root/drivers/mtd/hyperbus/hbmc-am654.c
// SPDX-License-Identifier: GPL-2.0
//
// Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com/
// Author: Vignesh Raghavendra <vigneshr@ti.com>

#include <linux/completion.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtd/cfi.h>
#include <linux/mtd/hyperbus.h>
#include <linux/mtd/mtd.h>
#include <linux/mux/consumer.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/sched/task_stack.h>
#include <linux/types.h>

#define AM654_HBMC_CALIB_COUNT 25

struct am654_hbmc_device_priv {
        struct completion rx_dma_complete;
        phys_addr_t device_base;
        struct hyperbus_ctlr *ctlr;
        struct dma_chan *rx_chan;
};

struct am654_hbmc_priv {
        struct hyperbus_ctlr ctlr;
        struct hyperbus_device hbdev;
        struct mux_control *mux_ctrl;
};

static int am654_hbmc_calibrate(struct hyperbus_device *hbdev)
{
        struct map_info *map = &hbdev->map;
        struct cfi_private cfi;
        int count = AM654_HBMC_CALIB_COUNT;
        int pass_count = 0;
        int ret;

        cfi.interleave = 1;
        cfi.device_type = CFI_DEVICETYPE_X16;
        cfi_send_gen_cmd(0xF0, 0, 0, map, &cfi, cfi.device_type, NULL);
        cfi_send_gen_cmd(0x98, 0x55, 0, map, &cfi, cfi.device_type, NULL);

        while (count--) {
                ret = cfi_qry_present(map, 0, &cfi);
                if (ret)
                        pass_count++;
                else
                        pass_count = 0;
                if (pass_count == 5)
                        break;
        }

        cfi_qry_mode_off(0, map, &cfi);

        return ret;
}

static void am654_hbmc_dma_callback(void *param)
{
        struct am654_hbmc_device_priv *priv = param;

        complete(&priv->rx_dma_complete);
}

static int am654_hbmc_dma_read(struct am654_hbmc_device_priv *priv, void *to,
                               unsigned long from, ssize_t len)

{
        enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
        struct dma_chan *rx_chan = priv->rx_chan;
        struct dma_async_tx_descriptor *tx;
        dma_addr_t dma_dst, dma_src;
        dma_cookie_t cookie;
        int ret;

        if (!priv->rx_chan || !virt_addr_valid(to) || object_is_on_stack(to))
                return -EINVAL;

        dma_dst = dma_map_single(rx_chan->device->dev, to, len, DMA_FROM_DEVICE);
        if (dma_mapping_error(rx_chan->device->dev, dma_dst)) {
                dev_dbg(priv->ctlr->dev, "DMA mapping failed\n");
                return -EIO;
        }

        dma_src = priv->device_base + from;
        tx = dmaengine_prep_dma_memcpy(rx_chan, dma_dst, dma_src, len, flags);
        if (!tx) {
                dev_err(priv->ctlr->dev, "device_prep_dma_memcpy error\n");
                ret = -EIO;
                goto unmap_dma;
        }

        reinit_completion(&priv->rx_dma_complete);
        tx->callback = am654_hbmc_dma_callback;
        tx->callback_param = priv;
        cookie = dmaengine_submit(tx);

        ret = dma_submit_error(cookie);
        if (ret) {
                dev_err(priv->ctlr->dev, "dma_submit_error %d\n", cookie);
                goto unmap_dma;
        }

        dma_async_issue_pending(rx_chan);
        if (!wait_for_completion_timeout(&priv->rx_dma_complete,  msecs_to_jiffies(len + 1000))) {
                dmaengine_terminate_sync(rx_chan);
                dev_err(priv->ctlr->dev, "DMA wait_for_completion_timeout\n");
                ret = -ETIMEDOUT;
        }

unmap_dma:
        dma_unmap_single(rx_chan->device->dev, dma_dst, len, DMA_FROM_DEVICE);
        return ret;
}

static void am654_hbmc_read(struct hyperbus_device *hbdev, void *to,
                            unsigned long from, ssize_t len)
{
        struct am654_hbmc_device_priv *priv = hbdev->priv;

        if (len < SZ_1K || am654_hbmc_dma_read(priv, to, from, len))
                memcpy_fromio(to, hbdev->map.virt + from, len);
}

static const struct hyperbus_ops am654_hbmc_ops = {
        .calibrate = am654_hbmc_calibrate,
        .copy_from = am654_hbmc_read,
};

static int am654_hbmc_request_mmap_dma(struct am654_hbmc_device_priv *priv)
{
        struct dma_chan *rx_chan;
        dma_cap_mask_t mask;

        dma_cap_zero(mask);
        dma_cap_set(DMA_MEMCPY, mask);

        rx_chan = dma_request_chan_by_mask(&mask);
        if (IS_ERR(rx_chan)) {
                if (PTR_ERR(rx_chan) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;
                dev_dbg(priv->ctlr->dev, "No DMA channel available\n");
                return 0;
        }
        priv->rx_chan = rx_chan;
        init_completion(&priv->rx_dma_complete);

        return 0;
}

static int am654_hbmc_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct am654_hbmc_device_priv *dev_priv;
        struct device *dev = &pdev->dev;
        struct am654_hbmc_priv *priv;
        struct resource res;
        int ret;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        platform_set_drvdata(pdev, priv);

        priv->hbdev.np = of_get_next_child(np, NULL);
        ret = of_address_to_resource(priv->hbdev.np, 0, &res);
        if (ret)
                goto put_node;

        if (of_property_present(dev->of_node, "mux-controls")) {
                struct mux_control *control = devm_mux_control_get(dev, NULL);

                if (IS_ERR(control)) {
                        ret = PTR_ERR(control);
                        goto put_node;
                }

                ret = mux_control_select(control, 1);
                if (ret) {
                        dev_err(dev, "Failed to select HBMC mux\n");
                        goto put_node;
                }
                priv->mux_ctrl = control;
        }

        priv->hbdev.map.size = resource_size(&res);
        priv->hbdev.map.virt = devm_ioremap_resource(dev, &res);
        if (IS_ERR(priv->hbdev.map.virt)) {
                ret = PTR_ERR(priv->hbdev.map.virt);
                goto disable_mux;
        }

        priv->ctlr.dev = dev;
        priv->ctlr.ops = &am654_hbmc_ops;
        priv->hbdev.ctlr = &priv->ctlr;

        dev_priv = devm_kzalloc(dev, sizeof(*dev_priv), GFP_KERNEL);
        if (!dev_priv) {
                ret = -ENOMEM;
                goto disable_mux;
        }

        priv->hbdev.priv = dev_priv;
        dev_priv->device_base = res.start;
        dev_priv->ctlr = &priv->ctlr;

        ret = am654_hbmc_request_mmap_dma(dev_priv);
        if (ret)
                goto disable_mux;

        ret = hyperbus_register_device(&priv->hbdev);
        if (ret) {
                dev_err(dev, "failed to register controller\n");
                goto release_dma;
        }

        return 0;
release_dma:
        if (dev_priv->rx_chan)
                dma_release_channel(dev_priv->rx_chan);
disable_mux:
        if (priv->mux_ctrl)
                mux_control_deselect(priv->mux_ctrl);
put_node:
        of_node_put(priv->hbdev.np);
        return ret;
}

static void am654_hbmc_remove(struct platform_device *pdev)
{
        struct am654_hbmc_priv *priv = platform_get_drvdata(pdev);
        struct am654_hbmc_device_priv *dev_priv = priv->hbdev.priv;

        hyperbus_unregister_device(&priv->hbdev);

        if (priv->mux_ctrl)
                mux_control_deselect(priv->mux_ctrl);

        if (dev_priv->rx_chan)
                dma_release_channel(dev_priv->rx_chan);
        of_node_put(priv->hbdev.np);
}

static const struct of_device_id am654_hbmc_dt_ids[] = {
        {
                .compatible = "ti,am654-hbmc",
        },
        { /* end of table */ }
};

MODULE_DEVICE_TABLE(of, am654_hbmc_dt_ids);

static struct platform_driver am654_hbmc_platform_driver = {
        .probe = am654_hbmc_probe,
        .remove = am654_hbmc_remove,
        .driver = {
                .name = "hbmc-am654",
                .of_match_table = am654_hbmc_dt_ids,
        },
};

module_platform_driver(am654_hbmc_platform_driver);

MODULE_DESCRIPTION("HBMC driver for AM654 SoC");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Vignesh Raghavendra <vigneshr@ti.com>");