data;
        struct omap_ssi_port *omap_port;
        int i;

        switch (event) {
        case PRE_RATE_CHANGE:
                dev_dbg(&ssi->device, "pre rate change\n");

                for (i = 0; i < ssi->num_ports; i++) {
                        omap_port = omap_ssi->port[i];

                        if (!omap_port)
                                continue;

                        /* Workaround for SWBREAK + CAwake down race in CMT */
                        disable_irq(omap_port->wake_irq);

                        /* stop all ssi communication */
                        pinctrl_pm_select_idle_state(omap_port->pdev);
                        udelay(1); /* wait for racing frames */
                }

                break;
        case ABORT_RATE_CHANGE:
                dev_dbg(&ssi->device, "abort rate change\n");
                fallthrough;
        case POST_RATE_CHANGE:
                dev_dbg(&ssi->device, "post rate change (%lu -> %lu)\n",
                        clk_data->old_rate, clk_data->new_rate);
                omap_ssi->fck_rate = DIV_ROUND_CLOSEST(clk_data->new_rate, 1000); /* kHz */

                for (i = 0; i < ssi->num_ports; i++) {
                        omap_port = omap_ssi->port[i];

                        if (!omap_port)
                                continue;

                        omap_ssi_port_update_fclk(ssi, omap_port);

                        /* resume ssi communication */
                        pinctrl_pm_select_default_state(omap_port->pdev);
                        enable_irq(omap_port->wake_irq);
                }

                break;
        default:
                break;
        }

        return NOTIFY_DONE;
}

static int ssi_get_iomem(struct platform_device *pd,
                const char *name, void __iomem **pbase, dma_addr_t *phy)
{
        struct resource *mem;
        void __iomem *base;
        struct hsi_controller *ssi = platform_get_drvdata(pd);

        mem = platform_get_resource_byname(pd, IORESOURCE_MEM, name);
        base = devm_ioremap_resource(&ssi->device, mem);
        if (IS_ERR(base))
                return PTR_ERR(base);

        *pbase = base;

        if (phy)
                *phy = mem->start;

        return 0;
}

static int ssi_add_controller(struct hsi_controller *ssi,
                                                struct platform_device *pd)
{
        struct omap_ssi_controller *omap_ssi;
        int err;

        omap_ssi = devm_kzalloc(&ssi->device, sizeof(*omap_ssi), GFP_KERNEL);
        if (!omap_ssi)
                return -ENOMEM;

        err = ida_alloc(&platform_omap_ssi_ida, GFP_KERNEL);
        if (err < 0)
                return err;
        ssi->id = err;

        ssi->owner = THIS_MODULE;
        ssi->device.parent = &pd->dev;
        dev_set_name(&ssi->device, "ssi%d", ssi->id);
        hsi_controller_set_drvdata(ssi, omap_ssi);
        omap_ssi->dev = &ssi->device;
        err = ssi_get_iomem(pd, "sys", &omap_ssi->sys, NULL);
        if (err < 0)
                goto out_err;
        err = ssi_get_iomem(pd, "gdd", &omap_ssi->gdd, NULL);
        if (err < 0)
                goto out_err;
        err = platform_get_irq_byname(pd, "gdd_mpu");
        if (err < 0)
                goto out_err;
        omap_ssi->gdd_irq = err;
        tasklet_init(&omap_ssi->gdd_tasklet, ssi_gdd_tasklet,
                                                        (unsigned long)ssi);
        err = devm_request_irq(&ssi->device, omap_ssi->gdd_irq, ssi_gdd_isr,
                                                0, "gdd_mpu", ssi);
        if (err < 0) {
                dev_err(&ssi->device, "Request GDD IRQ %d failed (%d)",
                                                        omap_ssi->gdd_irq, err);
                goto out_err;
        }

        omap_ssi->port = devm_kcalloc(&ssi->device, ssi->num_ports,
                                      sizeof(*omap_ssi->port), GFP_KERNEL);
        if (!omap_ssi->port) {
                err = -ENOMEM;
                goto out_err;
        }

        omap_ssi->fck = devm_clk_get(&ssi->device, "ssi_ssr_fck");
        if (IS_ERR(omap_ssi->fck)) {
                dev_err(&pd->dev, "Could not acquire clock \"ssi_ssr_fck\": %li\n",
                        PTR_ERR(omap_ssi->fck));
                err = -ENODEV;
                goto out_err;
        }

        omap_ssi->fck_nb.notifier_call = ssi_clk_event;
        omap_ssi->fck_nb.priority = INT_MAX;
        clk_notifier_register(omap_ssi->fck, &omap_ssi->fck_nb);

        /* TODO: find register, which can be used to detect context loss */
        omap_ssi->get_loss = NULL;

        omap_ssi->max_speed = UINT_MAX;
        spin_lock_init(&omap_ssi->lock);
        err = hsi_register_controller(ssi);

        if (err < 0)
                goto out_err;

        return 0;

out_err:
        ida_free(&platform_omap_ssi_ida, ssi->id);
        return err;
}

static int ssi_hw_init(struct hsi_controller *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        int err;

        err = pm_runtime_resume_and_get(ssi->device.parent);
        if (err < 0) {
                dev_err(&ssi->device, "runtime PM failed %d\n", err);
                return err;
        }
        /* Resetting GDD */
        writel_relaxed(SSI_SWRESET, omap_ssi->gdd + SSI_GDD_GRST_REG);
        /* Get FCK rate in kHz */
        omap_ssi->fck_rate = DIV_ROUND_CLOSEST(ssi_get_clk_rate(ssi), 1000);
        dev_dbg(&ssi->device, "SSI fck rate %lu kHz\n", omap_ssi->fck_rate);

        writel_relaxed(SSI_CLK_AUTOGATING_ON, omap_ssi->sys + SSI_GDD_GCR_REG);
        omap_ssi->gdd_gcr = SSI_CLK_AUTOGATING_ON;
        pm_runtime_put_sync(ssi->device.parent);

        return 0;
}

static void ssi_remove_controller(struct hsi_controller *ssi)
{
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);
        int id = ssi->id;
        tasklet_kill(&omap_ssi->gdd_tasklet);
        hsi_unregister_controller(ssi);
        clk_notifier_unregister(omap_ssi->fck, &omap_ssi->fck_nb);
        ida_free(&platform_omap_ssi_ida, id);
}

static inline int ssi_of_get_available_ports_count(const struct device_node *np)
{
        struct device_node *child;
        int num = 0;

        for_each_available_child_of_node(np, child)
                if (of_device_is_compatible(child, "ti,omap3-ssi-port"))
                        num++;

        return num;
}

static int ssi_remove_ports(struct device *dev, void *c)
{
        struct platform_device *pdev = to_platform_device(dev);

        if (!dev->of_node)
                return 0;

        of_node_clear_flag(dev->of_node, OF_POPULATED);
        of_device_unregister(pdev);

        return 0;
}

static int ssi_probe(struct platform_device *pd)
{
        struct platform_device *childpdev;
        struct device_node *np = pd->dev.of_node;
        struct device_node *child;
        struct hsi_controller *ssi;
        int err;
        int num_ports;

        if (!np) {
                dev_err(&pd->dev, "missing device tree data\n");
                return -EINVAL;
        }

        num_ports = ssi_of_get_available_ports_count(np);

        ssi = hsi_alloc_controller(num_ports, GFP_KERNEL);
        if (!ssi) {
                dev_err(&pd->dev, "No memory for controller\n");
                return -ENOMEM;
        }

        platform_set_drvdata(pd, ssi);

        err = ssi_add_controller(ssi, pd);
        if (err < 0) {
                hsi_put_controller(ssi);
                goto out1;
        }

        pm_runtime_enable(&pd->dev);

        err = ssi_hw_init(ssi);
        if (err < 0)
                goto out2;
#ifdef CONFIG_DEBUG_FS
        err = ssi_debug_add_ctrl(ssi);
        if (err < 0)
                goto out2;
#endif

        for_each_available_child_of_node(np, child) {
                if (!of_device_is_compatible(child, "ti,omap3-ssi-port"))
                        continue;

                childpdev = of_platform_device_create(child, NULL, &pd->dev);
                if (!childpdev) {
                        err = -ENODEV;
                        dev_err(&pd->dev, "failed to create ssi controller port\n");
                        of_node_put(child);
                        goto out3;
                }
        }

        dev_info(&pd->dev, "ssi controller %d initialized (%d ports)!\n",
                ssi->id, num_ports);
        return err;
out3:
        device_for_each_child(&pd->dev, NULL, ssi_remove_ports);
out2:
        ssi_remove_controller(ssi);
        pm_runtime_disable(&pd->dev);
out1:
        platform_set_drvdata(pd, NULL);

        return err;
}

static void ssi_remove(struct platform_device *pd)
{
        struct hsi_controller *ssi = platform_get_drvdata(pd);

        /* cleanup of of_platform_populate() call */
        device_for_each_child(&pd->dev, NULL, ssi_remove_ports);

#ifdef CONFIG_DEBUG_FS
        ssi_debug_remove_ctrl(ssi);
#endif
        ssi_remove_controller(ssi);
        platform_set_drvdata(pd, NULL);

        pm_runtime_disable(&pd->dev);
}

#ifdef CONFIG_PM
static int omap_ssi_runtime_suspend(struct device *dev)
{
        struct hsi_controller *ssi = dev_get_drvdata(dev);
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);

        dev_dbg(dev, "runtime suspend!\n");

        if (omap_ssi->get_loss)
                omap_ssi->loss_count =
                                omap_ssi->get_loss(ssi->device.parent);

        return 0;
}

static int omap_ssi_runtime_resume(struct device *dev)
{
        struct hsi_controller *ssi = dev_get_drvdata(dev);
        struct omap_ssi_controller *omap_ssi = hsi_controller_drvdata(ssi);

        dev_dbg(dev, "runtime resume!\n");

        if ((omap_ssi->get_loss) && (omap_ssi->loss_count ==
                                omap_ssi->get_loss(ssi->device.parent)))
                return 0;

        writel_relaxed(omap_ssi->gdd_gcr, omap_ssi->gdd + SSI_GDD_GCR_REG);

        return 0;
}

static const struct dev_pm_ops omap_ssi_pm_ops = {
        SET_RUNTIME_PM_OPS(omap_ssi_runtime_suspend, omap_ssi_runtime_resume,
                NULL)
};

#define DEV_PM_OPS     (&omap_ssi_pm_ops)
#else
#define DEV_PM_OPS     NULL
#endif

#ifdef CONFIG_OF
static const struct of_device_id omap_ssi_of_match[] = {
        { .compatible = "ti,omap3-ssi", },
        {},
};
MODULE_DEVICE_TABLE(of, omap_ssi_of_match);
#else
#define omap_ssi_of_match NULL
#endif

static struct platform_driver ssi_pdriver = {
        .probe = ssi_probe,
        .remove = ssi_remove,
        .driver = {
                .name   = "omap_ssi",
                .pm     = DEV_PM_OPS,
                .of_match_table = omap_ssi_of_match,
        },
};

static int __init ssi_init(void) {
        int ret;

        ret = platform_driver_register(&ssi_pdriver);
        if (ret)
                return ret;

        ret = platform_driver_register(&ssi_port_pdriver);
        if (ret) {
                platform_driver_unregister(&ssi_pdriver);
                return ret;
        }

        return 0;
}
module_init(ssi_init);

static void __exit ssi_exit(void) {
        platform_driver_unregister(&ssi_port_pdriver);
        platform_driver_unregister(&ssi_pdriver);
}
module_exit(ssi_exit);

MODULE_ALIAS("platform:omap_ssi");
MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
MODULE_DESCRIPTION("Synchronous Serial Interface Driver");
MODULE_LICENSE("GPL v2");