Merge tag 'nfs-for-4.1-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

[mirror_ubuntu-artful-kernel.git] / drivers / dma / dma-jz4740.c

/*
 *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
 *  JZ4740 DMAC support
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 */

#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/irq.h>
#include <linux/clk.h>

#include <asm/mach-jz4740/dma.h>

#include "virt-dma.h"

#define JZ_DMA_NR_CHANS 6

#define JZ_REG_DMA_SRC_ADDR(x)          (0x00 + (x) * 0x20)
#define JZ_REG_DMA_DST_ADDR(x)          (0x04 + (x) * 0x20)
#define JZ_REG_DMA_TRANSFER_COUNT(x)    (0x08 + (x) * 0x20)
#define JZ_REG_DMA_REQ_TYPE(x)          (0x0C + (x) * 0x20)
#define JZ_REG_DMA_STATUS_CTRL(x)       (0x10 + (x) * 0x20)
#define JZ_REG_DMA_CMD(x)               (0x14 + (x) * 0x20)
#define JZ_REG_DMA_DESC_ADDR(x)         (0x18 + (x) * 0x20)

#define JZ_REG_DMA_CTRL                 0x300
#define JZ_REG_DMA_IRQ                  0x304
#define JZ_REG_DMA_DOORBELL             0x308
#define JZ_REG_DMA_DOORBELL_SET         0x30C

#define JZ_DMA_STATUS_CTRL_NO_DESC              BIT(31)
#define JZ_DMA_STATUS_CTRL_DESC_INV             BIT(6)
#define JZ_DMA_STATUS_CTRL_ADDR_ERR             BIT(4)
#define JZ_DMA_STATUS_CTRL_TRANSFER_DONE        BIT(3)
#define JZ_DMA_STATUS_CTRL_HALT                 BIT(2)
#define JZ_DMA_STATUS_CTRL_COUNT_TERMINATE      BIT(1)
#define JZ_DMA_STATUS_CTRL_ENABLE               BIT(0)

#define JZ_DMA_CMD_SRC_INC                      BIT(23)
#define JZ_DMA_CMD_DST_INC                      BIT(22)
#define JZ_DMA_CMD_RDIL_MASK                    (0xf << 16)
#define JZ_DMA_CMD_SRC_WIDTH_MASK               (0x3 << 14)
#define JZ_DMA_CMD_DST_WIDTH_MASK               (0x3 << 12)
#define JZ_DMA_CMD_INTERVAL_LENGTH_MASK         (0x7 << 8)
#define JZ_DMA_CMD_BLOCK_MODE                   BIT(7)
#define JZ_DMA_CMD_DESC_VALID                   BIT(4)
#define JZ_DMA_CMD_DESC_VALID_MODE              BIT(3)
#define JZ_DMA_CMD_VALID_IRQ_ENABLE             BIT(2)
#define JZ_DMA_CMD_TRANSFER_IRQ_ENABLE          BIT(1)
#define JZ_DMA_CMD_LINK_ENABLE                  BIT(0)

#define JZ_DMA_CMD_FLAGS_OFFSET 22
#define JZ_DMA_CMD_RDIL_OFFSET 16
#define JZ_DMA_CMD_SRC_WIDTH_OFFSET 14
#define JZ_DMA_CMD_DST_WIDTH_OFFSET 12
#define JZ_DMA_CMD_TRANSFER_SIZE_OFFSET 8
#define JZ_DMA_CMD_MODE_OFFSET 7

#define JZ_DMA_CTRL_PRIORITY_MASK               (0x3 << 8)
#define JZ_DMA_CTRL_HALT                        BIT(3)
#define JZ_DMA_CTRL_ADDRESS_ERROR               BIT(2)
#define JZ_DMA_CTRL_ENABLE                      BIT(0)

enum jz4740_dma_width {
        JZ4740_DMA_WIDTH_32BIT  = 0,
        JZ4740_DMA_WIDTH_8BIT   = 1,
        JZ4740_DMA_WIDTH_16BIT  = 2,
};

enum jz4740_dma_transfer_size {
        JZ4740_DMA_TRANSFER_SIZE_4BYTE  = 0,
        JZ4740_DMA_TRANSFER_SIZE_1BYTE  = 1,
        JZ4740_DMA_TRANSFER_SIZE_2BYTE  = 2,
        JZ4740_DMA_TRANSFER_SIZE_16BYTE = 3,
        JZ4740_DMA_TRANSFER_SIZE_32BYTE = 4,
};

enum jz4740_dma_flags {
        JZ4740_DMA_SRC_AUTOINC = 0x2,
        JZ4740_DMA_DST_AUTOINC = 0x1,
};

enum jz4740_dma_mode {
        JZ4740_DMA_MODE_SINGLE  = 0,
        JZ4740_DMA_MODE_BLOCK   = 1,
};

struct jz4740_dma_sg {
        dma_addr_t addr;
        unsigned int len;
};

struct jz4740_dma_desc {
        struct virt_dma_desc vdesc;

        enum dma_transfer_direction direction;
        bool cyclic;

        unsigned int num_sgs;
        struct jz4740_dma_sg sg[];
};

struct jz4740_dmaengine_chan {
        struct virt_dma_chan vchan;
        unsigned int id;

        dma_addr_t fifo_addr;
        unsigned int transfer_shift;

        struct jz4740_dma_desc *desc;
        unsigned int next_sg;
};

struct jz4740_dma_dev {
        struct dma_device ddev;
        void __iomem *base;
        struct clk *clk;

        struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
};

static struct jz4740_dma_dev *jz4740_dma_chan_get_dev(
        struct jz4740_dmaengine_chan *chan)
{
        return container_of(chan->vchan.chan.device, struct jz4740_dma_dev,
                ddev);
}

static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
{
        return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
}

static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
{
        return container_of(vdesc, struct jz4740_dma_desc, vdesc);
}

static inline uint32_t jz4740_dma_read(struct jz4740_dma_dev *dmadev,
        unsigned int reg)
{
        return readl(dmadev->base + reg);
}

static inline void jz4740_dma_write(struct jz4740_dma_dev *dmadev,
        unsigned reg, uint32_t val)
{
        writel(val, dmadev->base + reg);
}

static inline void jz4740_dma_write_mask(struct jz4740_dma_dev *dmadev,
        unsigned int reg, uint32_t val, uint32_t mask)
{
        uint32_t tmp;

        tmp = jz4740_dma_read(dmadev, reg);
        tmp &= ~mask;
        tmp |= val;
        jz4740_dma_write(dmadev, reg, tmp);
}

static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
{
        return kzalloc(sizeof(struct jz4740_dma_desc) +
                sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
}

static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
{
        switch (width) {
        case DMA_SLAVE_BUSWIDTH_1_BYTE:
                return JZ4740_DMA_WIDTH_8BIT;
        case DMA_SLAVE_BUSWIDTH_2_BYTES:
                return JZ4740_DMA_WIDTH_16BIT;
        case DMA_SLAVE_BUSWIDTH_4_BYTES:
                return JZ4740_DMA_WIDTH_32BIT;
        default:
                return JZ4740_DMA_WIDTH_32BIT;
        }
}

static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
{
        if (maxburst <= 1)
                return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
        else if (maxburst <= 3)
                return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
        else if (maxburst <= 15)
                return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
        else if (maxburst <= 31)
                return JZ4740_DMA_TRANSFER_SIZE_16BYTE;

        return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
}

static int jz4740_dma_slave_config(struct dma_chan *c,
                                   struct dma_slave_config *config)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
        enum jz4740_dma_width src_width;
        enum jz4740_dma_width dst_width;
        enum jz4740_dma_transfer_size transfer_size;
        enum jz4740_dma_flags flags;
        uint32_t cmd;

        switch (config->direction) {
        case DMA_MEM_TO_DEV:
                flags = JZ4740_DMA_SRC_AUTOINC;
                transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
                chan->fifo_addr = config->dst_addr;
                break;
        case DMA_DEV_TO_MEM:
                flags = JZ4740_DMA_DST_AUTOINC;
                transfer_size = jz4740_dma_maxburst(config->src_maxburst);
                chan->fifo_addr = config->src_addr;
                break;
        default:
                return -EINVAL;
        }

        src_width = jz4740_dma_width(config->src_addr_width);
        dst_width = jz4740_dma_width(config->dst_addr_width);

        switch (transfer_size) {
        case JZ4740_DMA_TRANSFER_SIZE_2BYTE:
                chan->transfer_shift = 1;
                break;
        case JZ4740_DMA_TRANSFER_SIZE_4BYTE:
                chan->transfer_shift = 2;
                break;
        case JZ4740_DMA_TRANSFER_SIZE_16BYTE:
                chan->transfer_shift = 4;
                break;
        case JZ4740_DMA_TRANSFER_SIZE_32BYTE:
                chan->transfer_shift = 5;
                break;
        default:
                chan->transfer_shift = 0;
                break;
        }

        cmd = flags << JZ_DMA_CMD_FLAGS_OFFSET;
        cmd |= src_width << JZ_DMA_CMD_SRC_WIDTH_OFFSET;
        cmd |= dst_width << JZ_DMA_CMD_DST_WIDTH_OFFSET;
        cmd |= transfer_size << JZ_DMA_CMD_TRANSFER_SIZE_OFFSET;
        cmd |= JZ4740_DMA_MODE_SINGLE << JZ_DMA_CMD_MODE_OFFSET;
        cmd |= JZ_DMA_CMD_TRANSFER_IRQ_ENABLE;

        jz4740_dma_write(dmadev, JZ_REG_DMA_CMD(chan->id), cmd);
        jz4740_dma_write(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0);
        jz4740_dma_write(dmadev, JZ_REG_DMA_REQ_TYPE(chan->id),
                config->slave_id);

        return 0;
}

static int jz4740_dma_terminate_all(struct dma_chan *c)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&chan->vchan.lock, flags);
        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
                        JZ_DMA_STATUS_CTRL_ENABLE);
        chan->desc = NULL;
        vchan_get_all_descriptors(&chan->vchan, &head);
        spin_unlock_irqrestore(&chan->vchan.lock, flags);

        vchan_dma_desc_free_list(&chan->vchan, &head);

        return 0;
}

static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
{
        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
        dma_addr_t src_addr, dst_addr;
        struct virt_dma_desc *vdesc;
        struct jz4740_dma_sg *sg;

        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
                        JZ_DMA_STATUS_CTRL_ENABLE);

        if (!chan->desc) {
                vdesc = vchan_next_desc(&chan->vchan);
                if (!vdesc)
                        return 0;
                chan->desc = to_jz4740_dma_desc(vdesc);
                chan->next_sg = 0;
        }

        if (chan->next_sg == chan->desc->num_sgs)
                chan->next_sg = 0;

        sg = &chan->desc->sg[chan->next_sg];

        if (chan->desc->direction == DMA_MEM_TO_DEV) {
                src_addr = sg->addr;
                dst_addr = chan->fifo_addr;
        } else {
                src_addr = chan->fifo_addr;
                dst_addr = sg->addr;
        }
        jz4740_dma_write(dmadev, JZ_REG_DMA_SRC_ADDR(chan->id), src_addr);
        jz4740_dma_write(dmadev, JZ_REG_DMA_DST_ADDR(chan->id), dst_addr);
        jz4740_dma_write(dmadev, JZ_REG_DMA_TRANSFER_COUNT(chan->id),
                        sg->len >> chan->transfer_shift);

        chan->next_sg++;

        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id),
                        JZ_DMA_STATUS_CTRL_NO_DESC | JZ_DMA_STATUS_CTRL_ENABLE,
                        JZ_DMA_STATUS_CTRL_HALT | JZ_DMA_STATUS_CTRL_NO_DESC |
                        JZ_DMA_STATUS_CTRL_ENABLE);

        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_CTRL,
                        JZ_DMA_CTRL_ENABLE,
                        JZ_DMA_CTRL_HALT | JZ_DMA_CTRL_ENABLE);

        return 0;
}

static void jz4740_dma_chan_irq(struct jz4740_dmaengine_chan *chan)
{
        spin_lock(&chan->vchan.lock);
        if (chan->desc) {
                if (chan->desc->cyclic) {
                        vchan_cyclic_callback(&chan->desc->vdesc);
                } else {
                        if (chan->next_sg == chan->desc->num_sgs) {
                                list_del(&chan->desc->vdesc.node);
                                vchan_cookie_complete(&chan->desc->vdesc);
                                chan->desc = NULL;
                        }
                }
        }
        jz4740_dma_start_transfer(chan);
        spin_unlock(&chan->vchan.lock);
}

static irqreturn_t jz4740_dma_irq(int irq, void *devid)
{
        struct jz4740_dma_dev *dmadev = devid;
        uint32_t irq_status;
        unsigned int i;

        irq_status = readl(dmadev->base + JZ_REG_DMA_IRQ);

        for (i = 0; i < 6; ++i) {
                if (irq_status & (1 << i)) {
                        jz4740_dma_write_mask(dmadev,
                                JZ_REG_DMA_STATUS_CTRL(i), 0,
                                JZ_DMA_STATUS_CTRL_ENABLE |
                                JZ_DMA_STATUS_CTRL_TRANSFER_DONE);

                        jz4740_dma_chan_irq(&dmadev->chan[i]);
                }
        }

        return IRQ_HANDLED;
}

static void jz4740_dma_issue_pending(struct dma_chan *c)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        unsigned long flags;

        spin_lock_irqsave(&chan->vchan.lock, flags);
        if (vchan_issue_pending(&chan->vchan) && !chan->desc)
                jz4740_dma_start_transfer(chan);
        spin_unlock_irqrestore(&chan->vchan.lock, flags);
}

static struct dma_async_tx_descriptor *jz4740_dma_prep_slave_sg(
        struct dma_chan *c, struct scatterlist *sgl,
        unsigned int sg_len, enum dma_transfer_direction direction,
        unsigned long flags, void *context)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        struct jz4740_dma_desc *desc;
        struct scatterlist *sg;
        unsigned int i;

        desc = jz4740_dma_alloc_desc(sg_len);
        if (!desc)
                return NULL;

        for_each_sg(sgl, sg, sg_len, i) {
                desc->sg[i].addr = sg_dma_address(sg);
                desc->sg[i].len = sg_dma_len(sg);
        }

        desc->num_sgs = sg_len;
        desc->direction = direction;
        desc->cyclic = false;

        return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
}

static struct dma_async_tx_descriptor *jz4740_dma_prep_dma_cyclic(
        struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
        size_t period_len, enum dma_transfer_direction direction,
        unsigned long flags)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        struct jz4740_dma_desc *desc;
        unsigned int num_periods, i;

        if (buf_len % period_len)
                return NULL;

        num_periods = buf_len / period_len;

        desc = jz4740_dma_alloc_desc(num_periods);
        if (!desc)
                return NULL;

        for (i = 0; i < num_periods; i++) {
                desc->sg[i].addr = buf_addr;
                desc->sg[i].len = period_len;
                buf_addr += period_len;
        }

        desc->num_sgs = num_periods;
        desc->direction = direction;
        desc->cyclic = true;

        return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
}

static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
        struct jz4740_dma_desc *desc, unsigned int next_sg)
{
        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
        unsigned int residue, count;
        unsigned int i;

        residue = 0;

        for (i = next_sg; i < desc->num_sgs; i++)
                residue += desc->sg[i].len;

        if (next_sg != 0) {
                count = jz4740_dma_read(dmadev,
                        JZ_REG_DMA_TRANSFER_COUNT(chan->id));
                residue += count << chan->transfer_shift;
        }

        return residue;
}

static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
        dma_cookie_t cookie, struct dma_tx_state *state)
{
        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
        struct virt_dma_desc *vdesc;
        enum dma_status status;
        unsigned long flags;

        status = dma_cookie_status(c, cookie, state);
        if (status == DMA_COMPLETE || !state)
                return status;

        spin_lock_irqsave(&chan->vchan.lock, flags);
        vdesc = vchan_find_desc(&chan->vchan, cookie);
        if (cookie == chan->desc->vdesc.tx.cookie) {
                state->residue = jz4740_dma_desc_residue(chan, chan->desc,
                                chan->next_sg);
        } else if (vdesc) {
                state->residue = jz4740_dma_desc_residue(chan,
                                to_jz4740_dma_desc(vdesc), 0);
        } else {
                state->residue = 0;
        }
        spin_unlock_irqrestore(&chan->vchan.lock, flags);

        return status;
}

static void jz4740_dma_free_chan_resources(struct dma_chan *c)
{
        vchan_free_chan_resources(to_virt_chan(c));
}

static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
{
        kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
}

#define JZ4740_DMA_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
        BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))

static int jz4740_dma_probe(struct platform_device *pdev)
{
        struct jz4740_dmaengine_chan *chan;
        struct jz4740_dma_dev *dmadev;
        struct dma_device *dd;
        unsigned int i;
        struct resource *res;
        int ret;
        int irq;

        dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
        if (!dmadev)
                return -EINVAL;

        dd = &dmadev->ddev;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        dmadev->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(dmadev->base))
                return PTR_ERR(dmadev->base);

        dmadev->clk = clk_get(&pdev->dev, "dma");
        if (IS_ERR(dmadev->clk))
                return PTR_ERR(dmadev->clk);

        clk_prepare_enable(dmadev->clk);

        dma_cap_set(DMA_SLAVE, dd->cap_mask);
        dma_cap_set(DMA_CYCLIC, dd->cap_mask);
        dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
        dd->device_tx_status = jz4740_dma_tx_status;
        dd->device_issue_pending = jz4740_dma_issue_pending;
        dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
        dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
        dd->device_config = jz4740_dma_slave_config;
        dd->device_terminate_all = jz4740_dma_terminate_all;
        dd->src_addr_widths = JZ4740_DMA_BUSWIDTHS;
        dd->dst_addr_widths = JZ4740_DMA_BUSWIDTHS;
        dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
        dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
        dd->dev = &pdev->dev;
        INIT_LIST_HEAD(&dd->channels);

        for (i = 0; i < JZ_DMA_NR_CHANS; i++) {
                chan = &dmadev->chan[i];
                chan->id = i;
                chan->vchan.desc_free = jz4740_dma_desc_free;
                vchan_init(&chan->vchan, dd);
        }

        ret = dma_async_device_register(dd);
        if (ret)
                return ret;

        irq = platform_get_irq(pdev, 0);
        ret = request_irq(irq, jz4740_dma_irq, 0, dev_name(&pdev->dev), dmadev);
        if (ret)
                goto err_unregister;

        platform_set_drvdata(pdev, dmadev);

        return 0;

err_unregister:
        dma_async_device_unregister(dd);
        return ret;
}

static int jz4740_dma_remove(struct platform_device *pdev)
{
        struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
        int irq = platform_get_irq(pdev, 0);

        free_irq(irq, dmadev);
        dma_async_device_unregister(&dmadev->ddev);
        clk_disable_unprepare(dmadev->clk);

        return 0;
}

static struct platform_driver jz4740_dma_driver = {
        .probe = jz4740_dma_probe,
        .remove = jz4740_dma_remove,
        .driver = {
                .name = "jz4740-dma",
        },
};
module_platform_driver(jz4740_dma_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("JZ4740 DMA driver");
MODULE_LICENSE("GPL v2");