/*
 * TI Keystone DSP remoteproc driver
 *
 * Copyright (C) 2015-2017 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/workqueue.h>
#include <linux/of_address.h>
#include <linux/of_reserved_mem.h>
#include <linux/of_gpio.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
#include <linux/remoteproc.h>
#include <linux/reset.h>

#include "remoteproc_internal.h"

#define KEYSTONE_RPROC_LOCAL_ADDRESS_MASK       (SZ_16M - 1)

/**
 * struct keystone_rproc_mem - internal memory structure
 * @cpu_addr: MPU virtual address of the memory region
 * @bus_addr: Bus address used to access the memory region
 * @dev_addr: Device address of the memory region from DSP view
 * @size: Size of the memory region
 */
struct keystone_rproc_mem {
        void __iomem *cpu_addr;
        phys_addr_t bus_addr;
        u32 dev_addr;
        size_t size;
};

/**
 * struct keystone_rproc - keystone remote processor driver structure
 * @dev: cached device pointer
 * @rproc: remoteproc device handle
 * @mem: internal memory regions data
 * @num_mems: number of internal memory regions
 * @dev_ctrl: device control regmap handle
 * @reset: reset control handle
 * @boot_offset: boot register offset in @dev_ctrl regmap
 * @irq_ring: irq entry for vring
 * @irq_fault: irq entry for exception
 * @kick_gpio: gpio used for virtio kicks
 * @workqueue: workqueue for processing virtio interrupts
 */
struct keystone_rproc {
        struct device *dev;
        struct rproc *rproc;
        struct keystone_rproc_mem *mem;
        int num_mems;
        struct regmap *dev_ctrl;
        struct reset_control *reset;
        u32 boot_offset;
        int irq_ring;
        int irq_fault;
        int kick_gpio;
        struct work_struct workqueue;
};

/* Put the DSP processor into reset */
static void keystone_rproc_dsp_reset(struct keystone_rproc *ksproc)
{
        reset_control_assert(ksproc->reset);
}

/* Configure the boot address and boot the DSP processor */
static int keystone_rproc_dsp_boot(struct keystone_rproc *ksproc, u32 boot_addr)
{
        int ret;

        if (boot_addr & (SZ_1K - 1)) {
                dev_err(ksproc->dev, "invalid boot address 0x%x, must be aligned on a 1KB boundary\n",
                        boot_addr);
                return -EINVAL;
        }

        ret = regmap_write(ksproc->dev_ctrl, ksproc->boot_offset, boot_addr);
        if (ret) {
                dev_err(ksproc->dev, "regmap_write of boot address failed, status = %d\n",
                        ret);
                return ret;
        }

        reset_control_deassert(ksproc->reset);

        return 0;
}

/*
 * Process the remoteproc exceptions
 *
 * The exception reporting on Keystone DSP remote processors is very simple
 * compared to the equivalent processors on the OMAP family, it is notified
 * through a software-designed specific interrupt source in the IPC interrupt
 * generation register.
 *
 * This function just invokes the rproc_report_crash to report the exception
 * to the remoteproc driver core, to trigger a recovery.
 */
static irqreturn_t keystone_rproc_exception_interrupt(int irq, void *dev_id)
{
        struct keystone_rproc *ksproc = dev_id;

        rproc_report_crash(ksproc->rproc, RPROC_FATAL_ERROR);

        return IRQ_HANDLED;
}

/*
 * Main virtqueue message workqueue function
 *
 * This function is executed upon scheduling of the keystone remoteproc
 * driver's workqueue. The workqueue is scheduled by the vring ISR handler.
 *
 * There is no payload message indicating the virtqueue index as is the
 * case with mailbox-based implementations on OMAP family. As such, this
 * handler processes both the Tx and Rx virtqueue indices on every invocation.
 * The rproc_vq_interrupt function can detect if there are new unprocessed
 * messages or not (returns IRQ_NONE vs IRQ_HANDLED), but there is no need
 * to check for these return values. The index 0 triggering will process all
 * pending Rx buffers, and the index 1 triggering will process all newly
 * available Tx buffers and will wakeup any potentially blocked senders.
 *
 * NOTE:
 * 1. A payload could be added by using some of the source bits in the
 *    IPC interrupt generation registers, but this would need additional
 *    changes to the overall IPC stack, and currently there are no benefits
 *    of adapting that approach.
 * 2. The current logic is based on an inherent design assumption of supporting
 *    only 2 vrings, but this can be changed if needed.
 */
static void handle_event(struct work_struct *work)
{
        struct keystone_rproc *ksproc =
                container_of(work, struct keystone_rproc, workqueue);

        rproc_vq_interrupt(ksproc->rproc, 0);
        rproc_vq_interrupt(ksproc->rproc, 1);
}

/*
 * Interrupt handler for processing vring kicks from remote processor
 */
static irqreturn_t keystone_rproc_vring_interrupt(int irq, void *dev_id)
{
        struct keystone_rproc *ksproc = dev_id;

        schedule_work(&ksproc->workqueue);

        return IRQ_HANDLED;
}

/*
 * Power up the DSP remote processor.
 *
 * This function will be invoked only after the firmware for this rproc
 * was loaded, parsed successfully, and all of its resource requirements
 * were met.
 */
static int keystone_rproc_start(struct rproc *rproc)
{
        struct keystone_rproc *ksproc = rproc->priv;
        int ret;

        INIT_WORK(&ksproc->workqueue, handle_event);

        ret = request_irq(ksproc->irq_ring, keystone_rproc_vring_interrupt, 0,
                          dev_name(ksproc->dev), ksproc);
        if (ret) {
                dev_err(ksproc->dev, "failed to enable vring interrupt, ret = %d\n",
                        ret);
                goto out;
        }

        ret = request_irq(ksproc->irq_fault, keystone_rproc_exception_interrupt,
                          0, dev_name(ksproc->dev), ksproc);
        if (ret) {
                dev_err(ksproc->dev, "failed to enable exception interrupt, ret = %d\n",
                        ret);
                goto free_vring_irq;
        }

        ret = keystone_rproc_dsp_boot(ksproc, rproc->bootaddr);
        if (ret)
                goto free_exc_irq;

        return 0;

free_exc_irq:
        free_irq(ksproc->irq_fault, ksproc);
free_vring_irq:
        free_irq(ksproc->irq_ring, ksproc);
        flush_work(&ksproc->workqueue);
out:
        return ret;
}

/*
 * Stop the DSP remote processor.
 *
 * This function puts the DSP processor into reset, and finishes processing
 * of any pending messages.
 */
static int keystone_rproc_stop(struct rproc *rproc)
{
        struct keystone_rproc *ksproc = rproc->priv;

        keystone_rproc_dsp_reset(ksproc);
        free_irq(ksproc->irq_fault, ksproc);
        free_irq(ksproc->irq_ring, ksproc);
        flush_work(&ksproc->workqueue);

        return 0;
}

/*
 * Kick the remote processor to notify about pending unprocessed messages.
 * The vqid usage is not used and is inconsequential, as the kick is performed
 * through a simulated GPIO (a bit in an IPC interrupt-triggering register),
 * the remote processor is expected to process both its Tx and Rx virtqueues.
 */
static void keystone_rproc_kick(struct rproc *rproc, int vqid)
{
        struct keystone_rproc *ksproc = rproc->priv;

        if (WARN_ON(ksproc->kick_gpio < 0))
                return;

        gpio_set_value(ksproc->kick_gpio, 1);
}

/*
 * Custom function to translate a DSP device address (internal RAMs only) to a
 * kernel virtual address.  The DSPs can access their RAMs at either an internal
 * address visible only from a DSP, or at the SoC-level bus address. Both these
 * addresses need to be looked through for translation. The translated addresses
 * can be used either by the remoteproc core for loading (when using kernel
 * remoteproc loader), or by any rpmsg bus drivers.
 */
static void *keystone_rproc_da_to_va(struct rproc *rproc, u64 da, int len)
{
        struct keystone_rproc *ksproc = rproc->priv;
        void __iomem *va = NULL;
        phys_addr_t bus_addr;
        u32 dev_addr, offset;
        size_t size;
        int i;

        if (len <= 0)
                return NULL;

        for (i = 0; i < ksproc->num_mems; i++) {
                bus_addr = ksproc->mem[i].bus_addr;
                dev_addr = ksproc->mem[i].dev_addr;
                size = ksproc->mem[i].size;

                if (da < KEYSTONE_RPROC_LOCAL_ADDRESS_MASK) {
                        /* handle DSP-view addresses */
                        if ((da >= dev_addr) &&
                            ((da + len) <= (dev_addr + size))) {
                                offset = da - dev_addr;
                                va = ksproc->mem[i].cpu_addr + offset;
                                break;
                        }
                } else {
                        /* handle SoC-view addresses */
                        if ((da >= bus_addr) &&
                            (da + len) <= (bus_addr + size)) {
                                offset = da - bus_addr;
                                va = ksproc->mem[i].cpu_addr + offset;
                                break;
                        }
                }
        }

        return (__force void *)va;
}

static const struct rproc_ops keystone_rproc_ops = {
        .start          = keystone_rproc_start,
        .stop           = keystone_rproc_stop,
        .kick           = keystone_rproc_kick,
        .da_to_va       = keystone_rproc_da_to_va,
};

static int keystone_rproc_of_get_memories(struct platform_device *pdev,
                                          struct keystone_rproc *ksproc)
{
        static const char * const mem_names[] = {"l2sram", "l1pram", "l1dram"};
        struct device *dev = &pdev->dev;
        struct resource *res;
        int num_mems = 0;
        int i;

        num_mems = ARRAY_SIZE(mem_names);
        ksproc->mem = devm_kcalloc(ksproc->dev, num_mems,
                                   sizeof(*ksproc->mem), GFP_KERNEL);
        if (!ksproc->mem)
                return -ENOMEM;

        for (i = 0; i < num_mems; i++) {
                res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
                                                   mem_names[i]);
                ksproc->mem[i].cpu_addr = devm_ioremap_resource(dev, res);
                if (IS_ERR(ksproc->mem[i].cpu_addr)) {
                        dev_err(dev, "failed to parse and map %s memory\n",
                                mem_names[i]);
                        return PTR_ERR(ksproc->mem[i].cpu_addr);
                }
                ksproc->mem[i].bus_addr = res->start;
                ksproc->mem[i].dev_addr =
                                res->start & KEYSTONE_RPROC_LOCAL_ADDRESS_MASK;
                ksproc->mem[i].size = resource_size(res);

                /* zero out memories to start in a pristine state */
                memset((__force void *)ksproc->mem[i].cpu_addr, 0,
                       ksproc->mem[i].size);
        }
        ksproc->num_mems = num_mems;

        return 0;
}

static int keystone_rproc_of_get_dev_syscon(struct platform_device *pdev,
                                            struct keystone_rproc *ksproc)
{
        struct device_node *np = pdev->dev.of_node;
        struct device *dev = &pdev->dev;
        int ret;

        if (!of_property_read_bool(np, "ti,syscon-dev")) {
                dev_err(dev, "ti,syscon-dev property is absent\n");
                return -EINVAL;
        }

        ksproc->dev_ctrl =
                syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
        if (IS_ERR(ksproc->dev_ctrl)) {
                ret = PTR_ERR(ksproc->dev_ctrl);
                return ret;
        }

        if (of_property_read_u32_index(np, "ti,syscon-dev", 1,
                                       &ksproc->boot_offset)) {
                dev_err(dev, "couldn't read the boot register offset\n");
                return -EINVAL;
        }

        return 0;
}

static int keystone_rproc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct keystone_rproc *ksproc;
        struct rproc *rproc;
        int dsp_id;
        char *fw_name = NULL;
        char *template = "keystone-dsp%d-fw";
        int name_len = 0;
        int ret = 0;

        if (!np) {
                dev_err(dev, "only DT-based devices are supported\n");
                return -ENODEV;
        }

        dsp_id = of_alias_get_id(np, "rproc");
        if (dsp_id < 0) {
                dev_warn(dev, "device does not have an alias id\n");
                return dsp_id;
        }

        /* construct a custom default fw name - subject to change in future */
        name_len = strlen(template); /* assuming a single digit alias */
        fw_name = devm_kzalloc(dev, name_len, GFP_KERNEL);
        if (!fw_name)
                return -ENOMEM;
        snprintf(fw_name, name_len, template, dsp_id);

        rproc = rproc_alloc(dev, dev_name(dev), &keystone_rproc_ops, fw_name,
                            sizeof(*ksproc));
        if (!rproc)
                return -ENOMEM;

        rproc->has_iommu = false;
        ksproc = rproc->priv;
        ksproc->rproc = rproc;
        ksproc->dev = dev;

        ret = keystone_rproc_of_get_dev_syscon(pdev, ksproc);
        if (ret)
                goto free_rproc;

        ksproc->reset = devm_reset_control_get_exclusive(dev, NULL);
        if (IS_ERR(ksproc->reset)) {
                ret = PTR_ERR(ksproc->reset);
                goto free_rproc;
        }

        /* enable clock for accessing DSP internal memories */
        pm_runtime_enable(dev);
        ret = pm_runtime_get_sync(dev);
        if (ret < 0) {
                dev_err(dev, "failed to enable clock, status = %d\n", ret);
                pm_runtime_put_noidle(dev);
                goto disable_rpm;
        }

        ret = keystone_rproc_of_get_memories(pdev, ksproc);
        if (ret)
                goto disable_clk;

        ksproc->irq_ring = platform_get_irq_byname(pdev, "vring");
        if (ksproc->irq_ring < 0) {
                ret = ksproc->irq_ring;
                dev_err(dev, "failed to get vring interrupt, status = %d\n",
                        ret);
                goto disable_clk;
        }

        ksproc->irq_fault = platform_get_irq_byname(pdev, "exception");
        if (ksproc->irq_fault < 0) {
                ret = ksproc->irq_fault;
                dev_err(dev, "failed to get exception interrupt, status = %d\n",
                        ret);
                goto disable_clk;
        }

        ksproc->kick_gpio = of_get_named_gpio_flags(np, "kick-gpios", 0, NULL);
        if (ksproc->kick_gpio < 0) {
                ret = ksproc->kick_gpio;
                dev_err(dev, "failed to get gpio for virtio kicks, status = %d\n",
                        ret);
                goto disable_clk;
        }

        if (of_reserved_mem_device_init(dev))
                dev_warn(dev, "device does not have specific CMA pool\n");

        /* ensure the DSP is in reset before loading firmware */
        ret = reset_control_status(ksproc->reset);
        if (ret < 0) {
                dev_err(dev, "failed to get reset status, status = %d\n", ret);
                goto release_mem;
        } else if (ret == 0) {
                WARN(1, "device is not in reset\n");
                keystone_rproc_dsp_reset(ksproc);
        }

        ret = rproc_add(rproc);
        if (ret) {
                dev_err(dev, "failed to add register device with remoteproc core, status = %d\n",
                        ret);
                goto release_mem;
        }

        platform_set_drvdata(pdev, ksproc);

        return 0;

release_mem:
        of_reserved_mem_device_release(dev);
disable_clk:
        pm_runtime_put_sync(dev);
disable_rpm:
        pm_runtime_disable(dev);
free_rproc:
        rproc_free(rproc);
        return ret;
}

static int keystone_rproc_remove(struct platform_device *pdev)
{
        struct keystone_rproc *ksproc = platform_get_drvdata(pdev);

        rproc_del(ksproc->rproc);
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        rproc_free(ksproc->rproc);
        of_reserved_mem_device_release(&pdev->dev);

        return 0;
}

static const struct of_device_id keystone_rproc_of_match[] = {
        { .compatible = "ti,k2hk-dsp", },
        { .compatible = "ti,k2l-dsp", },
        { .compatible = "ti,k2e-dsp", },
        { .compatible = "ti,k2g-dsp", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, keystone_rproc_of_match);

static struct platform_driver keystone_rproc_driver = {
        .probe  = keystone_rproc_probe,
        .remove = keystone_rproc_remove,
        .driver = {
                .name = "keystone-rproc",
                .of_match_table = keystone_rproc_of_match,
        },
};

module_platform_driver(keystone_rproc_driver);

MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("TI Keystone DSP Remoteproc driver");