IB/core: Add mitigation for Spectre V1

[linux/fpc-iii.git] / drivers / dma / cppi41.c

#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/of_dma.h>
#include <linux/of_irq.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
#include <linux/of_address.h>
#include <linux/pm_runtime.h>
#include "dmaengine.h"

#define DESC_TYPE       27
#define DESC_TYPE_HOST  0x10
#define DESC_TYPE_TEARD 0x13

#define TD_DESC_IS_RX   (1 << 16)
#define TD_DESC_DMA_NUM 10

#define DESC_LENGTH_BITS_NUM    21

#define DESC_TYPE_USB   (5 << 26)
#define DESC_PD_COMPLETE        (1 << 31)

/* DMA engine */
#define DMA_TDFDQ       4
#define DMA_TXGCR(x)    (0x800 + (x) * 0x20)
#define DMA_RXGCR(x)    (0x808 + (x) * 0x20)
#define RXHPCRA0                4

#define GCR_CHAN_ENABLE         (1 << 31)
#define GCR_TEARDOWN            (1 << 30)
#define GCR_STARV_RETRY         (1 << 24)
#define GCR_DESC_TYPE_HOST      (1 << 14)

/* DMA scheduler */
#define DMA_SCHED_CTRL          0
#define DMA_SCHED_CTRL_EN       (1 << 31)
#define DMA_SCHED_WORD(x)       ((x) * 4 + 0x800)

#define SCHED_ENTRY0_CHAN(x)    ((x) << 0)
#define SCHED_ENTRY0_IS_RX      (1 << 7)

#define SCHED_ENTRY1_CHAN(x)    ((x) << 8)
#define SCHED_ENTRY1_IS_RX      (1 << 15)

#define SCHED_ENTRY2_CHAN(x)    ((x) << 16)
#define SCHED_ENTRY2_IS_RX      (1 << 23)

#define SCHED_ENTRY3_CHAN(x)    ((x) << 24)
#define SCHED_ENTRY3_IS_RX      (1 << 31)

/* Queue manager */
/* 4 KiB of memory for descriptors, 2 for each endpoint */
#define ALLOC_DECS_NUM          128
#define DESCS_AREAS             1
#define TOTAL_DESCS_NUM         (ALLOC_DECS_NUM * DESCS_AREAS)
#define QMGR_SCRATCH_SIZE       (TOTAL_DESCS_NUM * 4)

#define QMGR_LRAM0_BASE         0x80
#define QMGR_LRAM_SIZE          0x84
#define QMGR_LRAM1_BASE         0x88
#define QMGR_MEMBASE(x)         (0x1000 + (x) * 0x10)
#define QMGR_MEMCTRL(x)         (0x1004 + (x) * 0x10)
#define QMGR_MEMCTRL_IDX_SH     16
#define QMGR_MEMCTRL_DESC_SH    8

#define QMGR_NUM_PEND   5
#define QMGR_PEND(x)    (0x90 + (x) * 4)

#define QMGR_PENDING_SLOT_Q(x)  (x / 32)
#define QMGR_PENDING_BIT_Q(x)   (x % 32)

#define QMGR_QUEUE_A(n) (0x2000 + (n) * 0x10)
#define QMGR_QUEUE_B(n) (0x2004 + (n) * 0x10)
#define QMGR_QUEUE_C(n) (0x2008 + (n) * 0x10)
#define QMGR_QUEUE_D(n) (0x200c + (n) * 0x10)

/* Glue layer specific */
/* USBSS  / USB AM335x */
#define USBSS_IRQ_STATUS        0x28
#define USBSS_IRQ_ENABLER       0x2c
#define USBSS_IRQ_CLEARR        0x30

#define USBSS_IRQ_PD_COMP       (1 <<  2)

/* Packet Descriptor */
#define PD2_ZERO_LENGTH         (1 << 19)

struct cppi41_channel {
        struct dma_chan chan;
        struct dma_async_tx_descriptor txd;
        struct cppi41_dd *cdd;
        struct cppi41_desc *desc;
        dma_addr_t desc_phys;
        void __iomem *gcr_reg;
        int is_tx;
        u32 residue;

        unsigned int q_num;
        unsigned int q_comp_num;
        unsigned int port_num;

        unsigned td_retry;
        unsigned td_queued:1;
        unsigned td_seen:1;
        unsigned td_desc_seen:1;

        struct list_head node;          /* Node for pending list */
};

struct cppi41_desc {
        u32 pd0;
        u32 pd1;
        u32 pd2;
        u32 pd3;
        u32 pd4;
        u32 pd5;
        u32 pd6;
        u32 pd7;
} __aligned(32);

struct chan_queues {
        u16 submit;
        u16 complete;
};

struct cppi41_dd {
        struct dma_device ddev;

        void *qmgr_scratch;
        dma_addr_t scratch_phys;

        struct cppi41_desc *cd;
        dma_addr_t descs_phys;
        u32 first_td_desc;
        struct cppi41_channel *chan_busy[ALLOC_DECS_NUM];

        void __iomem *usbss_mem;
        void __iomem *ctrl_mem;
        void __iomem *sched_mem;
        void __iomem *qmgr_mem;
        unsigned int irq;
        const struct chan_queues *queues_rx;
        const struct chan_queues *queues_tx;
        struct chan_queues td_queue;

        struct list_head pending;       /* Pending queued transfers */
        spinlock_t lock;                /* Lock for pending list */

        /* context for suspend/resume */
        unsigned int dma_tdfdq;

        bool is_suspended;
};

#define FIST_COMPLETION_QUEUE   93
static struct chan_queues usb_queues_tx[] = {
        /* USB0 ENDP 1 */
        [ 0] = { .submit = 32, .complete =  93},
        [ 1] = { .submit = 34, .complete =  94},
        [ 2] = { .submit = 36, .complete =  95},
        [ 3] = { .submit = 38, .complete =  96},
        [ 4] = { .submit = 40, .complete =  97},
        [ 5] = { .submit = 42, .complete =  98},
        [ 6] = { .submit = 44, .complete =  99},
        [ 7] = { .submit = 46, .complete = 100},
        [ 8] = { .submit = 48, .complete = 101},
        [ 9] = { .submit = 50, .complete = 102},
        [10] = { .submit = 52, .complete = 103},
        [11] = { .submit = 54, .complete = 104},
        [12] = { .submit = 56, .complete = 105},
        [13] = { .submit = 58, .complete = 106},
        [14] = { .submit = 60, .complete = 107},

        /* USB1 ENDP1 */
        [15] = { .submit = 62, .complete = 125},
        [16] = { .submit = 64, .complete = 126},
        [17] = { .submit = 66, .complete = 127},
        [18] = { .submit = 68, .complete = 128},
        [19] = { .submit = 70, .complete = 129},
        [20] = { .submit = 72, .complete = 130},
        [21] = { .submit = 74, .complete = 131},
        [22] = { .submit = 76, .complete = 132},
        [23] = { .submit = 78, .complete = 133},
        [24] = { .submit = 80, .complete = 134},
        [25] = { .submit = 82, .complete = 135},
        [26] = { .submit = 84, .complete = 136},
        [27] = { .submit = 86, .complete = 137},
        [28] = { .submit = 88, .complete = 138},
        [29] = { .submit = 90, .complete = 139},
};

static const struct chan_queues usb_queues_rx[] = {
        /* USB0 ENDP 1 */
        [ 0] = { .submit =  1, .complete = 109},
        [ 1] = { .submit =  2, .complete = 110},
        [ 2] = { .submit =  3, .complete = 111},
        [ 3] = { .submit =  4, .complete = 112},
        [ 4] = { .submit =  5, .complete = 113},
        [ 5] = { .submit =  6, .complete = 114},
        [ 6] = { .submit =  7, .complete = 115},
        [ 7] = { .submit =  8, .complete = 116},
        [ 8] = { .submit =  9, .complete = 117},
        [ 9] = { .submit = 10, .complete = 118},
        [10] = { .submit = 11, .complete = 119},
        [11] = { .submit = 12, .complete = 120},
        [12] = { .submit = 13, .complete = 121},
        [13] = { .submit = 14, .complete = 122},
        [14] = { .submit = 15, .complete = 123},

        /* USB1 ENDP 1 */
        [15] = { .submit = 16, .complete = 141},
        [16] = { .submit = 17, .complete = 142},
        [17] = { .submit = 18, .complete = 143},
        [18] = { .submit = 19, .complete = 144},
        [19] = { .submit = 20, .complete = 145},
        [20] = { .submit = 21, .complete = 146},
        [21] = { .submit = 22, .complete = 147},
        [22] = { .submit = 23, .complete = 148},
        [23] = { .submit = 24, .complete = 149},
        [24] = { .submit = 25, .complete = 150},
        [25] = { .submit = 26, .complete = 151},
        [26] = { .submit = 27, .complete = 152},
        [27] = { .submit = 28, .complete = 153},
        [28] = { .submit = 29, .complete = 154},
        [29] = { .submit = 30, .complete = 155},
};

struct cppi_glue_infos {
        irqreturn_t (*isr)(int irq, void *data);
        const struct chan_queues *queues_rx;
        const struct chan_queues *queues_tx;
        struct chan_queues td_queue;
};

static struct cppi41_channel *to_cpp41_chan(struct dma_chan *c)
{
        return container_of(c, struct cppi41_channel, chan);
}

static struct cppi41_channel *desc_to_chan(struct cppi41_dd *cdd, u32 desc)
{
        struct cppi41_channel *c;
        u32 descs_size;
        u32 desc_num;

        descs_size = sizeof(struct cppi41_desc) * ALLOC_DECS_NUM;

        if (!((desc >= cdd->descs_phys) &&
                        (desc < (cdd->descs_phys + descs_size)))) {
                return NULL;
        }

        desc_num = (desc - cdd->descs_phys) / sizeof(struct cppi41_desc);
        BUG_ON(desc_num >= ALLOC_DECS_NUM);
        c = cdd->chan_busy[desc_num];
        cdd->chan_busy[desc_num] = NULL;

        /* Usecount for chan_busy[], paired with push_desc_queue() */
        pm_runtime_put(cdd->ddev.dev);

        return c;
}

static void cppi_writel(u32 val, void *__iomem *mem)
{
        __raw_writel(val, mem);
}

static u32 cppi_readl(void *__iomem *mem)
{
        return __raw_readl(mem);
}

static u32 pd_trans_len(u32 val)
{
        return val & ((1 << (DESC_LENGTH_BITS_NUM + 1)) - 1);
}

static u32 cppi41_pop_desc(struct cppi41_dd *cdd, unsigned queue_num)
{
        u32 desc;

        desc = cppi_readl(cdd->qmgr_mem + QMGR_QUEUE_D(queue_num));
        desc &= ~0x1f;
        return desc;
}

static irqreturn_t cppi41_irq(int irq, void *data)
{
        struct cppi41_dd *cdd = data;
        struct cppi41_channel *c;
        u32 status;
        int i;

        status = cppi_readl(cdd->usbss_mem + USBSS_IRQ_STATUS);
        if (!(status & USBSS_IRQ_PD_COMP))
                return IRQ_NONE;
        cppi_writel(status, cdd->usbss_mem + USBSS_IRQ_STATUS);

        for (i = QMGR_PENDING_SLOT_Q(FIST_COMPLETION_QUEUE); i < QMGR_NUM_PEND;
                        i++) {
                u32 val;
                u32 q_num;

                val = cppi_readl(cdd->qmgr_mem + QMGR_PEND(i));
                if (i == QMGR_PENDING_SLOT_Q(FIST_COMPLETION_QUEUE) && val) {
                        u32 mask;
                        /* set corresponding bit for completetion Q 93 */
                        mask = 1 << QMGR_PENDING_BIT_Q(FIST_COMPLETION_QUEUE);
                        /* not set all bits for queues less than Q 93 */
                        mask--;
                        /* now invert and keep only Q 93+ set */
                        val &= ~mask;
                }

                if (val)
                        __iormb();

                while (val) {
                        u32 desc, len;
                        int error;

                        error = pm_runtime_get(cdd->ddev.dev);
                        if (error < 0)
                                dev_err(cdd->ddev.dev, "%s pm runtime get: %i\n",
                                        __func__, error);

                        q_num = __fls(val);
                        val &= ~(1 << q_num);
                        q_num += 32 * i;
                        desc = cppi41_pop_desc(cdd, q_num);
                        c = desc_to_chan(cdd, desc);
                        if (WARN_ON(!c)) {
                                pr_err("%s() q %d desc %08x\n", __func__,
                                                q_num, desc);
                                continue;
                        }

                        if (c->desc->pd2 & PD2_ZERO_LENGTH)
                                len = 0;
                        else
                                len = pd_trans_len(c->desc->pd0);

                        c->residue = pd_trans_len(c->desc->pd6) - len;
                        dma_cookie_complete(&c->txd);
                        dmaengine_desc_get_callback_invoke(&c->txd, NULL);

                        pm_runtime_mark_last_busy(cdd->ddev.dev);
                        pm_runtime_put_autosuspend(cdd->ddev.dev);
                }
        }
        return IRQ_HANDLED;
}

static dma_cookie_t cppi41_tx_submit(struct dma_async_tx_descriptor *tx)
{
        dma_cookie_t cookie;

        cookie = dma_cookie_assign(tx);

        return cookie;
}

static int cppi41_dma_alloc_chan_resources(struct dma_chan *chan)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        struct cppi41_dd *cdd = c->cdd;
        int error;

        error = pm_runtime_get_sync(cdd->ddev.dev);
        if (error < 0) {
                dev_err(cdd->ddev.dev, "%s pm runtime get: %i\n",
                        __func__, error);
                pm_runtime_put_noidle(cdd->ddev.dev);

                return error;
        }

        dma_cookie_init(chan);
        dma_async_tx_descriptor_init(&c->txd, chan);
        c->txd.tx_submit = cppi41_tx_submit;

        if (!c->is_tx)
                cppi_writel(c->q_num, c->gcr_reg + RXHPCRA0);

        pm_runtime_mark_last_busy(cdd->ddev.dev);
        pm_runtime_put_autosuspend(cdd->ddev.dev);

        return 0;
}

static void cppi41_dma_free_chan_resources(struct dma_chan *chan)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        struct cppi41_dd *cdd = c->cdd;
        int error;

        error = pm_runtime_get_sync(cdd->ddev.dev);
        if (error < 0) {
                pm_runtime_put_noidle(cdd->ddev.dev);

                return;
        }

        WARN_ON(!list_empty(&cdd->pending));

        pm_runtime_mark_last_busy(cdd->ddev.dev);
        pm_runtime_put_autosuspend(cdd->ddev.dev);
}

static enum dma_status cppi41_dma_tx_status(struct dma_chan *chan,
        dma_cookie_t cookie, struct dma_tx_state *txstate)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        enum dma_status ret;

        /* lock */
        ret = dma_cookie_status(chan, cookie, txstate);
        if (txstate && ret == DMA_COMPLETE)
                txstate->residue = c->residue;
        /* unlock */

        return ret;
}

static void push_desc_queue(struct cppi41_channel *c)
{
        struct cppi41_dd *cdd = c->cdd;
        u32 desc_num;
        u32 desc_phys;
        u32 reg;

        c->residue = 0;

        reg = GCR_CHAN_ENABLE;
        if (!c->is_tx) {
                reg |= GCR_STARV_RETRY;
                reg |= GCR_DESC_TYPE_HOST;
                reg |= c->q_comp_num;
        }

        cppi_writel(reg, c->gcr_reg);

        /*
         * We don't use writel() but __raw_writel() so we have to make sure
         * that the DMA descriptor in coherent memory made to the main memory
         * before starting the dma engine.
         */
        __iowmb();

        /*
         * DMA transfers can take at least 200ms to complete with USB mass
         * storage connected. To prevent autosuspend timeouts, we must use
         * pm_runtime_get/put() when chan_busy[] is modified. This will get
         * cleared in desc_to_chan() or cppi41_stop_chan() depending on the
         * outcome of the transfer.
         */
        pm_runtime_get(cdd->ddev.dev);

        desc_phys = lower_32_bits(c->desc_phys);
        desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
        WARN_ON(cdd->chan_busy[desc_num]);
        cdd->chan_busy[desc_num] = c;

        reg = (sizeof(struct cppi41_desc) - 24) / 4;
        reg |= desc_phys;
        cppi_writel(reg, cdd->qmgr_mem + QMGR_QUEUE_D(c->q_num));
}

/*
 * Caller must hold cdd->lock to prevent push_desc_queue()
 * getting called out of order. We have both cppi41_dma_issue_pending()
 * and cppi41_runtime_resume() call this function.
 */
static void cppi41_run_queue(struct cppi41_dd *cdd)
{
        struct cppi41_channel *c, *_c;

        list_for_each_entry_safe(c, _c, &cdd->pending, node) {
                push_desc_queue(c);
                list_del(&c->node);
        }
}

static void cppi41_dma_issue_pending(struct dma_chan *chan)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        struct cppi41_dd *cdd = c->cdd;
        unsigned long flags;
        int error;

        error = pm_runtime_get(cdd->ddev.dev);
        if ((error != -EINPROGRESS) && error < 0) {
                pm_runtime_put_noidle(cdd->ddev.dev);
                dev_err(cdd->ddev.dev, "Failed to pm_runtime_get: %i\n",
                        error);

                return;
        }

        spin_lock_irqsave(&cdd->lock, flags);
        list_add_tail(&c->node, &cdd->pending);
        if (!cdd->is_suspended)
                cppi41_run_queue(cdd);
        spin_unlock_irqrestore(&cdd->lock, flags);

        pm_runtime_mark_last_busy(cdd->ddev.dev);
        pm_runtime_put_autosuspend(cdd->ddev.dev);
}

static u32 get_host_pd0(u32 length)
{
        u32 reg;

        reg = DESC_TYPE_HOST << DESC_TYPE;
        reg |= length;

        return reg;
}

static u32 get_host_pd1(struct cppi41_channel *c)
{
        u32 reg;

        reg = 0;

        return reg;
}

static u32 get_host_pd2(struct cppi41_channel *c)
{
        u32 reg;

        reg = DESC_TYPE_USB;
        reg |= c->q_comp_num;

        return reg;
}

static u32 get_host_pd3(u32 length)
{
        u32 reg;

        /* PD3 = packet size */
        reg = length;

        return reg;
}

static u32 get_host_pd6(u32 length)
{
        u32 reg;

        /* PD6 buffer size */
        reg = DESC_PD_COMPLETE;
        reg |= length;

        return reg;
}

static u32 get_host_pd4_or_7(u32 addr)
{
        u32 reg;

        reg = addr;

        return reg;
}

static u32 get_host_pd5(void)
{
        u32 reg;

        reg = 0;

        return reg;
}

static struct dma_async_tx_descriptor *cppi41_dma_prep_slave_sg(
        struct dma_chan *chan, struct scatterlist *sgl, unsigned sg_len,
        enum dma_transfer_direction dir, unsigned long tx_flags, void *context)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        struct cppi41_desc *d;
        struct scatterlist *sg;
        unsigned int i;

        d = c->desc;
        for_each_sg(sgl, sg, sg_len, i) {
                u32 addr;
                u32 len;

                /* We need to use more than one desc once musb supports sg */
                addr = lower_32_bits(sg_dma_address(sg));
                len = sg_dma_len(sg);

                d->pd0 = get_host_pd0(len);
                d->pd1 = get_host_pd1(c);
                d->pd2 = get_host_pd2(c);
                d->pd3 = get_host_pd3(len);
                d->pd4 = get_host_pd4_or_7(addr);
                d->pd5 = get_host_pd5();
                d->pd6 = get_host_pd6(len);
                d->pd7 = get_host_pd4_or_7(addr);

                d++;
        }

        return &c->txd;
}

static void cppi41_compute_td_desc(struct cppi41_desc *d)
{
        d->pd0 = DESC_TYPE_TEARD << DESC_TYPE;
}

static int cppi41_tear_down_chan(struct cppi41_channel *c)
{
        struct cppi41_dd *cdd = c->cdd;
        struct cppi41_desc *td;
        u32 reg;
        u32 desc_phys;
        u32 td_desc_phys;

        td = cdd->cd;
        td += cdd->first_td_desc;

        td_desc_phys = cdd->descs_phys;
        td_desc_phys += cdd->first_td_desc * sizeof(struct cppi41_desc);

        if (!c->td_queued) {
                cppi41_compute_td_desc(td);
                __iowmb();

                reg = (sizeof(struct cppi41_desc) - 24) / 4;
                reg |= td_desc_phys;
                cppi_writel(reg, cdd->qmgr_mem +
                                QMGR_QUEUE_D(cdd->td_queue.submit));

                reg = GCR_CHAN_ENABLE;
                if (!c->is_tx) {
                        reg |= GCR_STARV_RETRY;
                        reg |= GCR_DESC_TYPE_HOST;
                        reg |= c->q_comp_num;
                }
                reg |= GCR_TEARDOWN;
                cppi_writel(reg, c->gcr_reg);
                c->td_queued = 1;
                c->td_retry = 500;
        }

        if (!c->td_seen || !c->td_desc_seen) {

                desc_phys = cppi41_pop_desc(cdd, cdd->td_queue.complete);
                if (!desc_phys)
                        desc_phys = cppi41_pop_desc(cdd, c->q_comp_num);

                if (desc_phys == c->desc_phys) {
                        c->td_desc_seen = 1;

                } else if (desc_phys == td_desc_phys) {
                        u32 pd0;

                        __iormb();
                        pd0 = td->pd0;
                        WARN_ON((pd0 >> DESC_TYPE) != DESC_TYPE_TEARD);
                        WARN_ON(!c->is_tx && !(pd0 & TD_DESC_IS_RX));
                        WARN_ON((pd0 & 0x1f) != c->port_num);
                        c->td_seen = 1;
                } else if (desc_phys) {
                        WARN_ON_ONCE(1);
                }
        }
        c->td_retry--;
        /*
         * If the TX descriptor / channel is in use, the caller needs to poke
         * his TD bit multiple times. After that he hardware releases the
         * transfer descriptor followed by TD descriptor. Waiting seems not to
         * cause any difference.
         * RX seems to be thrown out right away. However once the TearDown
         * descriptor gets through we are done. If we have seens the transfer
         * descriptor before the TD we fetch it from enqueue, it has to be
         * there waiting for us.
         */
        if (!c->td_seen && c->td_retry) {
                udelay(1);
                return -EAGAIN;
        }
        WARN_ON(!c->td_retry);

        if (!c->td_desc_seen) {
                desc_phys = cppi41_pop_desc(cdd, c->q_num);
                if (!desc_phys)
                        desc_phys = cppi41_pop_desc(cdd, c->q_comp_num);
                WARN_ON(!desc_phys);
        }

        c->td_queued = 0;
        c->td_seen = 0;
        c->td_desc_seen = 0;
        cppi_writel(0, c->gcr_reg);
        return 0;
}

static int cppi41_stop_chan(struct dma_chan *chan)
{
        struct cppi41_channel *c = to_cpp41_chan(chan);
        struct cppi41_dd *cdd = c->cdd;
        u32 desc_num;
        u32 desc_phys;
        int ret;

        desc_phys = lower_32_bits(c->desc_phys);
        desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
        if (!cdd->chan_busy[desc_num]) {
                struct cppi41_channel *cc, *_ct;

                /*
                 * channels might still be in the pendling list if
                 * cppi41_dma_issue_pending() is called after
                 * cppi41_runtime_suspend() is called
                 */
                list_for_each_entry_safe(cc, _ct, &cdd->pending, node) {
                        if (cc != c)
                                continue;
                        list_del(&cc->node);
                        break;
                }
                return 0;
        }

        ret = cppi41_tear_down_chan(c);
        if (ret)
                return ret;

        WARN_ON(!cdd->chan_busy[desc_num]);
        cdd->chan_busy[desc_num] = NULL;

        /* Usecount for chan_busy[], paired with push_desc_queue() */
        pm_runtime_put(cdd->ddev.dev);

        return 0;
}

static void cleanup_chans(struct cppi41_dd *cdd)
{
        while (!list_empty(&cdd->ddev.channels)) {
                struct cppi41_channel *cchan;

                cchan = list_first_entry(&cdd->ddev.channels,
                                struct cppi41_channel, chan.device_node);
                list_del(&cchan->chan.device_node);
                kfree(cchan);
        }
}

static int cppi41_add_chans(struct device *dev, struct cppi41_dd *cdd)
{
        struct cppi41_channel *cchan;
        int i;
        int ret;
        u32 n_chans;

        ret = of_property_read_u32(dev->of_node, "#dma-channels",
                        &n_chans);
        if (ret)
                return ret;
        /*
         * The channels can only be used as TX or as RX. So we add twice
         * that much dma channels because USB can only do RX or TX.
         */
        n_chans *= 2;

        for (i = 0; i < n_chans; i++) {
                cchan = kzalloc(sizeof(*cchan), GFP_KERNEL);
                if (!cchan)
                        goto err;

                cchan->cdd = cdd;
                if (i & 1) {
                        cchan->gcr_reg = cdd->ctrl_mem + DMA_TXGCR(i >> 1);
                        cchan->is_tx = 1;
                } else {
                        cchan->gcr_reg = cdd->ctrl_mem + DMA_RXGCR(i >> 1);
                        cchan->is_tx = 0;
                }
                cchan->port_num = i >> 1;
                cchan->desc = &cdd->cd[i];
                cchan->desc_phys = cdd->descs_phys;
                cchan->desc_phys += i * sizeof(struct cppi41_desc);
                cchan->chan.device = &cdd->ddev;
                list_add_tail(&cchan->chan.device_node, &cdd->ddev.channels);
        }
        cdd->first_td_desc = n_chans;

        return 0;
err:
        cleanup_chans(cdd);
        return -ENOMEM;
}

static void purge_descs(struct device *dev, struct cppi41_dd *cdd)
{
        unsigned int mem_decs;
        int i;

        mem_decs = ALLOC_DECS_NUM * sizeof(struct cppi41_desc);

        for (i = 0; i < DESCS_AREAS; i++) {

                cppi_writel(0, cdd->qmgr_mem + QMGR_MEMBASE(i));
                cppi_writel(0, cdd->qmgr_mem + QMGR_MEMCTRL(i));

                dma_free_coherent(dev, mem_decs, cdd->cd,
                                cdd->descs_phys);
        }
}

static void disable_sched(struct cppi41_dd *cdd)
{
        cppi_writel(0, cdd->sched_mem + DMA_SCHED_CTRL);
}

static void deinit_cppi41(struct device *dev, struct cppi41_dd *cdd)
{
        disable_sched(cdd);

        purge_descs(dev, cdd);

        cppi_writel(0, cdd->qmgr_mem + QMGR_LRAM0_BASE);
        cppi_writel(0, cdd->qmgr_mem + QMGR_LRAM0_BASE);
        dma_free_coherent(dev, QMGR_SCRATCH_SIZE, cdd->qmgr_scratch,
                        cdd->scratch_phys);
}

static int init_descs(struct device *dev, struct cppi41_dd *cdd)
{
        unsigned int desc_size;
        unsigned int mem_decs;
        int i;
        u32 reg;
        u32 idx;

        BUILD_BUG_ON(sizeof(struct cppi41_desc) &
                        (sizeof(struct cppi41_desc) - 1));
        BUILD_BUG_ON(sizeof(struct cppi41_desc) < 32);
        BUILD_BUG_ON(ALLOC_DECS_NUM < 32);

        desc_size = sizeof(struct cppi41_desc);
        mem_decs = ALLOC_DECS_NUM * desc_size;

        idx = 0;
        for (i = 0; i < DESCS_AREAS; i++) {

                reg = idx << QMGR_MEMCTRL_IDX_SH;
                reg |= (ilog2(desc_size) - 5) << QMGR_MEMCTRL_DESC_SH;
                reg |= ilog2(ALLOC_DECS_NUM) - 5;

                BUILD_BUG_ON(DESCS_AREAS != 1);
                cdd->cd = dma_alloc_coherent(dev, mem_decs,
                                &cdd->descs_phys, GFP_KERNEL);
                if (!cdd->cd)
                        return -ENOMEM;

                cppi_writel(cdd->descs_phys, cdd->qmgr_mem + QMGR_MEMBASE(i));
                cppi_writel(reg, cdd->qmgr_mem + QMGR_MEMCTRL(i));

                idx += ALLOC_DECS_NUM;
        }
        return 0;
}

static void init_sched(struct cppi41_dd *cdd)
{
        unsigned ch;
        unsigned word;
        u32 reg;

        word = 0;
        cppi_writel(0, cdd->sched_mem + DMA_SCHED_CTRL);
        for (ch = 0; ch < 15 * 2; ch += 2) {

                reg = SCHED_ENTRY0_CHAN(ch);
                reg |= SCHED_ENTRY1_CHAN(ch) | SCHED_ENTRY1_IS_RX;

                reg |= SCHED_ENTRY2_CHAN(ch + 1);
                reg |= SCHED_ENTRY3_CHAN(ch + 1) | SCHED_ENTRY3_IS_RX;
                cppi_writel(reg, cdd->sched_mem + DMA_SCHED_WORD(word));
                word++;
        }
        reg = 15 * 2 * 2 - 1;
        reg |= DMA_SCHED_CTRL_EN;
        cppi_writel(reg, cdd->sched_mem + DMA_SCHED_CTRL);
}

static int init_cppi41(struct device *dev, struct cppi41_dd *cdd)
{
        int ret;

        BUILD_BUG_ON(QMGR_SCRATCH_SIZE > ((1 << 14) - 1));
        cdd->qmgr_scratch = dma_alloc_coherent(dev, QMGR_SCRATCH_SIZE,
                        &cdd->scratch_phys, GFP_KERNEL);
        if (!cdd->qmgr_scratch)
                return -ENOMEM;

        cppi_writel(cdd->scratch_phys, cdd->qmgr_mem + QMGR_LRAM0_BASE);
        cppi_writel(QMGR_SCRATCH_SIZE, cdd->qmgr_mem + QMGR_LRAM_SIZE);
        cppi_writel(0, cdd->qmgr_mem + QMGR_LRAM1_BASE);

        ret = init_descs(dev, cdd);
        if (ret)
                goto err_td;

        cppi_writel(cdd->td_queue.submit, cdd->ctrl_mem + DMA_TDFDQ);
        init_sched(cdd);
        return 0;
err_td:
        deinit_cppi41(dev, cdd);
        return ret;
}

static struct platform_driver cpp41_dma_driver;
/*
 * The param format is:
 * X Y
 * X: Port
 * Y: 0 = RX else TX
 */
#define INFO_PORT       0
#define INFO_IS_TX      1

static bool cpp41_dma_filter_fn(struct dma_chan *chan, void *param)
{
        struct cppi41_channel *cchan;
        struct cppi41_dd *cdd;
        const struct chan_queues *queues;
        u32 *num = param;

        if (chan->device->dev->driver != &cpp41_dma_driver.driver)
                return false;

        cchan = to_cpp41_chan(chan);

        if (cchan->port_num != num[INFO_PORT])
                return false;

        if (cchan->is_tx && !num[INFO_IS_TX])
                return false;
        cdd = cchan->cdd;
        if (cchan->is_tx)
                queues = cdd->queues_tx;
        else
                queues = cdd->queues_rx;

        BUILD_BUG_ON(ARRAY_SIZE(usb_queues_rx) != ARRAY_SIZE(usb_queues_tx));
        if (WARN_ON(cchan->port_num > ARRAY_SIZE(usb_queues_rx)))
                return false;

        cchan->q_num = queues[cchan->port_num].submit;
        cchan->q_comp_num = queues[cchan->port_num].complete;
        return true;
}

static struct of_dma_filter_info cpp41_dma_info = {
        .filter_fn = cpp41_dma_filter_fn,
};

static struct dma_chan *cppi41_dma_xlate(struct of_phandle_args *dma_spec,
                struct of_dma *ofdma)
{
        int count = dma_spec->args_count;
        struct of_dma_filter_info *info = ofdma->of_dma_data;

        if (!info || !info->filter_fn)
                return NULL;

        if (count != 2)
                return NULL;

        return dma_request_channel(info->dma_cap, info->filter_fn,
                        &dma_spec->args[0]);
}

static const struct cppi_glue_infos usb_infos = {
        .isr = cppi41_irq,
        .queues_rx = usb_queues_rx,
        .queues_tx = usb_queues_tx,
        .td_queue = { .submit = 31, .complete = 0 },
};

static const struct of_device_id cppi41_dma_ids[] = {
        { .compatible = "ti,am3359-cppi41", .data = &usb_infos},
        {},
};
MODULE_DEVICE_TABLE(of, cppi41_dma_ids);

static const struct cppi_glue_infos *get_glue_info(struct device *dev)
{
        const struct of_device_id *of_id;

        of_id = of_match_node(cppi41_dma_ids, dev->of_node);
        if (!of_id)
                return NULL;
        return of_id->data;
}

#define CPPI41_DMA_BUSWIDTHS    (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
                                BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
                                BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))

static int cppi41_dma_probe(struct platform_device *pdev)
{
        struct cppi41_dd *cdd;
        struct device *dev = &pdev->dev;
        const struct cppi_glue_infos *glue_info;
        int irq;
        int ret;

        glue_info = get_glue_info(dev);
        if (!glue_info)
                return -EINVAL;

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

        dma_cap_set(DMA_SLAVE, cdd->ddev.cap_mask);
        cdd->ddev.device_alloc_chan_resources = cppi41_dma_alloc_chan_resources;
        cdd->ddev.device_free_chan_resources = cppi41_dma_free_chan_resources;
        cdd->ddev.device_tx_status = cppi41_dma_tx_status;
        cdd->ddev.device_issue_pending = cppi41_dma_issue_pending;
        cdd->ddev.device_prep_slave_sg = cppi41_dma_prep_slave_sg;
        cdd->ddev.device_terminate_all = cppi41_stop_chan;
        cdd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
        cdd->ddev.src_addr_widths = CPPI41_DMA_BUSWIDTHS;
        cdd->ddev.dst_addr_widths = CPPI41_DMA_BUSWIDTHS;
        cdd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
        cdd->ddev.dev = dev;
        INIT_LIST_HEAD(&cdd->ddev.channels);
        cpp41_dma_info.dma_cap = cdd->ddev.cap_mask;

        cdd->usbss_mem = of_iomap(dev->of_node, 0);
        cdd->ctrl_mem = of_iomap(dev->of_node, 1);
        cdd->sched_mem = of_iomap(dev->of_node, 2);
        cdd->qmgr_mem = of_iomap(dev->of_node, 3);
        spin_lock_init(&cdd->lock);
        INIT_LIST_HEAD(&cdd->pending);

        platform_set_drvdata(pdev, cdd);

        if (!cdd->usbss_mem || !cdd->ctrl_mem || !cdd->sched_mem ||
                        !cdd->qmgr_mem)
                return -ENXIO;

        pm_runtime_enable(dev);
        pm_runtime_set_autosuspend_delay(dev, 100);
        pm_runtime_use_autosuspend(dev);
        ret = pm_runtime_get_sync(dev);
        if (ret < 0)
                goto err_get_sync;

        cdd->queues_rx = glue_info->queues_rx;
        cdd->queues_tx = glue_info->queues_tx;
        cdd->td_queue = glue_info->td_queue;

        ret = init_cppi41(dev, cdd);
        if (ret)
                goto err_init_cppi;

        ret = cppi41_add_chans(dev, cdd);
        if (ret)
                goto err_chans;

        irq = irq_of_parse_and_map(dev->of_node, 0);
        if (!irq) {
                ret = -EINVAL;
                goto err_irq;
        }

        cppi_writel(USBSS_IRQ_PD_COMP, cdd->usbss_mem + USBSS_IRQ_ENABLER);

        ret = devm_request_irq(&pdev->dev, irq, glue_info->isr, IRQF_SHARED,
                        dev_name(dev), cdd);
        if (ret)
                goto err_irq;
        cdd->irq = irq;

        ret = dma_async_device_register(&cdd->ddev);
        if (ret)
                goto err_dma_reg;

        ret = of_dma_controller_register(dev->of_node,
                        cppi41_dma_xlate, &cpp41_dma_info);
        if (ret)
                goto err_of;

        pm_runtime_mark_last_busy(dev);
        pm_runtime_put_autosuspend(dev);

        return 0;
err_of:
        dma_async_device_unregister(&cdd->ddev);
err_dma_reg:
err_irq:
        cppi_writel(0, cdd->usbss_mem + USBSS_IRQ_CLEARR);
        cleanup_chans(cdd);
err_chans:
        deinit_cppi41(dev, cdd);
err_init_cppi:
        pm_runtime_dont_use_autosuspend(dev);
err_get_sync:
        pm_runtime_put_sync(dev);
        pm_runtime_disable(dev);
        iounmap(cdd->usbss_mem);
        iounmap(cdd->ctrl_mem);
        iounmap(cdd->sched_mem);
        iounmap(cdd->qmgr_mem);
        return ret;
}

static int cppi41_dma_remove(struct platform_device *pdev)
{
        struct cppi41_dd *cdd = platform_get_drvdata(pdev);
        int error;

        error = pm_runtime_get_sync(&pdev->dev);
        if (error < 0)
                dev_err(&pdev->dev, "%s could not pm_runtime_get: %i\n",
                        __func__, error);
        of_dma_controller_free(pdev->dev.of_node);
        dma_async_device_unregister(&cdd->ddev);

        cppi_writel(0, cdd->usbss_mem + USBSS_IRQ_CLEARR);
        devm_free_irq(&pdev->dev, cdd->irq, cdd);
        cleanup_chans(cdd);
        deinit_cppi41(&pdev->dev, cdd);
        iounmap(cdd->usbss_mem);
        iounmap(cdd->ctrl_mem);
        iounmap(cdd->sched_mem);
        iounmap(cdd->qmgr_mem);
        pm_runtime_dont_use_autosuspend(&pdev->dev);
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        return 0;
}

static int __maybe_unused cppi41_suspend(struct device *dev)
{
        struct cppi41_dd *cdd = dev_get_drvdata(dev);

        cdd->dma_tdfdq = cppi_readl(cdd->ctrl_mem + DMA_TDFDQ);
        cppi_writel(0, cdd->usbss_mem + USBSS_IRQ_CLEARR);
        disable_sched(cdd);

        return 0;
}

static int __maybe_unused cppi41_resume(struct device *dev)
{
        struct cppi41_dd *cdd = dev_get_drvdata(dev);
        struct cppi41_channel *c;
        int i;

        for (i = 0; i < DESCS_AREAS; i++)
                cppi_writel(cdd->descs_phys, cdd->qmgr_mem + QMGR_MEMBASE(i));

        list_for_each_entry(c, &cdd->ddev.channels, chan.device_node)
                if (!c->is_tx)
                        cppi_writel(c->q_num, c->gcr_reg + RXHPCRA0);

        init_sched(cdd);

        cppi_writel(cdd->dma_tdfdq, cdd->ctrl_mem + DMA_TDFDQ);
        cppi_writel(cdd->scratch_phys, cdd->qmgr_mem + QMGR_LRAM0_BASE);
        cppi_writel(QMGR_SCRATCH_SIZE, cdd->qmgr_mem + QMGR_LRAM_SIZE);
        cppi_writel(0, cdd->qmgr_mem + QMGR_LRAM1_BASE);

        cppi_writel(USBSS_IRQ_PD_COMP, cdd->usbss_mem + USBSS_IRQ_ENABLER);

        return 0;
}

static int __maybe_unused cppi41_runtime_suspend(struct device *dev)
{
        struct cppi41_dd *cdd = dev_get_drvdata(dev);
        unsigned long flags;

        spin_lock_irqsave(&cdd->lock, flags);
        cdd->is_suspended = true;
        WARN_ON(!list_empty(&cdd->pending));
        spin_unlock_irqrestore(&cdd->lock, flags);

        return 0;
}

static int __maybe_unused cppi41_runtime_resume(struct device *dev)
{
        struct cppi41_dd *cdd = dev_get_drvdata(dev);
        unsigned long flags;

        spin_lock_irqsave(&cdd->lock, flags);
        cdd->is_suspended = false;
        cppi41_run_queue(cdd);
        spin_unlock_irqrestore(&cdd->lock, flags);

        return 0;
}

static const struct dev_pm_ops cppi41_pm_ops = {
        SET_LATE_SYSTEM_SLEEP_PM_OPS(cppi41_suspend, cppi41_resume)
        SET_RUNTIME_PM_OPS(cppi41_runtime_suspend,
                           cppi41_runtime_resume,
                           NULL)
};

static struct platform_driver cpp41_dma_driver = {
        .probe  = cppi41_dma_probe,
        .remove = cppi41_dma_remove,
        .driver = {
                .name = "cppi41-dma-engine",
                .pm = &cppi41_pm_ops,
                .of_match_table = of_match_ptr(cppi41_dma_ids),
        },
};

module_platform_driver(cpp41_dma_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");